1、Designation: E2835 11Standard 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 revision, the year o
2、f 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 device. The methodco
3、vers 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 standard does not purpo
4、rt 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 ASTM Standards:2D469
5、5 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 ofAirport and Highway Pavements3. Summary of Test Method3.1 This test method is a type of plate bearing test. The lo
6、adis 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 apreset drop height by the
7、 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 from each drop ateach
8、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 loadplate (see Note 1).NOTE
9、 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 canseldom be achieved. A
10、ccordingly, 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 reasonably uniform cont
11、act between the load plate and thesurface. See 5.1 in Test Method D1195.4.2 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 quality assura
12、nce of com-pacted layers, and for structural evaluation of load carryingcapacity (see Note 2 and Guide D4695).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, and the
13、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 the pavem
14、ent 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) and1This test method is under the jurisdiction of ASTM Committee E1
15、7 on Vehicle- Pavement Systems and is the direct responsibility of Subcommittee E17.41 onPavement Testing and Evaluation.Current edition approved June 1, 2011. Published June 2011. DOI: 10.1520/E2835112For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Servi
16、ce at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.tolerant to relatively high humidity, rain an
17、d spray, and otheradverse conditions such as dust, shock, and vibrations normallyencountered.5.3 Force-Generating Device (falling mass), capable ofbeing raised, using a guide system, to a preset fixed height anddropped onto a steel-spring subassembly. Designed to operatewith negligible friction or r
18、esistance.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. The stress distribution under theload plate dep
19、ends 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 that the angular rotation is minimized withresp
20、ect 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 accelerometers. The instrument shall beconstruct
21、ed 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 portable. Does not require a vehicle ortrailer
22、 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 msecor greater to ensure that the peak deflec
23、tion(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 Load Test device.7.3 Execute calibration at an
24、 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 sensor calibration inaccordance with manufacturer
25、s 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. (2)7.5.2 Precondition all (both new and use
26、d) 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 3 dB damping) withfilter characteristics as p
27、resented 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 of thisStandard under Section 5.7.5.7 Ensure
28、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 impact load (2).7.5.8 Clean the guide rod an
29、d 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.Additionally, ensure that the difference between the i
30、ndividu-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 the manufacturers recommendations and in cons
31、iderationof 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 and # 1.3 mm ( 30 mils and # 50 mils)7.6
32、.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 calibration when the difference
33、 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 3Replace the spring assembly when the
34、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 repeatable or are question-able. (se
35、e Note 4)8.2 Equipment requirements are as follows:E2835 1128.2.1 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 1.5 times the loadplate diameter.8.2.4 Fu
36、lly 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 verification testing using the following pr
37、oce-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 deflection values.8.4.6 Record supporti
38、ng information such as air tempera-ture, surface temperature, distance measurements, and othertest 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 mm 1.6 mils! (1)Definitions:Smax= ma
39、x(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)8.5.2.1Smean5(i 519Si9(3)Si= Deflection measure
40、ments for drop i (where i =1to 9), mmSmean= Mean deflection for a set of 9 verification testdrops on 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 device for calibration when the cond
41、itions 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 commissioning.This would also provide a b
42、aseline 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 whenelevating, dropping, and catc
43、hing 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 (see Note 6).10.2 Store test device
44、 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 height regularly to ensure that ther
45、elease 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 assemblyfrom dust and damage.11.1
46、1.1 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 (120 mils).12. Site Selection and P
47、reparation12.1 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 times larger thanthe diameter of the l
48、oading 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 depths are recommended:Material T
49、ype 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 thickness less than this influence depth will be a compositeE2835 113d
