1、Designation: D 4602 93 (Reapproved 2002)Standard Guide forNondestructive Testing of Pavements Using Cyclic-LoadingDynamic Deflection Equipment1This standard is issued under the fixed designation D 4602; the number immediately following the designation indicates the year oforiginal adoption or, in th
2、e case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This guide covers the preparation, equipment, calibra-tion of equipment, location of
3、test points, magnitudes andconfigurations of applied loads, cyclic frequencies, and presen-tation of data for nondestructive testing of pavements usingcyclic-loading dynamic deflection equipment.1.2 Cyclic-loading dynamic deflection equipment includes agroup of devices that induce a steady-state sin
4、usoidal vibrationin the pavement through cyclic generation of a dynamic load.All such devices apply a static load on the pavement surface,resulting in a static deflection, and then induce some sinusoidalload and consequent deflection around the static load anddeflection through an applied steady-sta
5、te dynamic load.1.3 As there are great differences between various cyclic-loading dynamic deflection devices, this guide is intended togive uniformly-applicable guidance, rather than specific in-structions, for their use. For instance, it will specify thatcalibration of the devices and their instrum
6、entation be carriedout at the frequencies and in accordance with proceduresrecommended by their manufacturers, rather than providingspecific instructions. Also, data is specified for collection thatshould prove adequate for usual applications of such deflectiondata, but no procedures are included fo
7、r “back-calculating”elastic moduli of pavement layers or other such applications.1.4 This guide does not apply to static deflection equipment,such as the “Benkelman Beam,” automated beam deflectionequipment, such as the “California Traveling Deflectometer,”or impulse deflection equipment, such as th
8、e “Falling WeightDeflectometer.”1.5 It is common practice in the engineering profession touse concurrently pounds to represent both a unit of mass (lbm)and of force (lbf). This implicitly combines two separatesystems of units, that is, the absolute system and the gravita-tional system. It is scienti
9、fically undesirable to combine the useof two separate sets of inch-pound units within a singlestandard. This guide has been written using the gravitationalsystem of units when dealing with the inch-pound system. Inthis system, the pound (lbf) represents a unit of force (weight).However, the use of b
10、alances or scales recording pounds ofmass (lbm), or the recording of density in lbm/ft3should not beregarded as nonconformance with this guide.1.6 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standar
11、d to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.1.7 This guide offers an organized collection of informationor a series of options and does not recommend a specificcourse of action. This document cannot replace education
12、 orexperience and should be used in conjunction with professionaljudgment. Not all aspects of this guide may be applicable in allcircumstances. This ASTM standard is not intended to repre-sent or replace the standard of care by which the adequacy ofa given professional service must be judged, nor sh
13、ould thisdocument be applied without consideration of a projects manyunique aspects. The word “Standard” in the title of thisdocument means only that the document has been approvedthrough the ASTM consensus process.2. Terminology2.1 Definitions of Terms Specific to This Standard:2.1.1 test locationt
14、he point at which the center of theapplied load or loads are located.3. Significance and Use3.1 Nondestructive testing of pavements to obtain deflectiondata for use in pavement evaluation and overlay design hasbecome common. While the diversity of equipment and dataapplications make specific procedu
15、res infeasible, this guide isintended to encourage the collection of sufficient deflection1This guide is under the jurisdiction of ASTM Committee E17 on Vehicle-Pavement Systems and is the direct responsibility of Subcommittee E17.41 onPavement Management.Current edition approved Sept. 15, 1993. Pub
16、lished November 1993. Originallypublished as D 4602 86. Last previous edition D 4602 86.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.data, adequate calibration of equipment, and implementation ofgeneral procedures leading to bette
17、r quality and more uniformdeflection measurements.4. Apparatus4.1 The most common commercially available devices arethe “Dynaflect” device and various models of the “RoadRater.”2NOTE 1This guide has not been written with the intent to exclude anycurrent or future manufacturer of equipment or of newe
18、r models ormodifications of equipment listed herein to perform these types of tests.The subcommittee welcomes information on such devices for inclusion infuture revisions of this guide.4.2 DynaflectA trailer-mounted device that has a staticweight of 2000 to 2100 lbf (8.88 to 9.24 kN) has been found
19、tobe satisfactory. The load is applied through two steel wheels,each 4 in. (102 mm) wide and 16 in. (406 mm) in diameter. Theloading surface of each wheel is coated with urethane having auniform thickness of about38 in. (9.53 mm). These wheels arespaced 20 in. (508 mm) apart, center to center, and a
20、pply a totalpeak-to-valley dynamic force of 1000 lbf (4.45 kN) at a fixedfrequency of 8 Hz. The total force applied varies fromapproximately 1500 to 2500 lbf (6.67 to 11.12 kN). Deflectionsare measured implicitly by five velocity transducers suspendedfrom a “placing bar” that may be lowered to place
21、 the sensorson the pavement. Sensor 1 is located equidistant between andin axial alignment with the load wheels. The other four are alsoequidistant from the load wheels, located at intervals of 1 ft(0.30 m) toward the front of the trailer.4.3 Road Rater DevicesSome models of Road Raterdevices are tr
22、ailer mounted, some models are mounted on thefront of a vehicle, and other versions are mounted in a van sothat the head is lowered just to the rear of the rear axle of thevehicle. Both loading frequency and magnitudes of dynamicloads may be varied by the operator. Depending on the model,normal oper
23、ating frequencies range from 10 to 60 Hz andmaximum dynamic forces range from 950 to 5500 lbf (2.00 to24.46 kN). The four models in common use are as follows:4.3.1 Model 400BThis model has a trailer weight of 3000lbf (13.33 kN). Its maximum rated static load is 2400 lbf (10.66kN), created by the wei
24、ght of the force actuation system andhydraulic pressure against the trailer. The peak-to-valley mag-nitudes of dynamic forces applied range is from 500 to 3000 lbf(2.22 to 13.33 kN). The loads are applied through two standardloading plates 4 in. (102 mm) wide by 7 in. (178 mm) long,located on 912 in
25、. (241 mm) centers, with the long dimensionsin the direction of trailer travel. Deflections are measuredimplicitly by four velocity transducers with sensor 1 equidis-tant between, and in axial alignment with, the load feet. Theother sensors are located at 1-ft (0.30-m) intervals. Additionalsensors m
26、ay be provided with different lengths of placementbars, or the same sensors can be mounted at different locations.4.3.2 Model 400AThis model is similar to the Model400B, but is mounted on the front bumper of the vehicle andprovides peak-to-valley magnitudes of dynamic forces from450 to 950 lbf (2.00
27、 to 4.23 kN). Five preset operatingfrequencies range from 10 to 40 Hz. The centers of the loadingplates are spaced at 10-in. (254-mm) intervals. This model mayhave from two to four sensors, depending on the age of theunit.4.3.3 Model 2000This model has a trailer weight of 4300lbf (19.1 kN), a maximu
28、m rated static load of 3800 lbf (16.9kN), and a peak-to-valley dynamic force ranging from 1000 to5500 lbf (4.44 to 24.46 kN). A van version utilizes the samerange of dynamic force. Loads are usually applied through asingle plate 18 in. (457 mm) in diameter. Sensor 1 is located atthe center of the lo
29、ading plate, with the other three (or more)sensors located at 1-ft (0.30-m) increments, as for the Model400B and the Dynaflect. There is an optional model for whichtwo rectangular plates 4 by 7 in. (102.6 by 177.8 mm) aresubstituted for the circular load plate.4.3.4 Model 2008This model has a traile
30、r load of 7000 lbf(31.09 kN), a maximum rated static load of 5800 lbf (25.76kN), and a peak-to-valley dynamic force ranging from 1200 to8000 lbf (5.34 to 35.54 kN). The same load plate andtransducers as used by Model 2008 are used for Model 2000.4.4 Either single or dual circular loading plates or l
31、oadwheels may be used.4.5 Although not critical to calculations using results ofdynamic deflection testing, most devices now have sensor 1 atthe center of load (see Note 2) and the other sensors at 1-ft(0.30-m) intervals from that point. This appears to be apractical spacing, but greater spacing may
32、 sometimes berequired for wide deflection basins experienced on heavy-dutyairfield pavements. Similarly, most deflection measurementdevices now have four or more sensors to satisfactorilymeasure the deflection basin. As many pavements have anumber of different layers, five sensors is the preferredmi
33、nimum number where layer elastic moduli are to be back-calculated. The number of layer moduli to be calculated cannotexceed the number of sensors.NOTE 2It is preferable that the sensors be in contact with thepavement and isolated from the loading plate (or plates).5. Calibration5.1 All cyclic-loadin
34、g dynamic deflection devices shall becarefully maintained and calibrated in accordance with themanufacturers operating and maintenance instructions for thedevices. As a minimum, loading frequency and load cellsmeasuring applied loads for devices with capabilities forvarying magnitude and frequency o
35、f loading shall be checkedevery fifth day of production testing, or when the operator hasreason to believe that indicated operating frequencies ormeasured loads are incorrect.5.2 DynaflectCalibration of the dynamic-load applicationdevice for the Dynaflect requires specialized equipment gen-erally no
36、t available except at the manufacturers location. Thedevice shall be calibrated at the time of purchase and certified2The Dynaflect device is manufactured by the SIE division of Geosource, Inc. ofFort Worth, TX. The Road Rater is manufactured by Foundation Mechanics, Inc. ofEl Segundo, CA. Cox and S
37、ons, Inc. of California have built custom devices,including a very sophisticated device for the Federal Highway Administrationnicknamed the “Thumper”. The U.S.Army Engineer Waterways Experiment Station(WES) also uses a custom-built cyclic-loading dynamic device called the “WES16-kip (71,172 N) Vibra
38、tor”. Shell also developed a “4-kip (17,793 N) Vibrator” forpavement evaluation.D 4602 93 (2002)2results shall be furnished the purchaser. Potential error fromvariations in applied loads for this device is nominal; thus,retesting after leaving the factory is not considered a require-ment. Calibratio
39、n for applied load shall be conducted indirectlymonthly by checking the frequency of the counter-rotating flywheels with a strobe light. Velocity transducers shall becalibrated each day the device is in use.5.3 Road RaterThe force transducer shall be calibrateddaily by checking the measured force un
40、der the known mass ofthe mass unit. At the beginning of each project and at five-dayintervals, a field calibration check of the velocity transducers asrecommended by the manufacturer shall be conducted byplacing all transducers equidistant from the load plate. Ifsignificant differences are noted for
41、 a transducer, it shall bereturned to the manufacturer for check or calibration understandard calibration vibration. The manufacturer recommendsthat velocity transducers be returned annually for check andrecalibration.6. Test Locations6.1 Locations selected for testing are necessarily dependenton th
42、e type of pavement, purpose of testing, and intendedutilization of test data. It is common practice to make mea-surements in wheel paths for both highway or airfield pave-ments; for comparison, a limited number of measurements areoften taken in less trafficked areas or along the edge of thepavement.
43、6.2 The distance between measurement series usually de-pends on: (1) type of pavement, ( 2) whether a single test is runat discrete intervals along the pavement or several tests are runat close spacing before moving another discrete interval for thenext measurement series, and (3) on the length of t
44、he pavementto be tested. For example, a measurement series every milemay be adequate for 100 miles (161 km) of highway, whereasa single test every 300 ft may be warranted for a 10 000-ft(3048-m) runway. In the latter case, test series are usuallyconducted along parallel paths, with test locations st
45、aggered toprovide closer spacing for individual tests. While test programsusually should be planned with some uniform discrete dis-tances between test locations, additional testing shall beconducted where unusual conditions are noted (an examplewould be an intermediate location where moisture is not
46、edseeping through cracks in the pavement).6.3 While single measurements at discrete intervals arecommon, some prefer to run “measurement series” in closeproximity to increase the confidence level in the test results ateach location.6.3.1 Jointed Concrete PavementsIn the case of jointedrigid pavement
47、s, tests are usually conducted in the wheel pathat mid-slab and with the load near a joint and sensors spanningthe joint to obtain data on joint efficiency. As wheel paths aredifficult to locate on rigid pavements, the center of load forhighway pavements may be placed between 18 and 24 in. (457and 6
48、10 mm) from the edge of the pavement or the edge of thelane. Deflections are also often taken with the load located atcorners for void detection. Where the test results are to be usedfor back-calculation of layer elastic moduli, it is usuallypreferable to test near the center of the slab to avoid ed
49、geeffects.6.3.2 Continuously Reinforced Concrete PavementsTesting is usually conducted as for jointed rigid pavements,except that the discrete slabs between cracks are usually smalland loading both at mid-slab and near a crack (in lieu of a joint)may not be appropriate for all measurements.7. Magnitudes of Applied Loads7.1 The nonlinear strain responses of the soil and soil-likecomponents of a pavement structure introduce an apparentadvantage for approximating as closely as possible the wheelloads expected in magnitude and applied pressure. Since onlya few of the de
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