1、Designation: D 4602 93 (Reapproved 2008)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 () 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 t
3、est 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 sinu
4、soidal 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-stat
5、e 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 instrume
6、ntation 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 for
7、 “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 the
8、 “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 scientif
9、ically 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 ba
10、lances 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 standard
11、 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 sho
13、uld 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 locationth
14、e 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 procedur
15、es 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 Testing, Evaluation, and Management Methods.Current edi
16、tion approved June 1, 2008. Published July 2008. Originally approvedin 1986. Last previous edition approved in 2002 as D 4602 93 (2002).1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.data, adequate calibration of equipment, and impl
17、ementation ofgeneral procedures leading to better 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 anycurren
18、t or future manufacturer of equipment or of newer 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 20
19、00 to 2100 lbf (8.88 to 9.24 kN) has been found 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 arespace
20、d 20 in. (508 mm) apart, center to center, and apply 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 suspendedf
21、rom a “placing bar” that may be lowered to place 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 Rate
22、r DevicesSome models of Road Raterdevices are trailer 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
23、the operator. Depending on the model,normal operating 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 stati
24、c load is 2400 lbf (10.66kN), created by the weight 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 m
25、m) wide by 7 in. (178 mm) long,located on 912 in. (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
26、 at 1-ft (0.30-m) intervals. Additionalsensors may 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 magni
27、tudes of dynamic forces from450 to 950 lbf (2.00 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
28、 a trailer weight of 4300lbf (19.1 kN), a maximum 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 diam
29、eter. Sensor 1 is located atthe center of the loading 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 lo
30、ad plate.4.3.4 Model 2008This model has a trailer 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 Ei
31、ther single or dual circular loading plates or loadwheels 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 t
32、o be apractical spacing, but greater spacing may 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 d
33、ifferent layers, five sensors is the preferredminimum 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
34、 (or plates).5. Calibration5.1 All cyclic-loading 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 c
35、apabilities forvarying magnitude and frequency of 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 Dynafl
36、ect requires specialized equipment gen-erally not 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 Founda
37、tion Mechanics, Inc. ofEl Segundo, CA. Cox and Sons, 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 dynam
38、ic device called the “WES16-kip (71,172 N) Vibrator”. Shell also developed a “4-kip (17,793 N) Vibrator” forpavement evaluation.D 4602 93 (2008)2results shall be furnished the purchaser. Potential error fromvariations in applied loads for this device is nominal; thus,retesting after leaving the fact
39、ory is not considered a require-ment. Calibration 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 c
40、alibrateddaily by checking the measured force under 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 loa
41、d plate. Ifsignificant differences are noted for 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 sel
42、ected for testing are necessarily dependenton the 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 tr
43、afficked areas or along the edge of thepavement.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 thenex
44、t measurement series, and (3) on the length of the 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 usuallyconduc
45、ted along parallel paths, with test locations staggered 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 b
46、e an intermediate location where moisture is notedseeping 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 Concre
47、te PavementsIn the case of jointedrigid pavements, 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 pavemen
48、ts may be placed between 18 and 24 in. (457and 610 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
49、 to test near the center of the slab to avoid edgeeffects.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
