1、Standard Specification for Preparation of Indirect Tension Performance Test Specimens AASHTO Designation: PP 95-18 Technical Section: 2d, Bituminous Materials Release: Group 3 (August) American Association of State Highway and Transportation Officials 444 North Capitol Street N.W., Suite 249 Washing
2、ton, D.C. 20001 TS-2d PP 95-1 AASHTO Proposed Standard Practice for Preparation of Indirect Tension Performance Test Specimens AASHTO Designation: PP 95-18 Technical Section: 2d, Bituminous Materials Release: Group 3 (August) 1. SCOPE 1.1. This practice covers the preparation of 150-mm diameter by 3
3、8- to 50-mm thick cylindrical test specimens for use in indirect tension dynamic modulus tests. This practice is intended for dense-, gap-, and open-graded asphalt mixtures with nominal maximum aggregate sizes up to 25 mm. 1.2. This standard may involve hazardous materials, operations, and equipment
4、. This standard does not purport to address all of the safety problems associated with its use. It is the responsibility of the user of this procedure to establish appropriate safety and health practices and to determine the applicability of regulatory limitations prior to its use. 2. REFERENCED STA
5、NDARDS 2.1. AASHTO Standards: R 83, Preparation of Cylindrical Performance Test Specimens Using the Superpave Gyratory Compactor T 166, Bulk Specific Gravity of Compacted Asphalt Mixtures Using Saturated Surface-Dry Specimens T 209, Theoretical Maximum Specific Gravity and Density of Bituminous Pavi
6、ng Mixtures T 269, Percent Air Voids in Compacted Dense and Open Bituminous Paving Mixtures T 312, Preparation and Determining the Density of Hot-Mix Asphalt (HMA) Specimens by Means of the Superpave Gyratory Compactor 2.2. ASTM Standard: D 5361, Practice for Sampling Compacted Bituminous Mixtures f
7、or Laboratory Testing 2.3. Other Publications: Barksdale, R.D., J. Alba, N.P. Khosla, Y.R. Kim, P.C. Lambe, and M.S. Rahman. Laboratory Determination of Resilient Modulus for Flexible Pavement Design, Final Report, National Cooperative Highway Research Program 1-28 Project, June 1997. Kim, Y. R., Y.
8、 Seo, M. King, and M. Momen. Dynamic Modulus Testing of Asphalt Concrete in Indirect Tension Mode. In Transportation Research Record: Journal of the Transportation Research Board, No. 1891, TRB, National Research Council, Washington, D.C., 2004. 2018 by the American Association of State Highway and
9、Transportation Officials. All rights reserved. Duplication is a violation of applicable law.TS-2d PP 95-2 AASHTO 3. TERMINOLOGY 3.1. gyratory specimenNominal 150 9 mm in diameter by minimal 150-mm high cylindrical specimen prepared in a gyratory compactor. 3.2. roadway specimenSpecimens obtained fro
10、m the pavement in accordance with ASTM D5361. Specimen dimensions consist of nominal 150 9 mm in diameter with a layer thickness greater than 50 mm. 3.3. test specimenNominal 150 9 mm diameter by 38-mm thick cylindrical specimen that is sawed and cored from the gyratory or roadway specimen. 3.4. ind
11、irect tension (IDT)a method of loading a material by applying a compressive force on a cylindrical specimen in one direction, which results in a tensile stress and strain in the perpendicular direction due to the Poissons effect, which describes lateral contraction or elongation due to axial elongat
12、ion or contraction under loading, respectively. 4. SUMMARY OF PRACTICE 4.1. This practice presents methods for preparing 150 9 mm in diameter by 38- to 50-mm thick cylindrical test specimens for use in an indirect tension dynamic modulus test. 5. SIGNIFICANCE AND USE 5.1. This practice should be use
13、d to prepare specimens for the following standard test: TP 131, Determining the Dynamic Modulus of Asphalt Concrete Using the Indirect Tension Test 5.2. This practice may also be used to prepare specimens for other non-standard tests requiring 150 9 mm in diameter by 38 to 50 mm thick cylindrical te
14、st specimens. 6. APPARATUS 6.1. Superpave Gyratory CompactorA compactor meeting the requirements of T 312 and capable of preparing specimens with a 150 9 mm diameter and a minimum height of 150 mm. 6.2. Mixture Preparation EquipmentBalances, ovens, thermometers, mixer, pans, and other miscellaneous
15、equipment needed to prepare gyratory specimens in accordance with T 312 and make specific gravity measurements in accordance with T 166, T 209, and T 269. 6.3. Masonry SawAn air or water-cooled diamond bladed masonry saw capable of cutting specimens to a nominal height of 38 to 50 mm. Note 1Single s
16、aws have been successfully used to prepare specimens meeting the dimensional tolerances given in Section 10.5.3. Accurate sawing requires a fixture to securely hold the specimen during sawing and to control the feed rate. 6.4. CalipersCalipers capable of measuring the specimen diameter, nominally 15
17、0 9 mm, to the nearest 0.25 mm and nominal 38- to 50-mm thick specimens to the nearest 0.1 mm. 6.5. Marking DeviceA marking device shall be used to mark mutually perpendicular axes on the front and back faces of the specimen through the center. An example is shown in Figure 1. 2018 by the American A
18、ssociation of State Highway and Transportation Officials. All rights reserved. Duplication is a violation of applicable law.TS-2d PP 95-3 AASHTO Figure 1Marking Device 6.5.1. The device shall be capable of marking axes on different sizes (thickness and diameter) of specimens. The axes shall be simul
19、taneously marked on the front and back faces of the specimen to ensure that the axes on the front and back lie in a single plane. The device shall be capable of marking axes perpendicular to the first marked axes. Figure 2 shows a schematic of the marking device shown in Figure 1. 6.5.2. A marking t
20、ool can be a wax pencil, permanent marker, or other device with a fine point and high contrast with the specimen. The mark should not wear off with water. 2018 by the American Association of State Highway and Transportation Officials. All rights reserved. Duplication is a violation of applicable law
21、.TS-2d PP 95-4 AASHTO Figure 2aSchematic View of the Marking DeviceFront View 4.7-mm Steel RodOffset 4.2 mmfrom the Left EdgeWindow Can Slideon and Rotateabout Steel RodMarking Edge5.3-mm Deep Cut-OutThin Lines Marked on Backof Window Spaced 9.5 mmon Center50.8-mm x 147.3-mmx 17.8-mm TransparentWind
22、ow with Notches toSlide over the Front Plate5.3-mm Deep Cut-Out101.6 mm12.7-mm Dia. Steel RodsSpaced 69.3 mm on Center28.6 mm41.3 mm38.4 mm104.4 mm86.1 mm19.1 mm38.1 mm15.9 mm9.5 mm6.4 mm9.5 mm20.3 mm9.5 mm19.1 mm15.8 mm9.5 mm12.7 mm34.9 mm 2018 by the American Association of State Highway and Trans
23、portation Officials. All rights reserved. Duplication is a violation of applicable law.TS-2d PP 95-5 AASHTO Figure 2bSchematic View of the Marking DeviceBack View 7. HAZARDS 7.1. This practice and associated standards involve handling of hot asphalt binder, aggregates and asphalt mixtures, and the u
24、se of sawing and coring machinery. Use standard safety precautions, equipment, and clothing when handling hot materials and operating machinery. 8. STANDARDIZATION 8.1. Items associated with this practice that require calibration are included in the AASHTO Standards referenced in Section 2. Refer to
25、 the pertinent section of the referenced standards for information concerning calibration. 9. SAMPLING 9.1. Gyratory SpecimensPrepare a minimum of two gyratory specimens, to produce four test specimens, in accordance with Sections 10.1 to 10.4. 9.2. Roadway SpecimensObtain roadway specimens from the
26、 pavement in accordance with ASTM D 5361. Mark an arrow with the traffic direction on the flat face of the core. Prepare cores with smooth and parallel surfaces that conform to the height and diameter requirements specified in Section 10.5.3. Prepare a minimum of three replicate cores. Marking ToolT
27、humb Screw12.7-mm Dia. Steel RodsSpaced 69.3 mm on Center5.3-mm Deep Cut-OutMarking Edge19.1 mm76.2 mm12.7 mm12.7 mm9.8 mm6.4 mm9.8 mm154.7 mm12.7 mm9.5 mm50.8 mm28.6 mm 2018 by the American Association of State Highway and Transportation Officials. All rights reserved. Duplication is a violation of
28、 applicable law.TS-2d PP 95-6 AASHTO 10. PROCEDURE 10.1. Asphalt Mixture Preparation 10.1.1. Prepare asphalt mixture for each test specimen and a companion maximum specific gravity test in accordance with Section 8 of AASHTO T 312. 10.1.2. The mass of mixture needed for each specimen will depend on
29、the gyratory specimen height, the specific gravity of the aggregate, the nominal maximum aggregate size, gradation (coarse or fine), and the target air void content for the test specimens. See Appendix X1 of AASHTO R 83, Preparation of Cylindrical Performance Test Specimens Using the Superpave Gyrat
30、ory Compactor for further information. 10.1.3. Perform mixture conditioning for the test specimens and companion maximum specific gravity test in accordance with Section 7.2 of AASHTO R 30, Short-Term Conditioning for Mixture Mechanical Property Testing. 10.2. Gyratory Specimen Compaction 10.2.1. Co
31、mpact the gyratory specimens in accordance with Section 9 of AASHTO T 312. 10.2.2. Compact the gyratory specimens to the target gyratory specimen height. Note 2Each laboratory should determine a target gyratory specimen height based on the procedure for evaluating test specimen uniformity, and an ev
32、aluation of the ability of the sawing equipment to maintain the dimensional tolerances given in Section 10.5.3. See Appendix X2 of AASHTO R 83-14, Preparation of Cylindrical Performance Test Specimens Using the Superpave Gyratory Compactor for further information. 10.3. Long-Term Conditioning (Optio
33、nal) 10.3.1. If it is desired to simulate long-term aging, condition the gyratory specimen in accordance with Sections 7.3.4 through 7.3.6 of AASHTO R 30. 10.3.2. To obtain accurate volumetric measurements on the long-term conditioned specimens, condition a sample of short-term conditioned loose mix
34、 meeting the sample size requirements of AASHTO T 209 in accordance with Sections 7.3.4 through 7.3.6 of AASHTO R 30. 10.4. Gyratory Specimen Density and Air Voids (Optional) 10.4.1. Determine the maximum specific gravity of the mixture in accordance with AASHTO T 209. Record the maximum specific gr
35、avity of the mixture. 10.4.2. For dense- and gap-graded mixtures, determine the bulk specific gravity of the gyratory specimen in accordance with AASHTO T 166. Record the bulk specific gravity of the gyratory specimen. 10.4.3. For open-graded mixtures, determine the bulk specific gravity of the gyra
36、tory specimen in accordance with Section 6.2 of AASHTO T 269. 10.4.4. Compute the air void content of the gyratory specimen in accordance with AASHTO T 269. Record the air void content of the gyratory specimen. Note 3Section 10.4 is optional because acceptance of the test specimen for mechanical pro
37、perty testing is based on the air void content of the test specimen, not the gyratory specimen. However, monitoring gyratory specimen density can identify improperly prepared specimens early in the specimen fabrication process. 2018 by the American Association of State Highway and Transportation Off
38、icials. All rights reserved. Duplication is a violation of applicable law.TS-2d PP 95-7 AASHTO 10.5. Test Specimen Preparation 10.5.1. Gyratory SpecimensCut the specimens to obtain two (2) test specimens with a nominal thickness of 38 to 50 mm. 10.5.1.1. Measure and cut at the center of the gyratory
39、 specimen to create two equal halves. 10.5.1.2. Measure the desired specimen thickness on each half and cut the specimens. It is recommended that both ends of the compacted specimen be sawed to obtain smooth surfaces. 10.5.1.3. Both the gyratory specimen and the saw shall be adequately supported to
40、ensure that the resulting test specimen meets the tolerances given in Section 10.5.3 for thickness. Note 4The purpose of removing the ends is to remove the vertical air void gradient present in gyratory specimens. See Appendix X2 of AASHTO R 83 Preparation of Cylindrical Performance Test Specimens U
41、sing the Superpave Gyratory Compactor to determine the height and air void distribution needed for uniform specimens. For two 38 mm or 50 mm specimens, a 150 mm gyratory specimen is recommended. 10.5.2. Roadway SpecimensCut the roadway core to obtain at least one (1) test specimen with a nominal thi
42、ckness of 38 to 50 mm from each layer. 10.5.2.1. Extend the point of the arrow down the side of the core with a marking device. 10.5.2.2. Cut at least 6 mm from both sides of each test specimen to provide smooth, parallel (saw-cut) surfaces for mounting the measurement gages. 10.5.2.3. Mark the face
43、 of the cut specimen with an arrow representing the traffic direction based upon the mark made in Section 10.5.2.1. 10.5.3. Test specimens shall meet the dimensional tolerances given in Table 1. Table 1Test Specimen Dimensional Tolerances Item Specification Method Average Diameter 150 9 mm Section 1
44、0.5.3.1 Standard Deviation of Diameter 0.25 mm Section 10.5.3.1 Average Thickness 38 3.0mm Section 10.5.3.2 Standard Deviation of Thickness 0.25 mm Section 10.5.3.2 10.5.4. Measure the diameter of the test specimen along two perpendicular axes using calipers. Reject specimens with an average diamete
45、r outside the tolerance listed in Table 1. Record the average diameter. 10.5.5. Using calipers, measure the thickness at four points of the test specimen along axes that are 90 apart. Record each of the four measurements to the nearest 0.25 mm. Calculate the average and the standard deviation of the
46、 four measurements. The standard deviation shall be less than 0.25 mm. Reject specimens not meeting the average and standard deviation requirements listed in Table 1. The average diameter and thickness, reported to the nearest 0.25 mm, shall be used in all material property calculations. 10.6. Test
47、Specimen Density and Air Voids 2018 by the American Association of State Highway and Transportation Officials. All rights reserved. Duplication is a violation of applicable law.TS-2d PP 95-8 AASHTO 10.6.1. Determine the maximum specific gravity of the mixture in accordance with AASHTO T 209. Record
48、the maximum specific gravity of the mixture. 10.6.2. For dense- and gap-graded mixtures, determine the bulk specific gravity of the test specimen in accordance with AASHTO T 166. Record the bulk specific gravity of the test specimen. Note 5When the wet saw method is used, measure the immersed mass f
49、ollowed by the surface dry mass followed by the dry mass to minimize drying time and expedite the specimen fabrication process. 10.6.3. For open-graded mixtures, determine the bulk specific gravity of the test specimen in accordance with Section 6.2 of AASHTO T 269. Record the bulk specific gravity of the test specimen. 10.6.4. Compute the air void content of the test specimen in accordance with AASHTO T 269. Record the air void content of the test specimen. Reject test specimens exceeding the air void tolerances specifi
