1、Standard Practice for Grading or Verifying the Performance Grade (PG) of an Asphalt Binder AASHTO Designation: R 29-15 American Association of State Highway and Transportation Officials 444 North Capitol Street N.W., Suite 249 Washington, D.C. 20001 TS-2b R 29-1 AASHTO Standard Practice for Grading
2、or Verifying the Performance Grade (PG) of an Asphalt Binder AASHTO Designation: R 29-15 1. SCOPE 1.1. This standard practice describes the testing required to determine the performance grade (PG) of an asphalt binder according to M 320, Table 1. It presents two approaches. In the first, the PG of a
3、n unknown asphalt binder is determined. In the second, the nominal PG of an asphalt binder is verified. It also provides an estimate of the time required to complete a single test sequence. 1.2. This standard practice may involve hazardous materials, operations, and equipment. This standard does not
4、 purport to address all of the safety concerns associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. 2. REFERENCED DOCUMENTS 2.1. AASHTO Standards: M
5、320, Performance-Graded Asphalt Binder R 28, Accelerated Aging of Asphalt Binder Using a Pressurized Aging Vessel (PAV) T 240, Effect of Heat and Air on a Moving Film of Asphalt Binder (Rolling Thin-Film Oven Test) T 313, Determining the Flexural Creep Stiffness of Asphalt Binder Using the Bending B
6、eam Rheometer (BBR) T 314, Determining the Fracture Properties of Asphalt Binder in Direct Tension (DT) T 315, Determining the Rheological Properties of Asphalt Binder Using a Dynamic Shear Rheometer (DSR) 3. SUMMARY OF THE PRACTICE 3.1. The tank (as-received) sample of asphalt binder is tested to d
7、etermine shear modulus (G*) and phase angle () (T 315). 3.2. The asphalt binder is aged in the rolling thin-film oven (RTFO) (T 240), and the residue is tested to determine the mass change (T 240) and the shear modulus (G*) and phase angle () (T 315). 3.3. The residue from the RTFO is aged in the pr
8、essurized aging vessel (R 28), and this residue is tested to determine the shear modulus (G*) and phase angle () (T 315), creep stiffness (S) and slope, m, of the log creep stiffness versus log time relationship at 60 s (T 313), and the failure strain in direct tension (T 314), as necessary. 3.4. Ba
9、sed on these test results, the asphalt binder is graded according to M 320, Table 1. 2015 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-2b R 29-2 AASHTO 4. SIGNIFICANCE AND USE 4.1. This practice describ
10、es the testing required for grading or verifying the PG of an asphalt binder according to M 320, Table 1. 5. ESTIMATED TIME NECESSARY FOR TESTING 5.1. For both grading and verification, if the analysis is started at the beginning of a morning work shift, all testing and analysis should be completed
11、during the afternoon of the next day. This schedule provides the 20 h needed for PAV conditioning. Of course, samples can be aged and analyzed in parallel, and the productivity of the laboratory thus increased. However, for the purpose of this document, analysis of a single asphalt binder will be di
12、scussed. 6. TEST PROCEDURE FOR GRADING AN UNKNOWN ASPHALT BINDER 6.1. Prepare samples and test specimens using the procedures specified in the applicable test methods. In the case where the grade of the asphalt binder is unknown, approximately 400 g of unaged asphalt binder is required to complete t
13、he tests with the necessary replicates. 6.2. Begin conditioning asphalt binder in the RTFO. Condition a sufficient amount of asphalt binder depending on the type and number of tests to be performed. Note 1Two BBR beams requiring PAV-aged material are needed at each test temperature. In addition, at
14、least six direct tension (DT) specimens requiring PAV-aged material may also be needed at each test temperature. A minimum of two test temperatures will be required. This testing will utilize approximately 200 g of RTFO residue. 6.3. Perform the DSR test (T 315) on the original asphalt binder beginn
15、ing at 58C, and increase or decrease the test temperature at 6.0C increments until a value for G*/sin 1.00 kPa is obtained. The highest test temperature where the value for G*/sin 1.00 kPa determines the starting PG grade. Note 2For example, if G*/sin is 0.60 kPa at 64C and 1.20 kPa at 58C, the star
16、ting asphalt binder grade is PG 58-xx. 6.4. After the RTFO conditioning (T 240) is complete, determine the mass change of the original asphalt binder. The mass change must be 1.00 percent to meet the requirements of M 320. 6.5. Perform the DSR test (T 315) on the RTFO residue at the test temperature
17、 used to determine the starting PG grade (Section 6.3) to confirm the high-temperature grade of the asphalt binder (e.g., PG 46-xx, 52-xx, 58-xx, etc.). The value for G*/sin of the RTFO residue must be 2.20 kPa. Choose the lower performance grade in cases where the test values in Sections 6.3 and 6.
18、5 give conflicting grades. 6.6. Age a sufficient quantity of RTFO residue in the PAV (R 28) (Note 1). Use an aging temperature of 90C for starting grades PG 46-xx or 52-xx and 100C for starting grades PG 58-xx and higher. A PAV temperature of 110C is used in simulating desert environments. Note 3Com
19、plete Sections 6.1 through 6.6 during the first day of testing. This schedule will allow further testing to begin on the second day after PAV aging is complete. 6.7. At the conclusion of the PAV aging procedure (R 28), including aging, combining, and degassing the binder, prepare two BBR specimens f
20、or each test temperature according to T 313. Retain sufficient residue to prepare at least six DT specimens for each test temperature, if required. 2015 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-2b R
21、 29-3 AASHTO 6.8. Perform the DSR test (T 315) on the PAV residue beginning at a test temperature of 16 and 19C, respectively, for starting grades PG 52-xx and 58-xx, 22C for starting grade PG 64-xx, and 28C for starting grade PG 70-xx, unless there is other information to suggest the temperature at
22、 which G*sin 5000 kPa. Decrease or increase the test temperature at 3.0C increments until the value for G*sin 5000 kPa. 6.9. Determine the beginning test temperature for the BBR test (T 313) on the PAV residue from Table 1 of M 320 using the starting PG grade determined in Section 6.3 and the lowest
23、 temperature from Section 6.8 where the value for G*sin 5000 kPa, unless there is other information to suggest the temperature at which the creep stiffness (S) 300 MPa and the slope (m) 0.300. 6.10. Test pairs of BBR specimens according to T 313 beginning at the test temperature selected in Section
24、6.9 and increasing at 6.0C increments, until a creep stiffness (S) and slope (m) meeting the requirements of M 320, Table 1 are obtained. Test fresh BBR specimens at each temperature. 6.11. Certain asphalt binders may satisfy the M 320, Table 1 slope requirement at substantially lower temperatures t
25、han they satisfy the creep stiffness (S) requirement. If the creep stiffness is between 300 and 600 MPa at a test temperature at which the slope, m, 0.300, it may be possible to satisfy the DT (T 314) failure strain requirement in lieu of the creep stiffness requirement. Test DT specimens according
26、to T 314 at the test temperature at which m 0.300, and determine if the failure strain 1.0 percent. Test a sufficient number of specimens so that a minimum of six valid test results are obtained. 6.12. If the failure strain 1.0 percent, test additional sets of DT specimens, increasing the test tempe
27、rature in 6.0C increments, until a failure strain 1.0 percent is obtained. 6.13. Using the results of Sections 6.8 through 6.12, determine the final grade of the asphalt binder. 7. TEST PROCEDURE FOR VERIFYING THE NOMINAL GRADE OF AN ASPHALT BINDER 7.1. Prepare samples and test specimens using the p
28、rocedures specified in the applicable test methods. In the case where the grade of the asphalt binder is being verified, approximately 250 g of unaged asphalt binder are required to complete the tests with the necessary replicates. 7.2. Begin conditioning asphalt binder in the RTFO. Condition a suff
29、icient amount of asphalt binder depending on the type and number of tests to be performed. Note 4Two BBR beams requiring PAV aged material are needed. In addition, at least six DT specimens requiring PAV-aged material may also be required. Only one test temperature will be required. This testing wil
30、l utilize approximately 100 g of RTFO residue. 7.3. Perform the DSR test (T 315) on the original asphalt binder at the test temperature indicated by the high-temperature grading designation. For example, test a PG 70-16 asphalt binder at 70C. The value for G*/sin must be 1.0 kPa to meet the requirem
31、ents of M 320. Note 5This step verifies the starting PG grade. For example, if a PG 58-22 is tested at 58C and G*/sin 1.00 kPa, the high-temperature grading designation for the asphalt binder is verified to be PG 58-xx. Note 6If the asphalt binder fails to meet the requirements of M 320, Table 1 for
32、 the grade designated, it may be treated as a binder of unknown grade and tested according to Section 6, or the testing may be stopped because the grade was not verified. 2015 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of
33、 applicable law.TS-2b R 29-4 AASHTO 7.4. After the RTFO conditioning (T 240) is complete, determine the mass change of the original asphalt binder. The mass change must be 1.00 percent to meet the requirements of M 320. 7.5. To verify the high-temperature properties of the binder, perform the DSR te
34、st (T 315) on the RTFO residue at the test temperature indicated by the high-temperature grading designation. For example, test a PG 70-16 asphalt binder at 70C. The value for G*/sin of the RTFO residue must be 2.20 kPa to meet the requirements of M 320, Table 1 (Note 6). 7.6. Age a sufficient quant
35、ity of RTFO residue in the PAV (R 28). Use an aging temperature of 90C for binders having a high-temperature grading designation of PG 46-xx or PG 52-xx and 100C for binders having high-temperature grading designations of PG 58-xx and higher. A PAV temperature of 110C is used in simulating desert en
36、vironments. Note 7Two BBR beams (requiring PAV-aged material) are required. In addition, six DT samples may also be needed requiring about 60 g of PAV-aged asphalt binder. Note 8Complete Sections 7.1 through 7.6 during the first day of testing. This schedule will allow further testing to begin on th
37、e second day after PAV aging is complete. 7.7. At the conclusion of the PAV aging procedure (R 28), including aging, combining, and degassing the binder, prepare two BBR specimens according to T 313. Retain sufficient residue to prepare at least six DT specimens if required. 7.8. Perform the DSR tes
38、t (T 315) on the PAV residue at the test temperature specified in Table 1 of M 320 for the high-temperature and low-temperature grading designation of the binder being verified. For example, test a PG 64-40 asphalt binder at 16C. The value for G*sin must not exceed 5000 kPa to meet the requirements
39、of M 320 (Note 6). 7.9. Test two BBR specimens according to T 313 at the test temperature specified in Table 1 of M 320 for the high-temperature and low-temperature grading designation of the binder being verified. For example, test a PG 58-28 asphalt binder at 18C. The value of the slope, m, must b
40、e 0.300 to meet the requirements of M 320, Table 1. The value of the creep stiffness (S) must be 300 MPa to meet the requirements of M 320, Table 1. Certain asphalt binders may satisfy the BBR slope requirement at substantially lower temperatures than they satisfy the BBR stiffness requirement (Note
41、 6). 7.10. If the creep stiffness (S) is between 300 and 600 MPa and the slope (m) 0.300 at the test temperature, it may be possible to satisfy the DT (T 314) failure strain requirement in lieu of the creep stiffness (S) requirement. Test DT samples according to T 314 at the same test temperature us
42、ed to test the BBR specimens. Test a sufficient number of specimens so that a minimum of six valid test results are obtained. The failure strain must be 1.0 percent to meet the requirements of M 320, Table 1 (Note 6). 8. REPORT 8.1. If the grade of the asphalt binder tested is determined, report the
43、 results of all tests performed and the high-temperature grading designation determined, followed by the low-temperature designation (e.g., PG 52-34). 8.2. If the grade of an asphalt binder is verified, report the results of all tests performed and if the binder meets the requirements of M 320, Tabl
44、e 1. 2015 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-2b R 29-5 AASHTO 9. KEYWORDS 9.1. Asphalt binder; performance grading. 2015 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.
