1、Designation:D693107 Designation: D6931 12Standard Test Method forIndirect Tensile (IDT) Strength of Bituminous Mixtures1This 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
2、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 test method covers procedures for preparing and testing laboratory-fabricated or field-recovered cores of
3、 bituminousmixtures 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 100101.6 mm (4 in.) diameter specimens, based on 2
4、8 labs usingeither 2 or 4 test replicates with 11 different mix samples. Additional data is provided in Table 1 for the users information. Thebetween-laboratory reproducibility of this test method is being determined and will be available on or before August 2011.2012.Therefore, this test method sho
5、uld not be used for acceptance or rejection of materials for purchasing purposes.1.3 The values stated in SI units are to be regarded as standard. The values given in parentheses are for information only.1.4 This standard does not purport to address all of the safety concerns, if any, associated wit
6、h 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.2. Referenced Documents2.1 ASTM Standards:2D1074 Test Method for Compressive Strength of Bituminous MixturesD1561
7、 Practice for Preparation of Bituminous Mixture Test Specimens by Means of California Kneading CompactorD3387 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 Preparation of Bituminous Mixtu
8、re Specimens for Dynamic Modulus TestingD3549 Test Method for Thickness or Height of Compacted Bituminous Paving Mixture SpecimensD3666 Specification for Minimum Requirements for Agencies Testing and Inspecting Road and Paving MaterialsD4013 Practice for Preparation of Test Specimens of Bituminous M
9、ixtures by Means of Gyratory Shear CompactorD4867/D4867M Test Method for Effect of Moisture on Asphalt Concrete Paving MixturesD5581 Test Method for Resistance to Plastic Flow of Bituminous Mixtures Using Marshall Apparatus (6 inch-DiameterSpecimen)D6925 Test Method for Preparation and Determination
10、 of the Relative Density of Hot Mix Asphalt (HMA) Specimens byMeans of the Superpave Gyratory CompactorD6926 Practice for Preparation of Bituminous Specimens Using Marshall ApparatusD6927 Test Method for Marshall Stability and Flow of Bituminous MixturesE1 Specification for ASTM Liquid-in-Glass Ther
11、mometers2.2 AASHTO Standards:3AASHTO T245 Standard Method for Resistance to Plastic Flow of Bituminous Mixtures Using Marshall ApparatusAASHTO T312 Standard Method for Preparing and Determining the Density of Hot Mix Asphalt (HMA) Specimens by Meansof the Superpave Gyratory Compactor3. Summary of Te
12、st Method3.1 The IDT strength of bituminous mixtures is conducted by loading a cylindrical specimen across its vertical diametral plane1This 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/
13、Mechanistic Tests.Current edition approved Feb. 1, 2007. Published February 2007. DOI: 10.1520/D6931-07.Current edition approved Feb. 1, 2012. Published February 2012. Previous version published in 2007 as D693112. DOI: 10.1520/D6931-12.2For referenced ASTM standards, visit the ASTM website, www.ast
14、m.org, or contact ASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.3Available from American Association of State Highway and Transportation Officials (AASHTO), 444 N. Capitol St., NW, Suite
15、 249, Washington, DC 20001,http:/www.transportation.org.1This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes
16、 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 document.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, Unite
17、d States.at a specified rate of deformation and test temperature. The peak load at failure is recorded and used to calculate the IDT strengthof the specimen.4. Significance and Use4.1 The values of IDT strength may be used to evaluate the relative quality of bituminous mixtures in conjunction withla
18、boratory mix design testing and for estimating the potential for rutting or cracking. The results can also be used to determine thepotential for field pavement moisture damage when results are obtained on both moisture-conditioned and unconditionedspecimens.5. Apparatus5.1 Loading DeviceLoading jack
19、 and ring dynamometer or a mechanical or servo-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 co
20、ncave surface having a radius of curvature equal to the nominal radius of thetest specimen. For specimens with nominal diameter of 101.6 mm (4 in.), mm, the loading strips shall be 12.70 6 0.3 mm (0.506 0.01 in.) wide. For specimens with nominal diameter of 150 mm (5.91 in.), mm, the loading strips
21、shall be 19.05 6 0.3 mm(0.75 6 0.01 in.) wide. The length of the loading strips shall exceed the thickness of the specimen. The outer edges of the loadingstrips 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,
22、in which the lower loading strip is mountedon a base having two perpendicular guide rods or posts extending 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 s
23、tripstogether without appreciable binding or loose motion in the guide rods.5.3 Temperature Control SystemAn air or water bath capable of maintaining the specimens at the specified test temperaturewithin 61.0C (61.8F). 61.0C.5.4 ThermometerAcalibrated liquid-in-glass thermometer of suitable range wi
24、th subdivisions readable to 0.1C (0.2F) or anyother thermostatic device of equal accuracy, precision, and sensitivity shall be used. Thermometers shall conform to therequirements of Specification E1.Source of DataNumberofReplicatesSpecimenDiameter(mm)LoadingRate(mm/min)TestTemperature(C)AverageStren
25、gth(kPa)StandardDeviationStrength(kPa)d2s(2.833SE)(kPa)TestTemperature(F)AverageStrength(psi)StandardDeviationStrength(psi)d2s(2.833SE)(psi)StandardDeviationStrength(% mean)d2s(2.833SE)(% mean)Anderson andMcGennisA3 150 12.5 -10 2870 200 566 14 415 29 82 7.0 19.8N CHRPReport 530B3 150 12.5 -10 - - -
26、 - 9 2232(4 aggregate types;4 binders)2 150 12.5 -10 - - - - 11(nom max size:9.5mmto25mm)Solaimanian andKennedyCdry4 100 50 25 - 103 292 77 1542 moisture-conditioned 50 25 - 83 234 77 1234 (9 labs; 3 aggregatetypes; 2 binders)Test Method D4867/D4867M(dry or conditioned)2 100 50 25 - 55 159 77 823 (1
27、9 labs;5 mixtures)Suggested SingleLab Precision50 25 80 77 12AR. M. Anderson and R. B. McGennis, “Ruggedness Evaluation of AASHTO TP7 and TP9,” Phase I, FHWA HIPT (Task J), Federal Highway Administration, November1998.BW. Christensen and R. F. Bonaquist, “Evaluation of Indirect Tensile Test (IDT) Pr
28、ocedures for Low-Temperature Performance of Hot Mix Asphalt,” NCHRP Report 530.CSolaimanian and T. W. Kennedy, “Precision of the Moisture Susceptibility Test Method TEX-531-C,” Project Summary Report 4909-S, November 2000.D6931 1225.5 MiscellaneousA tape, ruler, or set of calipers for specimen heigh
29、t measurement.NOTE 1If testing to determine the potential for moisture damage, the apparatus from Test Method D4867/D4867M or similar will also be necessary.6. Specimens6.1 Laboratory Molded SpecimensPrepare the laboratory-molded specimens in accordance with one of the followingstandards: Test Metho
30、ds D1074, D3387, D6925, D6926; Practices D1561, D3496, D4013; andAASHTO T245 orAASHTO T312.A minimum specimen height of 50.8 mm (2 in.) is required for specimens with a nominal diameter of 101.6 mm (4 in.). mm. Aminimum specimen height of 75 mm (2.95 in.) is required for specimens with a nominal dia
31、meter of 150 mm (5.91 in.).mm. Aminimum of three replicates shall be prepared for each mixture.6.2 Core SpecimensCores should have smooth, parallel surfaces and conform to the height and diameter requirementsspecified for laboratory-molded specimens, except that a minimum height of 38 mm (1.5 in.) i
32、s permitted for specimens with anominal diameter of 101.6 mm (4 in.).mm. A minimum of three replicates from an in-service pavement shall be prepared fortesting.FIG. 1 Diagram of an IDT Strength-Loading FixtureD6931 123NOTE 2Specimens with a nominal diameter of 101.6 mm (4 in.) are suitable for mixtu
33、res with a nominal maximum particle size of 19 mm (3/4 in.)or less. Specimens with a nominal diameter of 150 mm (5.91 in.) are suitable 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 Test Method D3549, to
34、 the nearest 1 mm (0.05 in.). mm.7.2 For core specimens, measure the diameter, at the mid height along axes that are 90 apart, and record the average to thenearest 1 mm (0.05 in.). mm.7.3 Bring the specimen to test temperature 61C (61.8F) by any of the following three alternative procedures. Thereco
35、mmended test temperature is 25C (77F). 25C.NOTE 3Based on previous experience, a standard temperature that has been used for most IDT strength testing is 25C (77F).25C. Other testtemperatures may be used at the discretion of the user.7.3.1 Procedure APlace the specimen in an air bath for a minimum o
36、f 4 hours.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.7.3.3 Procedure CPlace the specimen in a water bath for a minimum of 30 minutes but not longer than 120 minutes.7.4 Remove the specimen from the ai
37、r 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 loadingFIG. 2 Photograph of a Typical IDT Strength-Loading FixtureD6931 124strips are
38、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.7.5 Apply a vertical compressive ramp load until the maximum load is reached. The recommended deformation rate is 50 65 m
39、m/min (2.00 6 0.15 in./min).mm/min. Record the maximum load.NOTE 4This rate of loading has been commonly used for IDT strength specimens with a nominal diameter of 101.6 mm (4 in.) and is alsorecommended in Test Method D5581 when testing larger specimens for Marshall Stability with a nominal diamete
40、r of 150 mm (5.91 in.). mm. Researchhas not yet indicated if this deformation rate should be adjusted for IDT strength specimens with a nominal diameter of 150 mm (5.91 in.).mm. Someresearchers4have also used a rate of 3.75 mm/min (0.15 in./min) at higher temperatures (30-40C (86-104F) (30-40C) on s
41、pecimens 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)St52000 3 PP3t 3 D(1)orSt523PP3t3Dpsi!D6931-07_2 (2)D6931-12_1( kPa)where:St= IDT strength, kPa (psi)P = maximum load, N (lbf)t = specimen
42、height immediately before test, mm (in.)D = specimen diameter, mm (in.)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, nominalmaximum aggregate size, gradation, binder type).9.1.2 The meas
43、ured height and nominal (lab) or average (core) diameter of each specimen, to the nearest 1 mm (0.05 in.). mm.9.1.3 Test temperature, to the nearest 1C (1.8F). 1C.9.1.4 Deformation rate used in test, to the nearest mm/min (0.1 in./min). mm/min.9.1.5 Procedure used for conditioning specimen (as descr
44、ibed in 7.3), including the method of temperature control and total bathtime.9.1.6 Maximum compressive load, to the nearest 1 N (0.2 lbf). 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 (1 psi). kPa.10. Pr
45、ecision 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 100101.6 mm (4 in.) diameter specimens, based on 28 labs usingeither 2 or 4 test replicates with 11 di
46、fferent mix samples. Additional data is provided in Table 1 for the users information. Thebetween-laboratory reproducibility of this test method is being determined and will be available on or before August 2011.2012.Therefore, this Standard should not be used for acceptance or rejection of material
47、s for purchasing purposes.10.2 The precision of this test method depends on the ability of the personnel who are conducting the test and the capability,calibration, and maintenance of the equipment used. Suggested ways of maintaining the testing quality are contained inSpecification D3666.10.3 No in
48、formation can be presented on the bias of the procedure in this test method for measuring the tensile strength ofbituminous mixtures, because it is a destructive test and there is no basis for establishing a true reference value for comparison.11. Keywords11.1 asphalt mixture; bituminous mixture; in
49、direct tensile strength; IDT4D.W. Christensen, R. Bonaquist, and D.P. Jack, “Evaluation of Triaxial Strength as a Simple Test for Asphalt Concrete Rut Resistance”, Pennsylvania Department ofTransportation, Pennsylvania Transportation Institute, Final Report, August 2000.D6931 125ASTM 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 validity of any such
