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10

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"is displayed in the 

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 GeoGauge 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"is displayed in the 

STIFFNESS window. If you don't know if the last measurement 

has been stored, the GeoGauge will tell you.

StiF 

SENS OvLOAD 

5d

 

noiS

 

dAtA

Snr 

5I or Eg

  

ALrE  StorEd  

4.0: Display Messages

Содержание GeoGauge

Страница 1: ...product manual 09 14 H 4140 Humboldt GeoGauge ...

Страница 2: ...Gauge 13 6 0 GeoGauge Seating 14 7 0 Sequence Of Operations For A GeoGauge Stiffness Modulus Measurement 15 8 0 Transit Carrying Case 17 9 0 Replacing Batteries 17 10 0 Clock Date Adjustment 18 Appendix 1 Stiffness Based Compaction QC Method 19 Appendix 2 Stiffness Based QC On A Stabilized Base 23 Appendix 3 Stiffness Based QC On A Stabilized Subgrade 27 Appendix 4 GeoGauge Verifier Mass Guide 34 ...

Страница 3: ...al 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 Concrete Pavement Full Depth Pavements Full Depth Roadway Reclamation Airport Runways Infields Unpa...

Страница 4: ...t and supports the weight of the GeoGauge via 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 100 contact between ...

Страница 5: ...uch as typical site conditions will allow This allows GeoGauge measurements to be related to Resilient Modulus 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 The GeoGauge is better suited for the in place QC of unbound materials than any other available instrument for In place ...

Страница 6: ...nd at a much lower cost 2 3 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 Embank...

Страница 7: ...discarded Note When the GeoGauge memory is empty the first 20 measurements saved will contain the uniquely assigned measurement ID measurement 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 ...

Страница 8: ...OP 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 ...

Страница 9: ...00 measurements Mechanical External Materials Aluminum case foot rubber isolators seal Vibration 1 27 x 10 6 m 0 0005 in 125 Hz Level re Vertical 5 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 lbs Shipping with case 17 7 kg 39 lbs Standard Accessorie...

Страница 10: ...AS button Nothing is displayed simultaneously in the STIFFNESS window Indicates that the GeoGauge 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 displa...

Страница 11: ...ase 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 STIFF...

Страница 12: ...12 Young s modulus in SI value MPa Mega Pascals Stiffness in English value klbf in kilo pounds force per inch Young s modulus in English value ksi or kpsi kips per square in Eg 5 Eg Y 51 Y ...

Страница 13: ...sandy soils drying out rapidly and clays drying slowly 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 ...

Страница 14: ...not 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 ...

Страница 15: ...and bottom does not come into contact 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 GeoG...

Страница 16: ... 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 ...

Страница 17: ...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 2 Carefully lift and remove the spring and the battery contact retainer 3 Remove the batteries tilting and turning ...

Страница 18: ...ments 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 2 The represents AM Th...

Страница 19: ...19 Appendix 1 Stiffness Based Compaction QC Method ...

Страница 20: ... 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...

Страница 21: ...ve 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 at the start of the project a stiffness value of 23 klb in was assigned as a target corresponding to the specified 90 compac...

Страница 22: ...rict 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 index1 District 2 Thief River ...

Страница 23: ...23 Appendix 2 Stiffness Based QC Method Used On A Stabilized Base ...

Страница 24: ...e 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 series of unconfined compressive strength tests in the laboratory A strength of 300 psi to 500 psi was required with around 300 psi considered optimal...

Страница 25: ...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 ...

Страница 26: ...tments 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 construction season For more information contact Melvi...

Страница 27: ...27 Appendix 3 Stiffness Based QC Method Used On A Stabilized Subgrade ...

Страница 28: ...e 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 s...

Страница 29: ...act that 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 4...

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Страница 34: ...34 Appendix 4 GeoGauge Verifier Mass Guide ...

Страница 35: ...usions 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 a small amount of any lubricating oil on the should...

Страница 36: ...essary 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 stil...

Страница 37: ...37 Appendix 5 GeoGauge Data Download Guide ...

Страница 38: ...n 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 distinct file name for the GeoGauge download settings For example GeoGaugeDownload Select an appropriate icon Click OK It is through this new connection setting that all download data can be entered repeatedly with...

Страница 39: ...highlight Capture Text and click Stop Click Call Click Disconnect Click File Click Save 6 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 should look like 7 Press the Shift key and then the Erase key on the GeoGauge This will permanently erase the data just downloaded 8 Repeat 2 through 8 each time dat...

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Страница 42: ...75 Tollgate Road Elgin Illinois 60123 U S A Testing Equipment for U S A Toll Free 1 800 544 7220 Voice 1 708 456 6300 Fax 1 708 456 0137 Email support humboldtmfg com Construction Materials HUMBOLDT www humboldtmfg com ...

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