H-4140_-_GeoGauge - M&L Testing Equipment
Contents
1. 1 3 GeoGauge Applications The GeoGauge has an application anywhere there is a need to structurally evaluate a construction material in place Following are some examples _ 354RG Pax B The GeoGauge is better suited for the in place QC of v EM unbound materials than any other available instrument for Kab n place estimates of Resilient Modulus 1v Modulus measurements that relate well to relative Relating Stiffness To Modulus compaction Figure 4 Identifying structural anomalies Quantifying strength gain with time Obtaining precise measurements This is based on the findings of the Transportation Research Board s National Cooperative Research Program Project 10 65 The GeoGauge can be used in the QC of compacted subgrades and bases The QC method utilizes a control strip and initially established target stiffness values that are related to conventional relative compaction Ultimately target stiffness values are related to design values and expected values based on experience e g Resilient Modulus Appendix 1 is a case study of such a QC method The GeoGauge can be used in the QC of stabilized materials The QC method can determine how soon a material can bear construction loads determine the ultimate strength from measurements at the time of installation or assure structural uniformity of the material Appendix 2 is a case study of such a QC method on a cement treated bases Ap2. Pressing the SHIFT and then the MEAS buttons again will allow adjustment of the minute Scroll to the correct minute Pressing the SHIFT and then the MEAS buttons again will allow adjustment of the month Scroll to the correct month Repeat for day and then year Continuing the adjustments will rotate back to hour then minute then month then day then year At anytime you are satisfied with the settings press the SAVE button and then press the OFF button to get out of the clock adjustment mode Press ON to turn on unit for measurements Copyright 1999 2000 amp 2007 Humboldt Mfg Co Norridge IL 60706 U S A All rights reserved Printed in U S A GeoGauge User Guide Version 4 1 June 2007 Appendix 1 Stiffness Based Compaction QC Method Copyright 1999 2000 amp 2007 Humboldt Mfg Co Norridge IL 60706 U S A All rights reserved Printed in U S A Rev 1 15 06 Traditional subgrade compaction QC test methods do not evaluate in place material strength or the structural uniformity of each lift as placed Evaluating these two factors is essential if cost is to be held to a minimum while assuring the performance needed for the roadways intended function and projected life This type of evaluation is essential if the industry s trend towards modulus based mechanistic design and performance specifications for roadways are to be supported Also traditional methods do n
3. Log Main Line NBL_ 2 to 131 44 0 T j T Log Main Line_ SBL_ 8 to 133 97 0 2 4 6 8 10 12 ae 18 086 Log loop D Sec E _ Interchange R 0 0071 Day After Installation Humboldt Mfg Co 7300 West Agatite Ave Norridge IL 60706 U S A HUMBOLDT 708 456 6300 voice hmc humboldtmfg com email Figure 3 55 u 2 Ps a E 3 2 4 5 6 7 Day After Installation Humboldt Mfg Co 7300 West Agatite Ave Norridge IL 60706 U S A HUMBOLDT 708 456 6300 voice hmc humboldtmfg com email Table 1 Das 1 2 3 4 5 6 7 8 9 4 e Data Pois L 108 L 2 83 Average Modulus kpsi 165 183 188 202 193 216 214 224 226 22 Standard Deviation kpsi 25 34 52 29 45 39 40 33 29 36 COV 179 189 128 168 emen ns es ua a me es r ws 4 RN 44 Ag kgs ep 3 Average Modulus ksi Location Station Source File Date Avg Temp F 1 2 3 4 5 6 7 8 9 10 11 10 16 to 17 70 tsg01_VA288 10 24 to 10 29 43 8 20 1 30 8 NM 44 NM44 16 9 19 6 23 7 10 97 to 15 30 Ramp A_ Sec
4. Many current methods of measuring material modulus or lift stiffness in the field require large forces to produce a measurable deflection The GeoGauge uses technology borrowed from the military to measure very small deflections allowing much smaller loads The GeoGauge does not measure the deflection resulting from the GeoGauge weight Rather the GeoGauge vibrates producing small changes in force that produce small deflections The material deflects amount which is proportional to the outside radius of the ring foot R the Young s modulus E the shear modulus G and Poisson s ratio v of the soil The stiffness is the ratio of the force to displacement 8 The 1 Poulos H G and Davis E H Elastic Solutions For Soil amp Rock Mechanics 1974 page 167 168 Copyright 1999 2000 amp 2007 Humboldt Mfg Co Norridge IL 60706 U S A All rights reserved Printed in U S A GeoGauge User Guide 5 Version 4 1 June 2007 GeoGauge produces soil stress and strain levels common for pavement bedding and foundation applications 27 58 kPa or 4 psi Young s and shear modulus can be determined from GeoGauge measurements if a Poisson s ratio is assumed Fig 4 P GeoGauge measurements intentionally mimic Resilient Modulus measurements as much as typical site conditions _2 _ 26 will allow This allows GeoGauge measurements to 1 l v related to Resilient Modulus K
5. Humboldt Scientific Inc 551D Pylon Dr Raleigh NC 27606 U S A Voice 919 832 6509 Fax 919 833 5283 Email mahir ehumboldt com Copyright 1999 2006 Humboldt Mfg Co Norridge IL 60706 U S A All rights reserved Printed in U S A GeoGauge User Guide Version 4 1 June 2007 Appendix 5 GeoGauge Data Download Guide Copyright 1999 2000 amp 2007 Humboldt Mfg Co Norridge IL 60706 U S A All rights reserved Printed in U S A Humboldt GeoGauge Data Download Guide Version 2 0 March 2007 Page 1 of 1 Humboldt GeoGauge Data Download Guide For use with C series Humboldt GeoGauge Purpose To download data from the C series Humboldt H 4140 GeoGauge to a PC Equipment Required H 4140 12 Infrared Interface to serial port cable USB to serial port adapter optional Any PC running any version of Windows with HyperTerminal Operation Initial Setup 1 Attach the GeoGauge Infrared Interface Cable to a 9 pin serial port on the personal computer PC or to a USB port via an appropriate adapter Figures 1 2 amp 3 2 Attach the GeoGauge Infrared Interface Cable reader head to the slotted retainer on the top of the GeoGauge Be sure that the two infrared windows line up Figure 4 3 Turn on GeoGauge and PC 4 On the PC monitor click Start highlight Accessories click Communications and click HyperTerminal HyperTerminal is the Windows terminal emulation program 5 Enter a di
6. Stiffness vs Density Avg 1 495 Wilson Bridge 7 15 03 A 2 4 Material Maryland State Highway Administration Avg Stiffness kib in Pass Number Humboldt GeoGauge Avg Dry Density Humboldt Mfg Co 7300 West Agatite Ave Norridge IL 60706 U S A 708 456 6300 voice hmc humboldtmfg com email HUMBOLDT at the start of the project a stiffness value of 23 klb in was assigned as a target corresponding to the specified 90 compaction Moisture was measured approximately every 500 ft by either time domain reflectometry or field oven Density was measured randomly as a check on the method took precedence in judging quality if there was a conflict with stiffness The over 1 000 stiffness QC tests made on the TH200 project indicated that the level of compaction was from 87 to 97 18 2 klb in to 32 2 klb in for 95 of the data This was better than the best quality traditionally possible for the material in District 2 s experience Moisture content was typically 3 5 below optimum varying from about 6 to 12 This was consistent with the best quality traditionally possible The level of material compliance with the specification and small variability in the quality of compaction was unprecedented in the experience of MnDOT District 2 The real time nature of the stiffness QC tests forced the continuous attention of the contractor to compaction quality as was evident by the section
7. streaming onto the screen immediately The data should look like the example in Figure 4 When the data stops streaming click Transfer highlight Capture Text and click Stop Click Call Click Disconnect Click File Click Save Confirm that the data was saved by opening the csv file in Microsoft Excel Close HyperTerminal Figure 5 is an example of what a typical csv file show look like Press the Shift key and then the Erase key on the GeoGauge This will permanently erase the data just downloaded Repeat 2 through 8 each time data is downloaded The csv files can be cut amp pasted into an Excel spreadsheet Humboldt supplies Excel templates for various uses with these files Contact Humboldt for further information or for help in developing a custom spreadsheet Contact Mahir Al Nadaf Humboldt Scientific Inc 551D Pylon Dr Raleigh NC 27606 U S A Voice 919 832 6509 Fax 919 833 5283 Email mahir ehumboldt com Copyright 1999 2007 Humboldt Mfg Co Norridge IL 60706 U S A All rights reserved Printed in U S A Humboldt GeoGauge Data Download Guide Version 2 0 March 2007 Page 3 of 3 Figure 1 H 4140 12 Infrared Interface To Serial Port Cable Figure 2 Typical Serial To USB Adapter Figure 3 GeoGauge Connected To A PC Copyright 1999 2007 Humboldt Mfg Co Norridge IL 60706 U S A All rights reserved Printed in U S A Humboldt GeoGauge
8. 4 35 2 19 172 2048 2048 2048 2048 2406 3087 1952 1702 0 0 25 3 34 7 20 176 2048 2048 2048 2048 2381 3101 1927 1627 0 0 24 9 35 0 21 180 2048 2048 2049 2048 2360 3079 1908 1533 0 0 50 7 35 1 22 184 2048 2048 2049 2048 2335 3049 1893 1474 0 0 50 3 35 1 23 188 2048 2048 2048 2048 2312 3018 1880 1383 0 0 23 8 35 3 24 192 2048 2048 2048 2048 2290 3002 1870 1340 0 0 23 4 35 4 25 196 2048 2048 2048 2048 2269 2947 1861 1269 0 0 23 1 35 4 Data Used To Calculate The Real amp Imaginary Portions Of Force amp Deflection At Each Frequency contact Humboldt for further details Frequency Number 100 to 196 Hz in 4 Hz Increments Figure 5 Typical csv File First 20 Runs Records Will Have All The Data Shown Run 21 amp Higher Will Have Only The First Row In Each Record Copyright 1999 2007 Humboldt Mfg Co Norridge IL 60706 U S A All rights reserved Printed in U S A
9. A corresponding reduction in roadway maintenance cost was also observed Texas A amp M s results prompted the City of Bryan Texas to specify the construction method 20012 As shown in the figure to the right the QC test data followed the results achieved in the Texas A amp M study The City of Bryan has successfully used the method through the 2005 season The City of College Station Texas followed suit shortly after College Station adopting the City of Bryan s specification for continuous use During 2004 CEMEX the second largest supplier of cement products in North America began to promote the use of the micro cracking construction method in southern California This prompted the adoption and successful use of the Bryan Texas specification by the Cities of La Quinta and Santa Rosa California in 2005 As shown in the figures to the right the QC test data is very similar to that achieved in Texas 3 years earlier The construction method apparently affords consistent results job to job even with the expected variabilities in materials and construction CEMEX has also secured commitments from several other southern California cities to use the method In 2006 CEMEX will expand its promotion of this construction method to include all of the southwestern United States and Mexico During 2005 the Montana Department of Transportation judged the benefits sufficient to adopt the Bryan Texas specification for use during the 2006
10. Data Download Guide Version 2 0 March 2007 Page 4 of 4 Figure 4 Proper Orientation of Infrared Sensor on GeoGauge Sequential Run Number Assigned By GeoGauge When Data Is Saved Average Stiffness As Displayed By The GeoGauge Date Stamp Assigned By GeoGauge When Data Is Saved Time Stamp Assigned By GeoGauge When Data Is Saved Run as 9 19 WalFac 4 3564 Date C7 01 025 Time 1 100 2047 2048 2048 2048 2062 2085 2633 2598 0 0 55 3 28 7 2 104 2048 2048 2048 2048 2141 2167 2620 2633 0 0 29 129 4 3 108 2048 2048 2048 2048 2212 2255 2597 2655 0 0 29 0 30 0 4 112 2048 2048 2048 2049 2276 2348 2565 2665 0 0 28 956 7 5 116 2048 2049 2048 2048 2332 2440 2526 2662 0 0 28 8 57 2 6 120 2048 2049 2048 2048 2380 2534 2482 2647 0 0 28 6 57 7 7 124 2048 2048 2048 2048 2417 2627 2436 2620 0 0 28 4321 8 128 2048 2048 2048 2048 2449 2716 2389 2579 0 0 28 3 32 5 9 132 2048 2048 2048 2048 2472 2797 2335 2523 0 0 28 1 32 8 10 136 2048 2048 2048 2048 2482 2863 2287 2469 0 0 27 833 1 11 140 2048 2048 2048 2048 2490 2929 2238 2402 0 0 27 5 33 4 12 144 2048 2048 2048 2048 2492 2987 2191 2328 0 0 27 2 33 7 13 148 2048 2048 2049 2048 2488 3036 2148 2248 0 0 53 1 33 9 14 152 2048 2048 2048 2048 2479 3076 2107 2164 0 0 26 6 34 2 15 156 2048 2048 2048 2048 2468 3107 2069 2076 0 0 26 3 34 4 16 160 2048 2048 2048 2048 2453 3131 2035 1986 0 0 26 0 34 6 17 164 2048 2048 2048 2048 2434 3151 2004 1890 0 0 25 7 34 8 18 168 2048 2048 2049 2048 2414 3170 1984 1755 0 0 51
11. Jeff Wykoff Manager of Business Development CEMEX 909 238 8350 jefferyp wykoff cemexusa com 2 Outline Specifications For Section 100 Portland Cement Treated Base Plant Mix City of Bryan TX Rick Conlin CME Testing amp Engineering College Station TX 77840 HUMBOLDT Humboldt Mfg Co 7300Agatite Ave Norridge IL 60706 U S A 708 456 6300 voice hmc humboldtmfg com email No Change in Structural Uniformity GeoGauge User Guide Version 4 1 June 2007 Appendix 3 Stiffness Based QC Method Used On A Stabilized Subgrade Copyright 1999 2000 amp 2007 Humboldt Mfg Co Norridge IL 60706 U S A All rights reserved Printed in U S A VIRGINIA ROUTE 288 LIME STABILIZED SUBGRADE DATA ANALYSIS SUMMARY FEBRUARY 2003 PREPARED FOR KOCH PERFORMANCE ROADS INC 4111 EAST 37TH STREET NORTH WICHITA KANSAS 67220 PREPARED By HUMBOLDT 7300 WEST AGATITE AVE NORRIDGE IL 60706 U S A 708 456 6300 VOICE HMC HUMBOLDTMFG COM EMAIL The following represents a effort by Koch Performance Roads to quantify the performance of approximately 50 miles of lime stabilized silty clay 12 thick subgrade which was part to the Koch managed reconstruction of Virginia VA Route 288 As with similar jobs managed by Koch e g NM 44 the traditional 7 day waiting period between subgrade installation and resumption of construction was inconsistent with Koch s aggressive constru
12. Mfg Co Norridge IL 60706 U S A All rights reserved Printed in U S A Rev 1 15 06 For decades cement amending a roadway base has been a way of employing economical local materials in place of imported high cost aggregate These bases have the strength and low water permeability to potentially out perform flexible aggregate bases Unfortunately cement amended bases are prone to significant shrinkage cracking that concentrate and reflect traffic stress resulting in premature pavement cracking sufficient to warrant repair or rehabilitation Consequently cement amended bases seen limited use over the last twenty years A simple and economical construction method has been developed in Europe and implemented in the United States that minimizes shrinkage cracking in these bases Dr Tom Scullion of Texas A amp M University accomplished the implementation in response to a request from the City of College Station Texas The method included aspects that have been under investigation for many years such as controlling the amount of cement used 3 to 9 by weight the water content the quality of the subgrade and the type amp time of final surfacing What was new in the method was the controlled induction of micro cracks into the base The micro cracks prevent the development of the larger shrinkage cracks without significantly impacting stiffness of the base The performance of the mix was first verified through a ser
13. Office of Pavement Design guidelines this variability in subgrade modulus could support a 15 year pavement life The modulus and rate of change of modulus with time for the NM 44 lime stabilized subgrade from over two years prior falls within the data range for VA 288 Also core testing by Koch was consistent with the modulus data Where modulus data fell with in 36 of the average the corresponding strength data was acceptable The modulus cure rates for the individual sections generally follow that of the average see Figure 2 The correlation coefficients are not as good but do they need to be for QC QA purposes All data provided was used for the analysis with the exception of the following 5001 VA288 10 24 to 10 29 discarded for poor measurement quality precision e Main Line NBL_ 2 to 196 57 7 18 to 7 25 Day 8 questionable data quality missing information Humboldt Mfg Co 7300 West Agatite Ave Norridge IL 60706 U S A HUMBOLDT 708 456 6300 voice hmc humboldtmfg com email Additionally the data from loop D Sec E _ Interchange 7 18 to 7 22 was used because of good measurement quality but the data indicates that changes in the site conditions may have influenced the cure rate in an unexpected way Figure 3 shows the number of data points used in the analysis by day in the cure cycle almost 1 000 points This is many more that the 84 data points used to determine the NM 44 cure rate The fact t
14. R 0 3743 E Average Modulus 2 20 m 2 Sigma 4 2 Sigma 15 m NM 44 9 00 9 Log Average Modulus 2 O 36 re Avg Log 2 Sigma A Log 2 Sigma 5 4 1 2 3 4 5 6 7 8 9 10 1 Day After Installation 1 12 13 14 15 16 umboldt Co 7300 West Agatite Ave Norridge IL 60706 U S A HUMBOLDT 708 456 6300 voice hmnc humboldtmfg com email Figure 2 Effective Modulus kpsi VA 288 Lime Stabilized Subgrade Modulus vs Time By Section amp Ramp A Sec D 35 4 MTD GeoGauge x Main Line_ SBL 0 to 141431 y 1 7378Ln x 16 759 Main Line NBL_ 8 to 135 57 30 R 0 6722 Main Line NBL_ 4 to 149471 Main Line NBL_ 8 to 1354 90 25 y 6 2982Ln x 15 295 Main Line NBL 2 to 196457 Ri 29793 Main Line NBL_ 2 to 193451 y 3 026Ln x 16 341 Main Line NBL 2 to 131444 20 4 R 0 7503 Main Line SBL_ 8 to 133497 y 1 4947Ln x 17 756 loop D_ Sec E _ Interchange R 0 6423 Log Ramp Sec D 15 y 3 1143Ln x 14 411 Log MTD GeoGauge R 0 885 Log Main Line SBL_ 0 to 141 31 10 P Log Main Line_ NBL_ 8 to 135457 JE Log Main Line_ NBL_ 4 to 149 71 R 0 539 Log Main Line_ NBL_ 8 to 135 90 5 y 3 0067Ln x 17 004 Log Main Line_ NBL_ 2 to 196 57 R 0 9727 Log Main Line_ NBL_ 2 to 193 51 550811 9 046
15. When pushed the GeoGauge goes through an electronics check displays the present battery voltage and finally displays the value of the previous or last measurement made The gauge is then ready to perform a new measurement Turns off the gauge To execute any of the four buttons with a blue background ERASE PRINT TEST UNIT you must first press the SHIFT button After pressing SHIFT do not press the blue keys until SHIFT is displayed in the STIFFNESS window Note the STOP button does not require using SHIFT Erases all saved data Starts measurement ID at 1 Saves the current measurement This button must be pushed to save each measurement If it is not pushed the data for the last measurement will be discarded Note When the GeoGauge memory is empty the first 20 measurements saved will contain the uniquely assigned measurement ID measurement the time and date frequencies and the real and imaginary parts of the force and displacement Research Format There after only the measurement ID the displayed stiffness in SI units and the time and date will be saved for the next 480 measurements At this point the GeoGauge s memory is full and db full is displayed Begins the downloading of data via the IR COM port Shows the target stiffness value only in SI units in the ID TARGET window and the ratio of the measured stiffness to the target stiffness in the STIFFNESS window T
16. as reasonable Do not expose the gauge to precipitation Should the gauge get wet exposed to high humidity or suspected of containing moisture or condensation immediately dry out the gauge by removing and gently setting aside upside down without disconnecting the wires the display panel and battery caps and batteries Allow to air dry in a dry enough room overnight Carefully re assemble before using or packing back in case 10 0 Clock Date Adjustment Purpose The clock is used to stamp the time and date of each stiffness measurement When saved the measurements can be downloaded into a PC onto a spreadsheet template to analyze the complex data from the first twenty measurements saved Saved measurements number 21 to 500 show only the run stiffness value and time date Changing the batteries will not delete or lose the clock settings Operation 1 With the GeoGauge ON and in normal mode press the SHIFT button and then the MEAS button to get into the user input mode The Poisson s Ratio values will display Press SHIFT and MEAS buttons again the clock settings should display The represents AM The represents PM Pressing the INCR or DECR will scroll the values up or down With the first pressing of the SHIFT and MEAS buttons from step 1 and the clock displayed both time and date the hour will adjust Scroll to the correct hour and AM or PM
17. by section adjustments in roller patterns and watering This real time attention to quality also resulted in a significant reduction in the contractor time and effort traditionally needed to accomplish this kind of job The material strength achieved and its uniformity as evident from the stiffness tests was consistent with supporting a 20 year roadway life According to FHWA guidelines A coefficient of variation COV of less than or equal to 20 in subgrade strength will support a 20 year life The COV achieved for TH200 was less than 14 District 2 found that the material and construction uniformity enabled by this test method was sufficient to require stiffness testing intervals of no smaller than every 500 ft Since the completion of the TH200 job the stiffness measurements made as part of the test method has been shown to have a strong relationship to resilient modulus and so are useable as an in place index District2 Thief River Falls Construction Office of the Minnesota Department of Transportation has deemed the success of this first use of stiffness based compaction QC testing sufficient to warrant continuing and broadening use of it on subgrades and bases in the 2005 and 2006 construction seasons For more information contact Melvin Main Humboldt Mfg Co 717 650 6537 melmain humboldtmfg com or J T Anderson Resident Engineer MnDOT District 2 216 681 0927 J T Anderson dot state mn us Test
18. construction season For more information contact Melvin Main Humboldt Mfg Co 717 650 6537 melmain humboldtmfg com or QC Test Data Bryan TX Effects of Micro Cracking Miramont Subdivision Bryan TX Aug 01 to Jan 02 In Place Cement Stabilization amp Reuse m After 48 Hr Post Rolling Frequency Of Measurements 6 Increase in Structural Uniformity 0 10 20 30 40 50 60 70 80 90 Stiffness MN m QC Test Data La Quinta CA 46 Reduction In Average Stiffness Effects of Micro Cracking Madison St Southbound La Quinta CA March 05 In Place Cement Stabilization amp Reuse 46 Reduction In Average Stiffness 20 Increase in Structural Uniformity After 48 Hr Post Rolling Frequency Of Measurements 0 10 20 30 40 50 60 70 80 90 Stiffness MN m QC Test Data Santa Rosa CA Effects of Micro Cracking Carancho Rd Between Tortuga amp Calamar Santa Rosa CSD CA September October 05 In Place Cement Stabilization amp Reuse 30 38 Reduction In Average Stiffness Frequency Of Measurements 0 10 20 30 40 50 60 70 80 90 Stiffness MN m Dr Tom Scullion Texas A amp M University 979 845 9913 t scullion tamu edu Rick Conlin CME Testing amp Engineering College Station TX 979 778 2810 rconlinetxcyber com Steve Speer City Engineer City of La Quinta CA 760 777 7043 sspeer la quinta org
19. the GeoGauge from the Verifier Mass Reset it back onto the Verifier Mass When repeating measurements it is important to remove the GeoGauge from the Verifier Mass between measurements to account for placement and operator bias Place the GeoGauge on the Verifier at different rotational orientation each time 10 Normally five 5 measurements will be sufficient Average the measurements for a Copyright 1999 2006 Humboldt Mfg Co Norridge IL 60706 U S A All rights reserved Printed in U S A Humboldt GeoGauge Verifier Guide Version 4 0 October 2006 Page 2 of 2 result Record all measurements and save the records for long term monitoring of GeoGauge operation The values from each verifier measurement will oscillate up and down a small percentage and the average stiffness should be used to compare with the expected stiffness It is not necessary to verify daily Weekly or once a month or when questions about the validity of the stiffness modulus measurements occur then the use of the Verifier Mass is justified 11 An average stiffness of roughly 8 6 to 9 8 MN m is expected on the Verifier Mass If this is not achieved contact Humboldt for assistance The GeoGauge is built to withstand normal field instrument handling The gauge can still be damaged from mishandling and abuse It cannot be over emphasized that proper care and maintenance will give the owner long life and reliability from the instrument Contact Mahir Al Nadaf
20. 000 amp 2007 Humboldt Mfg Co Norridge IL 60706 U S A All rights reserved Printed in U S A GeoGauge User Guide 7 Version 4 1 June 2007 INCR With START scrolls through saved measurement data in order of increasing value see START above DECR With START scrolls through saved measurement data in order of decreasing value see START above 3 0 Technical Specification Conforms to ASTM D6758 Soil Measurement Range From To MN m klbf in MN m klbf in Stiffness 3 17 70 399 MPa kpsi MPa kpsi Young s Modulus 26 2 3 8 610 89 Measurement Precision typ Coefficient of Variation lt 10 Depth of Measurement from surface 220 to 310 mm 9 to 12 in Calibration Laboratory Accuracy of actual mass lt 1 Electrical Power Source 6 D size disposable cells Battery Life Sufficient for 500 to 1 500 measurements Mechanical External Materials Aluminum case amp foot rubber isolators amp seal Vibration 1 27 x 10 m 0 0005 125 Hz Level re Vertical 2357 Operating Temperature 0 C to 38 C ambient Storage Temperature 20 C to 50 C Humidity 98 without condensation Gauge Dimension 280 mm 11 Diameter 255 mm 10 Height without handle Weight Net 10 kg 22 165 Shipping with case 17 7 kg 39 16 Standard Accessories Transit Case 6 D Batteries User Guide Optional Accessories nfrared IR serial interface adapter cable with software t
21. D 7 25 to 7 30 76 0 16 9 18 3 21 0 186 45 to 189 67 MTD_GeoGauge 5 20 to 5 28 76 3 12 2 19 6 21 1 19 5 20 7 134 50 to 141 31 Main Line SBL_ 0 to 141 31 xls 8 16 to 8 14 86 7 19 5 22 6 23 8 132 98 to 135 57 Main Line NBL_ 8 to 135 57 xls 8 6 to 8 14 70 4 16 2 17 3 22 2 20 2 20 3 23 4 23 3 144 24 to 149 71 Main Line NBL 4 to 149 71 xls 8 2 to 8 6 76 3 17 9 18 8 21 1 135490 to 141474 Main Line NBL 8 to 135 90 xls 8 7 to 8 15 18 4 18 0 20 5 22 0 21 7 200 42 to 196457 Main Line NBL 2 to 196 57 xls 7 18 to 7 25 91 3 14 8 15 5 15 1 19 7 195432 to 193451 Main Line NBL 2 to 193 51 xls 7 29 to 8 1 87 6 20 4 19 6 20 8 22 9 129 62 to 131444 Main Line NBL 2 to 131 44 xls 8 9 to 8 15 70 6 192 21 4 22 6 22 7 23 5 130 00 to 133 97 Main Line SBL_ 8 to 133 97 xls 8 14 to 8 15 88 1 22 8 24 4 11 27 to 13 20 loop D_ Sec E __ Interchange xls 7 18 to 7 22 90 6 16 8 20 2 16 8 Humboldt Mfg Co 7300 West Agatite Ave Norridge IL 60706 U S A HUMBOLDT 708 456 6300 voice hmc amp humboldtmfg com email GeoGauge User Guide Version 4 1 June 2007 Appendix 4 GeoGauge Verifier Mass Guide Copyright 1999 2000 amp 2007 Humboldt Mfg Co Norridge IL 60706 U S A All rights reserved Printed in U S A Humboldt GeoGauge Verifier Guide Version 4 0 October 2006 Page 1 of 1 Humboldt GeoGauge Verifier Mass Guide For use with C series Humboldt GeoGauge Purpose To verify or check the operation of the C series Humboldt H 4140
22. GEOGAUGE USER GUIDE Model H 4140 Soil Stiffness Modulus Gauge patent pending manufactured sold and serviced by Humboldt Mfg Co 7300 West Agatite Avenue Norridge Illinois 60706 U S A Customer Service Voice 708 456 6300 Fax 708 456 5412 GeoGauge User Guide Version 4 1 June 2007 Table of Contents 1 0 Introduction 1 11 GeoGauge Benefits 1 2 How The GeoGauge Works 1 3 GeoGauge Applications 2 0 Button Keypad Functions 3 0 Technical Specification 4 0 Display Messages 5 0 Get Acquainted With The GeoGauge 6 0 GeoGauge Seating 7 0 Sequence Of Operations For A GeoGauge Stiffness Modulus Measurement 8 0 Transit Carrying Case 9 0 Replacing Batteries 10 0 Clock Date Adjustment Appendix 1 Stiffness Based Compaction QC Method Appendix 2 Stiffness Based QC On A Stabilized Base Appendix 3 Stiffness Based QC On A Stabilized Subgrade Appendix 4 GeoGauge Verifier Mass Guide Appendix 5 GeoGauge Data Download Guide Copyright 1999 2000 amp 2007 Humboldt Mfg Co Norridge IL 60706 U S A All rights reserved Printed in U S A go JA tA UC 12 14 14 15 GeoGauge User Guide 3 Version 4 1 June 2007 1 0 Introduction 1 1 GeoGauge Benefits The Humboldt GeoGauge is a hand portable instrument that provides a simple rapid and precise means of measuring in place two key engineering and mechanical properties of prepared soil and aggregate lift s
23. GeoGauge by running a measurement on top of the Verifier Mass It is not intended to calibrate the GeoGauge Equipment Required H 4140 20 Verifier Mass Assembly 10 kg with installed rubber isolation mounts Operation 1 Place the Verifier Mass Assembly on a relative flat and rigid surface The surface at this location should be approximately level A concrete floor that is generally crack free and well supported is ideal 2 Wipe clean the ring foot at the bottom of the GeoGauge Clean the v groove around the seal between the foot and gauge body Inspect the ring foot surface for deep gouges nicks protrusions or raised nicks The ring foot should be relatively flat Remove excessive protrusions or raised nicks by setting the GeoGauge on a flat abrasion sheet placed on a flat steel plate Rotate the GeoGauge via its handle 2 3 times until the protrusions are approximately flat with the ring foot surface Wipe off the abrasion dust from the ring foot 3 Turn on GeoGauge Set the GeoGauge to display stiffness in S I metric units 4 Smear small amount of any lubricating oil on the shoulder of the Verifier Mass 5 Gently set the GeoGauge s ring foot in position over the shoulder of the Verifier Mass 6 Rotate the gauge on the mass a random amount 7 Firmly press the MEAS button to make a measurement of the Verifier Mass stiffness 8 After 75 seconds the measured stiffness will be displayed Record the stiffness 9 Remove
24. Strip Stiffness vs Compaction perry Test Strip Assignment Of Target Stiffness Test Strip Data Select Granular TH200 Ada MnDOT 35 115 8 passes selected as typical bey ond which 30 material breakdown 8 recompaction occurs 10 5 105 100 Avg Moisture n Avg Stiffness kips in Avg Dry Density pdf Roller Pass Number Avg Moisture Max Dry Density Avg GeoGauge Optimum Moisture Avg Dry Density Test Strip Data Select Granular TH200 Ada MnDOT 120 Dry Density pcf Density 0 8118 Stiffness 88 225 R 0 79 Stiffness kips in Number of Data Points QC Test Data Histogram of Select Granular Subgrade Stiffness TH200 Ada MN 2004 MnDOT District 2 87 Compaction 97 Compaction n e tor L es Stiffness kips n 1 Development Of Resilient Modulus Prediction Models For Base And Subgrade Pavement Layers From In Situ Devices Test Results 2004 Ravindra Gudishala Louisiana State Universit Baton Rouge LA 70808 HUMBOLDT Humboldt Mfg Co 7300 West Agatite Ave Norridge IL 60706 U S A 708 456 6300 voice hmc humboldtmfg com email GeoGauge User Guide Version 4 1 June 2007 Appendix 2 Stiffness Based QC Method Used On A Stabilized Base Copyright 1999 2000 amp 2007 Humboldt
25. ction schedule To reduce the waiting period Koch needed at QC method that could quantitatively estimate when the subgrade was strong enough to support construction and estimate subgrade ultimate strength The method would have to determine these factors from measurements made within the first few days after installation Limited measurements made on a similar lime stabilized subgrade of New Mexico 44 in 2000 indicated that evaluating a material modulus vs time might provide the needed method This was accomplished by calculating a modulus from measurements of lift stiffness made using the Humboldt GeoGauge To confirm this a comprehensive evaluation of subgrade lift stiffness was conducted on VA 288 The construction specification used on NM 44 was also used on VA 288 The NM 44 data established that a modulus calculated from lift stiffness could be used as the estimate of strength If the VA 288 subgrade performance was consistent with the subgrade of NM 44 then stiffness based QC of the lime stabilized subgrade is indeed viable if not a practical and form the basis for a specification From the sum of the data provided by Koch it appears that the effective modulus of the lime stabilized subgrade increases with time at a logarithmic rate to a good degree of correlation see Figure 1 This data also shows that of the approximately 1 000 measurements made on the subgrade approximately 95 fall within 36 of the average modulus Based on FHWA
26. de 14 Version 4 1 June 2007 8 0 Transit Carrying Case The transit case has both key lock and combination lock The combination is set at factory 0 0 0 To re set the combination number 1 Open the case Looking at the back of the lock inside the case you will see a change lever Move this change lever from the normal position to the middle of the lock in the way that it hooks behind the change notch Move it sideways and then up 2 Now you set your combination number by turning the dials to the desired three number combination Record the numbers below 3 Move back the change lever to the normal position 4 To lock close the case securely and rotate one or more of the dials To un lock set the dials to the proper numbers Record the numbers 6 The key lock latch set requires the attached key to lock en 9 0 Replacing Batteries Model H 4140 requires six 6 size D 1 5 volts dry cell alkaline batteries Three 3 batteries in each of the two battery compartments accessible via two screw on caps on the top of the GeoGauge Replace all batteries with a fresh set Attempting to mix fresh batteries with used batteries will cause the fresh batteries to deteriorate very quickly to the level of the used batteries negating any advantage of fresh batteries 1 Turn off gauge Remove the battery caps by unscrewing counter clockwise A suitable coin may be helpful to loosen them Carefully lift and remove the spri
27. ear and modulus can be derived The GeoGauge weighs about 10 kg 22 Ib is 28 cm 11 in diameter 25 4 cm 10 tall and rests on the soil surface via a ring shaped foot Fig 2 The foot bears directly on the ground GeoGauge Schematic without penetrating it and supports the weight of the GeoGauge via Figure 2 rubber isolators Also attached to the foot are the shaker that drives the foot and sensors that measure the force and displacement frequency history of the foot The GeoGauge is placed on the ground to make a measurement with little or no preparation of surface Typically a slight rotation of the GeoGauge is needed obtain the desired 10096 contact between foot and ground Fig 3 On particularly hard or rough surfaces seating of the foot 1s assisted by the use of less than 10 mm 1 4 of moist wet material such as mortar sand Common field practice is as applicable to the GeoGauge as it is to most current field measurement of material performance The detailed procedure for using the GeoGauge and preparing the ground is described later in this guide The GeoGauge displays and logs the data in memory with sufficient capacity for a full day of data gathering 100s of measurements The data may be downloaded to a PC for archiving and further analysis It is powered by 6 disposable and common D cell batteries Measurements can be performed as close to operating construction equipment as operator safety will allow
28. emplate 3 5 floppy PC only Verifier Mass ALL TECHNICAL PERFORMANCE AND OTHER SPECIFICATIONS ARE SUBJECT TO CHANGE Copyright 1999 2000 amp 2007 Humboldt Mfg Co Norridge IL 60706 U S A All rights reserved Printed in U S A GeoGauge User Guide 8 Version 4 1 June 2007 4 0 Display Messages StiF SENS OvLOAD 5d noiS dAtA Snr 5I or Eg ALrE StorEd OVFLO 0 00 Announces the measured value of stiffness MN m displayed in ID window The measured value of stiffness is displayed simultaneously in the STIFFNESS window Indicates that the current measurement was aborted due to the sensors being overloaded The word SENS is displayed in the ID TARGET window and the word OvLOAD displayed in STIFFNESS window This can be caused by a too soft material a too stiff material or the foot being seated improperly When displayed the current measurement must be repeated Announces the standard deviation of all 25 frequency dependent stiffness measurements relative to the measured average value of stiffness displayed in ID TARGET window at the end of the current measurement The standard deviation is displayed simultaneously in the STIFFNESS window Indicates that the GeoGauge is measuring ambient noise displayed in ID TARGET window The noise measurement takes about 10 seconds after depressing the MEAS button Nothing is displayed simultaneously in the STIFFNESS window Indicates that the GeoGau
29. g Co Norridge IL 60706 U S A All rights reserved Printed in U S A GeoGauge User Guide 9 Version 4 1 June 2007 db on db off StorEd bAtt SELF TEST nO ErrOrS POI5 51 5 51 Y Eg 5 Eg Y Indicates that the View Memory data base mode has been entered It is displayed momentarily in the STIFFNESS window After this appears pressing the INCR or DECR buttons will scroll through the stored data Ordered pairs of measurement ID numbers and the measured values of stiffness will be displayed sequentially in the order they were measured in the ID TARGET and STIFFNESS windows respectively Indicated that the View Memory data base mode has been exited It is displayed momentarily in the STIFFNESS window Announces that the current measurement has been stored displayed in STIFFNESS window The assigned measurement ID number is displayed simultaneously in the ID TARGET window Announces the value of the combined voltage of the six 6 D batteries displayed in ID TARGET window The voltage is displayed simultaneously in the STIFFNESS window Indicates that the GeoGauge is going through a self test of its electronics The word SELF is displayed in the ID TARGET window and the word TEST is displayed in the STIFFNESS window Indicates that the results of the self test is within specified limits displayed in ID TARGET window Indicates the Poisson s Ratio value being displayed Scrollable from 0 20 t
30. ge is taking stiffness data over 25 frequencies between 100 and 196 Hz displayed in ID TARGET window This follows the noise measurement and takes about 55 seconds Nothing is displayed simultaneously in the STIFFNESS window Announces the display of the Signal Noise Ratio for the current measurement displayed in ID TARGET window at the end of the current measurement The Signal Noise Ratio in dB is displayed simultaneously in the STIFFNESS window This message indicates the ready mode and the stiffness units displayed in ID TARGET window The GeoGauge is ready to take the next measurement The Stiffness window shows the value of the last measurement in SI units MN n or English Eg units klbf in Indicates that the current measurement value has already been stored in the memory The word AlrE is displayed in the ID TARGET window and the word StorEd displayed in STIFFNESS window If you don t know if the last measurement has been stored the GeoGauge will tell you Indicates that the database memory is full No additional measurements may be taken You need to download or erase before additional measurements are taken Indicates that the last measurement was not accepted due to one of two reasons One that the sensors overloaded due to softness or extreme hardness too much movement Two that six or more of the 25 total frequencies were unacceptable from low Signal to Noise Ratio Copyright 1999 2000 amp 2007 Humboldt Mf
31. hat the correlation coefficients for the 11 sets of cure rate data are typically not as good as that for the one data set from NM 44 leads me to believe that the cure rates in the VA288 data may be masked by changing site conditions e g temperature moisture traffic material differences installation practice Based on first hand observations these types of conditions changed very little on NM 44 suggest that minimizing the effect of these variables should influence future section and test date selection Tables 1 and 2 contain the summary data used in the figures In my opinion Figure 1 embodies the basis for a trial specification Effective modulus should be within 20 of the target modulus average 95 of the time on any given day after installation This specification may be specific to the general materials and construction methods used Also sucha specification should include a practical spatial sample for QC testing e g every 500 ft Figure 1 also suggests that such a specification may be largely independent of site conditions or even job site Humboldt Mfg Co 7300 West Agatite Ave Norridge IL 60706 U S A HUMBOLDT 708 456 6300 voice hmc humboldtmfg com email Figure 1 VA 288 Lime Stabilized Subgrade Charterization of Modulus vs Time 2 8357Ln x 23 19 i 20 36 re Avg R 0 693 y 2 4666L n x 16 502 z 2e R 0 8674 2 0976Ln x 9 8142 25
32. he target value can be incrementally changed in graduations of 0 5 MN m by scrolling up or down using the INCR or DECR buttons respectively Press MODE again to return to the previous display Starts the actual stiffness measurement The measurement will be completed in about 70 seconds Pressing SHIFT and then MEAS will enter the Poisson s Ratio value display Each successive pressing of the SHIFT and then MEAS buttons will enter the time date display Press SAVE to save the new entry Begins the viewing or scrolling through the saved measurement data You need to press the INCR or DECR button to scroll up or down the measurement values along with the measurement ID You cannot take a measurement while viewing memory Exit this database mode status by pressing the STOP button Exits the viewing of the saved measurement data Pressing it returns the gauge to normal mode The SHIFT button is not used for this action System runs a self test Displays the electronic circuit board serial number battery voltage batt runs an internal electronic circuitry check SELF TEST and then displays the results no ErrorS The system runs the same test when the gauge is first turned on Pressing SHIFT and then UNITS alternates between SI and English measurement units Pressing just UNITS toggles between displaying stiffness and modulus Copyright 1999 2
33. ied levels of percent compaction The Humboldt GeoGauge is a 10 diameter 11 tall 22 lb electro mechanical instrument that when placed on the surface of the ground evaluates the stiffness of the top 9 to 12 of material It vibrates the ground over a range of discrete frequencies applies force measures the resulting deflection and displays the results in about minute It was chosen by MnDOT District 2 because measurements could be made at a rate greater than the rate of compaction it has no licensing or safety requirements and its performance reliability precision amp bias had been proven by FHWA Study 2 212 amp TRB NCHRP Project 10 65 In the summer of 2004 District 2 chose road TH200 in Ada MN for its initial use of this QC test method The method was contractually specified This was the only way District 2 thought that sufficient data could be collected for a comprehensive evaluation of the method The subgrade was an AASHTO A 1 b material placed in two 12 lifts over two miles of 2 lane roadway Stiffness was measure approximately every 100 ft on each lane for each compacted lift one 1 000 ft section at a time Based on test strip measurements CASE STUDY STIFFNESS BASED COMPACTION QC OF A GRANULAR SUBGRADE MINNESOTA DOT DISTRICT 2 423 WEST ZEH ST THIEF RIVER FALLS MN 56721 Significance In Use In Place Evaluation Of 5 Percent Compaction trength amp Uniformity esilient Modulus
34. ies of unconfined compressive strength tests in the laboratory A strength of 300 psi to 500 psi was required with around 300 psi considered optimal During the first two days of life the stiffness of the base was evaluated to assure sufficient ultimate strength The 6 to 12 lifts addressed by the method had to achieve a stiffness of about 50 to 60 Mega Newtons per meter MN m during this period At the end of this period limited vibratory rolling 1 to 4 passes using a 12 ton steel wheel roller was conducted to lower base stiffness by about 40 and thereby induce a network of micro cracks Stiffness was directly measured in real time without penetrating the base using the Humboldt GeoGauge The Humboldt GeoGauge is a 10 diameter 11 tall 22 lb electro mechanical instrument that when placed on the surface of the ground evaluates the stiffness of the top 9 to 12 of material It vibrates the ground over a range of discrete frequencies applies force measures the resulting deflection and displays the results in about a minute It was chosen by Texas A amp M because measurements could be made quickly it has no licensing or safety requirements and its performance reliability precision amp bias had been proven by FHWA Study 2 212 Four sections of Salzburg Ct Von Trapp Ct Newburg Ct and Sophia Lane in College Station Texas were constructed during October of 2000 The construction consisted of 6 of lime stabi
35. lized subgrade 6 of soil CASE STUDY MICRO CRACKING A CEMENT TREATED ROADWAY BASE TO MINIMIZE SHRINKAGE CRACKS TEXAS A amp M UNIVERSITY THE CITIES OF BRYAN amp COLLEGE STATION TX THE CITIES OF LA QUINTA amp SANTA ROSA CA CEMEX In Use Minimizing Reflective Cracking Humboldt GeoGauge Field Investigation Pre Cracking of Soil Cement Bases to Reduce Reflection Cracking 2001 Tom Scullion Texas A amp M University College Station TX 77843 HUMBOLDT Humboldt Mfg Co 7300Agatite Ave Norridge IL 60706 U S A 708 456 6300 voice hmc humboldtmfg com email cement 2 HMA surfacing The Salzburg Ct Von Trapp Ct and Newburg Ct Sections received the stiffness control and the micro cracking The Sophia Lane section did not Site conditions were generally wet during construction Bob Mosley City Engineer for College Station supervised the work Young Brothers Inc accomplished the construction The micro cracks were observed to greatly inhibit base shrinkage cracking Laboratory testing of core samples indicated that the base reached its design strength Apparently the micro cracks were induced early enough in its life so as not to significantly inhibit strength gain In more than 18 months of observations the roadway sections constructed with the micro cracking method exhibited at least 50 fewer reflection cracks in comparison to the section that did not
36. ments at a single location then seating is sufficient On loose or soft materials place the GeoGauge on the ground Rotate the GeoGauge no more that 1 2 of a revolution by holding the side or bottom of the gauge Now you can take the measurement Lifting the gauge from the measured spot and observing the imprint made can readily judge the degree of foot contact Occasionally the material is hard and smooth enough or rough and irregular enough that the imprint made by the foot cannot be seen This is where measurement precision will be the judge If the imprint made by the foot cannot be readily seen the simple solution is to apply a thin patted layer of clean moist mortar sand per ASTM C144 02 about 5 to 10 mm thick 1 8 to 1 4 inches on the spot to be measured Level and pat down firmly with your hand to roughly 10 mm thick Place the GeoGauge on the packed moist sand Rotate the GeoGauge no more that 1 4 of a revolution by holding the side or bottom of the gauge Now you can take the measurement When adding water to the mortar sand there is not enough water if it does not clump when squeezed in your hand There is too much water if water squirts between your fingers It is essential to be consistent in using moist sand and in the seating of the GeoGauge The influence of the moist sand in the measurement is negligible Use just enough moist sand that when the GeoGauge is placed on it the sand does not bunch up and touch the bottom of the in
37. n 1 MN m So the initial over sampling of a material is desirable to develop accurate profiles During the actual compaction the engineer will specify the measurement interval Intervals of 15 m 50 ft to 145 m 500 ft are typical for material quality control measurements The site and layout of measurement locations should allow for repeated measurements Six 6 locations is a good number Site conditions change continuously Moisture content for example Sandy soils dry out rapidly Clays take days to dry Making a comprehensive set of measurements rapidly assures material characterization under one set of conditions e g with in 1 hr of compaction Knowing site conditions is critical to characterizing a material Repeat measurements at each location at least three times These repeated measurements will get you familiar with GeoGauge precision for the corresponding surface conditions Seating the GeoGauge to the ground is the most important part of the measurement see GeoGauge Seating below Always remove the GeoGauge between measurements and do not touch the GeoGauge during a measurement The number of repeated measurements depends on the site Don t confuse the measurement precision repeatability with location to location variability in the material Perform GeoGauge measurements first before other companion measurements Performing measurements such as FWD or nuclear gauge measurements will disturb the material and affect any sub
38. ng and the battery contact retainer Remove the batteries tilting and turning the gauge upside down will facilitate removal Insert the fresh batteries with the positive side up in both compartments Carefully insert the battery contact retainers springs and then screw on clockwise the battery caps There is an o ring seal on the underside of the battery caps to seal out water and dirt Hand tighten only Occasionally during use insure that the battery caps are tight 6 Loosen the four 4 corner captive screws with a Phillips screwdriver Remove any static electricity in one self by touching a metal earth grounded object such as the back of a computer housing 7 Carefully lift up the display panel which contains the electronic circuitry on the underside On the left side are two toggle switches 1 and 2 8 Switch 1 to on as marked Turn on the unit by pressing the ON button The display will momentarily show reset and then revert to its normal display 9 Turn the 1 switch to off Turn off the unit by pressing the OFF button Replace the display panel back onto the unit and lightly tighten the screws The GeoGauge is ready for operation Era Copyright 1999 2000 amp 2007 Humboldt Mfg Co Norridge IL 60706 U S A All rights reserved Printed in U S A GeoGauge User Guide 15 Version 4 1 June 2007 Note The gauge exterior is not water proof or dust proof Attempts were made to make the gauge as tight
39. ntact with a trench wall pipe soil etc Enter Data Enter target stiffness from pre defined scrolled list via display if necessary Verify GeoGauge Operation daily Perform a check of GeoGauge operation per the GeoGauge Verifier Mass Guide see Appendix 4 The GeoGauge is operating properly if the mean stiffness is within approximately 8 6 MN m and 9 8 MN m Establish GeoGauge Precision daily Locate some compacted material that is representative of what is to be measured that test day Make a minimum of 3 measurements at the same test location GeoGauge precision is sufficient if the coefficient of variation of the measurements is less than 1096 Seating Of The Foot How to properly seat the foot will be determined by on site trial per the recommendations above see GeoGauge Seating Take The Measurement press Meas button 1 GeoGauge will measure noise as a function of frequency 2 GeoGauge will measure stiffness as a function of frequency 3 GeoGauge will display in sequence Signal to Noise ratio SNR in dB The stiffer the material the closer this value will be to 10 indicating that more than usual attention should be paid to seating Copyright 1999 2000 amp 2007 Humboldt Mfg Co Norridge IL 60706 U S A All rights reserved Printed in U S A GeoGauge User Guide 13 Version 4 1 June 2007 standard deviation 5d of all 25 frequency dependent stiffness measurements relati
40. o 0 70 in increments of 0 05 Pressing the save button after setting the Poisson s Ratio value will retain that value in memory for subsequent Young s modulus measurements Stiffness in SI value MN m Mega Newton per meter Young s modulus in SI value MPa Mega Pascals Stiffness in English value kIbf in kilo pounds force per inch Young s modulus in English value ksi or kpsi kips per square inch Copyright 1999 2000 amp 2007 Humboldt Mfg Co Norridge IL 60706 U S A All rights reserved Printed in U S A GeoGauge User Guide 10 Version 4 1 June 2007 5 0 Get Acquainted With The GeoGauge Before using the GeoGauge to make measurements that matter get acquainted with it Get used to what it takes to make a precise measurement Get acquainted with how the stiffness of prepared materials varies Select a site that is representative of the material you will be measuring Bases or subbases with high aggregate contents should be avoided for awhile until the technician gains some experience Layout measurement locations in a straight line with the increment between locations being about 6 meter 2 ft or less Walking over measurement locations will not disturb the surface and affect a measurement The physical properties of prepared construction materials can be extremely variable They can be much more variable than expected Over a 6 meter 2 ft increment it is not uncommon for soil stiffness to vary more tha
41. ory measurements The GeoGauge is intended to meet a need that has existed since quality has been important to earthworks construction This is the control of the construction process via the same physical parameters that earthworks are designed with For example in highways Lift Stiffness is used to assure the uniform amp effective transfer of loads from the pavement to the base subbase amp subgrade below and Material Modulus is used to assure that each material allows the highway system to structurally perform as needed Copyright 1999 2000 amp 2007 Humboldt Mfg Co Norridge IL 60706 U S A All rights reserved Printed in U S A GeoGauge User Guide 4 Version 4 1 June 2007 1 2 How The GeoGauge Works The GeoGauge measures a material s mechanical impedance at UNS the surface of the ground In other words it measures the force imparted to the soil and the resulting surface deflection as a function of frequency Stiffness force over deflection follows directly from the impedance The GeoGauge imparts very small displacements to the ground lt 1 27 x 10 m or lt 00005 at 25 steady state frequencies between 100 and 196 Hz Stiffness is determined at each frequency and the average from 25 frequencies is displayed The entire process takes about one minute At these low frequencies the impedance at the surface is stiffness controlled and is proportional to the shear modulus of the soil With Poisson s ratio sh
42. ot provide contractors with sufficient real time feedback so as to optimize the balance of quality and cost Accordingly a simple and precise modulus or stiffness based QC test method for subgrades was needed by the Minnesota Department of Transportation MnDOT District2 Thief River Falls Construction Office that would evaluate the required factors as compaction occurs At the same time this method needed to provide an index of percent compaction so as to fit within the framework of traditional specifications Finally the method needed to provide an index of resilient modulus to support the future use of mechanistic design and performance specifications District 2 selected an in place QC test method developed under FHWA Study 2 212 that did not interfere with or delay the construction process Without penetrating the ground the method used the Humboldt GeoGauge to measure the stiffness of each lift and thereby evaluate percent compaction Using a test section or strip of subgrade material lift stiffness at controlled moisture content was measured and spatially averaged as a function of compactive effort Initially this data was compared to density as a function of effort to confirm the findings of FHWA 2 212 that maximum stiffness occurs at optimum compaction as constrained by site conditions The resulting empirical relationship was used to establish QC stiffness targets for the subgrade that corresponded to the traditionally specif
43. pendix 3 15 a case study of use on a lime treated subgrade The GeoGauge can be used in place to estimate CBR and Resilient Modulus or estimate the results of plate load tests laboratory R Value FWD or DCP with more speed and simplicity and at a much lower cost 4 2 Development Of Models to Estimate The Subgrade And Subbase Layers Resilient Modulus From In Situ Devices Test Results For Construction Control 2005 Louay Mohammad Ananda Herath and Ravindra Gudishala Louisiana Transportation Research Center Baton Rouge LA 70808 FHWA LA 05 406 3 Assessment Of In Situ Test Technology For Construction Control Of Base Courses And Embankments 2004 Murad Y Abu Farsakh Ph D P E Khalid Alshibli Ph D P E Munir Nazzal and Ekrem Seyman Louisiana Transportation Research Center Baton Rouge LA 70808 FHWA LA 04 385 4 Field R Value Correlation Method Development 2006 Lary R Lenke Evan M C Kias Richard Jenkins Christopher Grgich University of New Mexico Department of Civil Engineering Albuquerque NM 87131 NMO4MSC 02 1 Copyright 1999 2000 amp 2007 Humboldt Mfg Co Norridge IL 60706 U S A All rights reserved Printed in U S A Soil Stiffness Device GeoGauge User Guide 6 Version 4 1 June 2007 2 0 Button Keypad Functions ON OFF SHIFT ERASE SAVE PRINT MODE MEAS START STOP TEST UNITS Turns on the gauge
44. sequent measurements Again practice making measurements before performing the measurements that matter Site conditions and the type of material will affect how you will want to place the GeoGauge on the surface Knowing how to properly seat the GeoGauge s foot on the surface as described below and being consistent in how you use the GeoGauge is critical to good measurements Remember compacted materials are not as structurally uniform as most people expect Stiffness is a sensitive enough measurement of a material to reveal this variability Be prepared to question and understand what you are doing with all the measurements you make not just the GeoGauge Process control for material structures is new and will take different thinking to effectively implement it Copyright 1999 2000 amp 2007 Humboldt Mfg Co Norridge IL 60706 U S A All rights reserved Printed in U S A GeoGauge User Guide 11 Version 4 1 June 2007 6 0 GeoGauge Seating A good GeoGauge measurement arises from good seating the foot to surface contact It cannot be emphasized enough that preparing the soil surface is key to good seating Merely having a level material surface is not enough the foot must have sufficient direct contact with the soil Experience shows that 100 of the foot s surface in contact with the material surface is needed If a measurement precision represented by a Coefficient of Variation of lt 10 is achieved from repeated measure
45. strict file name for the GeoGauge download settings For example GeoGaugeDownload Select an appropriate icon Click It is through this new connection setting that all download data can be entered repeatedly without having to re enter the settings every time 6 Inthe Connect To window select connect using Highlight the COM port to which the Infrared Interface Cable is connected Click 7 Inthe COM Properties dialog box under the Port Settings tab show Bits per second 4800 for GeoGauge serial numbers less than 326 or 1200 for GeoGauge serial numbers greater than or equal to 327 Data bits 8 Parity none Stop bits 1 Flow control Hardware Click OK click File and then click Save Copyright 1999 2007 Humboldt Mfg Co Norridge IL 60706 U S A All rights reserved Printed in U S A Humboldt GeoGauge Data Download Guide Version 2 0 March 2007 Page 2 of 2 Data Downloading 1 2 3 Repeat operations 1 2 and 3 above Double click on the HyperTerminal icon selected earlier In the window that opens Click Transfer Click Transfer Text Create a file for the data to be saved in A new file name will have to be entered for each new download A unique reference number and date are suggested The file name must end with csv Press the Shift key and then the Print key on the GeoGauge Data should be seen
46. ternal or exterior flanges It is important that no sand or other material come into contact with the foot flanges or the underside and sides of the GeoGauge body Only the ring foot surface should contact the soil A small area on the sides of the ring foot may touch the soil if the soil there is loose Dry sand or other cohesionless materials do not help the seating of the GeoGauge In fact dry sand will serve to decouple the GeoGauge from the ground Copyright 1999 2000 amp 2007 Humboldt Mfg Co Norridge IL 60706 U S A All rights reserved Printed in U S A GeoGauge User Guide 12 Version 4 1 June 2007 7 0 Sequence Of Operations For A GeoGauge Stiffness Modulus Measurement Making Stiffness Measurements With The GeoGauge Per The Following Procedure Conforms To ASTM D6758 Inspect The Condition Of The GeoGauge Prior To Testing 1 Is the foot clean and free of soil and other debris 2 Is the rubber seal in good condition Turn On The GeoGauge press ON button 1 The self test will be run electronics functionality 2 Ensure battery voltage is adequate 7 5 V 3 No warm up required before measurements Prepare The Surface To Be Tested see Site Preparation 1 Is the surface smooth and level 2 Coarse aggregate hard surfaces or stiff clay may require moist sand to be patted on the surface for good direct contact with the foot 3 Ensure the gauge has clearance on the side and bottom does not come into co
47. tiffness and material modulus Fig 1 Compaction Quality Control QC of subgrades bases and pavements based on modulus or stiffness as enabled by the GeoGauge will reduce compaction costs by 30 and roadway maintenance by at least 50 The GeoGauge unlike density gauges can measure in place the load bearing characteristics of compacted materials This enables real estimates of roadway performance and provides the basis for reducing construction margins lower construction costs by at least 20 The GeoGauge can be used in place to estimate CBR and Resilient Modulus or estimate the results of plate load tests laboratory R Value FWD or DCP with more speed and simplicity and at a much lower cost The GeoGauge can be used to evaluate the material strength gained by stabilization of any kind very soon after installation allowing construction to resume as soon as the material can support traffic loads while assuring ultimate material strength The GeoGauge can enable construction methods that reduce roadway maintenance by at least 50 Asphalt amp Concrete Pavement Full Depth Pavements Full Depth Roadway Reclamation Airport Runways amp Infields Unpaved Roadways Structures Buried Under Roadways The GeoGauge can be used to simply and rapidly build the quantitative basis for implementing mechanistic empirical roadway design by cataloging as built resilient modulus in a fraction of the time required for laborat
48. ve to the displayed average value of stiffness This number will be small for soft materials 1 MN m and larger for hard materials 5 MN m A large change in this number between test locations for a given material may indicate improper seating e g from 1 5 to 3 MN m A measurement should be repeated at such a location to assure proper seating If the measurement does not change then it is a true representation of the material Stiffness or Young s modulus or fraction of stiffness Target Ready for next measurement last measurement value still displayed Remove The GeoGauge From The Test Location 1 Examine the spot and ensure good foot contact see GeoGauge Seating 2 Clean any soil off of the foot that may have been caked on in the course of testing Store Data press SAVE button The measurement ID will be assigned to the stored data The GeoGauge will store data for 500 measurements as displayed Operational Mode Only the first 20 measurements stored will also include the complex frequency dependent components of displayed data Research Mode Turn The GeoGauge Off press OFF button When done for the day turn off to save battery power Transfer Data via optional Infrared interface Download data to a PC per GeoGauge Data Download Guide see Appendix 5 Copyright 1999 2000 amp 2007 Humboldt Mfg Co Norridge IL 60706 U S A All rights reserved Printed in U S A GeoGauge User Gui
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