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manual for fwd testing in the long

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3. 09 NOILOAS 1531 009 04 60989 00 9 00 0 09 0 TAAVEL dO NOILO3UIG 21 LTPP Manual For FWD Testing Version 2 0 February 1993 Jane Also the first effective panel totally within the section at station 0 00 should be tested and the actual station for the mid panel will typically be at station 0 01 to 0 06 With 20 effective panels for all CRCP sections a total of 100 tests will be run in the 500 foot section 60 DB tests and 40 LT tests Similar to the JCP plan the pass sequence in Figure 5 is used so the sensor spacing is only changed once on each section At each test point a sequence of 15 drops is used 3 seating drops at height 3 and 4 drops each at heights 2 3 and 4 Other FWD Operator Field Measurements General For the analysis of FWD deflection data pavement temperature gradients pavement distress and joint crack width that are not automatically measured and recorded in the FWD testing process are needed This section of the manual describes the procedures for obtaining this data Temperature Gradient Measurements The thermal gradient temperature versus depth through both bituminous and PCC layers is important for the analysis of deflection data However the automatic temperature sensors on the FWD only record ambient air temperature and pavement surface temperature Therefore FWD operators need to manually measure the temperature gradient in the pavement structure
4. 3 00 ANWId 340 302126 41 LTPP Manual For FWD Testing Version 2 0 February 1993 40195 1190 QAYOT NOILLVHSIIVO LI rg o o ELETUC ELC pd bd vd rd bd td 9 o o o o 40 245 1541 1 0 2993 82036 61 40145 15941 87 LT 5 STH S3Old 3691 m a 8 SABA BABS 7777 2 0 T 80 0 NO NO NO 330
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6. ON 09 9 92 BT 8 8 TT FO 201 3082 tsd 8t O 6 440 8 440 3 3 9 440 83240 369 7 480 2385enbew ua3g t euaxna3exedue 2 qour iru 3qi SLINA nur 3FN AWOT NOLTLWYEI TWO XNV IH xequnu 2098125 42 LTPP Manual For FWD Testing Version 2 0 February 1993 Using the Software for Data Collection and Data Backup Data Quality Checks in the FWD Data Collection Software Research data must be valid and accurate For the deflection data the FWD software uses up to five quality control checks as the data is collected The checks in use are selected in the setups and described below Details on handling data failing any quality control checks are described later in this chapter in the section on Rejecting tests 1 Roll off electrical check that the magnitude of the deflections 60 milli seconds after the trigger activated on FWD have decreased to less than 10 of the peak deflection readings If this condition is not met the REJECT prompt appears and allows the operator to either Q uit the test sequence or continue
7. n own comer Wnespat x 8 8 12 18 24 36 60 0 8 12 18 24 36 60 lt e m 0 8 12 18 24 36 60_ PE Pavement Edge Mid Panel ea 0 8 12 18 24 36 60 4 5 OWP Outer Wheelpath Crack Load 12 0 12 18 24 36 60 Transfer NOTE Maximum number of tests per pass 16 LTPP Manual For FWD Testing Version 2 0 February 1993 SaqlHO931VO LNAWAAVd 1531 914 5 151 TVNINON LN3SU3Hd3H 5 5135430 1VH3lVl 3LON 141541 38 GINOHS S13NVd 88 15 103413 30 WNWIXYW V SUWLA0 YSHLYNA 1 31 OL 933334 QINOHS HOlVH3dO LNAWSAVd NYSALIVd HOVYS ASYAASNVHYL ONIOVdS 01410345 TIIM X 1 TANVd STANVWd dO 3LON 73 IV dL 317501 OL AHVA SNINOIIVLIS 51531 30 13 19914 d 41 SNOIJ1V201 114 1531 2 51531 3101 00 1 7122 7777 3583 Ai1N3W3AVd 4 174 ddV FE ppdMMSy 4 9sapHpsMMFre Vpoepdgd 22 2 20 X
8. 09 NOILOAS 1531 009 OS 09 9 00 S 00 0 05 0 A dO NOI IO3HIG 17 LTPP Manual For FWD Testing Version 2 0 February 1993 The JCP test plan requires the most caution and judgment by FWD operators in the field to determine where to test The reason is threefold 1 panel lengths vary from less than 11 3 3m to greater than 50 15 2 2 panels with large joint spacing generally have transverse cracks present near the middle of the original panels For example if an original panel has one transverse crack FWD operators will view the original panel as two effective panels Similarly if there are two transverse cracks the original panel will be viewed as three effective panels Note For LTPP purposes an effective panel is defined as a continuous section of PCC pavement bound by two transverse breaks in the pavement The two transverse breaks can be any combination of joints cracks or full width patches 3 some JCP sections have non uniform or random joint spacing intervals that repeat throughout the section e g 10 19 17 13 joint spacing pattern The number of effective panels can vary from as few as 9 or 10 to as many as 35 or more on a 500 152m section Regardless of the total number of effective panels present no more than 20 effective panels are tested on a section Thus for JCP categories a maximum of 100 deflection tests will be made within a 500 152m section Any effecti
9. 1 0 HIVd 1 YALNO 4 dpm d 1 7 31311311113333331133133311311111331311 11213111 11111 231111111211112113111111 NOILOAS 1591 009 QO S 0090 Ges dO NOILOAYIC B 2 5 LTPP Manual For FWD Testing Version 2 0 February 1993 SNVI Ld vl ONILSAL TIY YOd 1531 GMS ZZ 8 83841914 SSONVASIO 1LN3SSSEd3U 8138440 4953197 301noHs NO SNOIAWOISIONdS BNYT ILON SISSVd YNOA 15 4 HZd SLNIOd 1931 NSASS JALON 8 011986 11V NO 054851 38 GINOKS SIANYd NIL SAON IER TU Dip m 3 4 A POPP 4444444 02 god 3003 3NY1 Q3NZGIA 9554294942594 990 9809 99909229 04099 8 002 6 4400400994449489090 0099 990940909896065 480986059906889 08940890 955 909400490680 9080949994 8 9 9 944909 442546 09080909689000129 4440609 962466464 999554 0000000959025090249952946 112217777777777777777777 77 99929009 000500700105000000055002057002555025222555207222 e
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11. due buliuoraeas 9 440 3duozd qoeley 5 330 104 3591 v NO 38senbewW ua3S SLINN 3694 LSAL XOWHO LNIOD 040 AIDIA dLa arnO xegumu uea3r uoriado 5 36 LTPP Manual For FWD Testing Version 2 0 February 1993 068L9Sv ZTO68L9STVCZTOG8L9SVCECTO68L9STECTO68L9STCCTOG68L9ST ECT 40155 LIVHdSV OH SUAAANA NOLLIGNOO I dan Old 013435 41541 943 5 061 01415 1541 PLOT 9 9 9IOUM LT STH PROT OT ee ee ee 3594 ET
12. 31 LTPP Manual For FWD Testing Version 2 0 February 1993 SNOILdO 5 YLYA WH LNINd 8 ANDIA GI oss 85446 ALIO OL HIG 16107510 26 08 0 uosa Aor yout 9 um 546 xNV IS gt e3elduej uora3o2esqng YSERA SUTWEN ot e3eiduey Aemproy oo 00 78 Kxoaoexig 79 5 JATI ec A y 26 buroeds SUIT o 2 4 UT YAbueq eo xequmu uea3i uorado 5 32 LTPP Manual For FWD Testing Version 2 0 February 1993 To continue setting up the software select Main Menu choice 1 Continue through the prompts until the TEST SETUP SCREEN appears If this is the first time through the software setups for the FWD test plans buffer conditioning and equipment calibration need to be created named and stored Screen prints of the setups with the proper settings are shown in Figures 9 through 17 Operators should create and save
13. TP Testing Plan The first deflection tests done at a test section excluding buffer conditioning are in the TP areas Regardless of the pavement category all testing in the TP areas will have the following common characteristics The first deflection tests at a section will the TP areas However TPs are only done during the first round of FWD testing and no additional testing is done in these areas for subsequent visits to the section The testing will be labeled as Pass Zero P The lateral offset for the testing is the OWP Only DB tests will be run Only do one test point at each TP area for a total of two for the section di zi FLEX Testing Plan Figure 3 and Table 1 summarize the FLEX esting plan for GPS Experiments 1 2 6 and 7 All pavements covered under this plan have an AC surface Two passes not including the TP are done one at ML and the other in the OWP On each pass DB tests are done at 25 7 6m intervals for a total of 21 test points per pass and 42 total test points in the 500 section At each test point a sequence of 19 drops is used 3 seating drops at height 3 and 4 drops each at heights 1 2 3 and 4 JCP Testing Plan Figure 4 and Table 1 summarize the JCP testing plan for GPS Experiments 3 4 and 9 pavements covered under this plan have jointed PCC pavement surfaces Three passes are done ML P PE and OWP For each panel tested one DB test is don
14. This check can fail if the pavement is close to bedrock if the deflections are very low frozen subgrade or if a sensor is not properly seated on the pavement If a sensor is suspect the sequence should be Q uit and the sensor examined If the check fails from bedrock or very low deflections a comment should be included in the file using the F6 Comment key Decreasing Deflections checks that deflections decrease with distance from the load The check is used for DB tests only If this condition is not met the REJECT prompt appears and allows the operator to Q uit the test sequence or continue Most often the condition is not met when transverse cracks exist between the sensors especially on full depth asphalt For this case the test should be continued and the distress and failed check noted in the file using the F6 Comment key This problem also occurs in JCP and CRCP DB tests but no corrective action is necessary Qut of Range checks that deflections are less than the 80 mil 2000 micron range of the sensors The notation Out of Range appears in the right margin next to drops which had deflections exceeding the allowable range In addition to this warning the REJECT prompt appears and allows the operator to Q uit the test sequence or continue If the condition is not met the sensors and pavement surface should be checked for potential problems If the deflections are large because the pavement is weak the l
15. on any section There may be occasions where time delays of days or weeks occur between FWD testing and sampling and FWD operators must mark the location of the FWD tests the TP areas Also pass testing is only performed for the BEFORE time period Test Point Identification FWD operators must properly record all longitudinal distances with the distance measuring instrument relative to 0 00 station reference for each section and follow the guidelines for lateral offset for the OWP and ML passes so all FWD testing can be repeated in the same general location Detailed Test Plan Test Pit Areas TP areas are tested identical to the procedures outlined for GPS testing in the main part of this manual Detailed Test Plan Test Sections For all SPS 5 test sections FWD testing procedures are identical for BEFORE AFTER and LONG TERM testing The procedure used is similar to the FLEX Testing Plan for GPS except the number of test points is reduced B 5 4 LTPP Manual For FWD Testing Version 2 0 February 1993 The test plan includes 11 FWD tests on each pass down the test section for both the ML and the OWP Deflection Basin tests begin at station 0 00 and continue to station 5 00 at 50 intervals Figure B 5 1 indicates the test locations for a section Each section has 22 test points for a total of 198 test points not including Test Pit locations for a project At a rate of 20 points per hour the FWD testing
16. Copy x where x is the set number usually 1 to 3 Line 4 FWD SN xxx where is the serial number of the FWD that tested the section Line 5 mm dd yy where mm dd yy is the date s the testing was performed Operators should label each diskette as they are used by FastBack Plus Specifics of FastBack Plus Operation FastBack Plus has the option to backup individual files directories or entire hard disks The actual FWD data files to backup can be selected individually or by directory C FWD DATA If a directory it should only contain the files to be backed up After the required directory or individual files have been selected for backup select the Perform Backup Insert diskettes at the prompts until the backup is complete Then print the History Report available on the Options menu to send to the RCO along with the diskettes Finally perform the same backup two more times acknowledging the warning message about identical backups for a total of three copies of the FWD data 51 LTPP Manual For FWD Testing Version 2 0 February 1993 Miscellaneous Supply Requirements FWD operators should obtain adequate supplies before extended trips While not complete the following supplies are recommended 2000 pages 8 5 x 11 21 6 27 9cm ink jet compatible paper Estimate using approximately 250 pages per week six ink cartridges Estimate using one cartridge per week 200 3 5
17. LN3S3Hd3H 5 13 430 IWHALVT ALON NOILOAS 1531 009 00 9 00 0 TAAVYL dO NOILO3MHIQ B 3 5 LTPP Manual FWD Testing Version 2 0 February 1993 THIS PAGE INTENTIONALLY LEFT BLANK B 3 6 LTPP Manual For FWD Testing Version 2 0 February 1993 Appendix B 4 FWD TESTING GUIDELINES FOR SPECIFIC PAVEMENT STUDIES SPS EXPERIMENT 4 PREVENTIVE MAINTENANCE EFFECTIVENESS OF RIGID PAVEMENTS INTRODUCTION This appendix provides guidelines and information specific to Falling Weight Deflectometer FWD testing at individual test sites for the Long Term Pavement Performance LTPP study experiment SPS 4 Preventive Maintenance Effectiveness of Rigid Pavements The intent of this document is to establish the specific testing requirements for SPS 4 sites based on a uniform set of assumptions It is recognized that not all sites will conform to all assumptions contained herein However the objectives and approach to deflection data collection must be consistent so data obtained can be analyzed in a consistent manner For deflection testing details not specifically addressed in the appendix refer to the general guidelines in this manual The objective of the SPS 4 experiment is to compare the effectiveness and mechanisms by which selected maintenance treatments preserve or extend pavement service life driver safety and ride quality on portland cement concrete pavements The impact of materials or construction pr
18. Maintenance of Records FWD operators are responsible for keeping a file for FWD FIELD ACTIVITY REPORTS MAJOR MAINTENANCE REPORTS and RELATIVE CALIBRATION REPORTS Copies of appropriate reports are forwarded to the RCO as needed to limit impacts on the testing schedule LTPP Headquarters should be informed of major problems but in general the RCO s are responsible for FWD operations 59 LTPP Manual For FWD Testing Version 2 0 February 1993 Equipment Repairs The are responsible for maintaining the FWDs The decisions required for proper maintenance and repair should be based on the testing schedule and expedited as necessary to prevent disruption of testing Most services are provided by local agencies however annual FWD overhauls for four successive years will be performed by Dynatest as part of the maintenance contract Accidents FWD operators will inform the RCOs and LTPP Headquarters as soon as practical after any accident Details of any accident shall be reported in writing Records FWD operators perform a great deal of work during a test day and much information needs to be manually recorded The following forms help organize this information without significantly adding to the work load The responsibility for equipment maintenance and repair rests with each RCO and a copy of each record form or log need not be forwarded to LTPP Headquarters Rather the RCO should keep LTPP Headquarters informed as ne
19. The sensors are stacked vertically in the stand one above another so that all sensors are subjected to the same pavement deflection Relative calibration assumes that the overall mean deflection as determined from simultaneous measurements by the full set of deflection sensors yields an accurate estimate of the true deflection This assumption requires that the deflection sensors must have first been subjected to the reference calibration procedure Some FWDs have fewer than or more than seven active deflection sensors If they do these procedures should be modified to calibrate the actual number of active sensors in use on the FWD Equipment FWD relative calibration stand with as many positions as the number of active deflection sensors For purpose of illustration a seven position stand is assumed herein FWD relative calibration software FWDCAL2 and documentation LTPP Manual For FWD Testing Version 2 0 February 1993 General Procedure The process involves rotation of the seven deflection sensors through the seven positions in the calibration stand Each combination of sensors and levels is considered a set and thus there are seven sets of data The test point is conditioned before beginning the calibration procedure to reduce the possibility that set will be significant in the data analysis The required order of movement of the sensors is shown in Table 2 Spare deflection sensors do not have to be calibrated until t
20. 55 REQUITEMENS me Row RU RE AS 56 EQUIPMENT MAINTENANCE AND 57 General ey ub HS Ead dede 57 Equipment Maintenance and Repair 57 Routine co saared a eee 57 Scheduled Major Maintenance 59 Equipment Problems Repairs 59 PROCECUICS QUEE 59 Maintenance of 59 dus cR 60 USO D 60 Records 423 60 Field Actvity REDON 60 Equipment Maintenance Records 62 Calibration x Vie See eae eh ace BRE hd kw xs 62 DEFINITIONS ABBREVIATIONS AND CONVERSIONS 65 REA re 65 List of 65 English Metric Conversions 66 APPENDIX A SHRP FWD CALIBRATION PROTOCOL APPENDIX B FWD TESTING GUIDELINES FOR SPS EXPERIMENTS vi LTPP Manual For FWD Testing Version 2 0 February 1993 LIST OF FIGURES Figure 1 SHARP 005 2 Deflection Sensor Spacing 3 FWD Test Plan Flexible Pavement Cat
21. 8 9cm 720 k diskettes Estimate 45 to 50 diskettes per week Note The second and third set of the FWD data backups can be reused as soon as the RCO notifies the FWD operator that the first set of data disks has been restored and that all the data was readable Daia Handling at the RCO Restoring Data Fastbacked FWD data received at the RCO must be restored to its original format using the FastBack Plus restore function Once the data has been restored and the RCO verifies the data files are complete and in a readable form the FWD operators can reuse the diskettes with the extra backup copies of this data RCO Deflection Data Evaluation This field guide does not go into detail on the review and analysis of deflection data at the RCO However the steps are listed for processing the data before it is included in the LTPP Information Management System IMS data base They are 1 52 All deflection data received at the RCO is restored using Fast Back Plus as described above Deflection data files are edited and stored Editing is limited to header information Station lane specification temperatures etc and deleting of deflection data accidently stored The program FWDSCAN is used to check the data file format and operator input data and also to create a separate file with only peak deflection data LTPP Manual For FWD Testing Version 2 0 February 1993 The program is used to analyze the deflect
22. Calibration Reports Results of both reference and relative calibration of the FWD are sent to the RCO and LTPP headquarters within seven working days after calibration The calibration reports consist of printouts from the FWDCAL and FWDREFCL software supplemented by print screens from the FWD data acquisition software as specified in Appendix A 62 LTPP Manual For FWD Testing Version 2 0 February 1993 MAJOR MAINTENANCE REPAIR ACTIVITY REPORT REGION EQUIPMENT MAKE ODOMETER DATE MODEL S N where applicable REASON FOR MAINTENANCE WORK CHOOSE ONE ONLY SCHEDULED DESCRIPTION OF MAINTENANCE AND REASON NON SCHEDULED AGENCY PERFORMING MAINTENANCE COST NAME STREET ADDRESS CITY PHONE NUMBER CONTACT NAME DATE IN DATE OUT COPIES TO RCO AND FHWA LTPP FIGURE 19 FORM FO3 ISSUED 15 FEBRUARY 1993 MAJOR MAINTENANCE REPAIR REPORT FORM SS SS SS SSS 63 LTPP Manual For FWD Testing Version 2 0 February 1993 THIS PAGE INTENTIONALLY LEFT BLANK LTPP Manual For FWD Testing Version 2 0 February 1993 VI DEFINITIONS ABBREVIATIONS AND CONVERSIONS Definitions Deflection Basin DB test a test with deflection sensors placed at radial offsets from the center of the load plate The test is used to record the shape of the deflection basin resulting from an applied load Information from this test is used to estimate material properties for a
23. I OVERVIEW OF THE LTPP PROGRAM 1 PW Deb ED TESTIIN al oe 803 29 3 OG Nea eb eed Diem 3 wah ay heres eee ah 3 Environmental Factors OG 3 Pavement Discontinuities 4 Variability in the Pavement Structure 5 Pavement edes epee eM 6 Test a neste ue 6 TESPIS dedi 6 Types of Deflection Tests 5 Deflection Sensor Spacing 7 Load Sequence Drop Heights 8 Drop SEQUENCE Sello oe 11 EWD Jes ng Plans E E YO Ra eng 12 Test Pit TP Area Soe ee a 13 EP Testing Planes cc ed ers eee dus meses 14 PLEX Tesuns 2 ux woo e 14 JCP Testing Plan 22555524655 dp he ERO PEDE 14 CREP Testing Plan aeo dad 20 Other FWD Operator Field Measurements 22 umor des era ve 22 Temperature Gradient Measurements 22 Pavement DISUeSS 2 diced 3480 de XC 27 Cra
24. given pavement structure Effective Panel continuous section of PCC defined by two adjacent transverse breaks in the pavement The transverse breaks can be expansion joints cracks or construction joints The transverse breaks are treated as working joints for FWD testing purposes and all tests on an effective panel are done in relation to the two transverse breaks defining the panel Load Transfer LT test a test usually on PCC pavement with deflection sensors on both sides of a transverse break in the pavement The test is used to determine the ability of the pavement to transfer load from one side of the break to the other Also the test data can be used to predict the existence of voids under the pavement List of Abbreviations AC Concrete CRCP Continuously Reinforced Concrete Pavement DB Deflection Basin DMI Distance Measuring Instrument FWD Falling Weight Deflectometer GPS General Pavement Study JCP Jointed Concrete Pavement JPCP Jointed Plain Concrete Pavement JRCP Jointed Reinforced Concrete Pavement LT Load Transfer LTPP Long Term Pavement Performance ML Mid Lane OWP Outside Wheel Path Portland Cement Concrete PE Pavement Edge Regional Coordination Office 65 LTPP Manual For FWD Testing Version 2 0 February 1993 SHRP Strategic Highway Research Program SPS Specific Pavement Study TP Test Pit English Metric Conversions Length 1
25. qQour irTU gqT SLINAQ 3692 1 581 d3503 NISVH 914 ddLu E arnO uear uorado 302125 35 LTPP Manual For FWD Testing Version 2 0 February 1993 102195 1591 LT 40 40 40 TIA LOTA 4584 OS 1 LY LI SVH 40195 LNG LV 195 SEC HOSNSS AMA ALON 40145 41684 9943 92025 761 4 1 45 415441 PROT 787 09 9 0 9 9 9 9 i 5 o O D STOUM gt STH PLOT 91 Ip I IP IG IJe IBe 453113 EE M 57 359 et 40314 T 09 96 PZ ST ZT TT 8 07 0 TU 8070 50 8 0 gt 6 440 qjsenbey puod 8 NO ggo 35
26. record the regression coefficients Enter the Regression Coefficients in FWDREFCL The regression coefficients should be entered in the data acquisition program FWDIREFCL Instructions for doing this can be found in the Load Setup section of the FWDRIEFCL User s Guide Any of the unused higher order terms should have their coefficients entered as 0 0 When the regression coefficients are entered in FWDREFCL the unbalanced zero the B and B calibration factors the load cell signal conditioner gain factor and the date of calibration should also be entered APPENDIX B FWD TESTING GUIDELINES FOR SPS EXPERIMENTS LTPP Manual For FWD Testing Version 2 0 February 1993 Appendix B 1 FWD TESTING GUIDELINES FOR SPECIFIC PAVEMENT STUDIES SPS EXPERIMENT 1 STRATEGIC STUDY OF STRUCTURAL FACTORS FOR FLEXIBLE PAVEMENTS INTRODUCTION This appendix provides guidelines and information specific to Falling Weight Deflectometer FWD testing at individual test sites for the Long Term Pavement Performance LTPP study experiment SPS 1 Strategic Study of Structural Factors for Flexible Pavements The intent of this document is to establish the specific testing requirements for SPS 1 sites based on a uniform set of assumptions It is recognized that not all sites will conform to all assumptions contained herein However the objectives and approach to deflection data collection must be consistent so data obtained can be analyzed in a consis
27. test section a total of 20 effective panels exist Therefore all 20 are tested Example 2 A pavement has a random joint spacing pattern of 10 19 17 13 15 average No transverse cracks are present A total of 33 effective panels exist However only 20 of the 33 effective panels are tested The actual effective panels to test must be selected by the FWD operator in the field The FWD operator should not select the first 20 effective panels or the last 20 effective panels Instead approximately six slabs out of every ten should be selected acceptable set of effective panel numbers to test is 1 2 4 5 7 8 11 12 15 16 18 19 21 22 25 26 29 30 32 and 33 However other sets of effective panels to test will also work In fact it is desirable to test at least one or two groups of four adjacent panels to study the characteristics of random panel size on deflection response For this case the following set of effective panel numbers to test may be 1 2 3 4 8 9 10 11 15 16 17 18 22 23 24 25 29 30 31 and 32 Example 3 A pavement has 40 12 2m uniform joint spacing with no mid panel cracks for a total of 13 effective panels With less than the 20 effective panels all 13 are tested Example 4 A pavement has 50 15 2m uniform joint spacing with transverse cracks near the middle of each original panel As result the effective panel length is 50 2 25 7 6m and about 20
28. vertical position With seven sets and 5 replicate drops data for a total of 35 drops is required see Figure 2 Relative Calibration Data Analysis A three way analysis of variance should be used to evaluate the data This will partition the variance into four sources 1 that due to sensor number 2 that due to position in the calibration stand 3 that due to set and 4 that due to random error of measurement This analysis is performed by the FWDCAL2 software In this analysis deflection is the dependent variable and sensor number position and set are he three main factors The three hypotheses that may be tested Hy Sensor number is a significant source of error Hy Data set number is a significant source of error Hy Position in the stand is a significant source of error Through the use of hypothesis testing it is possible to determine whether random error due to sensor number due to position in the calibration stand and due to set number are statistically significant The only factor that should result in a change in the deflection sensor calibration factors is sensor number A 14 LTPP Manual For FWD Testing Version 2 0 February 1993 If the random error due to sensor number is found to be statistically significant then the calculated adjustments in the calibration factors for each sensor should be made change is made in the calibration factor for one sensor then the calibration factors for all sensors
29. 00 9 TAAVEL 30 ALON ALON 31 0 00 0 09 0 6 7 LYPP Manual For FWD Testing Version 2 0 February 1993 Figure B 6 1 indicates the positions of the test locations for a given effective slab Each test section should have 10 effective slabs 20 in Sections 2 and 5 for a total of 450 FWD points not including TP locations At rate of 20 points per hour the entire process all eight test sections will take approximately 23 hours This does not include the time for testing TP locations or taking temperature gradient measurements The total time for all tasks should be approximately 30 hours DURING Rehabilitation Testimg For test sections 7 and 8 crack and seal sections testing is performed DURING the construction process on the cracked PCC surface The FWD test pattern used DURING rehabilitation is the same as that for FLEX Testing Plan for GPS except the stations for the points should correspond to the 71 tests from the ML tests P performed BEFORE rehabilitation The testing pattern for these sections is illustrated in Figure B 6 2 No tests are conducted at the PE and no Load Transfer tests are performed AFTER Rehabilitation Testing For test sections 1 2 and 5 the test plan for the AFTER rehabilitation testing is the same as that for BEFORE rehabilitation testing and the same effective slabs are tested The remaining sections all have an AC ove
30. 01 988 TIY 05168532 98918 4084133 SISNVI NIL ONILSSL 340438 94 NO 44 SNOILYDOT Ald 1934 JV SISAL OMA ILON 2222 lt rede t 3003 AVS tn HAVS VASHA U3AnOo a gee ee d RC RU ee LC 3384 Te 0000 A E mem lt NOILOSS LSAL 009 40999 0029 40090 09 0 ee 40 NOILOAYIC B 7 6 LTPP Manual For FWD Testing Version 2 0 February 1993 CRCP Pavements The pattern for testing SPS 7 CRCP is similar to the CRC Testing Plan outlined in the GPS portion of this manual except the number of tests is reduced Figure B 7 2 illustrates the testing pattern for all BEFORE and AFTER testing Panels slabs between transverse cracks should be tested at approximate 50 15 2m intervals so 10 panels are obtained The test pattern is the same regardless of the crack spacing typically 17 8 or 0 3m 2 4m AFTER Rehabilitation Testing For all test sections originally having JCP the test plan for AFTER rehabilitation testing is the same as BEFORE rehabilitation testing and the same effective slabs are tested This includes both Deflection Basin and Load Transfer tests in the same manner and locations as were done previously For CRCPs transverse cracks which defined
31. 1993 Reporting Requirements The FWD operator is responsible for sending copies of all calibration reports for both annual calibration and monthly relative calibration to the RCO and LTPP headquarters within seven working days after the calibration 56 LTPP Manual For FWD Testing Version 2 0 February 1993 V EQUIPMENT MAINTENANCE AND REPAIR General Background The extensive use of FWDs within LTPP makes good preventative maintenance practices especially important The RCO s are responsible for preventative maintenance to keep the equipment dependable and minimize deterioration The maintenance procedures in the manuals provided with each piece of equipment should be followed Coordination of schedules for traffic control sampling and testing and maintenance of the deflection testing equipment are critically important Scheduled preventive maintenance ensures proper equipment operation and helps identify potential problems Potential problems identified can be corrected to avoid costly delays or missing data that results if the equipment malfunctions while on site The testing requirements at a section usually prohibit FWD operators from doing more than initial checks and monitoring the operation of the equipment Any maintenance must typically be done at the end of the day after the testing is complete and should become part of the routine performed at the end of each test travel day and on days when no other work is scheduled
32. 259 SLINA 385981 T NISVE xequau wear uorado 309195 34 LTPP Manual For FWD Testing Version 2 0 February 1993 401545 LSAL 8G 240 40 01 DANO 5 15411 4 993 2035 61 402245 2541 81 LT EUR oe eres PROPRIE RI T Wes STH 91 BRB RB RBBB ORE 16 BALS SI eee ee eee eee ee eee reece eee rete xri IB3OTd 222229 7 9 9 e 4 2 068 95 96 eT 09 96 2 8 IT 8 TE 50 8070 50 2 154 ge O 6 NO 440 78 440 7 5 79 NO 440 34 24 6 2 FANON 330 1104 8 xoou D 3691 79 NO 440 38Senbew uas 76 77 nw edy
33. 5 5 5 22 per 3 hrs per 3 hrs SPS 5 22 per 3 hrs of Flexible section per site tion per site section per site Rehabilitation 5 5 6 50 5hrs SPS 6 per 3 hrs SPS 6 20 per 3 hrs section per site 1 section per site 1 section per site Rehabilitation 5 5 7 50 Shrs 5 5 6 0 per brs SPS 6 20 per 3 hrs of CRC section per site 2 section per site 2 section per site 1 FWD test plan is identical to SPS 6 test plan for sections 3 and 6 2 FWD test plan is similar to SPS 6 test plan for sections 3 and 6 except testing is done at previously tested C1 locations 5 8 8 B B 9 4
34. AFTER construction testing and the B 2 3 LTPP Manual For FWD Testing Version 2 0 February 1993 letter D as the first LONG TERM testing The pass character 8 is 1 for ML testing 2 for PE testing 3 for OWP testing and 4 for WLE testing as used for GPS testing For example files from AFTER FWD testing of section 3 14 foot lane at an SPS 2 site in Jowa would be 190203C1 190203C2 190203C3 and 190203C4 Test Pit Areas The SPS 2 experiment has no test pits Therefore pass testing is not performed in SPS 2 Test Point Identification FWD operators must properly record longitudinal distances with the distance measuring instrument relative to 0 00 station reference for each section and follow the guidelines for lateral offsets for the WLE PE OWP and ML passes so all FWD testing can be repeated in the same general location Detailed Test Plan Test Sections For SPS 2 test sections FWD testing procedures do not vary between AFTER and LONG TERM testing AFTER and LONG TERM Testing All sections in SPS 2 are tested similar to the GPS JCP Test Plan except that the number of tests is reduced There are 5 FWD tests performed in each slab tested on 12 foot lanes An additional 2 FWD tests are required in each slab for the widened lanes a total of 7 tests These include three Deflection Basin tests one in the center of the slab J1 one at the leave slab corner J2 and one at midslab at the edge of t
35. Centigrade Stn Request OFF ON Test Checks NONE Decreasing defls Roll Off RollOFF Decr Reject prompt ON Stationing doesn t matter Temp Request OFF ON Cond Request OFF ON Variation Load NOT Checked Deflections NOT Checked Diameter of Plate 11 8 Deflector distances doesn t matter keep what you have 1 2 3 4 Drop 1234567P8901234P5678901P2345678P9012345P6789012P3456789S Heights 44444 44444 44444 44444 4444 44444 4444451111111 Test Plots 2 Save Peaks ee KERR aK ee KE Arkki Load His Whole His Load another TEST SETUP Store the CURRENT TEST SETUP Wote Drop height should be adjusted to attain deflections within the specified range Figure 2 Relative Calibration Test Setup for the Dynatest FWD Relative Calibration of the Deflection Sensors Remove all of the deflection sensors from their holders on the FWD Make sure that the sensors are labeled e g from 1 to 7 0 to 6 with respect to their normal position on the FWD The center sensor is in position number 1 on the Dynatest FWD and in position number 0 on the KUAB FWD Label the seven levels on the sensor stand from A to The top level is usually labeled A Position the seven deflection sensors in the stand for the first of the seven sets Support the sensor stand in a vertical position Mark the location where the stand res
36. Character A is reserved for BEFORE construction testing on SPS experiments refers to SPS DURING construction testing not used in SPS 3 testing all SPS testing uses letter C as the first AFTER construction testing for a section not required in SPS 3 testing and the letter D as the first LONG TERM testing The pass character 8 is 1 for ML testing and 3 for OWP testing as used for GPS testing For example files from BEFORE FWD testing of section at an SPS 3 site in Iowa would be 19A301A1 and 19A301A3 When performed the FWD testing AFTER have the following filenames 19A301C1 and 19A301C3 test time B is skipped for SPS 3 as there is no testing during construction Files representing data collected for LONG TERM testing will have a D or higher as the seventh character B 3 2 LTPP Manual For FWD Testing Version 2 0 February 1993 Drop Sequence The drop sequence load levels and number of drops for SPS 3 testing 15 similar to the FLEX Testing Plan for GPS except the number of drops is reduced from four to three SPS 3 Testing Plan Drop Sequence No of Drops Drop Height Data Stored 3 3 3 Yes 3 2 Yes 3 3 Yes 3 4 Yes 2 No data stored seating drop only Deflection and load data is printed but not stored to a file Store deflection peaks for all three drops and a complete deflection time history for the third drop only Operators should use the FWD Field Program Main Menu ch
37. FWD 4 file using the F6 comment key as appropriate Pavement Types GPS Test Sections The GPS portion of the LTPP program involves experiments on eight specific types of pavement cross sections They are Experiment Pavement Structure 1 AC Pavement Over Granular Base AC AGG AC Pavement Over Bound Base AC BND Jointed Plain Concrete Pavement JPCP Jointed Reinforced Concrete Pavement JRCP Continuously Reinforced Concrete Pavement CRCP AC Overlay of AC Pavement AC AC AC Overlay of PCC Pavements AC PCC not identified Unbonded PCC Overlay of PCC Pavements PCC PCC 4 A WH FWD Test Plans The eight GPS experiments are divided by pavement characteristics into three specific FWD test plans as listed below and details for the test plans are found in the rest of this chapter FWD Test Plan GPS Experiment Number and Name FLEX 1 AC Pavement Over Granular Base AC AGG 2 AC Pavement Over Bound Base AC BND 6 AC Overlay of AC Pavement AC AC 7 AC Overlay of PCC Pavement AC PCC LTPP Manual For FWD Testing Version 2 0 February 1993 JCP 3 Jointed Plain Concrete Pavement JPCP 4 Jointed Reinforced Concrete Pavement RCP 9 Unbonded PCC Overlay of PCC Pavement PCC PCC CRCP 5 Continuously Reinforced Concrete Pavement CRCP Types of Deflection Tests In the GPS study two types of deflection tests are run 1 Deflection Basin DB test and 2 Load Transfer LT test
38. LVDT with Cannon connector Schaevitz metric LVDT calibrator C 4 1M Measurements Group Inc Vishay Model 2310 signal conditioner with factory modification for 15 VDC and 15 VDC excitation Keithley MetraByte Model DAS 16G A D data acquisition board with STA 16 screw terminal board and C 1800 ribbon cable The G2 version of the data acquisition board is recommended for IBM PC XT and PC AT computers and compatibles the G1 version is acceptable A Model DAS 16G board should be used with PS 2 microchannel bus computers connecting cables Vishay to and Vishay to MetraByte O FWD reference calibration software FWDREFCL and documentation custom built reference load cell 300 mm diameter 40 000 108 capacity connecting cable Vishay to load ceil A 20 LTPP Manual For FWD Testing Version 2 0 February 1993 Note Drawings of each of the special items of equipment and cabling diagrams are available from the Long Term Pavement Performance LTPP Division at the Federal Highway Administration Turner Fairbank Highway Research Center McLean Virginia IBM PC XT or PC AT or compatible computer recommended IBM PS 2 computer acceptable Configuration 80386 processor or higher 25 MHz faster processor speed co processor if applicable 1 100 megabyte or more hard drive e an 8 bit expansion slot for the MetraByte board Monitor e Colo
39. Procedures 2 Data Acquisition and Handling 3 Equipment Calibration and 4 Equipment Maintenance and Repair People involved with deflection testing are encouraged to discuss the contents of this Field Guide with the four Regional Coordination Offices RCOs The RCOs will keep LTPP staff in Washington D C informed of necessary changes and periodic reviews and necessary updates to this manual will help keep the FWD operational guidelines current and help maintain uniform test procedures between the four regions The test procedures recommended in this manual are a product of SHRP its contractors and the Deflection Testing and Backcalculation Expert Task Group The manual was originally developed by Pavement Consultancy Services a Division of Law Engineering PCS LAW under contract to the Strategic Highway Research Program SHRP National Research Council This second version of the manual was developed by PCS LAW and Braun Intertec Pavement Inc under contract to the Federal Highway Administration FHWA A special thanks to Lynne H Irwin Ph D SHRP consultant who was responsible for the preparation of Appendix A SHRP FWD Calibration Protocol to the SHRP H 101 Contractor staff who were responsible for the preparation of the SPS 3 and 4 FWD Testing Guidelines contained in Appendix B and to the Deflection Testing and Backcalculation Expert Task Group for their efforts in the development and review of the manual The publicat
40. SENSOR SPACING LTPP Manual For FWD Testing Version 2 0 February 1993 JCP and CRCP Testing Plans Het Target Load kips Acceptable Range kips 2 9 0 40 0kN 8 1 to 9 9 36 0kN to 44 0kN 3 12 0 53 3kN 10 8 to 13 2 48 1kN to 58 7kN 4 16 0 71 1kN 14 4 to 17 6 64 1KN to 78 3kN The impulse load induced and measured by the FWD is partially influenced by the pavement stiffness and loads measured from one pavement to another will vary even if the distance the weight falls is the same In addition changes in the temperature of the rubber buffers springs on the FWD cause the measured load to change even though the distance the weight falls is the same Typically the rubber buffers increase in temperature when testing and the measured loads decrease because the buffers are less stiff The FWD can generate the 6 kip to 16 kip 26 7 kN to 71 1 load used for testing the GPS sections using only one combination of mass and rubber buffers This combination uses three weights per side total of six and two rubber buffers per side total of four and is referred to as the 44016 200kg package On occasion it may be impossible to obtain the specified load for drop height one or four on certain pavements due to equipment limitations on minimum and maximum drop distance settings on the FWD For these cases the drop distance should be set to obtain loads as close to the target range as possible The recommended procedure for
41. a 38 sn stata ee a 2 2 Mee Me CIS 07 12 n ta nn e s e a s 5 5 5 5 TUYA SNOILOAS 314 SNOILO3S 11 3HOd38 7 9 LYPP Manual For FWD Testing Version 2 0 February 1993 Temperature readings are obtained at 30 minute intervals with the first readings prior to starting FWD testing on a section and the last readings after completion of the FWD testing on the section Joint Crack Widths Joint and crack width measurements for SPS 7 sites are obtained the same as for GPS sections under the JCP and CRCP Testing Plans B 7 10 LTPP Manual For FWD Testing Version 2 0 February 1993 Appendix B 8 FWD TESTING GUIDELINES FOR SPECIFIC PAVEMENT STUDIES SPS EXPERIMENT 8 STUDY OF ENVIRONMENTAL EFFECTS IN THE ABSENCE OF HEAVY LOADS INTRODUCTION This appendix provides information for Falling Weight Deflectometer FWD testing at individual test sites for the Long Term Pavement Performance LTPP study experiment SPS 8 Study of Environmental Effects in the Absence of Heavy Loads The intent of this document is to establish the testing requirements for SPS 8 sites based on a uniform set of assumptions It is recognized that not all sites will conform to all assumptions contained herein However the objectives and approach to deflection data collection must be consist
42. a LTPP Regional Calibration Center or any other properly equipped location The calibration of the FWD deflection sensors is further refined by comparing them to each other in a process referred to as relative calibration Relative calibration is done as a final step that accompanies reference calibration and it can also be carried out alone at any suitable location There is no corresponding relative calibration procedure for the load measurement system The procedure results in calibration factors which are entered into the FWD software as multipliers When the FWD measurements are multiplied by the calibration factors the result is a measurement which has been corrected to agree with the calibration instrumentation It is necessary that there be a place in the FWD software to enter the calibration factors That is the responsibility of the FWD manufacturer To use this procedure Dynatest FWDs must have Version 10 or higher software Earlier versions do not have the pause feature and do not allow programming the required number of drops in the test sequence Furthermore it is not possible to leave the load plate down as is called for in this procedure Thus Dynatest FWDs must be upgraded to Version 10 or higher software before calibration LTPP Manual For FWD Testing Version 2 0 February 1993 FREQUENCY OF CALIBRATION Reference calibration should be performed at least once per year or as soon as possible after a sensor has been replace
43. assess variations in sun exposure and wind conditions to select the most representative location adjacent to the section limits for temperature measurements Joint Crack Widths Joint and crack opening measurements for SPS 4 sites are obtained as defined under the JCP Testing Plan However FWD operators are encouraged to measure all joints cracks tested B 4 6 LTPP Manual For FWD Testing Version 2 0 February 1993 Appendix B 5 FWD TESTING GUIDELINES FOR SPECIFIC PAVEMENT STUDIES SPS EXPERIMENT 5 REHABILITATION OF ASPHALT CONCRETE PAVEMENTS INTRODUCTION This appendix provides guidelines and information specific to Falling Weight Deflectometer FWD testing at individual test sites for the Long Term Pavement Performance LTPP study experiment SPS 5 Rehabilitation of Asphalt Concrete Pavements The intent of this document is to establish the specific testing requirements for SPS 5 sites based on a uniform set of assumptions 1115 recognized that not all sites will conform to all assumptions contained herein However the objectives and approach to deflection data collection must be consistent so data obtained can be analyzed in a consistent manner For deflection testing details not specifically addressed in the appendix refer to the general guidelines in this manual The objective of the SPS 5 experiment is to investigate the performance of selected asphalt concrete AC pavement rehabilitation treatments A variety of rehabilitati
44. be made only when those changes are both significant and verified to be necessary The following guidelines are to be used to evaluate the need for adjustment to the calibration factors 1 Computed sensor adjustment ratios R between 0 997 and 1 003 inclusive are considered to be equivalent to a ratio of 1 000 In other words the required adjustments are trivial and need not be made 2 Where the adjustment ratios for one or more sensors fall outside of the range 0 997 to 1 003 the calibration process should be repeated If both sets of data agree within 0 003 the gains should be adjusted for ail sensors 3 The final calibration factor is calculated by multiplying the current calibration factor for a given sensor i by its adjustment ratio According to the recommendations of the FWD manufacturers a final calibration factor less than 0 98 or greater than 1 02 is possibly indicative of a damaged sensor which should be repaired by the manufacturer or replaced Final calibration factors that are within this range should be entered into the FWD data collection software 4 If any calibration factors are changed the relative calibration process must be repeated to verify the accuracy of the final values The resulting adjustment ratios should be within the range 0 997 to 1 003 for all sensors If they are not the test procedure should be repeated Reports The full FWD calibration report shal consist of the following Prin
45. calculate the degree of interlock Secondly short term daily variations in temperature cause vertical temperature gradients through the PCC that in turn cause differential expansion of materials with depth LTPP Manual For FWD Testing Version 2 0 February 1993 Differential expansion with depth causes the panels to curl in either a concave or convex form This curling action influences the deflection response of the PCC panels For negative temperature gradients surface cooler than the bottom of the PCC the panels are concave with the panel edges lifted and the mid panel resting on the base material This condition normally occurs during early morning hours and normally results in higher deflections near the panel edges For positive temperature gradients surface warmer than the bottom of the slab the panels are convex with the panel edges resting on the base material and the mid panel lifted off the base material This condition normally exists later in the day after the PCC has been exposed to the sun and results in higher deflection at the mid panel locations In general moisture in a pavement structure weakens the structure and causes deflections to increase Moisture changes are normally long term occurring over an annual cycle However pavement sections in areas with significant frost penetration can have extreme changes in deflection if significant moisture exists with fine grain soil With the structure frozen the defle
46. contain a B in the seventh character position 190607B1 and 190607B3 The AFTER testing will result in filenames with a C in the seventh position while LONG TERM testing will have a D or higher Test Pit Areas As in the GPS testing LTPP plans to link the material sampling testing program and FWD test results on all SPS 6 sites At each SPS 6 experiment site test pits TP are located approximately 50 15 2m to 60 18 3m from a particular test section Due to the length of the SPS 6 sites test pits are not located adjacent to every test section As a rule a minimum of three test pits are used at every SPS 6 site Each potential test pit location has FWD measurements taken in the OWP pass Subject to traffic control restrictions this pass Po is completed for the entire SPS 6 test site prior to testing of pass P on any section There may be occasions where time delays of days or weeks occur between FWD testing and sampling and FWD operators must mark the location of the FWD tests in the TP areas Also pass P testing is only performed for the BEFORE time period B 6 5 LTPP Manual For FWD Testing Version 2 0 February 1993 Test Point Identification FWD operators must properly record ali longitudinal distances with the distance measuring instrument relative to 0 00 station reference for each section and follow the guidelines for lateral offset for the PE OWP and ML passes so all FWD testing can be repeated in the same
47. diameter holes using a portable hammer drill to the depths determined in step 3 6 Clear holes of cuttings and dust by blowing them out with a short piece of 1 4 6mm diameter plastic tubing 7 Measure and record the depth of each hole to the nearest 0 1 2 mm on the Temperature Measurement Form see Figure 7 8 Fill the bottom of each hole with 1 2 13mm to 1 25mm of mineral oil provides thermal conduction at the bottom of the hole to a temperature probe inserted in the hole 9 Cover each hole with a short piece of duct tape to prevent water and debris from entering the hole The tape also prevents the sun from warming the oil in the 1 25 mm deep hole A small incision or hole can be made in the tape for inserting the temperature probe 10 Read temperatures to the nearest 0 1 F 0 05 C each hour during FWD testing The first temperature measurement should not be taken for at least 15 minutes after the oil is placed in the holes to allow heat from drilling to dissipate After inserting the temperature probe in a hole the reading should be allowed to stabilize for about one minute before recording the temperature All temperatures should be recorded on the Temperature Measurement Form Form 1 The last temperature measurement should be obtained immediately following the last FWD test 11 the holes after the last set of temperature measurements have been made A sealant such as silicon caulk that can be
48. general location Detailed Test Plan Test Pit Areas TP areas are tested identical to the procedures outlined for GPS testing in the main part of this manual Detailed Test Plan Test Sections For SPS 6 test sections FWD testing performed varies between BEFORE DURING and AFTER depending on the rehabilitation for the section BEFORE Rehabilitation Testing For SPS 6 sections the testing BEFORE rehabilitation is similar to that outlined for JCP pavement sections see Table B 6 2 except the number of tests is reduced Figure B 6 1 illustrates the BEFORE testing pattern for all sections and the AFTER testing pattern for Sections 1 2 and 5 For all sections except Section 2 and 5 10 effective slabs are tested the concept of effective slab is defined previously in this manual For Sections 2 and 5 which are 1000 feet long 20 effective slabs are tested The BEFORE test plan includes three passes along each section P Mid lane P Pavement edge and Outer wheel path A preliminary pass will also be made to evaluate the test pit locations where applicable FWD operators must consider end conditions joints cracks and patches of the effective slabs when selecting slabs to test The proportion of end conditions will determine the slabs tested For example if 24 total effective slabs are present with the following distribution 6 terminated by a joint at one end and a joint at the other 6 ter
49. gt aM a z 3003 AN3W3AVd er cf d 8 rip boe Cua oat d acl E DA 21 2 77777277777777 v4 FEAR TU Len aC v VEN l t rope el 9 970 NAYJ uzino c INV r 12 4 Xo i 551 1431144114 11144141 113 34340413 438 3 NOILOSAS 18531 008 1 0028 0050 TIAN JO 2 6 LTPP Manual For FWD Testing Version 2 0 February 1993 Other FWD Operator Field Measurements Temperature Gradient Measurements Temperature gradient measurements for SPS 2 sites are obtained similar to that for GPS sections with the two exceptions below Measurements are obtained at only one location for each test section It is up to the FWD operator to assess variations in sun exposure and wind conditions to select the most representative location adjacent to the section limits for temperature measurements Temperature readings at SPS 2 sites are obtained at 30 minute intervals with the first readings prior to start of FWD testing on the section and the last readings ending after completion of the FWD testing on the section Joint Crack Widths Joint and crack opening measurements for SPS 2
50. reference so all FWD test point locations can be located for future testing Three lateral transverse testing passes will be employed for 12 foot lanes with one additional pass for sections having 14 foot lane For SPS 2 a Pavement Edge is the shoulder pavement interface for 12 foot lanes and the outer edge of the painted shoulder stripe on 14 foot lanes widened pavement lanes For widened lane construction a Widened Lane Edge is defined as the outer edge of the pavement slab The four passes are B 2 2 LTPP Manual For FWD Testing Version 2 0 February 1993 ML Mid Lane located 6 0 0 5 1 8 m 0 15 m from the edge reference OWP Outer Wheel Path located 2 5 0 25 0 76 m 0 08 m from the edge reference 3 PE Pavement Edge Edge of load plate should be less than 3 76 mm from the edge reference 4 WLE Widened Lane Edge Edge of load plate should be less than 3 76 mm from the outside edge of the slab Notes 1 This pass applies only to sections built with 14 foot lane width 2 FWD tests at the WLE are actually on the shoulder and not the driving lane FWD operators must insure that the tests are located within the above tolerances The FWD operators are not expected to measure the position of each test point but excessive deviations must be avoided particularly for pavement edge and comer testing Testing widened lane construction in SPS 2 includes WLE testing in addition to P
51. setups identical to these The setups for the three FWD testing plans have item 14 Test Plots activated for the last drop in a sequence Test plots for any other drops will interrupt delay the test sequence Operators should monitor the test plot from test point to test point for indications of changes in the pavements deflection response In addition the operator should visually scan the printed output for each test to assure no questionable data has been obtained Setting Up FastBack Plus Backup Software Each FWD unit has been supplied with the Fastback Plus program for data backup The following program options for the backup of FWD data collected in the field must be set as follows 1 User level to ADVANCED allows operator to set the other options noted below m 2 Data Compression to SAVE DISKS reduces the required number of disks 3 Format Mode to ALWAYS FORMAT reduces the number of disks required for backup 4 Overwrite Warning to ANY USED DISK Error Correction to ON for data security purposes 6 Write Verify to WRITE for best security good use of extra time required The options selected above maximize the likelihood that the FWD data backed up using FastBack Plus will arrive at the RCO in a readable form but slightly increase the time required to perform the data backup The data backup should take less than 30 minutes to make three complete backups and FWD operators can typically use this time for co
52. site no crack opening measurements made however FWD operators must record pavement distress at test point locations as described in guidelines for GPS testing using the F6 Comment key 5 5 LTPP Manual For FWD Testing Version 2 0 February 1993 SNOILOSS 1531 S SdS HOJ 1931 LS 9 3unoilJ S39ONVISIG LN3SZUd38 NMOHS 8138330 1 SISAL AO 43 18813 Sv d NO 41 SNOI1VOOTI Lid 1531 1 51631 Od 3 E E 3 0 4 P 135 43100 0 3 4 2 Ky potete tenses Po P PPP INY T GIW E 05 9355 1531 00S 40926 0029 0020 08 0 TSAAVYEL JO NOILOAYIC B 5 6 LTPP Manual For FWD Testing Version 2 0 February 1993 LNAIGVYS SJUNLVYAdWAL SNYALIVd 9NITIIHG WOldAL 29 43 914 H31V3H9 HO 55 8 38 6 9NIOVdS 310H TIYA ALON HO IWHANIW SATOH TIHA lt SSANWMOIHL AOVAYNS OV 2 SSANWOIHL AOVAHNS OV 5 7 Manual For FWD Testing Version 2 0 February 1993 THIS PAGE INTENTIONALLY LEFT BLANK 5 8 LTPP Manual For FWD Testing Version 2 0 February 1993 Appendix B 6 FWD TESTING GUIDELINES FOR SPECIFIC PAVEMENT STUDIES SPS EXPERIMENT 6 REHABILITATION OF JOINTED PORTLAND CEMENT CONCRETE PAVEMENTS INTRODUCTION This appendix provides guid
53. sites are obtained as defined in the J CP Testing Plan for GPS B 2 7 LTPP Manual For FWD Testing Version 2 0 February 1993 THIS PAGE INTENTIONALLY LEFT BLANK B 2 8 LTPP Manual For FWD Testing Version 2 0 February 1993 Appendix 3 FWD TESTING GUIDELINES FOR SPECIFIC PAVEMENT STUDIES SPS EXPERIMENT 3 PREVENTIVE MAINTENANCE EFFECTIVENESS OF FLEXIBLE PAVEMENTS INTRODUCTION This appendix provides guidelines and information specific to Falling Weight Deflectometer testing at individual test sites for the Long Term Pavement Performance LTPP study experiment SPS 3 Preventive Maintenance Effectiveness of Flexible Pavements The intent of this document is to establish the specific testing requirements for SPS 3 sites based on a uniform set of assumptions It is recognized that not all sites will conform to all assumptions contained herein However the objectives and approach to deflection data collection must be consistent so data obtained can be analyzed in a consistent manner For deflection testing details not specifically addressed in the appendix refer to the general guidelines in this manual The objective of the SPS 3 experiment is to compare the effectiveness and mechanisms by which selected maintenance treatments preserve or extend pavement service life driver safety and ride quality on asphaltic concrete pavements The impact of materials or construction process is not a part of this study In addition the overall
54. the potential for variability of subgrade soils A minimum of three Test Pits are used on the total site B 5 1 LTPP Manual For FWD Testing Version 2 0 February 1993 Table 8 5 1 SPS 5 Test Section Numbering Scheme SES 5 Surface Overlay Overlay pe No Preparation Material inches Routine Maintenance p uu Minimum Recycled AC 2 NO B Intensive 2 j 2522 22 5 5 a oe B 5 2 LTPP Manual For FWD Testing Version 2 0 February 1993 FWD TEST PLAN General FWD testing for SPS 5 is performed 0 to 3 months prior to overlay construction labelled as BEFORE 3 to 6 months after overlay construction is completed labelled as AFTER and annually more than 6 months after the completion of overlay construction labelled as LONG TERM The preconstruction phase is used to characterize the existing pavement structure and provide a baseline for comparison of the various rehabilitation techniques Post construction testing is directed at verifying material properties and the as built pavement section for use in evaluating the effectiveness and long term performance of the rehabilitations LONG TERM FWD testing is performed to evaluate the effects of temperature moisture changes and traffic loading on pavement deflection and performance Only deflection basin tests are used in the SPS 5 testing The specific FWD te
55. 0 LTPP Manual For FWD Testing Version 2 0 February 1993 C3 DB test from Sta 0 00 to 5 00 in the at mid panel P5 C4 test from Sta 0 00 to 5 00 in the OWP at cracks defining the beginning of the panel with the load plate on approach slab C5 test from Sta 0 00 to 5 00 in the OWP at cracks defining the beginning of the panel with load plate on leave slab P NOTE Operators must change the lane specifications immediately before performing a test at a given location by using the F2 Location key in the FWD Field Program File naming convention file names consist of eight characters using the following format characters one thru six SHRP six digit Section ID character seven denote the number of times the section has been tested for the LTPP study Example first test is A second test 15 etc character eight pass number of the FWD on the section pass 0 OWP test pit locations pass 1 P ML within the 500 section pass 2 P PE within the 500 section pass 3 P OWP within the 500 section The extension FWD is used to identify the file as raw deflection data For example 373807A1 FWD is the file name for pass 1 of the first round of tests for SHRP Section 373807 Rejecting tests for the majority of cases the REJECT prompt appears because load or deflection data exceeds variation limits however nondecreasing deflections or data exceeding th
56. 0 mil 25 4 microns 1 0 micron 0 039 mils 1 0 ft 0 328 meters 1 0 meter 3 048 feet Force 1 0 lbf 0 0044 kN 1 0 224 8 lof 1 0 kip 4 45 1 0 kN 0 225 kips Pressure 1 0 psi 6 89 kPa 1 0 kPa 0 145 psi 66 APPENDIX SHRP FWD CALIBRATION PROTOCOL LTPP Manual For FWD Testing Version 2 0 February 1993 SHRP FWD CALIBRATION PROTOCOL INTRODUCTION This document describes the procedure for calibration of falling weight deflectometers FWD which was originally developed by the Strategic Highway Research Program SHRP This protocol is now administered by the Long Term Pavement Performance LTPP Division in the Federal Highway Administration The procedure is written primarily for use with the Dynatest falling weight deflectometer however it can also be used with the KUAB FWD Due to differences in the design of the KUAB certain details are not applicable Special procedures for the calibration of KUAB FWDs are included in Appendix It may be possible to use the procedure for other types of FWDs with minor modifications of the hardware and of the data acquisition software The procedure is not applicable to the calibration of cyclic loading and other types of pavement deflection testing equipment In this procedure the deflection and load transducers from the FWD are first calibrated individually against independently calibrated reference devices This is called reference calibration and it is performed at
57. 2 since a thorough quality control program is performed during construction FWD TEST PLAN General FWD testing for SPS 2 is performed during construction labelled as DURING 3 to 6 months after construction labelled as and annually more than 6 months after construction labelled as LONG TERM The AFTER testing verifies material properties of the as built pavement for evaluating the effectiveness and long term performance of the section LONG TERM testing evaluates the effect of temperature moisture changes and traffic loading on pavement deflections and performance Deflection Basin tests as well as Load Transfer tests will be used in the SPS 2 testing The specific FWD test plan for SPS 2 is similar to the JCP Testing Plan for GPS The factors inherent within this test plan are Test Point ID Number 71 72 73 74 75 77 and 78 Lane for Each FWD Pass Transverse location Test Interval Longitudinal location Test Type Basin or Load transfer Deflection Sensor Spacing Drop Sequence Load Levels Number of Drops AAP WN All FWD testing is done in the driving lane at three lateral offsets For each lateral offset a single pass through the test section is made to collect a particular type of deflection data When finished with a particular pass the FWD returns to the beginning of the section to start another pass All testing uses station 0 00 of the test section not the SPS site as the distance
58. 9050 0 06 0606 0 0 060 060 o CO OCOC OK OC OC 0 22250225 25 009050505992 52 25525 2525 52 2 25 6 0 25252 52 00 95 52 2 0006066 2 2505050 25959 05050669 55222 2 FIGURE SENSOR CONFIGURATION FOR DEFLECITON BASIN TESTING DIRECTION OF MOVEMENT 0 0 0 9 0 0 0 e 9 4 6 09 0 0 0 0 6 0 9 FIGURE 2B SENSOR CONFIGURATION FOR LOAD TRANSFER TESTING DIRECTION OF MOVEMENT 49 9 9 9 0 0 9 0 09 0 0 07070 0 0 9 9707070000007097070 9 0 0 9070 00707009 0 0 0700 0 0707 0 0 0 0 0 00 9 9 0 0 90 0 LOCION IIOS 0 9 0 0 0 0 06000 9 4 9 9 9 9 9 0 0 0 0900 09 099 0 009 3 0 0 990 0 9 90 6 0 09 9 00066 e 22505 5 00066 0006006000600 5505052 e 0909050900 0505 OOOO 2 0 09 0 OOOH COR 09000904990 S005 9050900 25 26 252 Ow 5252 0000 552262 0 S FIGURE 2B 1 FIGURE 2B 2 APPROACH SLAB LOAD TRANSFER LEAVE SLAB LOAD TRANSFER FIGURE 2 DEFLECTION
59. DB tests are used in all three test plans while LT tests are used only in the JCP and CRCP test plans DB tests are analyzed to estimate in situ characteristics of the materials in the pavement structure In contrast LT tests at joints and cracks in PCC pavements are analyzed to evaluate load transfer efficiency across the joints and cracks and also to evaluate the possible existence of voids under the pavement In summary the three major uses of deflection data are as follows Test Data Analysis Data Use DB Estimate Material Properties Distribution LT Joint Crack Load Transfer Efficiency LT Void Detection Deflection Sensor Spacing The LTPP FWDs have seven deflection sensors placed at radial offsets from the center of the load plate to define the shape of the deflection basin Deflection basin shape ranges significantly from steep basins for weak flexible pavements to shallow basins for stiff rigid This FWD test plan was referred to as RIGID in Version 1 0 of this manual LTPP Manual For FWD Testing Version 2 0 February 1993 pavements The shape varies most significantly within three feet 0 9m of the load plate for most highway pavements For any one pavement section an optimal set of sensor spacings exists for defining the basin shape However only one set of sensor spacings is used for all DB tests to simplify data collection decrease testing time and minimize errors in sensor spacings Figure 2a shows the sensor spaci
60. Data Backup a Read Final Temperatures and Seal Holes b Create Backup Data Disks and History Report See Chapter V C Complete and Check Field Activity Form and Temperature Form Prepare Equipment for Travel and Make Final Inspection a Covers on FWD b Computer and Printer Stored Final Walk Around Tow Vehicle and FWD 29 LTPP Manual For FWD Testing Version 2 0 February 1993 Operator Field Assistance At a site FWD operators need to carefully plan activities to make efficient use of time Time 15 most critical for GPS experiments in the JCP and CRCP testing plans Personnel at the site other than the FWD operator are strictly prohibited from driving the tow vehicle or operating the FWD These functions are the sole responsibility of the FWD operator However activities such as drilling temperature holes recording temperatures marking panels and measuring joint crack openings can be done by other personnel on the site e g traffic control people other RCO staff on site etc FWD operators should never directly ask personnel at the site for assistance Instead they should ask crew supervisors if volunteers are available to help FWD operators should not imply that assistance is expected from others at the site 30 LTPP Manual For FWD Testing Version 2 0 February 1993 DATA ACQUISITION AND HANDLING General The FWD operator s primary responsibility is FWD data collection With data collected in
61. E testing Pass 4 P has been assigned for WLE testing on sections with 14 foot lane width for doing one corner test and one mid panel test on this pass The following list of lane specifications are used to identify the type and location of tests performed JPC Category Pavements 10 NOT USED ON SPS 2 Ji all tests in the mid lane pass 12 comer tests in the pavement edge pass J3 mid panel tests in the pavement edge pass 74 approach slab tests the outer wheel path pass 15 leave slab tests in the outer wheel path pass 77 corner tests in the widened lane edge pass P 78 mid panel tests in the widened lane edge pass Lane specifications J7 and J8 are on the shoulder outside the edge stripe Naming Scheme Data Storage A unique 6 digit code identifies the individual test sections at an SPS 2 site similar to that for the GPS sections with the fourth character being 2 for SPS 2 The computer filenames are identical to those used in the GPS testing with the 6 character test section code followed by two characters indicating the times a section has been tested and the number of the pass within the section The times tested character 7 is a single letter which corresponds to the number of times the section has been tested Characters A and B are reserved for BEFORE and DURING construction testing on SPS experiments not used in SPS 2 testing all SPS testing uses letter as the first
62. EMPERATURE MEASUREMENT FORM 25 LTPP Manual For FWD Testing Version 2 0 February 1993 2 Two temperature probes one at least 24 0 6m long with probe diameter not greater than 1 4 6mm The probes should be stainless steel with a thermocouple sealed in the tip and calibrated against NIST traceable standards by the manufacturer 3 gasoline powered portable rotary hammer drill for drilling holes Note the electrical power from the DC to inverter in the tow vehicle only provides about 4 amps of AC power 500 watts which will not operate most electric hammer drills 4 The following supplies need to be available and replenished as needed several 1 2 13mm diameter carbide tipped bits for the hammer drill Lengths from 12 to 24 0 3m to 0 6m should handle all hole depths needed several 36 0 9 m pieces of 1 4 6 mm diameter plastic tube for blowing dust out of the temperature holes mineral oil and a bottle that can put a small volume of oil in the temperature holes without making a big mess duct tape for covering the temperature holes Temperature Measurement Form Form F01 several tubes of silicon caulk and a caulking gun for sealing the temperature holes after tes ng 1s complete For each set of temperature holes the information requested on the Temperature Measurement Form Form F01 must be properly and completely recorded by the FWD operator Time entries for the temperature measurements a
63. ESTS BASIN JT CRACK TP OWP PE ML ADDITIONAL REMARKS REGARDING TESTING FIELD SAMPLING AND TESTING CREW TRAFFIC CONTROL CREW NAMES AGENCY NAMES COPIES RCO FORM FO2 ISSUED 15 FEBRUARY 1993 FIGURE 18 FWD FIELD ACTIVITY REPORT FORM LTPP Manual For FWD Testing Version 2 0 February 1993 The FWD Field Activity Report is filled out for all travel days testing days and any days the FWD operator performs maintenance on the FWD or tow vehicle Reports for testing days must be completely filled out while reports for travel days and maintenance days are only partially filled out including the section ID for which the travelling is done For testing days it is important to obtain the names of personnel on site in case of an accident A line is provided for FWD operators to initial indicating that routine maintenance was conducted prior to any FWD testing The original report is kept in the tow vehicle and a copy is forwarded to the RCO along with the field data diskettes and a hardcopy of the data Equipment Maintenance Records Equipment maintenance records include the FWD Field Activity Report 202 and the Major Maintenance Repair Activity Report Form F03 see Figure 19 major maintenance or repair item that requires an outside agency is reported using Form F03 Routine maintenance before operation checks and minor repairs performed by FWD operators are reported on the FWD Field Activity Report Form 202
64. Equipment Maintenance and Repair Routine Maintenance Routine maintenance functions are performed easily with minimal disassembly and include procedures like checking the fluid levels in the tow vehicle checking vehicle lights etc These basic and easily performed maintenance measures should be done each day prior to using the equipment The following partial list of BEFORE OPERATIONS CHECKS show the extent and detail required for preventative maintenance These items are not to supersede manufacturer s minimum requirements for warranty compliance 57 LTPP Manual For FWD Testing Version 2 0 February 1993 Tow Vehicle Under hood fluid levels engine oil brake fluid power steering windshield washer engine coolant transmission fluid drive belt tension water pump alternator a c compressor battery cable connections general appearance leaks cracked hoses cracked insulation Exterior tires inflation and condition lights headlights signals flashers beacon arrow board glass clean no cracks electrical connections clean and corrosion free Interior general appearance clean and uncluttered equipment properly stowed glass clean and view unobstructed power inverter well ventilated and good electrical connections computer in good condition air conditioning functioning properly operate monthly to keep compressor lubricated temperature measuring equipment in good condition Trailer connection to va
65. FLEX Testing Plan No of Drops Drop Height Data Stored 3 3 4 1 Yes 4 2 Yes 4 3 Yes 4 4 Yes 2 JCP and CRCP Testing Plans No of Drops Drop Height Data Stored 3 3 No 4 2 Yes 4 3 Yes 4 4 Yes No data stored seating drop only Deflection and load data is printed but not stored to a file Store deflection peaks for all four drops and a complete deflection time history for the fourth drop only 11 LTPP Manual For FWD Testing Version 2 0 February 1993 FWD Testing Plans General The differences in the FLEX JCP AND CRCP testing plans used for the GPS experiment are as follows l Longitudinal location of test points spacing and stationing 2 Lateral location of test points distance from edge reference 3 Type of deflection test DB or LT test 4 Drop sequence drop heights and number of drops For longitudinal reference all test point locations will be measured from station 0 00 using the distance measuring instrument in the FWD tow vehicle The DMI should be checked at stations 1 00 2 00 3 00 4 00 and 5 00 and problems with the stationing for the section or the calibration of the instrument should be recorded For lateral reference all FWD testing is done in the lane containing the test section In general this will be the driving lane truck lane versus the passing lane of the highway Within the lane tested three lateral offsets measured from an edge reference are used to locate the
66. Factors from Reference Calibration FWD Relative Calibration Data Calibration Factors from Relative Calibration Final Calibration Factors mT Mode of Entry Source Manual Operator Manual Operator Automatic Computer Clock Manual Operator Manual Operator Manual Operator Manual Transducer Setup and Gain Printout Manual Transducer Setup and Gain Printout Automatic Configuration File Automatic Configuration File Automatic Configuration File Manual Transducer Setup and Gain Printout Manual Transducer Setup and Gain Printout Automatic Configuration File Automatic Configuration File Computed FWDREFCL Software Automatic FWDREFCL Software Manual FWD Computer Automatic Calibration Data Acquisition System Manual FWD Computer Automatic Calibration Data Acquisition System Computed FWDREFCL Software Automatic Relative Calibration Data Files Computed FWDCAL2 Software Manual Final Gain Worksheet SHRP FWDs Source may be different for FWDs from other manufacturers Reference calibration configuration file FWDREFCL CNEF pe A 6 LTPP Manual For FWD Testing Version 2 0 February 1993 signal conditioner with the load plate high so that there is no external load on the reference load cell Notes For accurate results it is critically important that the reference load cell be zeroed with the FWD load plate in the raised position Also the signal co
67. ML IWP LP load plate and D1 to D7 for the geophones Examples M TRANS CR BETWEEN D4 AND D5 L RUTTING OWP L PATCH UNDER LP Other factors to document using the F6 Comment key include data with nondecreasing deflections data with variations and unusual conditions or events Unusual conditions or events could include items such as delays in testing due to break downs or weather pavement changes within the section moisture seeping out of cracks or any other conditions that may help with or explain analysis results for the FWD data Joint Crack Openings Joint openings in rigid pavement systems affect deflection response and load transfer and cracks in AC pavements affect pavement response The following procedures are used for measuring joint crack openings for the three FWD testing plans FLEX Crack Openings For any GPS experiment under the FLEX testing plan no crack opening measurements are made however the FWD operator still needs to record any pavement distress at the test point locations using the F6 Comment key as previously discussed JCP and CRCP Joint Crack Widths The GPS experiments under the JCP and CRCP testing plans have joint crack opening measurements for at least 25 of the Load Transfer tests see Figure 4 and Table 1 however operators are encouraged to measure 100 of the joint cracks tested for load transfer if time allows Vernier calipers with tapered jaws for measuring inside dimensions are used for m
68. SHRP P 661 Manual for FWD Testing in the Long Term Pavement Performance Program PCS Law Engineering and Braun Intertec Pavement Inc Strategic Highway Research Program II National Research Council PF Washington DC 1993 SHRP P 661 Contract P 001 Program Manager Neil F Hawks Project Manager Cheryl Allen Richter Production Editor Marsha Barrett Program Area Secretary Cynthia Baker August 1993 key words deflection testing falling weight deflectometer non destructive testing pavement evaluation structural evaluation Strategic Highway Research Program National Academy of Sciences 2101 Constitution Avenue N W Washington DC 20418 202 334 3774 The publication of this report does not necessarily indicate approval or endorsement of the findings opinions conclusions or recommendations either inferred or specifically expressed herein by the National Academy of Sciences the United States Government or the American Association of State Highway and Transportation Officials or its member states 9 1993 National Academy of Sciences 350 NAP 893 Acknowledgments The research described herein was supported by the Strategic Highway Research Program SHRP SHRP is a unit of the National Research Council that was authorized by section 128 of the Surface Transportation and Uniform Relocation Assistance Act of 1987 111 LTPP Manual For FWD Testing Version 2 0 February 1993 TABLE OF CONTENTS Page
69. While releasing the load record a reading at 10 000 pounds and at zero load 12 Remove the upper bearing block and if necessary adjust the Trim knob the signal conditioner until the MetraByte board reads 0 bits Push and hold the Cal switch in the B position and record the reading Repeat for the B position Set the Auto Balance switch to OFF and again record the unbalanced zero voltage This reading should be within three bits of the earlier reading If it is not repeat the calibration procedure from step 4 be sure that the load cell is centered in the testing machine and be sure to repeat the 20 000 pound preloading procedure in step 6 Data Analysis Using a spreadsheet utility program such as Lotus 1 2 3 enter the results of the calibration In column A enter the nominal loads registered by the universal testing machine i e 0 1000 2000 etc In column B correct these loads to the NIST traceable loads based on the certificate of calibration for the testing machine In column C subtract the tare weight of the upper bearing block from the loads in column B In column D enter the MetraByte board readings in bits Note that the readings are negative In columns E F G and H calculate v2 and V5 respectively where V represents the readings in column D Use the spreadsheet regression utility to calculate a linear regression of corrected load as the Y variable versus bits as the X variable The regression
70. YO 22 81 28 48 BION 17180 42 110 gt STOH TUUA ONY SNOILOAS SONY SNOILOSS 4315 NYSLINd 88 2 3 SNOILOSS 11V 380338 B 6 12 LTPP Manual For FWD Testing Version 2 0 February 1993 wHALAV 8 ANY Z SNOILO3S VIVI LN3IQVH5 SNYALIVd 9NITIIHO 1751441 9 aunoid 8 2 SNOIJ93S 99d N330U8 NI SLNAWAYNSVAW AYNIVHSdWAL ON 3ZLON H31V3HU9 YO 00 8 38 AINOHS ONIOVdS 310H 11154 310N 110 J1OH 1118A 3 2 SNOILOAS 803 NY3LIVd H3ldV B 6 13 LTPP Manual For FWD Testing Version 2 0 February 1993 THIS PAGE INTENTIONALLY LEFT BLANK B 6 14 LTPP Manual For FWD Testing Version 2 0 February 1993 Appendix B 7 FWD TESTING GUIDELINES FOR SPECIFIC PAVEMENT STUDIES SPS EXPERIMENT 7 BONDED PORTLAND CEMENT CONCRETE OVERLAYS INTRODUCTION This appendix provides guidelines and information for Falling Weight Deflectometer FWD testing at individual test sites for Long Term Pavement Performance LTPP study experiment SPS 7 Bonded Portland Cement Concrete Overlays The intent of this document is to establish the specific testing requirements for these sites based on a uniform set of assumptions It is recognized that not all sites will conform to all assumptions contained herein However the objectives and approach to deflection data collection mus
71. a joint at one end and a crack at the other 6 terminated by a patch at one end and a crack at the other two or three of each type of effective slab should be tested while attempting to get both types of end conditions in each category above e g 1 or 2 with a joint at the approach end and a patch at the leave end and 1 or 2 with a patch at the approach end and a joint at the leave end Five FWD tests are performed in each effective slab tested These include a Deflection Basin test in the center of the slab 71 P a Deflection Basin test along the approach corner 72 and edge of the slab J3 on P and the two Load Transfer tests J4 and 15 on P Figure B 7 1 indicates the positions of the test locations for a given effective slab Each test section has 10 effective slabs for a total of 450 FWD points not including Test Pit locations At a rate of 20 points per hour the entire process all eight test sections will take approximately 23 hours This does not include the time for testing Test Pit locations or taking temperature gradient measurements The total time for all tasks should be approximately 30 hours B 7 5 LTPP Manual For FWD Testing Version 2 0 February 1993 1 SALNSIWSAYd NOILVLIMEGVHSY WSILAV ONY 2380338 ONILSSAL YOI LSAL GMS LZ 8 BYNDIlS S39NVASIO LN3S3UdZH8 NMOHS 85138310 ALON TANWd 41 OLABVA AYN ONINOIIJVAS 114 1551 ILON 8
72. activities provide FWD operators with an overall perspective of a typical day at a test section and it outlines the concepts and procedures presented in this Chapter Further guidance is included in Chapter and Chapter V Field Activities at a Typical Test Section Task 1 Arrive at Site Task 2 Coordinate Personnel Traffic Control Crew b Sampling and Testing Crew Only for first round of tests Other LTPP State DOT and RCO Personnel Task 3 Inspect Test Section a Test Pit Locations only for first round of tests b General Pavement Condition e Test Section Limits 28 4 Task 5 Task 6 Task 7 Task 8 Task 9 LTPP Manual For FWD Testing Version 2 0 February 1993 Initiate Pavement Temperature Gradient Measurement Select and Mark Locations for Holes Prepare Temperature Holes and Record Depths Record Initial Temperature Measurements Record Temperature Measurements Every 60 Minutes after the Initial Readings I Prepare FWD Equipment Covers trays off FWD Visual Check of Equipment Computer Printer Setup Initiate FWD Field Program mo Ss Check FWD Drop Heights a Select Location Outside Test Section b Condition Buffers Adjust Drop Heights to Obtain Loads Within Target Ranges Collect Deflection Data a Run FWD Tests at Test Pit Locations See Chapter b FWD Testing in Sequence of P P and See Chapter IIT Complete Data Collection and
73. al For FWD Testing Version 2 0 February 1993 readings than a pavement section without any discontinuities if all other factors are the same The FWD testing plan in this manual provides specifics on deflection testing at joints and transverse cracks for PCC pavements The testing plan also provides guidelines for recording any pavement distress near deflection tests It is important that FWD operators obtain typical deflection response data on each pavement section FWD operators should not bias deflection readings by testing only crack free areas or only cracked areas More details on test point location and distribution are discussed later in this manual Variability in the Pavement Structure For the GPS program pavement sections as uniform as possible were selected However pavement deflection response will vary not only between drops at a given load level but also between test points within the section Deflection variation at a given load level for a test point will generally be less than about 0 1 to 0 2 mils 3 to 5 microns and is statistically accounted for by doing four drops at each load level This variation occurs from limits on equipment repeatability for load and deflection measurement and from material changes in the pavement structure from the load applications In contrast deflection variation between test points within a section may be quite large ranging from 15 percent to more than 60 percent This variation reflec
74. als should be 1 millivolt or less Equipmens Preparation Inspect the reference load cell carefully before calibration Verify that the cable and the Amphenol connectors are making proper contact in their sockets eg fitting and locking tightly Make a continuity check to verify that there are no breaks in the wires Verify that the Allen screws on the load cell are tight Note The six Allen screws on the top and the bottom of the load cell were torqued to 100 10 and set with Locktite during assembly These screws should not be loosened unless it is absolutely necessary If any of the screws are loosened they should removed one at a time and their threads cleaned Locktite should be reapplied to their threads and they should be torqued to precisely 100 ib in A 28 LTPP Manual For FWD Testing Version 2 0 February 1993 Verify that the three steel pads on the bottom of the reference load cell are in good condition Verify that one of the wood aluminum bearing blocks has a nbbed rubber pad cemented to it If the edges of the rubber pad are loose use rubber cement to reattach it Install a spherically seated bearing block in the cross head of the universal testing machine Make the following settings on the front panel of the 2310 signal conditioner Excitation Voltage set to 10 volts Filter set to 1000 Hz AC IN button fully extended eg out Gain set to 5 5 100 Auto Balance switch OFF Verify that th
75. ar subgrade and subjected to similar traffic and environmental conditions will allow for comparison of the experimental factors Substantial deflection testing is required to evaluate the relative performance of the different sections Experiment sites should conform to criteria contained in Specific Pavement Studies Guidelines for Nomination and Evaluation of Candidate Projects for Experiment SPS 7 Bonded Portland Cement Concrete Overlays June 1990 The site characteristic affecting the FWD testing is the number of sections 7 1 LTPP Manual For FWD Testing Version 2 0 February 1993 Table B 7 1 details the LTPP test sections in an SPS 7 experiment site Criteria for selection limit the sites to a single structural cross section constructed of the same materials throughout under the same contract Location of test sections should avoid cut fill transitions bridges culverts and side hill fills to limit the potential for variability of subgrade soils A minimum of three Test Pits are used at a site FWD TEST PLAN General FWD testing for SPS 7 is performed in multiple phases 0 to 3 months prior to rehabilitation labelled as BEFORE 3 to 6 months after overlay construction labelled as AFTER and annually more than 6 months after the completion of rehabilitation labelled as LONG TERM The BEFORE testing is used to characterize the existing pavement structure and provide a baseline for comparison of the various construc
76. ary 1993 Table B 7 1 SPS 7 Test Section Numbering Scheme Surface Preparation Milling and Sand Blasting Milling and Sand Blasting MON omo EN shot Blasting No 05 Shot Blasting Yes 06 Shot Blasting ___ Yes 07 ____ No 08 Miling and Sand Blasting 29 Milling and Sand Blasting 7 3 LTPP Manual For FWD Testing Version 2 0 February 1993 Naming Scheme Data Storage A unigue 6 digit code identifies the individual test sections at an SPS 7 site similar to that for the GPS sections with the fourth character being 7 for SPS 7 The computer filenames are identical to those used in the GPS testing with the 6 character test section code followed by two characters indicating the times a section has been tested and the number of the pass within the section The times tested character 7 is a single letter which corresponds to the number of times the section has been tested Character A is reserved for BEFORE construction testing on SPS experiments refers to SPS DURING construction testing not used SPS 7 testing all SPS testing use letter C as the first AFTER construction testing and letter D as the first LONG TERM testing The pass character 8 is 0 for TP testing or JO 1 for ML testing 71 or C1 2 for PE testing 72 and J3 or C2 and C3 3 for OWP testing 74 and J5 or C4 and C5 as used in GPS testing For exampl
77. asin tests as well as Load Transfer tests are used in the SPS 4 testing The specific FWD test plan is similar to the JCP Testing Plan for GPS The factors inherent within this test plan are Test Point ID 14 15 and 76 Lane for Each FWD Pass Transverse Location Test Interval Longitudinal Location Test Type Basin and Load Transfer Deflection Sensor Spacing Drop Sequence Load Levels Number of Drops DAP WN I All FWD testing is done in the OWP of the driving lane located 2 5 0 25 0 76 m 0 08 from the edge reference defined for GPS testing testing uses station 0 00 of the test section not the SPS site as the distance reference so FWD test point locations can be located for future testing FWD operators must insure tests are located within the above tolerances FWD operators are not expected to measure the position of each test point but excessive deviations must be avoided The GPS load transfer sensor configuration 127 0 12 18 24 36 and 60 is used for all tests done on the single pass down the section The following list of lane specification codes identifies the type and location of tests performed JCP Category Pavements 74 approach slab tests in the OWP pass 15 leave slab tests in the OWP pass 76 mid panel tests OWP pass Lane Specification J6 uses the load transfer sensor configuration so FWD operators do not have to move the D2 Sensor for each panel
78. avement cross section factors there are three other sets of factors that significantly affect deflections Environmental Factors Pavement Discontinuities and Variability in the Pavement Structure Environmental Factors Temperature and moisture affect deflection response of both flexible pavements asphaltic concrete and rigid pavements Portland Cement Concrete The stiffness rigidity of asphalt concrete AC is very sensitive to temperature changes occurring over both long term seasonal and short term hourly periods As the temperature of the pavement increases the magnitude of deflection from a given impulse load will increase if all other factors remain the same Therefore deflections measured on a hot summer day will be larger than the deflections measured during a cooler period Also changes in temperature with depth vertical temperature gradients influence stresses in the AC layer The influence of vertical temperature gradients becomes more pronounced as the thickness of the AC increases Portland Cement Concrete PCC pavement behavior is affected by temperature in two ways First long term seasonal variations in temperature cause panels to contract during cool periods and expand during warm periods The expansion and contraction of panels influence the width of joints and cracks in the pavement and the degree of mechanical interlock between the panels The deflection response at the joints and cracks is used to
79. ck Openings versiuni Rs ae 27 Synthesis of Field Work Activity 28 Operator Field Assistance 30 II DATA ACQUISITION AND HANDLING 31 d bud 31 Setting up the Software for Data Collection 31 Setting up the FWD Field Program 31 Setting Up FastBack Plus Backup Software 33 Using the Software for Data Collection and Data Backup 43 Data Quality Checks in the FWD Data Collection Software 43 Field Data Collection Program 44 Closing Data File Bw hes eis Be Ye 50 FWD Data and Field Program Backup Procedures 50 Labelling Backup Diskettes for the Deflection Data Files 51 Specifics of FastBack Plus Operation 51 LTPP Manual For FWD Testing Version 2 0 February 1993 TABLE OF CONTENTS Continued Page Miscellaneous Supply Requirements 51 Data Handling at ine owt owes 51 Restonne 3222 8 99 48 ee NE 51 RCO Deflection Data Evaluation 51 PWD CALIBRATION ud oe ee hb Hoe de a a 55 1221 user wie es Bod ade Sane 55 Calibration Requirements 554 Se 5 2 ELA
80. ction and carefully record any abnormal conditions using the F6 Comment key or by making notes on the FWD Field Activity Report B 4 4 LTPP Manual For FWD Testing Version 2 0 February 1993 SNOILO3S 1531 545 1531 SAONVLSIC LN3S3Hd3H NMOHS 5135430 1vu31v1 ALON 5 011935 ONINIVWAY NO SNOILO3S 1V3S NO S I3NVd 11 1531 310 LNAW3AVd MOVHO 3SH3ASNYHL ONIOVdS LNIOF 01412345 NOdN 318VIHVA 13 4 fgg ALOT T 133H 1 TANVd X 6 P IU P I 335 1531 009 00 9 000 TAAVYL dO B 4 5 LYPP Manual For FWD Testing Version 2 0 February 1993 Other FWD Operator Field Measurements Temperature Gradient Measurements Temperature gradient measurements for SPS 4 sites are obtained similar to that for GPS sections with one exception as noted below Temperature measurements are taken as usual for the GPS section i e at each end and at two additional locations for the treatment sections throughout the duration of FWD testing at the site It is up to the FWD operator to
81. ctions are small In the spring as the structure thaws from the surface downward moisture trapped between the surface and subgrade saturate the soils making them very weak and deflections very high FWD operators should recognize that pavement deflections vary on the same pavement section throughout the day and throughout the year from temperature and moisture changes Thus deflection readings taken at different times on a specific pavement section may not be the same Deflection differences are considered normal and do not necessarily indicate equipment problems In fact the sections in the Seasonal Monitoring Study will help define the expected changes in deflection for temperature and moisture changes With the above background on environmental influences FWD operators must insure the success of the LTPP program by making sure the correct local time is recorded on all forms and data sheets for a section especially true for operators in regions spanning more than one time zone 2 making sure air and pavement temperatures automatically recorded by the FWD are reasonable and making sure locations for vertical temperature gradient measurements are in representative areas and temperatures are properly recorded Pavement Discontinuities pavement section with surface discontinuities such as cracks and or joints or subsurface discontinuities such as voids below the pavement will generally have higher deflection 4 LTPP Manu
82. cy of the participating agency Therefore pass P testing included in the SPS 5 and SPS 6 FWD plans will depend entirely on the agency s policy for Test Pit excavation B 9 2 LTPP Manual For FWD Testing Version 2 0 February 1993 Table B 9 1 Required FWD Testing by Pavement Type FWD Testing Required Existing Pavement Type BEFORE LONG TERM Flexible Yes Table B 9 2 FWD Test Plan by Pavement Type SPS FWD Test Plan BEFORE AFTER LONG TERM New Construction or N A 5 5 1 5 5 1 Reconstruction Rehabilitation of Flexible SPS 5 SPS 5 SPS 5 Rehabilitation of Jointed SPS 6 SPS 6 SPS 6 Concrete 1 1 Rehabilitation of SPS 7 SPS 6 SPS 6 Continuously Reinforced 2 2 1 FWD test plan is identical to SPS 6 test plan for sections 3 and 6 2 FWD test plan is similar to SPS 6 test plan for sections 3 and 6 except testing is done at previously tested C1 locations Existing Pavement Type 9 3 LTPP Manual For FWD Testing Version 2 0 February 1993 Table B 9 3 Number of Test Locations and Time Estimates BEFORE LONG TERM Pavement Type PLAN Number Time PLAN Number Time PLAN Number Time of Points Est of Points Est of Points New or N A N A 2 per 3 hrs 22 per 3 hrs Reconstruction section per site section per site Flexible 22 per 3 hrs SPS 5 2 per 3 hrs 5 5 5 22 3 hrs section per si tion per site section site Rehabilitation
83. d Calibration would also be necessary if the load cell fails to pass the unbalanced zero test within 5 percent as detected by the FWDREFCL program Equipment Universal testing machine A Static testing machine hydraulic screw powered with a load capacity of 120 000 pounds or more should be used for the reference load cell calibration Although the reference load cell will only be calibrated to a capacity of 20 000 pounds the higher capacity of the testing machine assures that the test frame will be adequately rigid The testing machine should have several load ranges among them 0 20 000 pound range slightly higher ranges such as 0 24 000 pounds etc would be acceptable Care must be taken to avoid overloading the reference load cell during its calibration Note Do not use a servo controlled closed loop testing system such as a MTS machine for this purpose In general such equipment does not provide the high degree of accuracy that is required for this calibration Bearing blocks special wood aluminum bearing blocks Measurements Group Inc Model 2310 Signal Conditioner This should the same signal conditioner that will be used in the reference calibration procedure A 27 LTPP Manual For FWD Testing Version 2 0 February 1993 Keithley MetraByte DAS 16G data acquisition board installed in the same computer that is used for reference calibration Push button trigger for activati
84. d in the same system of units b The coefficient m determined in step represents the adjustment factor for the calibration factor in the FWD Field Program The new calibration factor is computed by multiplying the former calibration factor by the coefficient m from step A is listed as the new calibration factor on FWDIREFCIL report LTPP Manual For FWD Testing Version 2 0 February 1993 C The standard error of the adjustment factor should be less than 0 0020 If a larger standard error is obtained for any sensor the reference calibration for that sensor should be repeated 2 Enter the new calibration factors for all sensors load and deflection transducers in the FWD Field Program before continuing with the relative calibration The new calibration factor for the FWD load cell is a final calibration factor while the new calibration factors for the deflection sensors are interim factors which will be further refined by doing relative calibration RELATIVE CALIBRATION PROCEDURE General Background Relative calibration of the FWD deflection sensors is used to ensure that all sensors on a given FWD are in calibration with respect to each other As such it serves as the final step in the overall FWD calibration process and as a quick means to periodically verify that the sensors are functioning properly and consistently Relative calibration uses the relative calibration stand supplied by the FWD manufacturer
85. d on the FWD Relative calibration should be performed on the deflection sensors at least once per month It should also be performed immediately after a deflection sensor is replaced PERSONNEL FWD System Operator Calibration System Operator REFERENCE CALIBRATION PROCEDURE Equipment Preparation The FWD should be in good operating condifion prior to performing reference calibration Particular attention should be paid to cleaning the magnetic deflection sensor bases to insure that they seat properly Also verify that the FWD load plate is firmly attached to the load cell In the event that the load plate is loose the lower bolts should be tightened to a torque of 7 5 Ibf ft and set with Locktite before proceeding Note This torque requirement is applicable to the Dynatest FWDs For non Dynatest FWDs consult the manufacturer All electrical connectors should be inspected and if necessary cleaned and firmly seated The FWD should be at room temperature If the FWD has been outdoors at a very low ora very high temperature sufficient time should be allowed for it to equilibrate to room temperature It is recommended that a series of warm up drops be performed immediately prior to beginning calibration to assure that the rubber buffers have been thoroughly warmed up Set the FWD mass and drop heights to produce loads within 10 percent of 6 9 12 and 16 kips 27 40 53 and 71 For the Dynatest FWD it is possible to be withi
86. d the deflection sensor holder The end of the aluminum beam holding the LVDT should be just behind the trailer wheels near the place where the foot of the KUAB A frame rests on the floor KUAB FWDs must have operational program SFWD version 4 0 or higher to perform reference calibrations This version can be obtained from the manufacturer Before the reference calibration procedure is performed the FWD Operator should first conduct a static calibration of the deflection sensors The KUAB software will automatically file the static calibration factors The manufacturer recommends that the dynamic calibration factors be entered as 1 05 for all sensors These values should not be changed during or after the reference calibration Due to the larger distance between the center of the load plate and the seismometer holder it may not be possible to achieve the specified deflection of 16 mils at 16 000 pounds The deflection should be as large as possible To achieve the specified load levels the manufacturer recommends using Load Mode 3 9 9 small buffers 2 stack weights Adjust the drop height endswitches as necessary to be within the load tolerances In general the KUAB will be tested with the 17 millisecond rubber buffers installed The reference data acquisition system and the FWDREFCL software allow for calibration using the 25 millisecond buffers but the movement of the aluminum beam should be checked carefully to assure that there is no
87. dge of the test pad but it is not required nor is it possible that the test pad should deflect uniformly across the entire area of the pad Because the inertial block supporting the aluminum reference beam must be placed adjacent to but not on the calibration test pad the maximum possible distance from the sensor holder to the edge of the test pad will be about five feet Note Fatigue calculations indicate that acceptable fatigue life can be achieved with a 5 inch thick portland cement concrete slab resting on an 8 inch open graded crushed stone base A layer of filter fabric should be placed below the base to protect it from intrusion of subgrade 19 LTPP Manual For FWD Testing Version 2 0 February 1993 fines To achieve adequate deflections the subgrade modulus should be less than 12 000 psi 80 MPa with bedrock deeper than 25 30 feet Where bedrock exists at depths of 15 to 25 feet a subgrade modulus of 7 500 psi 50 Mpa or less will be needed Test pads located where bedrock is less than 15 feet deep are likely to be very sensitive to minor variations in subgrade moisture and hence are not advisable Equipment concrete inertial block 4 000 Ibs 5 foot aluminum reference beam Air Cel low frequency rubber isolation pads for support of the concrete block mounting hardware deflection sensor holder assembly magnetic tip for Schaevitz Model GCD 121 125 0 125 inch stroke DC
88. dges culverts and side hill fills to limit the potential for variability of subgrade soils Unlike other GPS and SPS experiments no TPs are excavated for SPS 1 since a thorough quality control program is performed during construction B 1 1 LTPP Manual For FWD Testing Version 2 0 February 1993 FWD TEST PILAN General FWD testing for SPS 1 is performed during construction labelled as DURING 3 to 6 months after construction labelled as AFTER and annually more than 6 months after construction labelled as LONG TERM The AFTER testing verifies material properties of the as built pavement for evaluating the effectiveness and long term performance of the section LONG TERM testing evaluates the effect of temperature moisture changes and traffic loading on pavement deflections and performance The specific FWD test plan for SPS 1 is similar to the Flex Testing Plan for GPS The factors inherent within this test plan are Test Point ID F1 and F3 Lane for Each FWD Pass Transverse Location Test Interval Longitudinal Location Test Type Basin Deflection Sensor Spacing Drop Sequence Load Levels Number of Drops ey ah All FWD testing is done in the driving lane at two lateral offsets The two lateral offsets are the ML and OWP as defined in the GPS portion of this manual For a given lateral offset a single pass through the test section is made to collect a particular type of deflection data W
89. drilled out for future testing without gumming up or binding the drill bit should be used The following equipment and material are needed for temperature gradient measurements L A hand held battery powered digital temperature meter with resolution to 1 0 05 C over the range O F to 140 F 17 C to 60 C 23 LTPP Manual For FWD Testing Version 2 0 February 1993 SNOIAJO3S LNSNSAVE 549 NI LN3W3UnSV3l YIYO LN3IOVMS 34 804 SNYIALLIVd SNITTIEG IWOIdAL 9 JANDA AINO B3AV dOL AHL OLNI S3 0H 3UnivuszdWMil JJYHL 11190 SNOIAOZS 6 8495 5 51104 QUIHA 3NO AINO 8310 JYNIVYADNAL 11080 1 8 5531 1 5 011035 2 1 49 NI 2294806 OV JI 5 5 9 0 SATOH 177194 1 599 504 JSN 6 90 62 49 ASN 24 LTPP Manual For FWD Testing Version 2 0 February 1993 SHRP REGION STATE CODE SHRP ASSIGNED 10 STATE TESTING DISTRICT LTPP EXPERIMENT CODE ROUTE HIGHWAY NUMBER TEMPERATURE MEASUREMENTS TESTING DATE SHEET NUMBER FIELD SET NO LOCATION STATION NOTES 1 D DEPTH BELOW PAVEMENT SURFACE INCHES 2 T TEMPERATURE AT DEPTH i F 3 0 ONLY FOR GPS 7 IN ACCORDANCE WITH FIGURE 6 OF THE FWD MANUAL 4 USE ONLY THESE WEATHER TERMS SUNNY PARTLY CLOUDY CLOUDY RAIN NIGHT TEST COMPLETED ee FWO OPERATOR MONTH DAY YEAR AFFILIATION FORM 1 55 15 FEBRUARY 1993 FIGURE 7 T
90. e Load Levels Number of Drops FWD testing is done the driving lane at several lateral offsets given lateral offset a single pass through the test section is made to collect a particular type of deflection data When finished with a particular pass the FWD returns to the beginning of the section to start another pass All testing uses station 0 00 of the test section not the SPS site as the distance reference so FWD test point locations can be located for future testing The testing of joint load transfer efficiency for the saw and seal treatment Test Section Number 4 requires additional lane specification codes to properly identify the location of the testing The sawed joints will be tested in the OWP both on the approach and the leave side of the joint The lane specification for the approach side shall be F4 and for the leave side F5 which correspond to the 14 and 5 specifications JCP The following table briefly summarizes the lane specification codes for the FLEX category as modified for SPS 6 rehabilitation treatments B 6 3 LTPP Manual For FWD Testing Version 2 0 February 1993 Table B 6 2 SPS 6 FWD Testing Periods and Appropriate FWD Operational Category j FLEX _ see Note See additional text on modifications FLEX Testing Plan B 6 4 LTPP Manual For FWD Testing Version 2 0 February 1993 FLEX Category Pavements FO basi
91. e files from FWD testing of section 1 at an SPS 7 site in Minnesota would be 270701A0 270701 1 270701A2 and 270701A3 The AFTER testing would have filenames with a in the seventh position while LONG TERM testing would have a D or higher Test Pit reas As in the GPS testing efforts are made to link the material sampling testing program and FWD test results on all SPS 7 sites At each experiment site test pits TP are located approximately 50 15 2m to 60 18 3m from a particular test section This distance varies due to site conditions Due to the length of the project sites test pits are not located adjacent to every test section As a rule a minimum of three test pits are located at every site Each potential test pit location has FWD measurements taken along the OWP pass P This pass is completed for the entire test site prior to testing of pass P on any section There may be occasions where time delays of days or weeks occur between the testing programs and FWD operators must mark the location of the FWD tesis in the TP Test Pit areas Also pass P testing is only performed for the BEFORE time period Test Point Identification FWD operators must properly record all longitudinal distances with the distence measuring instrument relative to 0 00 station reference for each section and follow the guidelines for lateral offset for the PE OWP and ML passes so all FWD testing can be repeated in
92. e LTPP program has approximately 1000 in service pavement sections in the General Pavement Study GPS area and an increasing number of in service pavement sections in the Specific Pavement Study SPS area In addition approximately 64 of the GPS sections are included in the Seasonal Monitoring program Details specific to this program are contained in the SHRP LTPP Seasonal Monitoring Program Data Collection Guidelines for Core Experiment and State Supplements December 1991 Many details of the FWD testing on GPS SPS and Seasonal Monitoring sites are the same and they are discussed in the body of this manual Testing details specific to each of the currently identified SPS experiments are included in the Appendix NORTH CENTRAL 006 ALASKA LTPP Manual For FWD Testing Version 2 0 February 1993 PUERTO RICO SOUTHERN P 008 FIGURE 1 SHRP REGIONS WESTERN LTPP Manual For FWD Testing Version 2 0 February 1993 FWD FIELD TESTING Background Accurate measurement of deflection data with the Falling Weight Deflectometer FWD is a key element in the LTPP monitoring effort Factors other than normal variation in the pavement cross section layer thickness layer material type material quality and subgrade support exist that influence the deflection response of a pavement Each FWD operator needs a general knowledge of these factors so correct and meaningful deflection data is collected In addition to p
93. e Tape Playback switch on the rear panel of the signal conditioner is OFF Position the signal conditioner and the computer several feet apart near the testing machine and attach them to ac line power Computer Preparation Use the same computer system for reference load cell calibration that is used for FWD calibration A graphics printer must be available Load the software LDCELCAL into the reference system computer This program should be located in the same subdirectory with FWDREFCL EXE and FWDREFCL CNF A disk with the files REFLCCAL WK1 and REFLCCAL FMT on it should be inserted in drive A The computer must be running under DOS and not under WINDOWS during the calibration The computer program LDCELCAL is designed to interact with a Lotus 1 2 3 version 2 3 spreadsheet to accomplish the data analysis The subdirectory containing the 1 2 3 program must be on the PATH in order for the two programs to work together successfully The WYSIWYG add in utility should be installed according to the Lotus directions Defaults in Lotus 1 2 3 should be set as follows Default directory Auto execute macros on A 29 LTPP Manual For FWD Testing Version 2 0 February 1993 Auto attach add in 1 C LOTUS WYSIWYG See the Lotus User s Manual for instructions regarding setting the defaults If the program is correctly installed and set up the data analysis will be run a listing of the data will be produced and graphica
94. e is not level 3 Outside Wheel Path 2 5 0 25 0 76m 0 08m for nominal 12 3 6 m wide lanes Note On some sections the OWP may be shifted from this location if the lane is either narrower or wider than normal For these sections the lateral offset for testing may have to be different than the 2 5 For the actual data collection FWD tests are done at one lateral offset for each pass down the test section and one type of deflection data is collected When a pass is complete the FWD returns to the beginning of the section to start on another lateral offset The detailed testing plans later in the manual contain more information on the order of the passes and the type of data collected on each pass FWD test points need to be accurately located so future tests can be done in the same locations For the longitudinal location FWD operators only need to check that the DMI is calibrated functioning properly and accurately referenced to station 0 00 The lateral location will not be measured for any test points however excess deviation from the tolerances provided should be avoided especially for the PE offset As long as these guidelines are followed the general location of any test point can be identified in the field longitudinally within one foot and laterally within less than one foot The test points do not need to be marked on the pavement Information on the spacing of test points the type of deflection tests
95. e on the ML pass two DB tests are done on the PE pass and two LT tests are done on the OWP pass for a total of five test points per panel tested At each test point a sequence of 15 drops is used 3 seating drops at height 3 and 4 drops each at heights 2 3 and 4 14 LTPP Manual For FWD Testing Version 2 0 February 1993 6 LNAWSAVd X314 NV Id 1531 S3ONVLISIG 1 353 43 NMOHS 5135110 1 1 9 130 YAHLYNA 318 1 AAS 616314 30 138 15413 NO 44 SNOILVOOT 1531 GALONGNOD 38 01 8518531 4 ALON 3 LON 744444444 VE 1 OF DE 133HM YHSLNO 09 NOILOAS 1541 009 09 98 009 30 NOILO3HUIQ 00 0 05 0 15 LTPP Manual For FWD Testing Version 2 0 February 1993 xm OWP Outer Wheclpathy a tte 0 8 12 18 24 36 60 2 e ME ovia tamo pe 0 8 12 18 24 36 60 OWP Outer Wheelpath 0 8 12 18 24 36 60 a owe uter wnecipam 0 5 12 18 24 36 60 2 as T ra oe Pavement Category
96. e range of the geophones can also activate the REJECT prompt Operators should examine the data on the screen to determine the cause A appears next to a deflection or load value if the data has failed the variance criteria see Chapter II of this manual and messages for nondecreasing deflections or out of range data are displayed if they occur 47 48 LTPP Manual For FWD Testing Version 2 0 February 1993 For all cases the operator has to decide whether to reject or accept the data If the data is rejected the operator must repeat the test In many cases one load or deflection reading will be the problem and a single repeat test is all that is needed The following guidelines will help decide what to do when the REJECT prompt occurs The normal procedure is to reject the test and re test the location without moving the equipment In many cases the data will meet variation criteria on the second test if it 15 an isolated problem sensor may have been on a small stone and slipped off during the test hydraulics settled if test delayed while mass up truck passing in adjacent lane especially on JCP etc If variation occurs a second time at the location the operator should check for equipment problems Operators should compare changes in deflection at a drop height with changes in load to see if the problem is with the load or a geophone If deflections at a given drop height are very consistent but the load va
97. e the results of the first two trials and enter the average final calibration factors in the FWD computer In the example above after Trial 2 the data marked did not meet this criterion If three trials are performed compute the mean and the standard deviation of the three results for each deflection sensor If the standard deviations based on 1 degrees of freedom are all less than 0 003 enter the average final calibration factors in the FWD computer If any of the standard deviations exceed 0 003 repeat the entire relative calibration test A 25 LTPP Manual For FWD Testing Version 2 0 February 1993 THIS PAGE INTENTIONALLY LEFT BLANK A 26 LTPP Manual For FWD Testing Version 2 0 February 1993 APPENDIX D REFERENCE LOAD CELL CALIBRATION PROCEDURE Introduction The reference load cell is a precision instrument capable of measuring loads within 0 3 percent or better Such a high degree of precision can be attained however only if this calibration procedure is followed exactly It is essential that the reference load cell be calibrated using a universal testing machine that is properly maintained and accurately calibrated Frequency of Calibration Calibration of the reference load cell should be performed at least once per year It should also be performed immediately after any of the six Allen head screws that attach the load measurement links to the upper or lower plates of the reference load cell are loosene
98. ealing test sections and underseal test sections is the same as the JCP Testing Plan for GPS when FWD testing is done alone However for underseal test sections the drop sequence is as follows when testing is done with other equipment for void detection i e Benkelman Beam SPS 4 Loss of Support Testing Plan Drop Sequence Used Only with Other Equipment Present No of Drops Drop Height Data Stored 3 3 3 1 Yes 3 2 Yes 3 3 Yes No data stored seating drop only Deflection and load data is printed but not stored to a file Store deflection peaks only Operators should use the FWD Field Program Main Menu choice 1 to create name and store the SPS 4 FWD test plan setup for use in conjunction with Benkelman Beam for loss of support testing This setup will be similar to that for GPS Operational Category JCP see Figure 10 in main text except as follows B 4 3 LTPP Manual For FWD Testing Version 2 0 February 1993 13 Heights 111222333 14 Test Plots 15 Save Peaks 2 16 Load HiS 2 17 BiS 2354 93 This setup is only used on underseal sections and only when Benkelman Beam testing is done at the same time The reduced drop sequence lets the FWD keep up with the Benkelman Beam Test Pit Areas The SPS 4 experiment has no test pits Therefore pass testing is not performed in SPS 4 Test Point Identification FWD operators must properly r
99. easuring the openings The vernier caliper scale should have a resolution of 0 01 0 2 mm 27 LTPP Manual For FWD Testing Version 2 0 February 1993 On transverse cracks the goal is to measure the opening that extends through the pavement the cracks are spalled the opening may have to be carefully estimated On sawed joints the goal is to measure the sawed opening as opposed to the actual opening through the pavement It may be necessary to depress the joint sealant to measure the opening especially if the joints are spalled JoinUcrack openings should be measured at several points along the opening in the OWP and the average value entered at the condition request prompt immediately following the LT test The measurement is entered as an integer value between 5 and 99 1 e 0 50 is entered as 50 Measurements less than 0 05 are hard to make with a vernier caliper because the caliper jaws will not enter the joint crack When this occurs the operator should enter a 5 in the condition request data field Measurements in excess of 0 99 should be entered as 99 because the condition request data field only accepts two characters For joints cracks tested for load transfer where openings are not measured FWD operators must clear the condition request data field because the last entry in the field repeats until it is changed or the field is cleared Synthesis of Field Work Activity The following list of field
100. ecord longitudinal distances with the distance measuring instrument relative to 04 00 station reference for each section and follow the guidelines for lateral offset for the OWP pass so all FWD testing can be repeated in the same general location Detailed Test Plan Test Sections For SPS 4 test sections the type of FWD testing performed varies between AFTER and LONG TERM testing only if testing is done in conjunction with Benkelman Beam for loss of support testing Deflection testing always consists of a single pass in the OWP Tests are done on each side of the joint and or crack and at the mid slab as shown in Figure B 4 1 using the GPS load transfer test sensor configuration The standard test procedure for joint and crack sealing test sections control sections and state test sections is to test the first joint and the center of the first slab and every third joint and slab thereafter transverse crack within the slabs is also tested For the underseal test sections all slabs in the sections are tested The total number of test points and hence time requirements for SPS 4 sections will depend on the slab size number of cracks present number of supplemental agency sections and whether loss of support testing is done in conjunction with Benkelman Beam Conditions encountered in the field may present unique and unanticipated situations For these situations FWD operators must use their best judgement in slab sele
101. ed after identifying the source of the problem and correcting it FWD Deflection Sensor Calibration Procedure 1 Initialize the computer data acquisition program This would include entry of the operator names FWD serial number FWD deflection sensor serial number and its current calibration factor Clean the spring loaded tip of the LVDT Use non lubricating contact cleaner in a pressurized can to spray cleaner into the bearing sleeve until the tip goes in and out without noticeable friction Check by working the tip in and out The stroke should be smooth without bumps If the LVDT cannot be made to operate smoothly do not continue with the calibration Use the micrometer calibrator to calibrate the LVDT do this the LVDT should first be positioned in the calibrator and set to the null point zero voltage output with the micrometer set to 5 mm The micrometer should then be advanced slightly beyond 7 mm and returned to the 7 mm mark Verify that the MetraByte board reads within 30 bits of 2000 bits If necessary adjust the Gain knob on the 2310 signal conditioner in increments A 7 8 LTPP Manual For FWD Testing Version 2 0 February 1993 of 0 1 for instance from a setting of 1 50 x1 to a setting of 1 40 x1 to achieve the required reading The LVDT voltage output and the micrometer reading 7 mm should be recorded The micrometer should be moved in 0 5 mm increments to a final reading of 3 0 mm with the m
102. eded of any major problems concerning deflection testing equipment Three types of records are required These records should be up to date with one complete set kept in the tow vehicle and another set on file at the RCO The three forms reports required are FWD Field Activity Report Form 202 2 Maintenance Repair Activity Report Form 203 3 Calibration Reports Field Activity Report The FWD Field Activity Report Form 202 see Figure 18 is used by FWD operators to record daily activities for the FWD and tow vehicle On this report the section information data information related to productivity and any conditions affecting deflection data not recorded in the FWD files should be recorded The information required includes travel time and mileage to from a site length of time traffic control was in place number of FWD tests performed any down time and the names and agencies of both Field Sampling amp Testing and Traffic Control personnel 60 LTPP Manual For FWD Testing Version 2 0 February 1993 SHRP REGION STATE CODE SHRP ASSIGNED ID STATE TESTING DISTRICT LTPP EXPERIMENT CODE ROUTE HIGHWAY NUMBER FWD FIELD ACTIVITY REPORT TESTING DATE SHEET NUMBER FIELD SET NO FWD AND TOW VEHICLE BEFORE OPERATION CHECKS initial TIME ODOMETER START TRAVEL TRAVEL READY TO TEST TRAFFIC CONTROL READY BEGIN TESTING END TESTING START TRAVEL END TRAVEL DOWN TIME HOURS REASON S NUMBER OF T
103. effective panels exist Therefore all 20 effective panels are tested For this case the effective panels are defined by a normal joint on one end and a transverse crack on the other end The transverse crack is viewed as a working joint for FWD testing purposes but comments in the field data should identify it as a transverse crack Example 5 A pavement has 50 15 2m uniform joint spacing with transverse cracks near the third points of each original panel As a result the effective panel length is 50 3 16 7 5 1m and about 30 effective panels exist However only 20 of the 30 effective panels are tested For this case the effective panels are defined by 1 normal joint on one end and transverse crack on the other end 2 a transverse crack on both ends The actual effective panels to test must be selected by the FWD operator in the field The FWD operator should not select the first 20 effective panels or the last 20 effective panels Instead approximately seven panels out of every ten should be selected 19 LTPP Manual For FWD Testing Version 2 0 February 1993 The above examples do not cover all JCP conditions that exist and FWD operators must use their best field judgment for selecting and documenting the effective panels tested using the following guidelines 1 Avoid testing effective panels that extend outside the section limits from station 04 00 and 5 090 2 Number effective panels with panel N
104. eflection sensor holder It is important however that the FWD should not come in contact with the beam or any other part of the reference system during the testing Remove the deflection sensors from their holders on the FWD beam and verify that they are free of dirt and grime which would adversely affect their seating in the reference system deflection sensor holder Run the magnetic base over a piece of fine grained emery paper that is placed on a firm flat surface such as the upper flange of the aluminum beam to assure that it is clean 10 LTPP Manual For FWD Testing Version 2 0 February 1993 Place one deflection sensor in the sensor holder and position the LVDT holder so that the LVDT and the FWD sensor are aligned Place a second deflection sensor on top of the LVDT holder so that it will measure the movement of the end of the beam and hence of the LVDT housing Complete the following sequence of drops as shown in Figure 1 for a single test 3 seating drops at height 3 data not recorded followed by a pause 5 drops at height 1 with a pause after each drop 5 drops at height 2 with a pause after each drop 5 drops at height 3 with a pause after each drop 5 drops at height 4 with a pause after each drop except the last Stop after the last drop plate remains down As shown in Figure 1 it is useful to program six drops at each height rather than five so that one can be considered a spare in case a drop is
105. egories 4 FWD Test Plan JCP Pavement 5 3 FWD Test Plan CRCP Pavement Categories 6 Typical Drilling Patterns for Temperature Gradient Data Measurement in GPS Pavement Sections vu v back NOR ee ete ee 7 Temperature Measurement Form 8 Printer and Data Storage Options 9 FLEX Test OX 10 JCP CRCP DB Test Setup 11 EI Test Seng Be 12 Condition Buffers for Asphalt Setup 13 Condition Buffers for PCC Setup 14 Relative Calibration at Height 3 Setup 15 Relative Calibration at Height 4 Setup 16 Reference Calibration for Geophone Setup 17 Reference Calibration for Load Cell Setup 18 Field Activity Report Form 19 Major Maintenance Repair Report Form LIST OF TABLES Table 1 PWD Pest Plan add ec vii viii LTPP Manual For FWD Testing Version 2 0 February 1993 THIS PAGE INTENTIONALLY LEFT BLANK Abstract Non destructive deflection testing with Falling Weight Deflectometers FWDs 1s a critical element of the pavement monitor
106. elines and information for Falling Weight Deflectometer FWD testing at individual test sites for the Long Term Pavement Performance LTPP study experiment SPS 6 Rehabilitation of Jointed Portland Cement Concrete Pavements The intent of this document is to establish the specific testing requirements for SPS 6 sites based on a uniform set of assumptions It is recognized that not all sites will conform to all assumptions contained herein However the objectives and approach to deflection data collection must be consistent so data obtained can be analyzed in a consistent manner For deflection testing details not specifically addressed in the appendix refer to the general guidelines in this manual The objective of the SPS 6 experiment is to investigate the performance of selected rehabilitation treatments for jointed portland cement concrete PCC pavements A variety of rehabilitation techniques can be applied to jointed PCC pavements to restore condition and extend service life The techniques included in this experiment include a combination of types of pavement preparation ranging from minimal treatment to full Concrete Pavement Restoration CPR as well as cracking breaking and seating overlays of different thicknesses are included depending on the type and extent of pavement preparation Characterization of materials and environmental conditions between test sections is required to explain performance differences and provide a basis for
107. ent Studies GPS SPS has controlled construction of multiple test sections at a single site The main SPS 2 experiment has jointed plain concrete with 15 foot joint spacings supplemental experiment SPS 2A has jointed plain concrete using undoweled skewed joints at variable spacings and supplemental experiment SPS 2B has jointed reinforced concrete with 30 foot joint spacings The main SPS 2 experiment has 12 test sections SPS 2A has 6 sections and SPS 2B has 8 sections The supplemental experiments are built in conjunction with the main experiment site and are never constructed as individual projects Therefore SPS 2 projects have a minimum of 12 sections and up to 18 or 26 sections if one or both of the supplemental experiments are constructed Experiment sites should conform to criteria contained in Specific Pavement Studies Guidelines for Nomination and Evaluation of Candidate Projects for Experiment SPS 2 Strategic Study of Structural Factors for Rigid Pavements April 1990 The project characteristic affecting FWD testing is the number of test sections B 2 1 LTPP Manual For FWD Testing Version 2 0 February 1993 LTPP test sections in SPS 2 experiment are tested the same regardless of cross section Location of test sections should avoid cut fill transitions bridges culverts and side hill fills to limit the potential for variability of subgrade soils Unlike other GPS and SPS experiments no Test Pits are excavated for SPS
108. ent so data obtained can be analyzed in a consistent manner For deflection testing details not specifically addressed in this appendix refer to the general guidelines in this manual The objective of the SPS 8 experiment is to measure the deterioration in pavement performance in the absence of heavy traffic loads The proposed experiment encompasses both flexible and rigid pavement structures built on conventional non drained base materials over subgrades of coarse inactive fine grained and active fine grained soils The factors addressed are pavement type layer thickness and subgrade soil type across a factorial of temperature and moisture conditions The analysis of data from this experiment will provide improved design of rigid and flexible pavements for environmental effects Experiment sites should conform to criteria contained in Specific Pavement Studies Guidelines for Nomination and Evaluation of Candidate Projects for Experiment SPS 8 Study of Environmental Effects in the Absence of Heavy Loads August 1991 Project sites may be included as part of new construction or reconstruction of flexible pavements or may be constructed as part of SPS 1 or SPS 2 projects FWD TEST PLAN FWD testing for SPS 8 is performed in two phases AFTER and LONG TERM The AFTER testing 3 to 6 months after construction verifies material properties of the as built pavement section for evaluating the effectiveness and long term performance of the sect
109. eps the RCO informed on the condition of the FWD and tow vehicle Services in this category are engine tune ups tow vehicle brake work drive belts etc Refer to equipment owner s manuals for appropriate service intervals unless instructed to do otherwise Equipment Problems Repairs Regardless of the maintenance program there will be equipment failures and repairs must be done in a timely fashion Repairs are easily handled when no testing is scheduled however if they occur during mobilization or testing adjustments in the schedule will be needed to allow for repairs To minimize the impact of equipment problems FWD operators should notify the RCO immediately and any other agencies necessary Sufficient spare parts should be kept in the tow vehicle to cover anticipated repairs The length of time for repairs must be considered for rescheduling traffic control on future sites Therefore it is essential that maintenance be done in advance of field work in order to minimize rescheduling of traffic control When emergency repairs are performed by an outside agency FWD operators report this information using the MAJOR MAINTENANCE REPORT form as an UNSCHEDULED maintenance activity Circumstances making the work necessary should be included in the report Any repairs by FWD operators should be noted on the FWD FIELD ACTIVITY REPORT for that day regardless of whether the report is for a testing day travel day or just repairs Procedures
110. er testing at individual test sites for the Long Term Pavement Performance LTPP study experiment SPS 2 Strategic Study of Structural Factors for Rigid Pavements The intent of this document is to establish the specific testing requirements for SPS 2 sites based on a uniform set of assumptions It is recognized that not all sites will conform to all assumptions contained herein However the objectives and approach to deflection data collection must be consistent so data obtained can be analyzed in a consistent manner For deflection testing details not specifically addressed in the appendix refer to the general guidelines in this manual The objective of the SPS 2 experiment is to define the relative influence of structural factors affecting performance of rigid pavements The primary structural factors addressed include pavement subsurface drainage base type concrete strength and thickness and lane width Secondary factors addressed in the study include load transfer joint orientation and steel reinforcement The study will determine the influence of environmental conditions and soil type on these factors Results of the study will improve design and construction of new and reconstructed rigid pavements Characterization of materials and environmental conditions between test sections is required to explain performance differences between test sections and provide a basis for improved rigid pavement design In contrast to the LTPP General Pavem
111. f 5 000 to 20 000 pounds per minute Temporarily remove the upper wood aluminum bearing block Set the Auto Balance switch the 2310 signal conditioner to OFF Read and record the unbalanced zero voltage If this voltage is in excess of 5 volts the load cell has been damaged by yielding and it should be returned to the manufacturer for repair LTPP Manual For FWD Testing Version 2 0 February 1993 8 Push down the Auto Balance switch on the signal conditioner to the RESET position and release it to the ON position Adjust the Trim knob until the MetraByte board reads 0 bits 9 Replace and align the upper bearing block rubber pad down Verify that the three guide fingers do not come in contact with the upper bearing block 10 Apply a load of 20 000 pounds and while it is held relatively constant verify that the MetraByte board reads within 30 bits of 2000 bits If necessary adjust the Gain knob on the 2310 signal conditioner in 0 1 increments for example from a setting of 5 50 x100 to 5 40 x100 to achieve the required reading Release the load Record the gain setting Note When the load is released the MetraByte board will not read exactly zero because it was zeroed without the upper bearing block in place Do not rezero the signal conditioner at this point 11 Apply load at rate faster than 1 000 pounds per minute Record the MetraByte board readings at 1 000 pound intervals up to a maximum load of 20 000 pounds
112. g Version 2 0 February 1993 4 NOLIVLITISVH3H 14 SNOILOAS NOIJV TIGVHAY 2 SNOILO3S YOANV1d 1531 29 8 3Hn5lJ Sa3ONVLSIQ TVNINON LN3S3Hd3H NMOHS 85138430 1VH3JV1 41 0 A1SnOlAd3Hd Q31S31 SNOI1V901 LNIOd 1531 HOLVW OL AYVA Z X 61 1 1 LNIOd 1531 310 NOILOAS 1831 009 1 8 dO 0 B 6 9 LYPP Manual For FWD Testing Version 2 0 February 1993 1 NOILYLITISVHSY NOILOAS 304 NV 1d 1931 9 g 914 SaONVASIG 1 598 424 NMONS 95128240 SNOIJAVOO01 TINYd QIN NI 81887 014221130 SS Vg ANIOP G3AVS IY 51581 546 QVO 9029 SSVd m TM HJAVd TIIHMA YILNO 2 E 9 5 RS INV T OIW t di X 111131112311111131111111111111111111333111 1111 1311111111011 0111 20220021 1 2 ff 0 fo 20022302 NOILOSS 1631 008 40 1 B 6 10 LTPP Manual For FWD Testing Version 2 0 February 1993 For the BEFORE testing temperature gradient measurements required at 3 depths Temperature gradient measurements are not required for the DURING construction testing For temperature gradients measured AFTER and LONG TERM either 3
113. goal is to compare the performance of treated sections to untreated sections The impact of a preventive maintenance treatment is based on the process or type of treatment e g a slurry seal Process parameters for material design and construction specification known to work reasonably well in each individual climatic zone were selected The primary factors addressed in the experimental design include moisture and temperature conditions subgrade type and traffic loading The secondary factors include the individual treatments crack sealing chip seal slurry seal and thin overlays Other second level factors include pavement condition at the time the treatment is placed and the structural capacity of the pavement for the traffic loads applied to the pavement FWD TEST PLAN General The LTPP test sections in an SPS 3 experiment are tested the same before and after maintenance regardless of treatment The site characteristic affecting FWD testing is the number of sections 3 1 LTPP Manual For FWD Testing Version 2 0 February 1993 FWD testing is performed 0 to 3 months prior to application of the maintenance treatment labelled as BEFORE 3 to 6 months after application of the maintenance treatment labelled as AFTER not required and biannually more than 6 months after the application of the maintenance treatment labelled as LONG TERM In addition sections should be tested just prior to removal of the section from the e
114. he pavement 73 and two Load Transfer tests one on the approach side of the joint 14 and one on the leave side of the joint 25 For widened lanes two additional Deflection Basin tests are taken one along the approach comer J7 and one midslab at the physical edge of the slab J8 Figures B 2 1 and B 2 2 show the position of the test locations for the 12 and 14 foot lane widths respectively Each test section will have 10 slabs tested for a total of 50 FWD points for 12 foot lanes and 70 for the widened lanes For the main SPS 2 experiment this totals 720 test points At a rate of 20 points per hour the FWD testing will take about 36 hours With about 30 minutes per section for temperature gradient measurements the total time for all tasks will be about 42 hours FWD testing and temperature measurements for SPS 2A would add an additional 360 test points about 21 hours while SPS 2B would add 480 test points about 28 hours FWD operators must use their best field judgement in the slab selection process and carefully note any abnormal conditions or unique situations encountered in the field However only 10 slabs should be tested on a given test section B 2 4 LTPP Manual For FWD Testing Version 2 0 February 1993 SNV T La ONILSSL 1531 12 98 391514 SNOIJO3S NO 31531 13Nvd NJL ALON S3SSVd JJYHL NI 13NVd H3d SLNIOd 1531 BAIS TALON 9
115. hen finished with a particular pass the FWD returns to the beginning of the section start another pass All testing uses station 04 00 of the test section not the SPS project site as the distance reference so FWD test point locations can be located for future testing Naming Scheme Data Storage A unique 6 digit code identifies the individual test sections at an SPS 1 site similar to that for the GPS sections with the fourth character being 1 for SPS 1 The computer filenames are identical to those used in the GPS testing with the 6 character test section code followed by two characters indicating the times a section has been tested and the number of the pass within the section The times tested character 7 is a single letter which corresponds to the number of times the section has been tested Characters A and B are reserved for BEFORE and DURING construction testing on SPS experiments not used in SPS 1 testing all SPS testing uses letter C as the first AFTER construction testing and letter D as the first LONG TERM testing The pass character 8 is 1 for testing and 3 for OWP testing as used for GPS testing For example files from AFTER FWD testing of section 2 at an SPS 1 site in Iowa would be 190102C1 and 190102 3 B 1 2 LTPP Manual For FWD Testing Version 2 0 February 1993 Test Pit Areas The SPS 1 experiment has no test pits Therefore pass testing is not performed in SPS 1 Test Poin
116. hey are in active use Table 2 Relative Calibration Sensor Positions by Set Level ia Sensor Deflection Sensor Number in the Stand Stand Set 1 2 3 4 gt 6 1 1 2 3 4 5 6 7 B 2 3 6 5 6 7 1 3 4 5 6 7 1 2 D 4 5 6 7 1 2 3 5 6 7 1 2 3 4 F 6 7 1 2 3 4 5 G 7 1 2 3 4 5 6 Bottom Note The rotation must be done as prescribed above in order for the software FWDCAL2 to work properly For instance for Set 2 move Sensor 2 to the position formerly occupied by Sensor 1 etc When done in conjunction with reference calibration the relative calibration procedure shall be repeated twice Acceptance criteria based upon the repeatability of the calibration factor are identified in the relative calibration procedure If the results persist in failing the acceptance criteria then the cause of the erratic results should be identified and corrected After the relative calibration is completed the final calibration factors shall be entered into the FWD computer A sample relative calibration setup screen for the Dynatest FWD with version 10 or version 20 software is given in Figure 2 The information in Figure 2 can also be used as the basis for setup of Dynatest FWDs running version 25 and higher software ah 12 13 14 15 16 17 18 19 Q ON AUS WP gt LTPP Manual For FWD Testing Version 2 0 February 1993 Relative Calibration Test UNITS lbf mil inch kPa mu mm Temperature Fahrenheit
117. ibration factors is as follows calculations are done automatically within the FWDCAL2 software 1 Compute the mean deflection measurement x for each sensor average for the seven sets and the overall mean x for all of the sensors averaged together 2 Compute the adjustment ratio R of the overall mean to the sensor mean for each sensor x R lt x Adjustment of Calibration Factors When relative calibration is conducted in conjunction with reference calibration the procedure is repeated two times If the two sets of calibration factors agree within 0 003 for 15 LTPP Manual For FWD Testing Version 2 0 February 1993 each deflection sensor then the results of the two tests shall be averaged If they are outside the limit then a third relative calibration shall be performed If the standard deviation of the three results based on n 1 degrees of freedom 15 less than 0 003 then the three results shall be averaged If the standard deviation exceeds 0 003 the relative calibration procedure should be repeated An example of the calculations following this procedure is shown in Appendix C The average final calibration factors should be computed and the factor for each deflection sensor should be entered into the FWD computer software e g the FWD Field Program When relative calibration is done alone typically on a monthly basis then adjustment of the calibration factors in the FWD Field Program should
118. icrometer reading and LVDT voltage output recorded at each 0 5 mm step Turn the barrel of the micrometer in one direction only to avoid errors due to backlash Analyze the resulting data using a linear regression to determine the coefficient m in the equation m X b where Y is the position of the LVDT tip in microns as measured by the micrometer and X is the corresponding voltage output in bits as read by the computer data acquisition board The FWDREFCL software provides prompts for this entire process reads and records the requisite data and performs the computations The slope m will be approximately 1 00 microns per bit The standard error of the slope should be less than 0 0010 If a larger standard error is obtained the LVDT calibration should be repeated Enter the LVDT calibration results into the computer data acquisition system This is handled automatically by the IFWIDREIFCIL software After the calibration results are entered the signal conditioner gain must not be changed Secure the LVDT in its holder on the reference system aluminum beam so that it is near the null point eg zero voltage output Verify with a spirit level that the LVDT is vertical in its holder If it is not vertical adjust the position of the aluminum beam to attain verticality This may require shimming the beam where it is bolted to the concrete block Position the FWD trailer so that the load plate is as close as possible to the d
119. ill be required by the operator if many variations occur regardless of how much time is available for retests it is more important to test all test points than to do repeat tests at all points with variations If the operator can determine that a pavement condition is causing the variations and not a problem with the equipment it may not be feasible to do more than a couple of repeat tests to verify that the problem or condition is inherent to the pavement structure Some particular pavement conditions that can cause variations include New overlay leveling course or patch compacting under the load plate Uneven surface from rutting patching pavement repair or roll off at the pavement edge PCC sections only causing load variation from uneven contact pressure under the load plate Unstable layer in the pavement structure which is altered by the load applications from the FWD Such layers could be a distressed surface stripped base cement stabilized subgrade saturated granular base or a saturated subgrade For these conditions at least one complete set of three repeat tests should be saved for analysis to determine what effect the repeat testing or conditioning of the pavement has on the results from analysis of the data Accidental Acceptance if a reject test is accidentally accepted the operator must take one of the following steps l If the error is caught before the next test is started or a comment is entered u
120. improved rehabilitation design In contrast to the LTPP General Pavement Studies GPS SPS has controlled construction of multiple test sections at a single site On a SPS 6 site there are 7 test sections and one control section Five of the experimental sections have AC overlays Experiment sites should conform to criteria contained in Specific Pavement Studies Guidelines for Nomination and Evaluation of Candidate Projects for experiment SPS 6 Rehabilitation of Jointed Portland Cement Concrete Pavements November 1989 The site characteristic affecting FWD testing is the number of sections Table B 6 1 lists the LTPP test sections in an SPS 6 experiment site Criteria for selection limit the sites to a single structural cross section constructed of the same materials throughout under the same contract Location of test sections should avoid cut fill transitions bridges culverts and side hill fills to limit the potential for variability of subgrade soils A minimum of three Test Pits are used at a site B 6 1 B 6 2 LYPP Manual For FWD Testing Version 2 0 February 1993 Table B 6 1 SPS 6 Test Section Numbering Scheme AC Overlay Thickness Joints in AC Overlay pri 07 Crack Break and Seat LTPP Manual For FWD Testing Version 2 0 February 1993 FWD TEST PLAN General FWD testing for SPS 6 is performed 0 to 3 months prior to rehabilitation labelled as BEFORE immediately following cracking and seating of
121. ing effort for the Long Term Pavement Performance LTPP test sections of the Strategic Highway Research Program Data obtained through this testing serves as the primary mechanism for assessing structural conditions within each LTPP test section For the LTPP deflection data to serve its intended purpose the deflection testing unit must be conducted consistently with accurately calibrated FWDs This report documents the procedures to be followed in the conduct of the LTPP deflection testing It provides detailed testing programs for deflection testing within each of the LTPP experiments developed to date as well as field quality assurance and data handling guidelines applicable to all deflection testing In addition the SHRP FWD Calibration Protocol presented in Appendix A provides the first generally applicable independent procedure for verifying and refining the calibration of FWDs LTPP Manual For FWD Testing Version 2 0 February 1993 FOREWORD Presently no universally accepted comprehensive standard test procedures for falling weight deflectometer FWD testing exist This manual was developed for use by personnel responsible for collecting deflection data on pavement test sections in the long term pavement performance LTPP study The manual discusses the role of deflection testing in the LTPP Study and provides field operational guidelines for data collection under the following headings 1 Falling Weight Deflectometer Field Test
122. ing is conducted 0 to 3 months prior to overlay construction labelled as B 9 1 LTPP Manual For FWD Testing Version 2 0 February 1993 BEFORE 3 to 6 months after construction labelled as AFTER and annually more than 6 months after construction labelled as LONG TERM Projects constructed as part of new or reconstruction of flexible pavements only AFTER and LONG TERM testing will be performed The BEFORE testing assesses the condition of the existing pavement structure The AFTER testing verifies material properties of the as built pavement section for evaluating the effectiveness and long term performance of the section LONG TERM testing is performed to evaluate the effect of temperature and moisture changes and traffic loading on pavement deflections and performance The pavement types included in an SPS 9 project are summarized in Table B 9 1 along with the required FWD testing Table B 9 2 presents the SPS FWD Plan to use for each pavement type Table B 9 3 summarizes the number of test points and time requirements for each pavement type including the time for the temperature gradient measurements 30 minutes per location Each SPS plan referenced in Table B 9 2 has test locations layouts and other information presented in terms of the time of testing relative to construction of the overlay i e BEFORE AFTER and LONG testing On rehabilitation projects Test Pits may excavated based on the poli
123. ion LONG TERM testing annually more than 6 months after construction is used to evaluate the effect of temperature and moisture changes and traffic loading on pavement deflections and performance B 8 1 LTPP Manual For FWD Testing Version 2 0 February 1993 The pavement types in SPS 8 are flexible asphalt concrete on a granular base and rigid jointed plain concrete on a granular base These pavements are built on the same or separate projects Deflection testing is done according to the FWD test plans developed for the SPS 1 and SPS 2 experiments Table B 8 1 indicates the SPS FWD Plan applicable to testing of each SPS 8 pavement type For SPS 8 test sections the type of FWD testing performed depends on the pavement type and appropriate test plan in Table B 8 1 Table B 8 2 summarizes the number of test points and approximate time requirements for each pavement type including the time for the temperature gradient measurements 30 minutes per location FWD operators must use their best judgement and carefully note any abnormal conditions or unique situations encountered in the field However no more than 22 points on a given flexible section or 50 points on a rigid section are tested 8 2 LTPP Manual For FWD Testing Version 2 0 February 1993 Table B 8 1 FWD Test Plan by Pavement Type Pavement Type LONG TERM SPS 1 Jointed Plain Concrete SPS 2 SPS 2 Table B 8 2 Number of Test Locations and Ti
124. ion data for reasonable and uniform data within the 500 section and also to check that the TP data is representative of the rest of the section The deflection data are entered into the Regional Information Management System RIMS The data in RIMS is periodically forwarded to the National Information Management System NIMS using the edited FWD files collected in the field 53 54 LTPP Manual For FWD Testing Version 2 0 February 1993 THIS PAGE INTENTIONALLY LEFT BLANK LTPP Manual For FWD Testing Version 2 0 February 1993 IV FWD CALIBRATION Background Highly accurate deflection data are required if meaningful estimates of the structural characteristics of a pavement are to be derived from FWD data For this reason periodic calibration of any FWD collecting data for the LTPP study is required The detailed procedures for FWD calibration are provided in Appendix A of this document However these procedures supplement rather than replace the manufacturer s calibration of the FWD measurement systems and are not intended to serve as the basic or initial calibration of the FWD The FWD calibration is a two part procedure The first part referred to as reference or occasionally absolute calibration involves calibration of the FWD load and deflection measurement systems against an independent reference system Within the overall calibration procedure reference calibration ensures that the FWD load and deflectio
125. ion factor for the 300 mm load plate is entered in the same manner The calibration factor for the large 450 mm load plate should remain unchanged Most KUAB FWDs do not have a calibration stand for performing relative calibration Thus it will not be possible to perform the relative calibration procedure as described herein Limited experience in the calibration of KUAB FWDs has shown that the combination of static calibration and dynamic calibration may be adequate to yield a satisfactory calibration and accurate final calibration factors However relative calibration further refines the reference calibration factors and it allows a monthly check of the accuracy of the deflection sensors Thus it is highly recommended that a means of performing relative calibration with the KUAB FWD be developed A 24 Sensor Notes 1 2 LTPP Manual For FWD Testing Version 2 0 February 1993 APPENDIX C SAMPLE COMPUTATION OF FINAL CALIBRATION FACTORS Final Calibration Factors From Relative Calibration Average Final Standard Trial 1 Trial 2 Trial 3 Calibration Factors Deviation 1 014 1 011 1 015 1 013 0 0035 1 010 1 007 1 012 1 010 0 0035 1 012 1 010 1 013 1 011 0 0035 1 016 1 020 1 012 1 016 0 0035 1 017 1 018 1 018 1 018 0 0035 1 008 1 012 1 011 1 010 0 0035 1 012 1 012 1 009 1 011 0 0035 If the results from the first two trials agree within 0 003 for each deflection sensor then it is not necessary to perform a third test Averag
126. ion of this manual does not necessarily indicate approval or endorsement of the findings opinions conclusions or recommendations either inferred or specifically expressed herein by the National Academy of Sciences the United States Government or the American Association of Highway and Transportation Officials or its members LTPP Manual For FWD Testing Version 2 0 February 1993 1 OVERVIEW OF THE LTPP PROGRAM The SHRP Long Term Pavement Performance LTPP study is one of four major technical research areas in the five year 150 million program One of the primary objectives of the LTPP study is to improve prediction models for pavement behavior and pavement performance by collecting and analyzing pavement response and performance data on a broad spectrum of in place pavement sections For data collection and coordination the agencies from the United States and Canada participating in SHRP have been assigned to one of four Regional Coordination Offices RCO Boundaries for the four RCOs are shown in Figure 1 The deflection response of the pavement to an applied load is an important indicator of structural capacity material properties and subsequent pavement performance The LTPP Study uses Falling Weight Deflectometers FWDs to collect deflection data The FWD applies an impulse load and measures deflection response at seven radial distances The impulse load can be adjusted from 1 600 158 to 27 000 lbs 7 KN to 120 kN Th
127. is done or the Shift F8 Exit key to close the last file for the day FWD Data and Field Program Backup Procedures A backup copy of the FWD field program and configuration files should always be kept up to date The field program informs operators when changes need to be saved to the backup disk FWD operators should take a backup copy out of the tow vehicle when they are not with the equipment 50 LTPP Manual For FWD Testing Version 2 0 February 1993 FWD operators also have the responsibility to safeguard the FWD data files by keeping copies of the data in more than one location Without exception all deflection data files must be backed up before leaving the site Three complete backup copies are made using FastBack Plus software The three copies used as follows Copy one is transmitted to the RCO along with the printed copy of the deflection data and a history report from FastBack Plus of the files backed up Copy two and three serve as backups if the copy sent to the RCO is lost or damaged One of these copies must be removed from the tow vehicle whenever the FWD operator is not with the testing equipment Labelling Backup Diskettes for the Deflection Data Files The format to use for the diskette labels is as follows Line 1 where xxxxxx 15 the SHRP six digit section ID Line 2 Volume x of where x is the disk number within the set and is the total number of disks in the set Line 3
128. l output will be printed automatically A demonstration version of LDCELCAL is available to use with Lotus 1 2 3 to verify that your computer system can interact properly with the program Calibration Procedure 1 30 Attach the cable from the signal conditioner to the reference load turn on the signal conditioner and allow the system to warm up for at least 15 minutes Attach the cables connecting the signal conditioner to the computer Attach the push button trigger in the blue terminal box of the MetraByte data acquisition system Turn on the computer and the printer If an hydraulic universal testing machine is used turn the pump on and allow it to warm up for 15 minutes Place a wood aluminum bearing block with no rubber pad in the center of the testing machine platen Place the reference load cell on top of the bearing block with the three steel pads down i e in contact with the top surface of the lower bearing block Place the second bearing bleck on top of the load cell with the cemented rubber pad down i e in contact with the top surface of the load cell Carefully align the edges of the load cell and the two bearing blocks and center the system under the upper loading block of the universal testing machine Set the testing machine on a range equal to or slightly larger than 20 000 pounds Apply a nominal load of 20 000 pounds to the reference load cell three times Apply the load at a rate in the range o
129. laced with the 300 millimeter load plate in order to attain accurate results special holder is provided for mounting the KUAB seismometer under the LVDT The Dynatest geophone holder should be removed and the KUAB holder bolted down in its place The LVDT mounting plate that attaches to the end of the aluminum beam should be removed from its position under the beam and reinstalled on top of the beam The KUAB deflection sensors will be slid upward off the two rods that hold them in position on the sensor beam in the trailer Remove the tripod foot by loosening its holding screw and then slip the deflection sensor over the peg on the holder under the L VDT Tighten the holding screw firmly Conducting load plate calibration is particularly difficult on the KUAB because it is hard to detect when the FWD mass has been released To make this easier a double layer or thicker of duct tape should be wrapped around the guide post down which the runners under the falling mass roll located an inch or two above the botiom of the stroke The proper position for the tape can be found when the mass is at its lowest drop height Adjust the KUAB load sensitivity in the reference system computer to a value of S to 10 bits Remove the tape after completion of the reference calibration Enter the new calibration factors for the deflection sensors as the Calibration Factors under the Calibrate menu in the operational program The calibrat
130. ll three calibration factors shall be discarded and the load cell calibration procedure should be repeated Upon completion of the calibration testing raise the FWD load plate and remove the reference load cell LTPP Manual For FWD Testing Version 2 0 February 1993 The presence of any one or more of the following conditions invalidates the load cell calibration test results Excessive noise messages for drop heights 2 3 or 4 For the low drop height e g the 6000 pound load level there is seldom enough free fall time for the vibration caused by the release of the mass to attenuate before the mass strikes the plate Thus excess noise messages at the low drop height may in general be disregarded The noise due either to electrical noise or mechanical vibrations is of concern only if it results in an erroneous zero value or an erroneous peak reading The time history graphs provided by the FWDREFCL software should be viewed to determine if the noise is of concern before rejecting the calibration Standard deviations for the five readings at any drop height that differ by more than a factor of three between the reference system data set and the FWD data set Standard error of the adjustment factor see Reference Calibration Data Analysis in excess of 0 0020 Failure to satisfy the repeatability criteria for multiple calibration tests Should any of these conditions occur the load cell calibration test procedure must be repeat
131. load magnitude The tolerance range for deflections is set as follows X 0 08 mils 0 01 or 2 microns 0 01X Where average normalized deflection for a geophone for all drops at that height For example if the average normalized deflection for geophone 1 for four drops at drop height 1 is 20 mils 508 microns the allowable normalized deflection range would be 20 0 08 0 01 20 or 19 7 mils to 20 3 mils 508 2 0 01 508 or 501 microns to 515 microns Field Data Collection Program FWD operators must answer several prompts in the FWD Field Program for each pavement section tested These prompts are described below 44 LTPP Manual For FWD Testing Version 2 0 February 1993 Operator ID FWD operators should enter their full name using the format Last Name First Name Middle Initial Cancel automatic time of day recording NO default setting is NO lt rtn gt key use automatic time of day recording to time stamp all deflection data Operators should make sure the internal computer clock calendar is set to the correct local time Use existing file generally NO default NO unless testing was interrupted for some reason and a file was closed and must be opened to finish testing In some cases certain errors that occur during testing will exit the FWD Field Program and return to the operating system In this case the existing file should be opened to continue testing NOTE A sepa
132. me Estimates Pavement Type LONG TERM PLAN Number of Time PLAN Number of Time Points Estimate Points Estimate Flexible SPS 1 22 per 3 hrs SPS 1 22 3 hrs section section section section Jointed Plain SPS 2 50 per 5 hrs per SPS 2 50 5 hrs Concrete section section section section 8 3 LYPP Manual For FWD Testing Version 2 0 February 1993 THIS PAGE INTENTIONALLY LEFT BLANK B 8 4 LTPP Manual For FWD Testing Version 2 0 February 1993 Appendix B 9 FWD TESTING GUIDELINES FOR SPECIFIC PAVEMENT STUDIES SPS EXPERIMENT 9 VALIDATION OF SHRP ASPHALT SPECIFICATIONS AND MIX DESIGN AND INNOVATIONS IN ASPHALT PAVEMENTS INTRODUCTION This appendix provides information for Falling Weight Deflectometer FWD testing at individual test sites for the Long Term Pavement Performance LTPP study experiment SPS 9 Validation of SHRP Asphalt Specifications and Mix Design and Innovations in Asphalt Pavements The intent of this document is to establish the testing requirements for SPS 9 sites based on a uniform set of assumptions It is recognized that not all sites will conform to all assumptions contained herein However the objectives and approach to deflection data collection must be consistent so data obtained can be analyzed in a consistent manner For deflection testing details not specifically addressed in this appendix refer to the general guidelines in this ma
133. minated by a joint at one end and a patch at the other 6 terminated by a joint at one end and a crack at the other 6 terminated by a patch at one end and a crack at the other two or three of each type of effective slab should be tested while attempting to get both types of end conditions in each category above e g 1 or 2 with a joint at the approach end and a patch at the leave end and 1 2 with a patch at the approach end and a joint at the leave end Five FWD tests are performed in each effective slab tested These include a Deflection Basin test in the center of the slab J1 on P a Deflection Basin test along the approach comer 2 and edge of the slab 73 on and two load transfer tests at the joints 34 and JS on B 6 6 LTPP Manual For FWD Testing Version 2 0 February 1993 NOLWLITIGVHAY Ha3ldV S 21 SNOILOAS NOILVLITIGVH3H 438 ONILSAL 1531 V9 8389 914 SAONVLSIG 1VNINON LN3Sa3Hd3H NMOHS 5135440 1VH3JV1 H15N3 NI 000L 3HV 9 SNOI123S 1531 5 011985 714 00011 11V NO STANWd SNOILO3S 414009 NO 031631 GINOHS S I3NVd 01 NAL NOIAVLITISVH3H 314 LON 61831 dO 135 15914 d NO 41 Lid 1531 51531 Psp 3003 LN3W3 vd Y32LNO PPD PARDEE 2 09 NOILOAS 1531 0OS 09 9
134. missed by the reference system instrumentation If the first five drops are successfully recorded then the data for the sixth drop can be discarded The plate should not be raised at any time after the seating drops One complete FWD time history plot should be studied for the fifth drop at each drop height to verify that the calibration beam does not move during the test period The presence of any of the following conditions invalidates the calibration data Movement of the calibration beam as measured by the deflection sensor resting on the top of the beam prior to or simultaneous with the peak deflection reading from the device under test It is entirely possible that there will ultimately be some movement of the beam as the deflection wave passes under the concrete inertial block The important criterion is whether the beam moved prior to the time that the deflection sensor on the ground registered its peak reading Beam movement can be determined by inspection of the FWD time history data files At the moment when the sensor being calibrated shows A 9 LTPP Manual For FWD Testing Version 2 0 February 1993 lis peak reading the sensor on the reference beam should show no more than 0 08 mils 2 microns of displacement Excessive noise messages for drop heights 2 3 or 4 For the low drop height eg the 6000 pound load level there is seldom enough free fall time for the vibration caused by the release of the mass to attenua
135. motion before the ground deflection peaked out The FWDREFCL software contains an number of special features to accommodate the KUAB and thus in initializing the software the FWD type should be set for KUAB The deflection sensor that is mounted through the load plate i e the center sensor is called sensor number zero on the KUAB and it is in position number O as far as FWDREFCL is concerned KUAB FWDs with version 4 0 software are able to pause during the drop sequence prior to releasing the mass This is achieved by entering the letter P after the drop height position code during programming of the drop sequence For example the required reference calibration drop sequence would be entered as follows drop height number of drops 23 LTPP Manual For FWD Testing Version 2 0 February 1993 333 1P 6 2P 6 3P 6 4P The pause occurs with the mass elevated ready to drop The mass will not be released until the FWD operator sirikes a key To repeat the drop sequence without raising the load plate from the ground strike the ESC key twice immediately following the final drop This will interrupt the initial drop sequence allowing a second drop sequence to be started without raising the plate Because the top of the reference load cell is 300 millimeters in diameter it will only be possible to calibrate the small 300 mm load plate on the KUAB If the KUAB is outfitted with the large 450 mm load plate it should be rep
136. mpleting other tasks between changing data disks 33 LTPP Manual For FWD Testing Version 2 0 February 1993 40195 1591 6 88001 5 1581 1885 00 993 22035 6 LSAL 3euaoue 781 wierd I STH STOUM LT er a ee eee 122 44 42 9 S 5 97 AM bM 3691 68 98 ON t t 09 9 ZT 8 Tr FO OX 50 1 80 0 80202 506 8 0 6 330 38enbew puo 8 NO 38enbew duel L 35694 buruoraeas 79 76 330 11 sizp 4 2 SHYOSYD ASSL 7 NO 440 38enbew uas 76 C qour iru zqi
137. mputer Directions for performing reference calibration using this software are provided in the FWDREFCL User s Guide Before doing any calibrations verify that the computers for the FWD and the reference data acquisition system are registering the correct date and time If either is set incorrectly correct it before proceeding A 3 4 2 3 5 5 6 7 8 9 0 1 LTPP Manual For FWD Testing Version 2 0 February 1993 Reference Calibration Test UNITS bf mil inch kPa mu an Temperature Fahrenheit Centigrade Stn Request OFF 0 Test Checks NONE Decreasing defls Roll Off RollOFF lt Decr Reject prompt OFF 01 Stationing Doesn t matter Temp Request OFF ON Cond Request OFF 03 Variation Load NOY Checked 1 Deflections Checked 1 Diameter of Plate 11 8 Deflector distances Doesn t matter Keep that you have 2 Drop 123P4PSP6P7PEPOPOP iP2P3PGPSP P7PBPOPOPTP2PSPGPSP PTS Heights CCCPIPIPIPIPIPIP2P2P2P2P2P2P3P3PSPSPSPSP4P4LP4P4P4P4P 11117170797 Test Plots Save Peaks Load His Load another TEST SETUP Store the CURRENT TEST SETUP Equipment Figure 1 Reference Calibration Test Setup for the Dynatest FWD As described in Appendix A FWD Load Cell Calibration Procedure 4 If the reference load cell has not been calibrated within the last 12 months then it should be recalibrated in accordance with the
138. n ball tight safety chains in place breakaway cable for electric brakes in place tires properly inflated and good condition lights functioning properly brake turn signal battery electrolyte level good and tight clean connections covers and latches good working condition hydraulic oil proper level and viscosity load plate swivel proper lubrication general appearance clean and paint in good condition FWD catch head lubricated weight guide rollers clean and lubricated weight guide shaft clean and dry lubrication raise lower bar cable not frayed properly adjusted and positioned geophone holder bases undamaged free of corrosion and silicon lube on foam guides pressure switches rubber boots in good condition and full of grease transport locks undamaged and functioning properly raise lower bar front guide mechanism undamaged and split pin in place when in transit trailer connection box undamaged and properly latched FWD operators must indicate that the BEFORE OPERATION CHECKS were performed by initialing this item on the FWD FIELD ACTIVITY REPORT Form 202 58 LTPP Manual For FWD Testing Version 2 0 February 1993 Scheduled Major Maintenance Scheduled major maintenance includes much more than routine checks These services require some disassembly of equipment and services typically beyond the skill of FWD operators or RCO staff The MAJOR MAINTENANCE REPAIR REPORT form Form F03 is used to record major repairs and ke
139. n measurement systems are unbiased with respect to independently calibrated reference systems traceable to National Institute of Standards and Technology NIST standards The second part of the calibration procedure referred to as relative calibration involves calibration of the FWD deflection sensors against each other This ensures that all sensors read the same with respect to each other Also relative calibration done on a monthly basis verifies the stability of the FWD deflection measurement system Calibration Requirements As a minimum any FWD collecting data for the LTPP study is required to undergo full calibration including both reference and relative calibration at least once per year This calibration must be done at one of the four calibration centers established by SHRP or equivalent as determined by the LTPP Division staff following the procedures provided in Appendix or subsequent versions of the SHRP FWD Calibration Protocol Full calibration is also required immediately after replacement of a load cell and as soon as possible after replacement of any major components of the FWD such as deflection sensors signal processing modules etc In addition monthly relative calibration of the FWD deflection sensors is required Under no circumstance should the time from the last relative calibration exceed 31 days when using an FWD for collecting data for the LTPP study 55 LTPP Manual For FWD Testing Version 2 0 February
140. n tests at both TP sites Fl all tests in the ML Pj F3 all basin tests in the OWP F4 approach slab LT tests in the OWP F5 leave slab LT tests in the OWP The GPS load transfer sensor configuration 12 0 12 18 24 36 and 60 is used for lane specifications F4 and F5 in pass Ps Naming Scheme Data Storage unique 6 digit code identifies the individual test sections at an SPS 6 site similar to that for the GPS sections with the fourth character being 6 for SPS 6 The computer filenames are identical to those used in the GPS testing with the 6 character test section code followed by two characters indicating the times a section has been tested and the number of the pass within the section The times tested character 7 is a single letter which corresponds to the number of times the section has been tested Characters A and B are reserved for BEFORE and DURING construction testing all SPS testing uses letter C as the first AFTER construction testing and the letter D as the first LONG TERM testing The pass character 8 is 0 for TP testing 1 for ML testing 2 for PE pass corner and mid panel edge testing and 3 or 5 for OWP load transfer testing as used for GPS testing For example files from BEFORE FWD testing of section 1 at an SPS 6 site in Iowa would be 190601A0 190601A1 190601A2 and 190601A3 Files representing data collected DURING construction for sections 7 and 8 only would
141. n this tolerance for the highest load and yet to have the drop height set too high Before placing the reference load cell under the load plate and with the mass positioned at drop height four the highest position verify that there is at least a four inch clearance between the highest point on the mass subassembly and the underside of the brace between the two columns that surround the cylinders that raise and lower the load plate If the clearance is too small reposition the target for the fourth drop height to achieve the required clearance This should assure that there will be adequate clearance when the reference load cell is in position under the load plate 2 LTPP Manual For FWD Testing Version 2 0 February 1993 Before beginning any calibration work and throughout the entire calibration period it is necessary that there be no data filters in operation in the FWD Verify that the peak smoothing processor has been turned off This feature is accessed from the Dynatest Main Menu by selecting Road Options item 3 followed by item 12 where Peak Readings should show direct and not smooth General Procedure The FWD load cell should be calibrated at least twice Multiple calibration tests are performed on the load cell and the results are averaged since it is not possible to perform relative calibration on the load cell Acceptance criteria based upon the repeatability of the calibration factor are identified in the l
142. nditioner excitation and gain must be set exactly to the levels at which the reference load cell was calibrated Complete the following sequence of drops as shown in Figure 1 for a single test 3 seating drops at height 3 data not recorded followed by a pause 5 drops at height 1 with a pause after each drop 5 drops at height 2 with a pause after each drop 5 drops at height 3 with a pause after each drop S drops at height 4 with a pause after each drop except the last Stop after the last drop plate remains down As shown in Figure 1 it is useful to program six drops at each height rather than five so that one can be considered a spare in case a drop is missed by the reference system instrumentation If the first five drops are successfully recorded then the data for the sixth drop can be discarded The piate should not be raised at any time during the sequence Data from both the FWD 1084 and the reference system should be recorded for all drops except the three seating drops Perform the load cell reference calibration twice If the two calibration factors agree within 0 003 then the results of the two tests shall be averaged If they are outside this limit then a third calibration of the load cell shall be performed If the standard deviation of the three results is less than 0 003 based on 1 degrees of freedom then the three results shall be averaged If the standard deviation exceeds 0 003 then a
143. ng the data acquisition system The reference load cell and its cable and the associated signal conditioner data acquisition board and computer should be considered a system of instruments which should be calibrated together and used together Calibration of Equipment The universal testing machine should be calibrated according to ASTM procedure E 74 within twelve months prior to conducting this procedure The device s used to calibrate the universal testing machine should be certified to be traceable to the National Institute for Science and Technology NIST formerly the National Bureau of Standards calibration s The certificate of calibration provided for the universal testing machine should be used to develop an adjustment algorithm which will correct the indicated load on the universal testing machine to the NIST load It is highly recommended that the reference load cell be calibrated soon after the universal testing machine is calibrated The MetraByte board should be calibrated according to the procedure described in the manufacturer s instruction manual Its accuracy should be verified using a reference voltage source such as a 1 350 volt mercury cell eg camera battery in new condition The 2310 signal conditioner amplifier should be balanced according to the procedure described in the manufacturer s instruction manual With the signal input terminals shorted together at gain 100 the ac noise on the 10 volt output termin
144. ng used for all DB tests When LT tests are done the set of sensor spacings shown in Figure 2b is used The only difference between the spacings for the DB test and LT test is that sensor No 2 at 8 203mm for the DB test is moved to 12 305mm for LT test Figure 2b 1 shows the load plate on the approach slab of a joint and Figure 2b 2 shows the load plate on the leave slab of the same joint however the sensor spacing does not change Load Sequence Drop Heights The testing plans for FLEX JCP and CRCP have similar but not identical drop sequences and separate test setups need to be created and stored in the software for the testing plans For the FLEX test plan four drop heights are used with the target load and acceptable load range at each height as follows 1 0 kips 1000 165 FLEX Testing Plan Het Target Load kips Acceptable Range 1 6 0 26 7kN 5 4 to 6 6 24 0kN to 29 4kN 2 9 0 40 8 1 to 9 9 36 0kN to 44 0kN 3 12 0 53 3kN 10 8 to 13 2 48 1kN to 58 7kN 4 16 0 71 1kN 14 4 to 17 6 64 1 to 78 3kN For the JCP and CRCP testing plans three drop heights are used with the target load and acceptable load range at each height as follows LTPP Manual For FWD Testing Version 2 0 February 1993 e a DIRECTION OF MOVEMENT 203 306mm 467mm 610mm 2 4 5 On RO O0 606000000000000 09006 60098 6 0 6 0 9090499000994 000 0 0 0 0 0 0 1 7 TK URE 30905050
145. nt to the section limits for temperature measurements B 7 7 LTPP Manual For FWD Testing Version 2 0 February 1993 SLNSNSAYd 4989 NO NOILVLITISVHSY 4344 ONY 22840438 ONILSAL TIY 1531 GMA 24 834 14 S3S39NVASIO IVNINON LNISSUdSIY NAVOHS 68188420 TVYAIVI TAN dX H3JNSO OL ABVA AVIA 114 1931 ILON 8 011988 11V NO 051854 SEVIS 241493443 SIANYS NIL ONILSSL 23804526 98 NO di Lid 1931 IV 81931 0844 4 M 1 Sz 5 390 2 AVE 79 035 p Hivd 3100 5 UT L 0 9 ee oe INV d 9 1 uum j nummum utitur inni 409 946 1631 008 05 9979 0029 0020 09 0 gt 40 7 8 LTPP Manual For FWD Testing Version 2 0 February 1993 LNAIGVYS JunivHadWil HOd SNYHALIVd ONITIIHG WOldAL S3HNDIS HO 8t 6 ONIOVdS 11144 3LON HO IWYSANIW AE H 21383221 ee ae uelut DONDE LRL DAL
146. nual The objective of the SPS 9 experiment is to compare the performance of asphalt pavements using specifications and mix design procedure developed by the SHRP Asphalt Research group to current participating agency specifications and procedures The primary factors addressed are mix design method and asphalt concrete materials Also the study includes a detailed climatic factorial experiment Accomplishing these objectives will provide improved tools for the design and construction of new and reconstructed flexible pavements and rehabilitation of rigid and flexible pavements using asphalt concrete overlays FWD and laboratory testing will be used to characterize the materials and the variation within and between test sections to provide a basis for comparing the performance of the different sections at a site Experiment sites should conform to criteria contained in Specific Pavement Studies Guidelines for Nomination and Evaluation of Candidate Projects for Experiment SPS 9 Validation of SHRP Asphalt Specification and Mix Design and Innovations in Asphalt Pavements February 1992 Project sites are included as part of new construction on AC and or PCC or reconstruction of flexible pavements or may be constructed as part of the rehabilitation of existing flexible jointed concrete JCP or continuously reinforced CRCP pavements FWD TEST PLAN FWD testing for SPS 9 is performed in multiple phases For project sites on existing pavements test
147. o 1 being the first panel completely in the test section limits at station 0 00 3 Select a maximum of 20 effective panels to test based on the examples given above and conditions in the field 4 Mark the effective panels with chalk or lumber crayon to avoid testing the wrong effective panels 5 Record the panel numbers tested on the Field Activity Sheet discussed later in this manual or document the effective panels tested using a sketch of the section showing joints and cracks and indicate the effective panels tested CRCP Testing Plan Figure 5 and Table 1 summarize the CRCP FWD test plan for GPS Experiment 5 This plan is like the JCP plan with the major exception for the location of the load plate for Test Point ID No C2 For the JCP plan tesi point No J2 is a corner load condition However for the CRCP plan test point No C2 has the load plate centered on the transverse crack defining the beginning of the effec ve panel being tested during the PE pass Effective panels for CRCP are defined by two adjacent transverse cracks typically at a spacing of 1 to 8 0 3m to 2 5m In general the 20 effective panels tested should include stationing at 25 7 6m intervals starting from station 0 00 test effective panels at station 0 00 0 25 0 50 04 75 1 00 1 25 14 50 1 75 2 00 24 25 2 50 2 75 3 00 34 25 3 50 3 75 4 00 44 25 4 50 and 4 75 no test at station 5 09 Any effective panel tested mus
148. oad cell calibration procedure If the results persist in failing the acceptance criteria then the cause of the erratic results should be identified and corrected Each deflection sensor shall be calibrated once Spare deflection sensors do not have to be calibrated until they are in active use After all load and deflection sensors have been calibrated the interim calibration factors shall be entered into the FWD computer before proceeding with relative calibration A sample reference calibration setup screen for the Dynatest FWD with version 10 or version 20 software is given in Figure 1 The information in Figure 1 can also be used as the basis for setup of Dynatest FWDs running version 25 and higher software A complete summary of the data to be recorded is given in Table 1 Before beginning to perform the calibrations FWD specific information should be recorded via printouts from the FWD data acquisition program screens e g showing the deflection sensor serial numbers and calibration factors load cell serial number calibration factor and sensitivity and voltage screens from the Dynatest software which have been annotated with the date and FWD identification information i e FWD model and serial number Locate the calibration data acquisition system as close as possible to the FWD computer so that the two systems operators will be able to converse easily Load the reference calibration software FWDREFCL into the reference system co
149. oads should not be changed Comments should be included in the file using the F6 Comment key 43 LTPP Manual For FWD Testing Version 2 0 February 1993 4 Load Variation checks that the loads at a particular drop height are grouped within a specified tolerance If the condition 15 not met appears next to the load outside the acceptable range A Reject prompt appears at the end of the test sequence and allows the operator to either reject or accept the data See Section 10 under Field Data Collection Program on Rejecting tests The tolerance range for load is set as follows X 40 Ibs 0 02X or X 2 5 kPa 0 02X Where X average load for all drops at that height For example if the average load for four drops at drop height 1 is 6000 Ibs 377 3 kPa the allowable load range would be 6000 40 0 02 6000 or 5840 Ibs to 6160 lbs 377 3 2 5 0 02 377 3 or 367 2 kPa to 387 4 kPa 9 Deflection Variation checks that the normalized deflections for an individual geophone at a particular drop height are grouped within a specified tolerance If the condition is not met a V appears next to the deflection outside the acceptable range A Reject prompt appears at the end of the test sequence and allows the operator to either reject or accept the data Section 10 under Field Data Collection Program on Rejecting tests Normalized deflections are the measured deflections raw data adjusted to a constant
150. ocess is not a part of this study In addition the overall goal is to compare the performance of treated sections to untreated sections The impact of a preventive maintenance treatment is based on the process or type of treatment e g undersealing Process parameters for material design and construction specification known to work reasonably well in each individual climatic zone were selected The primary factors addressed in the experimental design include moisture and temperature conditions subgrade type and traffic loading The secondary factors include the individual treatments crack joint sealing and undersealing Other second level factors include pavement condition at the time the treatment is placed and the type of subbase FWD TEST PLAN General The LTPP test sections in an SPS 4 experiment are tested the same before and after maintenance regardless of treatment The site characteristic affecting FWD testing is the number of sections FWD testing is performed 0 to 3 months prior to application of the maintenance treatment labelled as BEFORE 3 to 6 months after application of the maintenance treatment labelled 4 1 LTPP Manual For FWD Testing Version 2 0 February 1993 as AFTER not required and biannually more than 6 months after the application of the maintenance treatment labelled as LONG TERM In addition sections should be tested just prior to removal of the section from the experiment Deflection B
151. oice 1 to create name and store the SPS 3 FWD test plan setup This setup will be similar to the FLEX Testing Plan for GPS Figure 9 in main text except as follows 13 Heights CCC111222333444 14 Test Plots k 15 Save Peaks Kk kk k ke e kx x x x 16 Load His 17 Whole His ICQ Nu SEMEL Test Pit Areas The SPS 3 experiment has no test pits Therefore pass P testing is not performed in SPS 3 Test Point Identification FWD operators must properly record longitudinal distances with the distance measuring instrument relative to 0 00 station reference for each section and follow the guidelines for lateral offset for the OWP and ML passes so all FWD testing can be repeated in the same general location B 3 3 LTPP Manual For FWD Testing Version 2 0 February 1993 Detailed Test Plan Test Sections For SPS 3 test sections FWD testing procedures do not vary between BEFORE AFTER and LONG TERM testing For all test sections in SPS 3 experiments testing is similar to the FLEX Tes ng Plan for GPS except that the number of tests is reduced The test plan includes 6 FWD tests on each pass down the test section for both the ML pass P and the OWP pass Deflection Basin tests are at 100 foot intervals beginning at station 0 00 and continuing to station 54 00 Figure B 3 1 indicates the test locations for a section Each test section has 12 deflection basin test points fo
152. on techniques can be applied to AC pavements to restore condition and extend service life The techniques included in this experiment include a combination of types and thicknesses of AC overlay using either virgin or recycled AC mixes Another variable examined is the extent of surface preparation Characterization of the materials and their variation between test sections is required to explain performance differences and provide a basis for improved rehabilitation design In contrast to the LTPP General Pavement Studies GPS SPS has controlled construction of multiple test sections at a single site On a SPS 5 site there are 8 test sections and one control section sections have either two or five inch AC overlays using either virgin or recycled AC mixes and either minimum or intensive pre overlay surface preparation Experiment sites should conform to criteria contained in Specific Pavement Studies Guidelines for Nomination and Evaluation of Candidate Projects for experiment SPS 5 Rehabilitation of Asphalt Concrete Pavements November 1989 The site characteristic affecting FWD testing is the number of sections Table B 5 1 lists the LTPP test sections contained in an SPS 5 experiment Criteria for selection limit the sites to a single structural cross section constructed of the same materials throughout under a single contract Location of test sections should avoid cut fill transitions bridges culverts and side hill fills to limit
153. or 5 depths are used depending on whether or not an AC overlay is present For sections with an AC overlay on an unbroken PCC layer sections 3 4 and 6 five depths per section are required For sections 1 2 and 5 three depths per section are used Test sections 7 and 8 the cracked and seated PCC with AC overlay have three depths all in the AC overlay ONLY Figures B 6 4 and B 6 5 illustrate the drilling patterns used for obtaining the temperature gradient data Measurements are obtained at only one location for each section It is up to the FWD operator to assess variations in sun and wind exposure to select the most representative location adjacent to the section limits for temperature measurements Temperature readings are obtained at 30 minute intervals with the first reading prior to Starting FWD testing on a section and the last readings after completion of the FWD testing on the section Joint Crack Widths Joint and crack opening measurements for SPS 6 sites are obtained the same as for GPS sections with one exception as noted below For Test Section 4 AFTER after saw and seal the width of the sealed sawcuts are measured and recorded for 25 of the sawcuts tested for load transfer efficiency B 6 11 LTPP Manual For FWD Testing Version 2 0 February 1993 WING YOU SNYSLIVd WOIdAL 9 8 39193 8 4 SNOILOSS YOJA 8 9 8 39 914 33 ALON
154. periodically during the deflection testing The specific field procedures for temperature gradient measurement are basically the same for all GPS experiments The only exceptions are for 1 GPS sections in Experiments 1 or 2 which use two temperature holes at one third points if the existing AC surface layer is less than 2 51 mm thick 2 GPS Experiment 7 AC PCC which uses five temperature holes per set instead of the three holes per set used on the rest of the GPS experiments and 3 GPS Experiment 9 PCC PCC which uses three temperature holes drilled into the top PCC layer only The steps for temperature gradient measurement are as follows 1 Select one location at each end just outside the test section limits in the OWP typically near station 0 03 5 03 It is up to the FWD operator to make sure the locations are representative of sun exposure and wind conditions for the section The locations selected should never be within the test section limits 22 LTPP Manual For FWD Testing Version 2 0 February 1993 2 Estimate the thickness of all AC and or PCC layers using available information for the pavement structure 3 Determine the number and depth of temperature holes See Figure 6 to determine whether to drill three or five holes at each location and to what depth each hole should be drilled 4 Mark locations for the holes in the OWP There should be at least 18 0 5m between holes 5 Drill 1 2 13mm
155. procedure given in Appendix D Initialize the computer data acquisition program This will include entry of operator names FWD serial number FWD load cell serial number and its current calibration factor Position the FWD so that the load plate is near the center of the calibration test pad or on any other stiff smooth surface Verify that there is no sand or other loose debris under the reference load cell Attach the cable from the signal conditioner data acquisition system to the reference load cell Position the reference load cell beneath the FWD load plate making sure that the three guides are aligned around the plate Zero the LTPP Manual For FWD Testing Version 2 0 Febrvary 1993 Table 1 FWD Calibration Data Reporting Requirements Data Item FWD Operator Name Calibration System Operator Name Date and Time of Calibration FWD Serial ID Number FWD Manufacturer FWD Owner FWD Load Cell Serial Number FWD Deflection Sensor Serial Numbers Reference Load Cell Serial Number Reference LVDT Serial Number FWD Calibration Center Location Current Calibration Factor for FWD Load Cell Current Cal Factors for FWD Deflection Sensors Ref Load Cell Calibration Constants Ref Load Cell Calibration Date Ref LVDT Calibration Constants Ref LVDT Calibration Date FWD Load Cell Readings 20 total Ref Load Cell Readings 20 total FWD Deflection Readings 20 per sensor Ref LVDT Readings 20 per sensor Interim Cal
156. r a total of 36 to 72 test points for a project depending on the number of treatments used Ata rate of 20 points per hour the FWD tes ng will take about 2 to 4 hours With about 30 minutes per section for temperature gradient measurements the total time for all tests should be approximately 4 to 7 hours FWID operators must use their best judgement and carefully note any abnormal conditions or unique situations encountered in the field However only 12 points should be tested on a given section Other FWD Operator Field Measurements lemperature Gradient Measurements Temperature gradient measurements for SPS 3 sites are obtained similar to that for GPS sections with the one exception below Temperature measurements are taken as usual for the GPS section 1 at each end and at two additional locations for the treatment sections throughout the duration of FWD testing at the site It is up to the FWD operator to assess variations in sun exposure and wind conditions to select the most representative location adjacent to the section limits for temperature measurements Crack Widths For any SPS 3 site no crack opening measurements are made however FWD operators must record pavement disiress at test point locations as described in guidelines for GPS testing using the F6 Comment key 3 4 LTPP Manual For FWD Testing Version 2 0 February 1993 SNOILO3S SdS HOA 1531 12 3319143 SHONVLSIC
157. r monitor monochrome not recommended e VGA recommended EGA acceptable Graphics Printer Laser printer recommended dot matrix acceptable but very slow Where both recommended and acceptable options are given in the above specifications an effort has been made in the software development to accommodate both alternatives However since most of the testing has been done on computer hardware meeting the recommended specifications installation of the calibration station will go more smoothly if those specifications are met A demonstration version of the FWDREFCL software is available from the LTPP Division in the Federal Highway Administration located at the Turner Fairbank Highway Research Center McLean VA which can be used to determine if the computer and peripherals will work satisfactorily with the program A 21 LTPP Manual For FWD Testing Version 2 0 February 1993 THIS PAGE INTENTIONALLY LEFT BLANK A 22 LTPP Manual For FWD Testing Version 2 0 February 1993 APPENDIX B SPECIAL PROCEDURES FOR TESTING THE KUAB FWD Reference calibration of the KUAB FWD can be carried out in a manner very similar to the procedure outlined for the Dynatest FWD However because the KUAB has its load plate forward of the deflection sensor beam i e toward the towing vehicle it will be necessary to place the trailer on an angle with respect to the test pad so that the load plate can be positioned as close as possible to the LVDT an
158. radient Measurements Temperature gradient measurements for SPS 1 sites are obtained similar to that for GPS sections with the two exceptions below Measurements are obtained at only one location for each test section It is up to the FWD operator to assess variations in sun exposure and wind conditions to select the most representative location adjacent to the section limits for temperature measurements B 1 3 DIRECTION OF TRAVEL PP Manual For FWD Testing Version 2 0 Feb ruary 1993 FIGURE 11 FWD TEST PLAN FOR SPS 1 SECTIONS LTPP Manual For FWD Testing Version 2 0 February 1993 Temperature readings at SPS 1 sites are obtained at 30 minute intervals with the first readings prior to starting FWD testing on the section and the last readings after completion of the FWD testing the section Crack Widths For any SPS 1 site no crack opening measurements are made however FWD operators must record pavement distress at test point locations as described in guidelines for GPS testing using the F6 Comment key 1 5 B 1 6 LTPP Manual For FWD Testing Version 2 0 February 1993 THIS PAGE INTENTIONALLY LEFT BLANK LTPP Manual For FWD Testing Version 2 0 February 1993 Appendix B 2 FWD TESTING GUIDELINES FOR SPECIFIC PAVEMENT STUDIES SPS EXPERIMENT 2 STRATEGIC STUDY OF STRUCTURAL FACTORS FOR RIGID PAVEMENTS INTRODUCTION This appendix provides guidelines and information specific to Falling Weight Deflectomet
159. rate data file is used for each pass down the test section Roadway ID Enter information using the following format Highway classification and designation direction of lane s distance reference to a large city and state abbreviation Examples IH 94 EASTBOUND LANES 1 2 MILES EAST OF ALBANY MN US 2 EASTBOUND LANE 5 0 MILES WEST OF GRAND RAPIDS MN ST 15 NORTHBOUND LANE 3 0 MILES SOUTH OF LAFEYETTE MN 5 day air temp press lt rtn gt to cancel use of this option Subsection ID enter 6 digit SHRP section ID Starting DMI enter distance in feet for the load plate measured from station 0 00 The FWD load plate must be positioned at the station entered before the key is hit to enter the DMI reading The distance should be entered as follows l At the distance prompt first clear the field using the F1 key Enter which sets the DMI to increase distance as the tow vehicle moves forward 3 Enter the polarity of the station use for station 0 00 4 Enter the distance in feet from station 04 00 without polarity 45 46 LTPP Manual For FWD Testing Version 2 0 February 1993 For example the following key strokes would be used for station 0 50 1 Key 50 NOTE The display on the computer screen for distance should have the next to the 50 If the sign is left justified the station was entered incorrectly and the DMI reading will decrease go more negative as the tow
160. re annotated as necessary to explain any problems which might have been encountered LTPP Manual For FWD Testing Version 2 0 February 1993 THIS PAGE INTENTIONALLY LEFT BLANK LTPP Manual For FWD Testing Version 2 0 February 1993 APPENDIX A REFERENCE CALIBRATION EQUIPMENT AND FACILITIES Facilities Indoor space with easy access for FWD and towing vehicle level floor large enough so that both the FWD trailer and the towing vehicle can sit level during the test and be enclosed indoors 6 reasonably constant temperature between 50 and 100 F and humidity 40 90 percent heated but not necessarily air conditioned good security for calibration equipment Test pad 15 feet by 15 feet with an 8 foot wide clear zone around perimeter for maneuvering FWDs and the reference data acquisition system smooth crack free portland cement concrete surface A modest amount of hairline cracking is permissible Should the test pad develop cracks which are visibly open 1 16 inch or more it should be replaced isolated by impregnated felt bond breaker or sawed and caulked joint from the area where the concrete inertial block supporting the aluminum reference beam will rest slab deflection of at least 16 mils due to 16 000 Ib load at the position of the deflection sensor holder when the FWD is in the specified position for calibration The sensor holder should be located not closer than two feet from the e
161. re local time using a four digit military time format e g use 1615 for 4 15 and 0825 for 8 25 AM The depth of temperature holes are measured and recorded to the nearest 0 1 2 mm Temperatures measured and recorded to the nearest 0 1 F 0 050 In addition to reading the temperature gradients FWD operators should monitor the ambient air temperature and pavement surface temperatures automatically recorded to make sure the values recorded are reasonable i e consistent with actual conditions or compared to hand held meters used for temperature holes 26 LTPP Manual For FWD Testing Version 2 0 February 1993 Pavement Distress The type and severity of pavement distress influence the deflection response for a pavement Therefore FWD operators need to record any distress located from about one foot in front of geophone No 7 to about three feet behind the load plate This information should be recorded in the FWD file using the F6 Comment key in the field program immediately following the test Abbreviations can be used for common distresses and L M and H for L ow M edium and H igh severity 1 e medium severity alligator cracking M ALLIG CR FWD operators should refer to the LTPP Distress Identification Manual for information on distress type and severity When appropriate the location of the distress relative to the geophones or load plate should be recorded Abbreviations to make this easier include OWP
162. ries significantly then the load reading 1s suspect If the loads at a given drop height are very consistent but a sensor has significant deflection variation then that sensor is suspect The following equipment checks should be done Check load cell and geophones electrically using the drift check in the auxiliary menu of the FWD Field Program Very little if any noise should be present Check magnetic coupling of the geophones in the holders Check cables and connections Check that the four targets for the drop heights tight if load variations occur 11 LTPP Manual For FWD Testing Version 2 0 February 1993 If no equipment problems are found or if minor problems are found and corrected the location is tested a third time If the data still fails the variation criteria and it is at crack joint 72 74 75 C2 C4 or C5 lane specification the FWD can not be repositioned and the third test with data variation is saved along with a comment F6 Comment key in the data file If the data 5411 fails the variation criteria and it is a DB test not adjacent to a joint crack F1 F3 71 13 and maybe C1 and C3 depending on the size of the panel raise the load plate move the FWD forward two feet and test the new location This set of data is saved regardless of load or deflection variation However the F6 Comment key should be used if the data failed the variation criteria Field judgement w
163. rlay and the test plan is different Only Deflection Basin tests are performed for test sections 3 6 7 and 8 These are performed in both the pass and pass for each effective slab tested BEFORE rehabilitation The stations for and F3 must correspond to the stations for 71 tests performed BEFORE rehabilitation The testing pattern for these sections is illustrated in Figure B 6 2 No tests are conducted at the PE and no Load Transfer tests are performed Test section 4 has the same Deflection Basin test plan as sections 3 6 7 and 8 In addition Load Transfer tests are performed at the sawed and sealed joint locations corresponding to the J4 and 25 locations in the BEFORE testing The sawed joints must correspond with the slab joints transverse cracks and patches which were used to define the original effective slabs Figure B 6 3 illustrates the testing pattern for this particular test section FWD operators must use their best judgement in the slab selection process and carefully note any abnormal conditions or unique situations encountered in the field However only 10 effective slabs should be tested within a given section except for sections 2 and 5 where 20 slabs are tested Other FWD Operator Field Measurements Temperature Gradient Measurements Temperature gradient measurements for SPS 6 sites are obtained similar to that for GPS sections with three exceptions as noted below B 6 8 LTPP Manual For FWD Testin
164. s EL MR EP pa PM NS S3OTd 3691 vI IIISttCttOOdECECECOOdCCCCEDDdEECEECEODdEECECECEOOdEECEEEODdEEEEEOOO 8S068L9SvdEtZT1068Ld9SPECIOd68L9STPEdZIO6BL9dSPEZIO6d8L9STEZT 6 t 09 9t BT 8 TT B TT JO 5027 8070 0 Z tsd 8670 76 NO 3 78 440 3senbew duej 7 3994 butuotqeqs 79 480 yoeley 6 7220 STJD ANON 8X29U2 3691 F 440 35 76 2 SLINA 3594 LHOH 9 DINV IH xequnu 302125 39 LTPP Manual For FWD Testing Version 2 0 February 1993 LY 4 1 5 NOLLVSSITVO MALLV TIHW 61 80014 80485 1591 993 92035 61 dOLdS 454 zxeua3o0ue peor 8 cece cer eese eher 57 eqQOUM LT i MEE T PLOT 9T 6 SARS SY ae
165. setting the drop distance for the four drop heights 15 as follows l After arriving at a test section and before any test data is collected select a point outside the 500 foot test section and run 64 drops to condition warm up the FWD buffers for ambient temperatures greater than 50 F 10 C or 128 drops for lower temperatures 2 Next adjust the drop heights to obtain loads on the high side of the acceptable range As a general rule the recorded loads decrease during a typical testing day as the temperature of the rubber buffers continue to increase 3 a target load cannot be achieved within the normal range of drop distance for a given drop height on the FWD set the drop distance to obtain a load as close to the target range as possible Under no circumstance will the FWD mass buffer combination be changed to achieve a target load 10 LTPP Manual For FWD Testing Version 2 0 February 1993 4 Obtain loads as close to the 9 kip 40 target load as possible 9 kips represents the load on one set of dual tires for a standard 18 000 lb axle historically used for pavement design purposes 3 After the drop heights are set begin data collection on the section The drop heights are not to be changed after data collection has started on the section even if measured loads go outside the target ranges Drop Sequence The drop sequence drop heights and number of drops for the three testing plans is as follows
166. should be changed in accordance with the calculations If position in the stand is statistically significant it is likely that the stand was not held vertical throughout all of the sets during the test Or a connection in the stand may have been loose The problem should be corrected and the test should be repeated If set is statistically significant there may have been a systematic change in the properties of the pavement materials for instance due to compaction or liquefaction The test should be repeated after the testing site has been further conditioned according to the procedure If the deflection readings do not become relatively constant during the conditioning then another site should be selected for the testing The mere fact that either position or set or both are significant does not necessarily invalidate the relative calibration Judgement must be used to assess whether or not these factors may be of sufficient physical significance as opposed to statistical significance to require that the relative calibration should be repeated or that a new test site should be selected The standard error of measurement e g the square root of the mean square error due to error should be on the order of 0 08 mils 2 microns or less if the system is working properly and the calibration test was conducted carefully The analysis of the data obtained from the relative calibration procedure and the method used to determine revised cal
167. should be forced through zero A 31 LTPP Manual For FWD Testing Version 2 0 February 1993 yielding an equation of the form Y m where Y is the corrected load column C V is the voltage column D and m is the slope of the line of best fit The coefficient m should be approximately 10 pounds per bit Use the regression utility to calculate a fifth degree polynomial regression of the form A V V where the coefficients A are determined by the regression Evaluate the polynomial solution according to the following criteria 1 The standard error of the Y estimate should be less than 50 pounds 2 The standard error of each of the coefficients should be small with respect to the coefficient Generally speaking the coefficient should be at least a factor of ten larger than its standard error For instance if the coefficient A is 0 15 its standard error should be 0 015 or smaller If this is not the case the regression coefficient is not significant If the standard error any of the coefficients is 00 large eg not significant repeat the regression using a fourth degree polynomial of the form Y A V A A V Again evaluate the polynomial according to the criteria in 1 and 2 above When the evaluation criteria are satisfied and all of the coefficients are significant usually this will happen with either a fourth degree polynomial or a third degree polynomial
168. sing the F6 comment key the data set can be deleted using the 49 LTPP Manual For FWD Testing Version 2 0 February 1993 F5 File key and answering Y es to the prompt for Repeat the last test The last data set is erased from the file and the message Previous data set deleted is printed to the hardcopy 2 Mark the data to delete from the file in the left margin on the printout with a RED pen and use the F6 Comment key to include a note in the file that the data was accidentally accepted and should be removed from the data file at the RCO NOTE If data for the test point is deleted in most cases the test point must be retested If the data was deleted because the wrong location was tested then the location does need to be retested 12 Crack joint width measurements crack Joint openings are measured to the nearest 0 01 and recorded in the two character field as hundredths of a inch Example 3 4 inch 0 75 is recorded as 75 If the joint crack opening exceeds 0 99 enter 99 If the joint crack opening is less than 0 05 enter 05 13 _ F6 Comment key use this key to include comments about anything unusual that might affect the deflection data or its interpretation pavement distress data failing variation criteria extreme temperature changes delays in testing etc Closing a Data File The FWD data files must be closed properly at the 2nd of each pass This is done using the F5 File key if additional testing
169. st plan to be implemented for SPS 5 is similar to the FLEX Testing Plan for GPS The factors inherent within each test plan are Test Point ID F10 F1 F3 Lane for Each FWD Pass Transverse Location Test Interval Longitudinal Location Test Type Basin Deflection Sensor Spacing Drop Sequence Load Levels Number of Drops ee Iur All FWD testing is done in the driving lane at two lateral offsets The two lateral offsets are the ML and OWP as defined in the GPS portion of this manual For a given lateral offset a single pass through the test section is made to collect a particular type of deflection data When finished with a particular pass the FWD returns to the beginning of the section to start another pass All testing uses station 04 00 of the test section not the SPS site as the distance reference so FWD test point locations can be located for future testing Naming Scheme Data Storage A unique 6 digit code identifies test sections at an SPS 5 site similar to that for the GPS sections with the fourth character being 5 for SPS 5 The computer filenames are identical to those used in the GPS testing with the 6 character test section code followed by two characters indicating the times a section has been tested and the number of the pass within the section The times tested character 7 is a single letter which corresponds to the number of times the section has been tested Character A is reserved for BEFORE construc
170. t Identification FWD operators must properly record longitudinal distances with the distance measuring instrument relative to 0 00 station reference for each section and follow the guidelines for lateral offset for the OWP and ML passes so all FWD testing can be repeated in the same general location Detailed Test Plan Test Sections For SPS 1 test sections FWD testing procedures do not vary between AFTER and LONG TERM testing AFTER and LONG TERM Testing All sections in SPS 1 are tested similar to the GPS FLEX Testing Plan except that the number of tests is reduced The test plan includes 11 FWD tests on each pass down the test section for both the ML and the OWP Deflection Basin tests begin at station 0 00 and continue to station 5 00 at 50 intervals Tests at ML use the lane specification F1 and tests in the OWP use the lane specification F3 Figure B 1 1 indicates the test locations for a section Each section has 22 test points for a total of 264 test points for a project At a rate of 20 points per hour the FWD testing will take about 13 hours With about 30 minutes per section for temperature gradient measurements the total time for all tasks will be approximately 19 hours FWD operators must use their best judgement and carefully note any abnormal conditions or unique situations encountered in the field However only 22 points should be tested on a given section Other FWD Operator Field Measurements Temperature G
171. t be consistent so data obtained can be analyzed in a consistent manner For deflection testing details not specifically addressed in this appendix refer to the general guidelines in this manual The objectives of the SPS 7 experiment are to measure the additional pavement life from bonded concrete overlays to evaluate the effectiveness of surface preparation techniques prior to overlay and to investigate the environmental influence on the performance of bonded concrete overlays The experiment includes overlays on jointed plain JPCP jointed reinforced and continuously reinforced CRCP concrete pavements The factors addressed in this experiment include surface preparation use of bonding grout and overlay thickness Analysis of data from this experiment will provide improved tools for evaluating the effectiveness of bonded concrete overlays as a rehabilitation technique for existing concrete pavements In contrast to the LTPP General Pavement Studies GPS SPS has controlled construction of multiple test sections at a single site SPS 7 site there are 8 test sections and one control section Four of the test sections have a 3 inch thick concrete overlay and four have a 5 inch overlay Combinations of surface preparation milling or shot blasting and grout or no grout cover the construction factors investigated in this experiment Complete data records starting from construction and multiple test sections constructed on simil
172. t have all five test points for that panel located with reference to the same effective panel no matter how small or large the panel In fact on CRCP pavements it is possible to have all five test points no more than 1 0 3 m apart longitudinally FWD operators must not bias deflection data by deviating from the above stationing in order to test all large panels However in some cases field judgement will shift selection of effective panels from the above stations because transverse cracks may not be fully developed or the effective panel may be wedge shaped and not extend the full width of the 20 LTPP Manual For FWD Testing Version 2 0 February 1993 S3lHOD31VO LNAWAAVd 1531 9 SAONVLSIG TVNINON 1 353 43 NMOHS 5135440 1VH31V1 ALON STWLAG Y 3HLYNA t 335 310N 51831 30 135 185019 94 NO 41 SNOI1VOO1 114 1531 51631 310 21 TY 54 4446 44 PERIL d 444 4 2444444 rov 222 PROG Qe 3NY I QIN ni
173. te before the mass strikes the plate Thus excess noise messages at the low drop height may in general be disregarded The noise due either to electrical noise or mechanical vibrations is of concern only if it results in an erroneous zero value or an erroneous peak reading The time history graphs provided by the IFWIDRIEFCIL software should be viewed to determine if the noise is of concern before rejec ng the calibration Standard deviations for the five readings at any drop height that differ by more than a factor of three between the reference system data set and the FWD data sei Standard error of the adjustment factor see Reference Calibration Data Analysis in excess of 0 0020 Should any of these conditions occur the calibration test for the deflection sensor must be repeated after identifying the source of the problem and correcting it Reference Calibration Data Analysis A 10 Analyze the data as follows calculations are done automatically by the FWDREFCL software a Perform a least squares regression forced through zero for all of the data for each measurement device 1 20 pairs of data per test 5 replicates at each of 4 load levels The result of this regression will be the coefficient for an equation of the form Y m X where Y represenis the response of the reference system X represents the response of the FWD measurement device and m is the slope of the regression line Both X and Y should be measure
174. tent manner For deflection testing details not specifically addressed in the appendix refer to the general guidelines in this manual The objective of the SPS 1 experiment is to define the relative influence of structural factors affecting performance of flexible pavements The primary structural factors addressed include pavement subsurface drainage base type and pavement layer thickness The study will help determine the influence of environmental conditions and soil type on these factors Results of the SPS 1 experiment will improve design and construction of new and reconstructed flexible pavements Characterization of materials and environmental conditions between test sections 15 required to explain performance differences and provide a basis for improved flexible pavement design In contrast to the LTPP General Pavement Studies GPS SPS has controlled construction of multiple test sections at a single site On a SPS 1 site there are 12 test sections Experiment sites should conform to criteria contained in Specific Pavement Studies Guidelines for Nomination and Evaluation of Candidate Projects for Experiment SPS 1 Strategic Study of Structural Factors for Flexible Pavements February 1990 The site characteristic affecting FWD testing 15 the number of test sections LTPP test sections in a SPS 1 experiment are tested the same after construction regardless of cross section Location of test sections should avoid cut fill transitions bri
175. test points two offsets used on FLEX and three on JCP and CRCP In this guide the edge reference is the lane shoulder interface on a normal paving lane usually a 12 foot wide lane and the outside edge of the painted shoulder stripe on a wide paving lane usually 13 fcot wide lane or greater If the outside edge of the painted shoulder stripe is over six inches inside the lane shoulder interface then use the outside edge of the painted shoulder stripe as the edge reference If the lane shoulder interface is inside the painted shoulder stripe the interface should be used as the edge reference The three lateral offsets as measured from the edge reference towards the centerline of the roadway are as follows l Mid Lane ML 6 0 0 5 1 8m 0 15m 2 Pavement Edge PE 0 5 0 25 0 15m 0 08m Note With a 0 5 0 15m radius load plate the load plate will be tangent to the edge reference when the center of the load plate is 0 5 0 15m from the edge and the load plate will be 0 25 0 08m from the edge reference when the center of the load plate is 0 5 0 25 0 15m 0 08m from the edge reference 12 LTPP Manual For FWD Testing Version 2 0 February 1993 Note The center of the load plate should never be less than 0 5 0 15m from the edge reference because this would place part of the load plate outside of the lane being tested Also the load plate and load cell could be damaged if the lane shoulder interfac
176. tested Naming Scheme Data Storage A unique 6 digit code identifies the individual test sections of an SPS 4 project similar to that for the GPS sections with the fourth character being 4 for SPS 4 The computer filenames are identical to those used in the GPS testing with the 6 character test section code followed by two characters indicating the times a section has been tested and the 4 2 LTPP Manual For FWD Testing Version 2 0 February 1993 number of the pass within the section The times tested character 7 is a single letter which corresponds to the number of times the section has been tested Character A is reserved for BEFORE construction testing on SPS experiments B refers to SPS DURING construction testing not used in SPS 4 testing all SPS testing uses letter as the first AFTER construction testing for a section not required in SPS 4 testing and the letter D as the first LONG TERM testing The pass character 8 is OWP testing as used for GPS testing For example computer file from BEFORE FWD testing of section 1 at an SPS 4 site in Iowa would be 19A401A3 When performed the FWD testing AFTER has the filename 19 401 3 test time B is skipped for SPS 4 as there is no testing during construction Files representing data collected for LONG TERM testing will have a D or higher as the seventh character Drop Sequence The drop sequence load levels and number of drops for joint crack s
177. the PCC surface in sections 7 and 8 but before placement of the AC overlay labelled as DURING 3 to 6 months after rehabilitation is completed labelled as AFTER and annually more than 6 months after the completion of rehabilitation labelled as LONG TERM The BEFORE testing is used to characterize the existing pavement structure and provide a baseline for comparison of the various rehabilitation techniques Testing DURING construction is used to characterize the strength of the cracked and seated PCC layer The AFTER testing is directed at verifying material properties and the as built pavement section for use in evaluating the effectiveness and long term performance of the rehabilitations LONG TERM testing is performed to evaluate the effects of temperature moisture changes and traffic loading on pavement deflection and performance Deflection Basin tests and Load Transfer tests are used in the SPS 6 testing The specific FWD test plan to be implemented for SPS 6 is similar to the JCP and FLEX modified Testing Plan for GPS Table B 6 2 contains the FWD Operational Categories corresponding to SPS 6 BEFORE DURING AFTER and LONG TERM testing periods The factors inherent within each test plan are Test Point ID J0 J1 J2 J3 J4 and J5 F1 F3 F4 and F5 Lane for Each FWD Pass Transverse Location Test Interval Longitudinal Location Test Type Basin or Load Transfer Deflection Sensor Spacing Drop Sequenc
178. the four regions by many operators certain guidelines are needed to maintain uniform data collection The guidelines are divided into the following three areas and described in detail Setting up the Software for Data Collection 2 Using the Software for Data Collection and Data Backup 3 Processing FWD and Related Data at the RCO Setting up the Software for Data Collection This section of the manual discusses setting up the software for collecting and backing up deflection data for GPS sections Further details on the FWD Field Program for data collection are located in manuals from the FWD manufacturer Setting up the FWD Field Program When the FWD Field Program is loaded the Main Menu for the program displays the following choices Perform MEASUREMENTS with FWD S N PRINT contents of FWD Data Files Set Printer Disc and Road ID Options Check Deflectors against LVDT Calibrate Install Optional Equipment Temp Sensors DMI EXIT the Program and return to Operating System pee mie The first time the program is run Option 3 should be selected to set printer and data storage options The operator should set each item to the values shown in Figure 8 After all 12 options are set hit the return key to save the changes and display the Main Menu The new settings will be retained until they are manually changed Operators should refer to the equipment operators manual for the FWD for explanation of Main Menu choices 2 6 8 and
179. the panels tested in BEFORE testing may not ever reflect through the overlay Edge tests C3 and deflection basin tests C1 are performed at the same stations as BEFORE Load transfer C4 and C5 and comer tests C2 are performed at the first transverse crack behind the deflection basin test LONG TERM Rehabilitation Testing For all SPS 7 sections the plan for the LONG TERM rehabilitation testing follows the same logic as that for the AFTER rehabilitation testing The same effective slabs are tested as were tested previously Note the location of CRCP test points especially C2 C4 and C5 may change as additional cracks reflect through the overlay FWD operators must use their best judgement in the slab selection process and carefully note any abnormal conditions or unique situations encountered in the field However only 10 effective slabs should be tested on a given section Other FWD Operator Field Measurements Temperature Gradient Measurements Temperature gradient measurements for SPS 7 sites are obtained similar to that for GPS sections with three exceptions as follows For all testing BEFORE AFTER and LONG TERM temperature gradients measured at 3 depths are required as illustrated in Figure B 7 3 Measurements will be obtained at only one location for each section It is up to the FWD operator to assess variations in sun and wind exposures to and select the most representative location adjace
180. the same general location B 7 4 LTPP Manual For FWD Testing Version 2 0 February 1993 Detailed Test Plan Test Pit Areas TP areas are tested identical to the procedures outlined for GPS testing in the main part of this manual Detailed Test Plan Test Sections For SPS 7 test sections the type of FWD testing does not vary between BEFORE and AFTER rehabilitation testing BEFORE Rehabilitation Testing Jointed Pavements For all SPS 7 sections the testing BEFORE rehabilitation is similar to that outlined in the JCP Testing Plan for GPS except the number of tests is reduced The concept of effective slab is as defined previously Figure B 7 1 illustrates the testing pattern for all BEFORE and AFTER testing For all test sections 10 effective slabs are tested The BEFORE and AFTER test plan includes three passes along each section P Mid lane Pavement edge and Pj Outer wheel path preliminary pass P is also made in BEFORE testing to evaluate the test pit locations when appropriate FWD operators must consider the end conditions joints cracks and patches of the effective slabs when selecting slabs to test The proportion of end conditions will determine the slabs tested For example if 24 total effective slabs are present with the following distribution 6 terminated by a joint at one end and a joint at the other 6 terminated by a joint at one end and a patch at the other 6 terminated by
181. tion factors The AFTER testing is directed at verifying material properties and the as built pavement section for use in evaluating the effectiveness and long term performance of the rehabilitations LONG TERM testing is performed to evaluate the effects of the temperature moisture changes and traffic loading on pavement deflections and performance Deflection Basin tests and Load Transfer tests are used in the SPS 7 testing The specific FWD test plan to be implemented is similar to the JCP or CRCP Testing Plan for GPS The factors inherent within the test plan are Test Point ID JO Ji 12 13 14 and 75 C1 C2 C3 and C5 Lane for Each FWD Pass Transverse Location Test Interval Longitudinal Spacing Test Type Basin or Load Transfer Deflection Sensor Spacing Drop Sequence Load Levels Number of Drops ie aT All FWD testing is in the driving lane at three lateral offsets The three lateral offsets are the MIL PE and OWP as defined in the GPS portion of this manual For a given lateral offset a single pass through the test section is made to collect a particular type of deflection data When finished with a particular pass the FWD returns to the beginning of the section to start another pass testing uses station 0 00 of the test section not the SPS site as the distance reference so FWD test point locations can be located for future testing 7 2 LTPP Manual For FWD Testing Version 2 0 Febru
182. tion testing on SPS experiments B refers to SPS DURING construction testing not used in SPS 5 testing all SPS testing uses the letter C as the first AFTER B 5 3 LTPP Manual For FWD Testing Version 2 0 February 1993 construction testing and letter D as the first LONG TERM testing The pass character 8 18 for TP testing 1 for ML testing and 3 for OWP testing as used for the GPS testing For example files from BEFORE FWD testing of section 1 at an SPS 5 site in Iowa would be 190501A0 190301 1 and 190501A3 FWD testing AFTER results in the following files 190501C0 190501C1 and 190501C3 test time is skipped for SPS 5 as there is no during construction testing Files representing data collected for LONG TERM testing will have a 12 or higher as the seventh character lest Pit reas As in the GPS testing efforts are made to link the material sampling testing program and FWD test results on all SPS 5 sites At each SPS 5 experiment site test pits TP are located approximately 50 15 2m to 60 18 3m from a particular test section Due to the length of the SPS 5 sites test pits are not located adjacent to every test section As rule a minimum of three test pits are used at every SPS 5 site Each potential test pit location has FWD measurements taken in the OWP pass Subject to traffic control restrictions this pass is completed for the entire SPS 5 test site prior to testing of pass
183. to run and the drop height sequence are discussed later in the manual under the individual testing plans for FLEX JCP and CRCP Test Pit TP Areas At the TP areas FWD testing and destructive material sampling are run sequentially to the extent possible in order to correlate the results from the two programs At each GPS section TPs for the sampling and testing study are located approximately at station 0 50 and 5 60 For TPs under the FLEX testing plan deflection basin tests should be at station 0 50 and 5 60 regardless of the pavement condition For the JCP testing plan the TP are shifted to mid slab and the new station recorded And for the CRCP testing plan the station for the may have to be shifted slightly to keep the sampling between cracks and the new Station recorded 13 LTPP Manual For FWD Testing Version 2 0 February 1993 Typically a 12 inch diameter core hole is located at station 0 50 in the OWP and a four foot by six foot piece of pavement is removed at station 5 60 Unless informed otherwise by a RCO engineer each GPS section will have FWD measurements in the at these two potential TP areas When possible FWD testing and field sampling are done on the same day However time delays may occur between the testing programs If the field sampling is delayed the FWD operator should mark the FWD test locations in the TP areas The rest of this chapter gives details for TP FLEX JCP and CRCP testing plans
184. touts of the following Dynatest FWD Field Program screens or equivalent for non Dynatest FWDs A 16 LTPP Manual For FWD Testing Version 2 0 February 1993 Transducer Setup and Calibration Factors Voltages Load Cell Calibration Each of the above printouts is to be annotated with the FWD unit identification e g manufacturer s serial number or agency ID and the calibration date All printouts from the FWDREFCL software The final printouts from the FWDCAL2 software for all relative calibration trials The Final Calibration Computation worksheet see Appendix Distribution of this report shall be as follows Original retained by FWD operator for submission to his agency LTPP Regional Engineer for LTPP FWDs One copy transmitted to LTPP Division Office within one week of calibration One copy retained on file by calibration center for a period of at least three years The diskettes on which the reference and relative calibration data are stored should be kept in the FWD It is recommended that labeled backup copies be kept on file with the calibration report at the office out of which the FWD is operated For the LTPP FWDs additional backup copies of the calibration diskettes are to be kept on file at the LTPP Regional Office When relative calibration is done alone e g as a monthly calibration check the relative calibration report will consist of all printouts from the FWDCAL2 softwa
185. ts changes in layer thickness material properties moisture and temperature conditions subgrade support and contact pressure under the load plate These are normal conditions and FWD operators should not be concerned with deflection variations from changes in these conditions Also some variation occurs from the test procedure reduced load from warming of the FWD buffers and changes in placement of deflection sensors relative to the edge of the pavement FWD operators need to minimize these variations by conditioning the buffers prior to testing and by following test procedures in the manual No guideline on acceptable data variation at a test point can cover all potential conditions However variation checks in the software help screen data as it is collected so FWD operators can determine whether data at a test point is acceptable These data checks are discussed in chapter three along with other quality control checks and criteria for accepting and rejecting data No data variation checks are used in the software to detect changes in deflection response over the length of a section because the changes are considered normal and unknown before the data is collected However FWD operators should watch for large changes in deflection and try to identify possible causes and pass such information on to RCO engineers for further LYPP Manual For FWD Testing Version 2 0 February 1993 evaluation Explanatory comments should be entered into the
186. ts so that it can be relocated precisely on the same spot This may be done by gluing a washer to the pavement or by making a small divot in the pavement with a chisel Select the FWD drop height and the distance from the loading plate to the sensor stand to yield deflections on the order of 400 to 600 microns 16 to 24 A 13 LTPP Manual For FWD Testing Version 2 0 February 1993 mils If deflections in this range cannot be achieved then it may be necessary to relocate the FWD to a different pavement In general a concrete pavement on a relatively weak subgrade will yield the required deflection In most cases the reference calibration test pad should be usable for relative calibration 6 Warm up the FWD rubber buffers and condition the test point by repeating a sequence of ten drops until the loads and deflections that are registered are nearly uniform The deflections in a sequence of ten drops should not be showing a steadily increasing or decreasing trend If liquefaction or compaction is indicated by the warm up data relocate the FWD to another pavement 7 Lower the FWD loading plate NOT raise the loading plate or move the FWD during the relative calibration testing This will assure a constant distance between the center of the load plate and the base of the sensor stand 8 For each set make two seating drops no data recorded followed by five replicate drops for which data is recorded while holding the stand in a
187. ve panel tested must have all five test points for that panel located with reference to that same effective panel no matter how small or large the panel On JCP sections the five tests could be from 5 to more than 25 apart longitudinally In summary FWD operators must determine the total number of effective panels in a JCP test section before testing begins In addition the effective panels to be tested maximum of 20 should be marked for easy identification while testing When counting effective panels panel No 1 should be identified as the first panel totally included within the section limits This will prevent negative stationing for any of the 20 effective panels and also provide consistency between operators on panel numbering At station 5 00 any panel extending past station 5 00 should not be selected for testing for three reasons First the panel is not totally within the 500 foot section so it is not protected from material sampling Second temperature holes are located in this location Third conflicts with equipment collecting material samples during the first round of FWD tests will be minimized The following examples of typical JCP joint crack spacings will assist FWD operators in selecting effective panels to test 18 LTPP Manual For FWD Testing Version 2 0 February 1993 Example 1 A pavement has 25 7 6m uniform joint spacing A visual check finds no transverse cracks in the slabs For the 500 152m
188. vehicle moves forward positive direction NOTE Excessive changes in direction can accumulate significant error in the DMI reading and operators should always check the DMI at stations 1 00 2 00 3 00 4 00 and 5 00 Lane specification the entries for this field are two digit codes that include information on the pavement type test type DB or LT test and test point location The codes are listed below according to the FWD testing plans and include the pass number when the data is collected FLEX Testing Plan see Figure 3 FO DB test at the test pits in the OWP DB test from Sta 0 00 to 54 00 in the ML F3 DB test from Sta 0 00 to 5 00 in the OWP P3 JCP Testing Plan see Figure 4 JO DB test at the test pits in the OWP DB test from Sta 0 00 to 5 09 in the ML at the mid panel 2 DB test from Sta 0 00 to 5 00 in the PE at the panel comer 73 DB test from Sta 0 00 to 5 00 in the PE at mid panel P5 74 LT test from Sta 0 00 to 5 00 in the OWP at joints cracks with the load plate on approach slab P J5 LT test from Sta 0 00 to 5 00 in the OWP at joints cracks with load plate on leave slab CRCP Testing Plan see Figure 5 CO DB test at the test pit in the OWP Pg Cl DB test from Sta 0 00 to 5 00 in the ML at mid panel C2 DB test Sta 0 00 5 00 in the PE at with the load plate centered on the crack defining the beginning of the panel 1
189. will take approximately 10 hours This does not include the time for testing Test Pit locations or the temperature gradient measurements The total time for all tasks should be approximately 16 hours FWD operators must use their best judgement in the testing process and carefully note any abnormal conditions or unique situations encountered in the field However only 22 points should be tested on a given section exclusive of test pits located adjacent to the section Other FWD Operator Field Measurements Temperature Gradient Measurements Temperature gradient measurements for SPS 5 sites are obtained similar to that for GPS sections with the three exceptions below Temperature measurements are required at 2 depths at one third points if the existing bituminous surface layer is less than 2 inches thick Otherwise three depths are always used just like normal GPS testing Figure B 5 2 illustrates the drilling patterns to use for temperature gradient data Measurements are obtained at only one location for each SPS 5 section It is up to the FWD operator to assess variations in sun exposure and wind conditions to select the most representative location adjacent to the section limits for temperature measurements Temperature readings are obtained at 30 minute intervals with the first readings prior to starting FWD testing on a section and the last readings after completion of the FWD testing on the section Crack Widths For any SPS 5
190. xperiment The specific FWD test plan to be implemented will be similar to the GPS Operational Category FLEX The factors inherent within this test plan are Test Point ID F1 F3 Lane for Each FWD Pass Transverse Location Test Interval Longitudinal Location Test Type Basin Deflection Sensor Spacing Drop Sequence Load Levels Number of Drops All FWD testing is done in the driving lane at two lateral offsets The two lateral offsets the ML and OWP as defined in the GPS portion of this manual For a given lateral offset a single pass through the test section is made to collect a particular type of deflection data When finished with a particular pass the FWD returns to the beginning of the section to start another pass All testing uses station 0 00 of the test section not the SPS project site as the distance reference so FWD test point locations can be located for future testing Naming Scheme Data Storage A unique 6 digit code identifies the individual test sections of an SPS 3 site similar to that for the GPS sections with the fourth character being 3 for SPS 3 The computer filenames are identical to those used in the GPS testing with the 6 character test section code followed by two characters indicating the times a section has been tested and the number of the pass within the section The times tested character 7 is a single letter which corresponds to the number of times the section has been tested

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