1、Designation: D6931 12D6931 17Standard Test Method forIndirect Tensile (IDT) Strength of BituminousAsphaltMixtures1This standard is issued under the fixed designation D6931; 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 covers procedures for preparing and testing laboratory-fabricated or field-recovered cores of bitum
3、i-nousasphalt mixtures to determine the Indirect Tensileindirect tensile (IDT) Strength.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 for 101.6 mm diameter specimens, ba
4、sed on 28 labs using either 2 or 4 testreplicates with 11 different mix samples. Additional data is provided in Table for the users information. The between-laboratoryreproducibility of this test method is being determined and will be available on or beforeAugust 2012. Therefore, this test methodsho
5、uld not be used for acceptance or rejection of materials for purchasing purposes.1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.1.3 This standard does not purport to address all of the safety concerns, if any, associated
6、with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use.1.4 This international standard was developed in accordance with internationally recognized principles on stan
7、dardizationestablished in the Decision on Principles for the Development of International Standards, Guides and Recommendations issuedby the World Trade Organization Technical Barriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2D1074 Test Method for Compressive Strength of A
8、sphalt MixturesD1561D1561/D1561M Practice for Preparation of Bituminous Mixture Test Specimens by Means of California KneadingCompactorD3387 Test Method for Compaction and Shear Properties of Bituminous Mixtures by Means of the U.S. Corps of EngineersGyratory Testing Machine (GTM)D3496 Practice for
9、Preparation of Bituminous Mixture Specimens for Dynamic Modulus Testing (Withdrawn 2010)3D3549D3549/D3549M Test Method for Thickness or Height of Compacted Bituminous Paving Mixture SpecimensD3666 Specification for Minimum Requirements for Agencies Testing and Inspecting Road and Paving MaterialsD40
10、13 Practice for Preparation of Test Specimens of Bituminous Mixtures by Means of Gyratory Shear Compactor (Withdrawn2013)3D4867/D4867M Test Method for Effect of Moisture on Asphalt Concrete Paving MixturesD5581 Test Method for Resistance to Plastic Flow of Bituminous Mixtures Using Marshall Apparatu
11、s (6 inch-DiameterSpecimen)D6925 Test Method for Preparation and Determination of the Relative Density of Asphalt Mix Specimens by Means of theSuperpave Gyratory CompactorD6926 Practice for Preparation of Asphalt Mixture Specimens Using Marshall ApparatusD6927 Test Method for Marshall Stability and
12、Flow of Asphalt Mixtures1 This test method is under the jurisdiction of ASTM Committee D04 on Road and Paving Materials and is the direct responsibility of Subcommittee D04.26 onFundamental/Mechanistic Tests.Current edition approved Feb. 1, 2012July 1, 2017. Published February 2012July 2017. Previou
13、s version published in 2007 Originally approved in 2007. Last previousedition approved in 2012 as D6931 12. DOI: 10.1520/D6931-12.10.1520/D6931-17.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standard
14、svolume information, refer to the standards Document Summary page on the ASTM website.3 The last approved version of this historical standard is referenced on www.astm.org.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes
15、 have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official
16、 document.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1E1 Specification for ASTM Liquid-in-Glass Thermometers2.2 AASHTO Standards:4AASHTO T245T 245 Standard Method for Resistance to Plastic Flow of Bituminous Mixtures Using Marshal
17、l ApparatusAASHTO T312T 312 Standard Method for Preparing and Determining the Density of Hot Mix Asphalt (HMA) Specimens byMeans of the Superpave Gyratory Compactor4 Available from American Association of State Highway and Transportation Officials (AASHTO), 444 N. Capitol St., NW, Suite 249, Washing
18、ton, DC 20001,http:/www.transportation.org.TABLE 1 Single-Laboratory Repeatability and ReproducibilitySource of DataNumberofReplicatesSpecimenDiameter(mm)LoadingRate(mm/min)TestTemperature(C)AverageStrength(kPa)StandardDeviationStrength(kPa)d2s(2.83SE)(kPa)StandardDeviationStrength(% mean)d2s(2.83SE
19、)(% mean)Anderson andMcGennisA 3 150 12.5 -10 2870 200 566 7.0 19.8Anderson andMcGennisA 3 150 12.5 10 2870 200 566 7.0 19.8N CHRPReport 530B 3 150 12.5 -10 - - - 9 2232N CHRPReport 530B 3 150 12.5 10 - - - 9 22 32(4 aggregatetypes;4 binders)2 150 12.5 -10 - - - 11(4 aggregatetypes;4 binders)2 150 1
20、2.5 10 - - - 11(nom max size:9.5 mm to 25mm)SolaimanianandKennedyCdry4 100 50 25 - 103 292 SolaimanianandKennedyC dry4 100 50 25 - 103 292 - -moisture-conditioned 50 25 - 83 234 moisture-conditioned 50 25 - 83 234 - -(9 labs; 3aggregatetypes; 2binders)Test MethodD4867/D4867M(dry or condi-tioned)2 10
21、0 50 25 - 55 159 Test MethodD4867/D4867M(dry or condi-tioned)2 100 50 25 - 55 159 - -(19 labs;5 mixtures)SuggestedSingleLab Precision50 25 80A R. M. Anderson and R. B. McGennis, “Ruggedness Evaluation of AASHTO TP7 and TP9,” Phase I, FHWA HIPT (Task J), Federal Highway Administration, November1998.B
22、 W. Christensen and R. F. Bonaquist, “Evaluation of Indirect Tensile Test (IDT) Procedures for Low-Temperature Performance of Hot Mix Asphalt,” NCHRP Report 530.C Solaimanian and T. W. Kennedy, “Precision of the Moisture Susceptibility Test Method TEX-531-C,” Project Summary Report 4909-S, November
23、2000.D6931 1723. Summary of Test Method3.1 The IDT strength of bituminousasphalt mixtures is conducteddetermined by loading a cylindrical specimen across itsvertical diametral plane at a specified rate of deformation and test temperature. The peak load at failure is recorded and used tocalculate the
24、 IDT strength of the specimen.4. Significance and Use4.1 The values of IDT strength may be used to evaluate the relative quality of bituminousasphalt mixtures in conjunction withlaboratory mix design testing and for estimating the potential for rutting or cracking. The results can also be used to de
25、termine thepotential for field pavement moisture damage when results are obtained on both moisture-conditioned and unconditionedspecimens.NOTE 1The quality of the results produced by this standard are dependent on the competence of the personnel performing the procedure and thecapability, calibratio
26、n, and maintenance of the equipment used. Agencies that meet the criteria of Specification D3666 are generally considered capableof competent and objective testing, sampling, inspection, etc. Users of this standard are cautioned that compliance with Specification D3666 alone doesnot completely ensur
27、e reliable results. Reliable results depend on many factors; following the suggestions of Specification D3666 or some similaracceptable guideline provides a means of evaluating and controlling some of those factors.5. Apparatus5.1 Loading DeviceLoading jack and ring dynamometer or a mechanical or se
28、rvo-hydraulic testing machine with anelectronic load cell, in accordance with Test Method D6927, capable of applying a compressive load at a controlled deformationrate while measuring the load and deformation.5.2 Loading StripsSteel loading strips with a concave surface having a radius of curvature
29、equal to the nominal radius of thetest specimen. For specimens with nominal diameter of 101.6100 mm, the loading strips shall be 12.70 6 0.3 mm wide. Forspecimens with nominal diameter of 150 mm, the loading strips shall be 19.05 6 0.3 mm wide. The length of the loading stripsshall exceed the thickn
30、ess of the specimen. The outer edges of the loading strips shall be beveled slightly to remove sharp edges.5.2.1 The loading strips shall be part of a test fixture, similar to that shown in Fig. 1, in which the lower loading strip is mountedon a base having two perpendicular guide rods or posts exte
31、nding upward. The upper loading strip shall be clean and freely slidingon the posts. Guide sleeves in the upper segment of the test fixture shall be in such a position as to direct the two loading stripstogether without appreciable binding or loose motion in the guide rods.5.3 Temperature Control Sy
32、stemAn air or water bath capable of maintaining the specimens at the specified test temperaturewithin 61.0C.61.0 C.5.4 ThermometerA calibrated liquid-in-glass thermometer of suitable range with subdivisions readable to 0.1C0.1 C or anyother thermostatic device of equal accuracy, precision, and sensi
33、tivity shall be used. Thermometers shall conform to therequirements of Specification E1.5.5 MiscellaneousA tape, ruler, or set of calipers for specimen height measurement.NOTE 2If testing to determine the potential for moisture damage, the apparatus from Test Method D4867/D4867M or similar will also
34、 be necessary.6. Specimens6.1 Laboratory Molded Laboratory-Molded SpecimensPrepare the laboratory-molded specimens in accordance with one ofthe following standards: Test Methods D1074, D3387, D6925, D6926; Practices D1561D1561/D1561M, D3496, D4013, D6926;and AASHTO T245 T 245 or AASHTO T312. T 312.
35、A minimum specimen height of 50.850 mm is required for specimens witha nominal diameter of 101.6100 mm. A minimum specimen height of 75 mm is required for specimens with a nominal diameterof 150 mm. A minimum of three replicates shall be prepared for each mixture.6.2 Core SpecimensCores should have
36、smooth, parallel smooth surfaces and conform parallel faces, conforming to the heightand diameter requirements specified for laboratory-molded specimens, except that a minimum height of 38 mm is permitted forspecimens with a nominal diameter of 101.6100 mm.Aminimum of three replicates from an in-ser
37、vice pavement shall be preparedfor testing.NOTE 3Specimens with a nominal diameter of 101.6100 mm are suitable for mixtures with a nominal maximum particle size of 19 mm or less.Specimens with a nominal diameter of 150 mm are suitable for mixtures with a nominal maximum particle size of 37.5 mm or l
38、ess.7. Procedure7.1 Determine the specimen height in accordance with Test Method D3549D3549/D3549M, to the nearest 1 mm.7.2 For core specimens, measure the diameter,diameter at the mid height along axes that are 9090 apart, and record the averageto the nearest 1 mm.7.3 Bring the specimen to test tem
39、perature61C61 C by any of the following three alternative procedures. The recommendedtest temperature is 25C.25 C.NOTE 4Based on previous experience, a standard temperature that has been used for most IDT strength testing is 25C.25 C. Other test temperaturesmay be used at the discretion of the user.
40、D6931 1737.3.1 Procedure APlace the specimen in an air bath for a minimum of 4 hours.h.7.3.2 Procedure BPlace the specimen in a heavy duty leak-proof plastic bag and then place the specimen in a water bath fora minimum of 2 hours.h.7.3.3 Procedure CPlace the specimen in a water bath for a minimum of
41、 30 minutesmin but not longer than 120 minutes.min.7.4 Remove the specimen from the air or water bath, remove the specimen from the plastic bag (if necessary), and place ontothe lower loading strip. Slowly lower the top loading strip to bring it into light contact with the specimen. Ensure that the
42、loadingstrips are parallel and centered on the vertical diametral plane. The elapsed time between removal of test specimens from the bathand the final load determination shall not exceed 2 minutes.min.7.5 Apply a vertical compressive ramp load until the maximum load is reached. The recommended defor
43、mation rate is 50 65 mm/min. Record the maximum load.NOTE 5This rate of loading has been commonly used for IDT strength specimens with a nominal diameter of 101.6100 mm and is also recommendedin Test Method D5581 when testing larger specimens for Marshall Stability with a nominal diameter of 150 mm.
44、 Research has not yet indicated if thisFIG. 1 Diagram of an IDT Strength-Loading FixtureD6931 174deformation rate should be adjusted for IDT strength specimens with a nominal diameter of 150 mm. Some researchers5 have also used a rate of 3.75mm/min at higher temperatures (30-40C) (30 to 40 C) on spe
45、cimens with a nominal diameter of 150 mm to evaluate rutting potential.58. Calculation8.1 Calculate the IDT strength as follows:St 5 20003P3t3D (1)( kPa)where:St = IDT strength, kPaP = maximum load, Nt = specimen height immediately before test, mmD = specimen diameter, mm5 Christensen, D.W., Bonaqui
46、st, R. , D. W., Bonaquist, R., and Jack, D.P., D. P., “Evaluation of Triaxial Strength as a Simple Test for Asphalt Concrete Rut Resistance,”Pennsylvania Department of Transportation, Pennsylvania Transportation Institute, Final Report, August 2000.FIG. 2 Photograph of a Typical IDT Strength-Loading
47、 FixtureD6931 175St = IDT strength, kPa,P = maximum load, N,t = specimen height immediately before test, mm, andD = specimen diameter, mm.9. Report9.1 Report the following information:9.1.1 Type of samples tested (laboratory-molded specimens or core specimens) and description of mixture (such as,as
48、nominalmaximum 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.9.1.3 Test temperature, to the nearest 1C.1 C.9.1.4 Deformation rate used in test, to the nearest mm/min.9.1.5 Procedure used for condit
49、ioning specimen (as described in 7.3), including the method of temperature control and total bathtime.9.1.6 Maximum compressive load, to the nearest 1 N.9.1.7 The IDT strength of each of the three replicate specimens and the average IDT strength for the set of specimens, to thenearest 10 kPa.10. Precision and Bias10.1 The within-laboratory repeatability standard deviation, for the recommended rate of loading (50 mm/min) and testtemperature (25C),(25 C), has been determined to be 80 kPa for 101.6 mm 100-mm diameter sp
