1、Designation: D 6931 07Standard Test Method forIndirect Tensile (IDT) Strength of Bituminous Mixtures1This standard is issued under the fixed designation D 6931; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revis
2、ion. 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 test method covers procedures for preparing andtesting laboratory-fabricated or field-recovered cores of bitu-minous mixtu
3、res to determine the Indirect Tensile (IDT)Strength.1.2 The within-laboratory repeatability standard deviation,for the recommended rate of loading (50 mm/min) and testtemperature (25C), has been determined to be 80 kPa (12 psi)for 100 mm (4 in.) diameter specimens, based on 28 labs usingeither 2 or
4、4 test replicates with 11 different mix samples.Additional data is provided in Table 1 for the users informa-tion. The between-laboratory reproducibility of this testmethod is being determined and will be available on or beforeAugust 2011. Therefore, this test method should not be used foracceptance
5、 or rejection of materials for purchasing purposes.1.3 The values stated in SI units are to be regarded as thestandard. The values given in parentheses are for informationonly.1.4 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsib
6、ility 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:2D 1074 Test Method for Compressive Strength of Bitumi-nous MixturesD 1561 Practice for Preparati
7、on of Bituminous Mixture TestSpecimens by Means of California Kneading CompactorD 3387 Test Method for Compaction and Shear Propertiesof Bituminous Mixtures by Means of the U.S. Corps ofEngineers Gyratory Testing Machine (GTM)D 3496 Practice for Preparation of Bituminous MixtureSpecimens for Dynamic
8、 Modulus TestingD 3549 Test Method for Thickness or Height of CompactedBituminous Paving Mixture SpecimensD 3666 Specification for Minimum Requirements forAgen-cies Testing and Inspecting Road and Paving MaterialsD 4013 Practice for Preparation of Test Specimens of Bitu-minous Mixtures by Means of G
9、yratory Shear CompactorD 4867/D 4867M Test Method for Effect of Moisture onAsphalt Concrete Paving MixturesD 5581 Test Method for Resistance to Plastic Flow ofBituminous Mixtures Using Marshall Apparatus (6 inch-Diameter Specimen)D 6925 Test Method for Preparation and Determination ofthe Relative De
10、nsity of Hot Mix Asphalt (HMA) Speci-mens by Means of the Superpave Gyratory CompactorD 6926 Practice for Preparation of Bituminous SpecimensUsing Marshall ApparatusD 6927 Test Method for Marshall Stability and Flow ofBituminous MixturesE1 Specification for ASTM Liquid-in-Glass Thermometers2.2 AASHT
11、O Standards:3AASHTO T245 Standard Method for Resistance to PlasticFlow of Bituminous Mixtures Using Marshall ApparatusAASHTO T312 Standard Method for Preparing and Deter-mining the Density of Hot Mix Asphalt (HMA) Speci-mens by Means of the Superpave Gyratory Compactor3. Summary of Test Method3.1 Th
12、e IDT strength of bituminous mixtures is conductedby loading a cylindrical specimen across its vertical diametralplane at a specified rate of deformation and test temperature.The peak load at failure is recorded and used to calculate theIDT strength of the specimen.4. Significance and Use4.1 The val
13、ues of IDT strength may be used to evaluate therelative quality of bituminous mixtures in conjunction withlaboratory mix design testing and for estimating the potentialfor rutting or cracking. The results can also be used todetermine the potential for field pavement moisture damagewhen results are o
14、btained on both moisture-conditioned andunconditioned specimens.1This test method is under the jurisdiction of ASTM Committee D04 on Roadand Paving Materials and is the direct responsibility of Subcommittee D04.26 onFundamental/Mechanistic Tests.Current edition approved Feb. 1, 2007. Published Febru
15、ary 2007.2For 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 page onthe ASTM website.3Available from American Association of State Highwa
16、y and TransportationOfficials (AASHTO), 444 N. Capitol St., NW, Suite 249, Washington, DC 20001,http:/www.transportation.org.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.5. Apparatus5.1 Loading DeviceLoading jack and ring dynamome
17、teror a mechanical or servo-hydraulic testing machine with anelectronic load cell, in accordance with Test Method D 6927,capable of applying a compressive load at a controlled defor-mation rate while measuring the load and deformation.5.2 Loading StripsSteel loading strips with a concavesurface havi
18、ng a radius of curvature equal to the nominal radiusof the test specimen. For specimens with nominal diameter of101.6 mm (4 in.), the loading strips shall be 12.70 6 0.3 mm(0.50 6 0.01 in.) wide. For specimens with nominal diameterof 150 mm (5.91 in.), the loading strips shall be 19.05 6 0.3mm (0.75
19、 6 0.01 in.) wide. The length of the loading stripsshall exceed the thickness of the specimen. The outer edges ofthe loading strips shall be beveled slightly to remove sharpedges.5.2.1 The loading strips shall be part of a test fixture, similarto that shown in Fig. 1, in which the lower loading stri
20、p ismounted on a base having two perpendicular guide rods orposts extending upward. The upper loading strip shall be cleanand freely sliding on the posts. Guide sleeves in the uppersegment of the test fixture shall be in such a position as todirect the two loading strips together without appreciable
21、binding or loose motion in the guide rods.5.3 Temperature Control SystemAn air or water bathcapable of maintaining the specimens at the specified testtemperature within 61.0C (61.8F).5.4 ThermometerA calibrated liquid-in-glass thermom-eter of suitable range with subdivisions readable to 0.1C(0.2F) o
22、r any other thermostatic device of equal accuracy,precision, and sensitivity shall be used. Thermometers shallconform to the requirements of Specification E1.5.5 MiscellaneousA tape, ruler, or set of calipers forspecimen height measurement.NOTE 1If testing to determine the potential for moisture dam
23、age, theapparatus from Test Method D 4867/D 4867M or similar will also benecessary.6. Specimens6.1 Laboratory Molded SpecimensPrepare the laboratory-molded specimens in accordance with one of the followingstandards: Test Methods D 1074, D 3387, D 6925,D 6926; Practices D1561, D3496, D 4013;andAASH-T
24、O T245 or AASHTO T312. A minimum specimen height of50.8 mm (2 in.) is required for specimens with a nominaldiameter of 101.6 mm (4 in.). A minimum specimen height of75 mm (2.95 in.) is required for specimens with a nominalSource of DataNumberofReplicatesSpecimenDiameter(mm)LoadingRate(mm/min)TestTem
25、perature(C)AverageStrength(kPa)StandardDeviationStrength(kPa)d2s(2.833SE)(kPa)TestTemperature(F)AverageStrength(psi)StandardDeviationStrength(psi)d2s(2.833SE)(psi)StandardDeviationStrength(% mean)d2s(2.833SE)(% mean)Andersonand McGennisA3 150 12.5 -10 2870 200 566 14 415 29 82 7.0 19.8NCHRPReport 53
26、0B3 150 12.5 -10 - - - - 9 2232(4 aggregate types;4 binders)2 150 12.5 -10 - - - - 11(nom max size:9.5mmto25mm)Solaimanian andKennedyC-dry4 100 50 25 - 103 292 77 15 42 moisture-conditioned 50 25 - 83 234 77 12 34 (9 labs;3 aggregate types;2 binders)Test MethodD 4867/D 4867M(dry or conditioned)2 100
27、 50 25 - 55 159 77 8 23 (19 labs;5 mixtures)SuggestedSingle LabPrecision50 25 80 77 12AR.M Anderson and R.B. McGennis, 9Ruggedness Evaluation of AASHTO TP7 and TP99, Phase I, FHWA HIPT (Task J), Federal Highway Administration, November1998BW. Christensen and R.F. Bonaquist, 9Evaluation of Indirect T
28、ensile Test (IDT) Procedures for Low-Temperature Performance of Hot Mix Asphalt9, NCHRP Report 530C. Solaimanian and T.W. Kennedy, 9Precision of the Moisture Susceptibility Test Method TEX-531-C9, Project Summary Report 4909-S, November 2000D6931072diameter of 150 mm (5.91 in.). A minimum of three r
29、eplicatesshall be prepared for each mixture.6.2 Core SpecimensCores should have smooth, parallelsurfaces and conform to the height and diameter requirementsspecified for laboratory-molded specimens, except that a mini-mum height of 38 mm (1.5 in.) is permitted for specimens witha nominal diameter of
30、 101.6 mm (4 in.). A minimum of threereplicates from an in-service pavement shall be prepared fortesting.NOTE 2Specimens with a nominal diameter of 101.6 mm (4 in.) aresuitable for mixtures with a nominal maximum particle size of 19 mm (3/4in.) or less. Specimens with a nominal diameter of 150 mm (5
31、.91 in.) aresuitable for mixtures with a nominal maximum particle size of 37.5 mm(1.5 in.) or less.7. Procedure7.1 Determine the specimen height in accordance with TestMethod D 3549, to the nearest 1 mm (0.05 in.).7.2 For core specimens, measure the diameter, at the midheight along axes that are 90
32、apart, and record the average tothe nearest 1 mm (0.05 in.).7.3 Bring the specimen to test temperature 61C (61.8F)by any of the following three alternative procedures. Therecommended test temperature is 25C (77F).NOTE 3Based on previous experience, a standard temperature that hasbeen used for most I
33、DT strength testing is 25C (77F). Other testtemperatures may be used at the discretion of the user.7.3.1 Procedure APlace the specimen in an air bath for aminimum of 4 hours.7.3.2 Procedure BPlace the specimen in a heavy dutyleak-proof plastic bag and then place the specimen in a waterbath for a min
34、imum of 2 hours.7.3.3 Procedure CPlace the specimen in a water bath fora minimum of 30 minutes but not longer than 120 minutes.7.4 Remove the specimen from the air or water bath,remove the specimen from the plastic bag (if necessary), andplace onto the lower loading strip. Slowly lower the toploadin
35、g strip to bring it into light contact with the specimen.Ensure that the loading strips are parallel and centered on thevertical diametral plane. The elapsed time between removal oftest specimens from the bath and the final load determinationshall not exceed 2 minutes.7.5 Apply a vertical compressiv
36、e ramp load until the maxi-mum load is reached. The recommended deformation rate is 506 5 mm/min (2.00 6 0.15 in./min). Record the maximum load.NOTE 4This rate of loading has been commonly used for IDTstrength specimens with a nominal diameter of 101.6 mm (4 in.) and isFIG. 1 Diagram of an IDT Stren
37、gth-Loading FixtureD6931073also recommended in Test Method D 5581 when testing larger specimensfor Marshall Stability with a nominal diameter of 150 mm (5.91 in.).Research has not yet indicated if this deformation rate should be adjustedfor IDT strength specimens with a nominal diameter of 150 mm (5
38、.91 in.).Some researchers4have also used a rate of 3.75 mm/min (0.15 in./min) athigher temperatures (30-40C (86-104F) on specimens with a nominaldiameter of 150 mm (5.91 in.) to evaluate rutting potential.48. Calculation8.1 Calculate the IDT strength as follows:St52000 3 PP3t 3 D(1)( kPa)orSt52 3 PP
39、3t 3 D(2)(psi)where:St= IDT strength, kPa (psi)P = maximum load, N (lbf)t = specimen height immediately before test, mm (in.)D = specimen diameter, mm (in.)9. Report9.1 Report the following information:4D.W. Christensen, R. Bonaquist, and D.P. Jack, “Evaluation of TriaxialStrength as a Simple Test f
40、or Asphalt Concrete Rut Resistance”, PennsylvaniaDepartment of Transportation, Pennsylvania Transportation Institute, Final Report,August 2000.FIG. 2 Photograph of a Typical IDT Strength-Loading FixtureD69310749.1.1 Type of samples tested (laboratory-molded specimensor core specimens) and descriptio
41、n of mixture (such as,nominal maximum aggregate size, gradation, binder type).9.1.2 The measured height and nominal (lab) or average(core) diameter of each specimen, to the nearest 1 mm (0.05in.).9.1.3 Test temperature, to the nearest 1C (1.8F).9.1.4 Deformation rate used in test, to the nearest mm/
42、min(0.1 in./min).9.1.5 Procedure used for conditioning specimen (as de-scribed in 7.3), including the method of temperature controland total bath time.9.1.6 Maximum compressive load, to the nearest 1 N (0.2lbf).9.1.7 The IDT strength of each of the three replicatespecimens and the average IDT streng
43、th for the set of speci-mens, to the nearest 10 kPa (1 psi).10. Precision and Bias10.1 The within-laboratory repeatability standard deviation,for the recommended rate of loading (50 mm/min) and testtemperature (25C), has been determined to be 80 kPa (12 psi)for 100 mm (4 in.) diameter specimens, bas
44、ed on 28 labs usingeither 2 or 4 test replicates with 11 different mix samples.Additional data is provided in Table 1 for the users informa-tion. The between-laboratory reproducibility of this testmethod is being determined and will be available on or beforeAugust 2011. Therefore, this Standard shou
45、ld not be used foracceptance or rejection of materials for purchasing purposes.10.2 The precision of this test method depends on the abilityof the personnel who are conducting the test and the capability,calibration, and maintenance of the equipment used. Suggestedways of maintaining the testing qua
46、lity are contained inSpecification D 3666.10.3 No information can be presented on the bias of theprocedure in this test method for measuring the tensile strengthof bituminous mixtures, because it is a destructive test andthere is no basis for establishing a true reference value forcomparison.11. Key
47、words11.1 asphalt mixture; bituminous mixture; indirect tensilestrength; IDTASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validit
48、y of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comment
49、s are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken,
