1、Designation: E2835 11 (Reapproved 2015)Standard Test Method forMeasuring Deflections using a Portable Impulse Plate LoadTest Device1This standard is issued under the fixed designation E2835; the number immediately following the designation indicates the year oforiginal adoption or, in the case of re
2、vision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method applies to measuring plate deflectionsusing a Portable Impulse Plate Load Test de
3、vice. The methodcovers the measurement of deflection of the load plate ratherthan the deflection of the surface of the pavement or foundationlayers (see Note 1).1.2 The values stated in SI units are to be regarded as thestandard. The values given in parentheses are for informationonly.1.3 This stand
4、ard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 AS
5、TM Standards:2D4695 Guide for General Pavement Deflection Measure-mentsD1195 Test Method for Repetitive Static Plate Load Tests ofSoils and Flexible Pavement Components, for Use inEvaluation and Design of Airport and Highway Pave-ments3. Summary of Test Method3.1 This test method is a type of plate
6、bearing test. The loadis a force pulse generated by a falling mass dropped onto aspring assembly that transmits the load pulse to a plate restingon the material under test.3.2 The mass is raised to a preset height and then dropped todeliver the desired force pulse. The device is calibrated to aprese
7、t drop height by the manufacturer. The preset drop heightshall not be changed by the user.3.3 The resulting plate deflection is measured using suitableinstrumentation. Multiple drops from the same preset dropheight may be performed at the same test location.3.4 The peak plate deflection resulting fr
8、om each drop ateach location is recorded in micrometers or other unit ofmeasure, as appropriate.4. Significance and Use4.1 This test method covers the determination of platedeflection resulting from the application of an impulse load.The deflection is measured at the center of the top of the loadpla
9、te (see Note 1).NOTE 1If the load plate is in “perfectly uniform” contact with theunbound material under the plate, then deflection of the load plate shouldbe equal to the deflection of the surface of the unbound material under test.However, with typical unbound materials a 100% uniform contact cans
10、eldom be achieved. Accordingly, the test surface shall be as clean andsmooth as possible with loose granules and protruding material removed.For gravel surfaces it is recommended that a thin layer of fine sand beplaced over the test point. For fine-grained materials, this will help inobtaining a rea
11、sonably uniform contact between the load plate and thesurface. See 5.1 in Test Method .4.2 Deflections may be either correlated directly to pave-ment performance or used to determine in-situ material char-acteristics of the pavement foundation layers. Some uses of thedata include quality control and
12、 quality assurance of com-pacted layers, and for structural evaluation of load carryingcapacity (see Note 2 and Guide ).NOTE 2The volume of the pavement foundation materials affected bythe applied load is a function of the magnitude of the load, plate size andrigidity, loading rate, buffer stiffness
13、, and the stiffness and shear strengthof the pavement foundation materials. Therefore, care must be taken whenanalyzing the results because the data obtained by the Portable ImpulsePlate Load Test may be obtained under substantially different conditionsthan when a heavy moving wheel load passes over
14、 the pavement surfaceafter construction is complete.5. Apparatus5.1 Instrumentation System, conforming to the followinggeneral requirements.5.2 Instruments Exposed to the Elements, operable in thetemperature range from 0C to 50C (32F to 120F) andtolerant to relatively high humidity, rain and spray,
15、and otheradverse conditions such as dust, shock, and vibrations normallyencountered.1This test method is under the jurisdiction of ASTM Committee E17 on Vehicle- Pavement Systems and is the direct responsibility of Subcommittee E17.41 onPavement Testing and Evaluation.Current edition approved Sept.
16、1, 2015. Published December 2015. Originallyapproved in 2011. DOI: 10.1520/E283511R152For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary
17、page onthe ASTM website.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States15.3 Force-Generating Device (falling mass), capable ofbeing raised, using a guide system, to a preset fixed height anddropped onto a steel-spring subassembly. Des
18、igned to operatewith negligible friction or resistance.5.4 Force pulse, a half-sine or haversine shaped load pulse,with a loading time between 10 and 30 msec, and reproduciblewithin the requirements of 7.5.5.5 Load Plate, shall be rigid and capable of transferring theimpulse force to the surface. Th
19、e stress distribution under theload plate depends on both load plate rigidity and materialtype, and therefore can be parabolic, inverse parabolic, oruniform (1).5.6 Deflection Sensor(s), capable of measuring the maxi-mum vertical plate movement. The deflection sensor or sensorsshall be mounted so th
20、at the angular rotation is minimized withrespect to its measuring plane at the maximum expecteddeflection. The number and spacing of the sensors is optionaland will depend upon the purpose of the test and the materialcharacteristics. Sensors may be of several types such asvelocity transducers or acc
21、elerometers. The instrument shall beconstructed to measure the vertical plate deflection at the centerof the point of impact.5.7 Data Processing and Storage System, displays andoptionally records the deflection data.5.8 Portable Impulse Plate Load Test Device, shall be smallenough to be considered p
22、ortable. Does not require a vehicle ortrailer for transport.6. Reagents and Materials6.1 Adhere to the precision and bias requirements of thisStandard.6.2 Display and store deflection measurements with a reso-lution of 6 20 m (6 0.8 mils) or less.6.3 Store deflection measurements for a period of 50
23、msecor greater to ensure that the peak deflection(s) are recorded.7. Sampling7.1 Calibrate the force-generating device and the deflectionsensor(s) once per year.7.2 Calibrate the force-generating device and the deflectionsensor(s) using a measurement system independent of thePortable Impulse Plate L
24、oad Test device.7.3 Execute calibration at an accredited laboratory using anapproved calibration procedure (2).7.4 Verify deflection measurements after the independentcalibration is complete (See Section 8).7.5 Force-Generating DeviceCalibrate the force-generating device prior to the deflection sens
25、or calibration inaccordance with manufacturers recommendations and in con-sideration of the following requirements:7.5.1 Precondition new spring assemblies with at least 100drops before the calibration procedure is started. Start thecalibration procedure no earlier than 1 hour after precondition-ing
26、. (2)7.5.2 Precondition all (both new and used) spring assem-blies immediately prior to the calibration sequence with threedrops of the falling mass.7.5.3 Use a load cell rated from 20 to 50 kN (2).7.5.4 Test amplifier with a low-pass filter of at least thefourth order (critical frequency 200 Hz at
27、3 dB damping) withfilter characteristics as presented by Butterworth (2).7.5.5 Measure and store the entire force record using anoscilloscope or other suitable measuring device with theappropriate resolution and storage, or a personal computer (2).7.5.6 Ensure the force pulse meets the requirements
28、of thisStandard under Section 5.7.5.7 Ensure that the reference load cell is uniformly sup-ported by a rigid base (i.e. a concrete foundation not less than0.8 m 32 in in length, 0.8 m 32 in in width and 0.5 m 20in thick). The rigid base shall not generate any interferingvibrations as a result of the
29、 impact load (2).7.5.8 Clean the guide rod and ensure that it remains verticalto minimize friction.7.5.9 Release the drop mass no less than ten times from thesame drop height.7.5.10 Adjust the drop height until the deviation of the meanforce is within 6 1 percent of the desired force value.Additiona
30、lly, ensure that the difference between the individu-ally measured force values and the mean force does not exceed6 2 percent (see Note 3).7.5.11 Record each peak load level.7.5.12 Permanently display the calibrated drop height on thedevice.7.6 Deflection SensorCalibrate sensor(s) in accordancewith
31、the manufacturers recommendations and in considerationof the following requirements7.6.1 Measure the peak load during deflection sensor cali-bration.7.6.2 Check conformity of deflection measurements withinat least the following three ranges:7.6.2.1 0.1 mm and 0.7 ( 4 mils and 30 mils)7.6.2.2 0.7 mm
32、and 1.3 mm ( 30 mils and 50 mils)7.6.2.3 1.3 mm and 2.0 mm ( 50 mils and 80 mils)7.6.3 For each deflection range, drop the falling mass noless than ten times from the drop height determined duringcalibration of the force-generating device.7.6.4 Adjust the data processing and storage system andrepeat
33、 calibration when the difference between the mean of thedeflection measured by this unit and the deflection measured bythe independent control unit is more than 0.02 mm (0.8 mils).Ensure that the difference between individual measured valuesis less than or equal to 0.04 mm (1.6 mils) (2).NOTE 3Repla
34、ce the spring assembly when the measured impactduration deviates 6 2 msec or greater from the specified impact duration.8. Verification Testing8.1 Perform verification testing to establish the repeatabilityof deflection measurements under well defined conditionswhen on-site measurements are not repe
35、atable or are question-able. (see Note 4)8.2 Equipment requirements are as follows:E2835 11 (2015)28.2.1 Rigid (that is, concrete) foundation as the testingplatform8.2.2 Pads to allow deflection measurements in the rangesspecified for the calibration procedure.8.2.3 Pad dimensions no smaller than 1.
36、5 times the loadplate diameter.8.2.4 Fully charged batteries8.3 Meet the following environmental requirements:8.3.1 Complete verification testing at a temperature rangefrom 16C to 22C (60F to 72F).8.3.2 Allow sufficient time for the equipment to reach thisspecified temperature range.8.4 Perform veri
37、fication testing using the following proce-dure:8.4.1 Mark test location on rigid foundation and test pad(s).8.4.2 Place pad(s) on marked test location.8.4.3 Place test device on marked test pad(s).8.4.4 Perform nine mass drops using the specified procedure(See Section3).8.4.5 Record resulting peak
38、deflection values.8.4.6 Record supporting information such as airtemperature, surface temperature, distance measurements, andother test identification data as needed.8.5 Complete the following calculations (2) or similaranalyses to ensure repeatability of deflection measurements:8.5.1Smax2 Smin#0.04
39、 mm 1.6 mils! (1)Definitions:Smax= max(S1,S2,S3,S4,S5,S6,S7,S8,S9)Smin= min(S1,S2,S3,S4,S5,S6,S7,S8,S9)Si= Deflection measurements for drop i (where i =1to9), mmSmax= maximum deflection measurement, mmSmin= minimum deflection measurement, mm8.5.2?Smean2 Si? #0.02 mm 0.8 mils! for each Si(2)8.5.2.1Sm
40、ean5(i519Si9(3)Si= Deflection measurements for drop i (where i =1to9), mmSmean= Mean deflection for a set of 9 verification test dropson the given pad configuration, mm8.5.3 | Si-Smeancalibration| 0.02 mm (0.8 mils) (see Note5)8.6 Repeat above procedure on remaining pad configura-tions.8.7 Submit de
41、vice for calibration when the conditions out-lined in 8.5 are not met for any pad configuration.NOTE 4It may be beneficial to perform verification testing on newlypurchased or recently calibrated devices to ensure the device is workingproperly prior to Portable Impulse Plate Load Test device commiss
42、ioning.This would also provide a baseline to which later verification testing couldbe compared.NOTE 5This calculation is carried out if deflections during calibrationwere measured under the same conditions as the subsequent verificationtests.9. Hazards9.1 Keep back straight and lift with leg muscles
43、 whenelevating, dropping, and catching the mass.9.2 Make sure that hands are not positioned beneath theelevated mass.9.3 Secure load mass into the lower locked position prior toand during transportation between test locations.10. Maintenance and Handling10.1 Inspect equipment for necessary repairs (
44、see Note 6).10.2 Store test device in a dry place when not in use.10.3 Protect the guide rod from contact with unboundmaterials.10.4 Clean the force-generating device by removing any dirtwith a dry cloth. Do not grease the guide rod since it isgenerally made of stainless steel.10.5 Check the drop he
45、ight regularly to ensure that therelease mechanism has not moved from the preset heightdetermined during calibration.10.6 Maintain battery charge greater than 50 percent.NOTE 6For some devices, ensure that the rubber bellow enclosing thespring assembly is providing a tight seal to protect the spring
46、 assemblyfrom dust and damage.11.11.1 Perform unbound material test at the time of compac-tion and immediately after corrective actions.11.2 Ensure pavement foundation layers are not frozen. (2).11.3 Perform test when the deflection measurements aregreater than 0.2 mm (8 mils) and less than 3.0 mm (
47、120 mils).12. Site Selection and Preparation12.1 Create a relatively smooth and level spot that willallow the guide rod to remain vertical and prevent translationof the load plate during testing.12.2 Ensure the test area slope is less than 4 percent.12.3 Prepare a test area that is at least 1.5 time
48、s larger thanthe diameter of the loading plate.12.4 Remove loose, dried, cracked, or uneven material priorto testing.12.5 Perform tests by placing the load plate at a uniformdepth. Ensure consistent plate test depths are maintainedthroughout the project for any given material type. Thefollowing test
49、 depths are recommended:E2835 11 (2015)3Material Type Portable Impulse PlateLoad Test Depth (see Note 7)SW, SP, SW-SM, SW-SC,SP-SM, SPSC# one-half lift thickness (see Note 8)GW, GP, GW-GM, GW-GC,GP-GM, GP-GC, GM, GC,CL,ML, CH, MH, OL/OH,SM, SCCompacted with Padfoot Roller:Bottom of deepest indentation of thepadfoot penetration.Compacted with Smooth-Drum Roller:Compaction Surface (0 mm)NOTE 7The depth of influence is roughly 1 to 1.5 times the platediameter. Consequently, deflection measurement obtained for a compactedlift with a thickn
