1、Standard Method of Test for Determination of Performance Grade of Physically Aged Asphalt Binder Using Extended Bending Beam Rheometer (BBR) Method AASHTO Designation: TP 122-161 Release: Group 3 (August 2016) American Association of State Highway and Transportation Officials 444 North Capitol Stree
2、t N.W., Suite 249 Washington, D.C. 20001 TS-2b TP 122-1 AASHTO Standard Method of Test for Determination of Performance Grade of Physically Aged Asphalt Binder Using Extended Bending Beam Rheometer (BBR) Method AASHTO Designation: TP 122-161Release: Group 3 (August 2016) 1. SCOPE 1.1. This test meth
3、od covers the determination of the low-temperature performance grade (i.e., minimum design pavement temperature) of asphalt binders by means of a bending beam rheometer after going through a physical aging (physical hardening) process. It is applicable to material having a flexural stiffness value f
4、rom 20 MPa to 1 GPa (creep compliance values in the range of 50 nPa-1 to 1 nPa-1) and can be used with material aged using T 240 (RTFO) or R 28 (PAV) or with recovered asphalt binder. The test apparatus is designed for testing within the temperature range from 36 to 0C. 1.2. The bending beam rheomet
5、er method used in T 313 conditions samples for 1 h and tests at a temperature 10C warmer than the low-temperature performance grade to determine if the asphalt binder passes the low-temperature requirement. This standard requires testing at two temperatures, to determine by extrapolation a limiting
6、temperature for each of the three conditioning times and two conditioning temperatures. 1.3. Low-temperature physical aging of asphalt varies as a function of temperature and time. This standard conditions at 10C and 20C warmer than the low-temperature performance grade for periods of 1 h, 24 h, and
7、 72 h to simulate the effect of extended conditioning at two different cold temperatures. 1.4. Test results are not valid for beams of asphalt binder that deflect more than 4 mm or less than 0.08 mm when tested in accordance with this method. 1.5. The values stated in SI units are to be regarded as
8、the standard. 1.6. This standard does not purport to address all of the safety concerns, if any, 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.
9、 2. REFERENCED DOCUMENTS 2.1. AASHTO Standards: R 28, Accelerated Aging of Asphalt Binder Using a Pressurized Aging Vessel (PAV) R 29, Grading or Verifying the Performance Grade (PG) of an Asphalt Binder 2016 by the American Association of State Highway and Transportation Officials.All rights reserv
10、ed. Duplication is a violation of applicable law.TS-2b TP 122-2 AASHTO 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 Beam Rheometer (BBR) 2.2. Ontario Ministry of Tran
11、sportation: LS 308, Method of Test for Determination of Performance Grade of Physically Aged Asphalt Cement Using Extended Bending Beam Rheometer (BBR) Method 3. TERMINOLOGY 3.1. Definitions: 3.1.1. asphalt binderan asphalt-based cement that is produced from petroleum residue either with or without
12、the addition of organic modifiers that are dissolved, dispersed, or reacted to enhance performance. 3.1.2. performance grade (PG XX-YY)the performance grade of an asphalt binder with grading designations “XX” related to the number of degree days over 10C and “-YY” related to the minimum design pavem
13、ent temperature. 3.1.3. physical hardeninga time-dependent stiffening of asphalt binder that results from the time-delayed increase in stiffness when the asphalt binder is stored at low temperatures. The increase in stiffness due to physical hardening is reversible when the temperature is raised abo
14、ve the glass transition temperature region. 3.2. Descriptions of Terms Specific to This Standard: 3.2.1. conditioning time (t)the time the sample is to be conditioned when placed in the air-cooled freezer prior to each round of testing. 3.2.2. grade lossthe difference between the limiting grade at 1
15、 h for TLCand the LTLG, (TLBBRLTLG). 3.2.3. limiting grade (TL)the warmer of the limiting temperatures. 3.2.4. limiting temperature10C colder than either Tmor TS, (Tm 10C or TS 10C). 3.2.5. low-temperature grading designation (YY)the minimum design pavement temperature, also referred to as the low-t
16、emperature performance grade specified for the asphalt binder, and the “-YY” specified for the asphalt binder where the performance grade specified is PG XX-YY. 3.2.6. low-temperature limiting grade (LTLG)the warmest of the limiting grades. 3.2.7. m-valueabsolute value of the slope of the logarithm
17、of the stiffness curves versus the logarithm of the time. 3.2.8. THCthe higher conditioning temperature, 20C warmer than the low-temperature grading designation, THC= (20C + “-YY”). 3.2.9. THTthe higher test temperature, 16C warmer than the low-temperature grading designation, THT= (16C + “-YY”). 3.
18、2.10. TLBBRthe limiting grade for the conditioning temperature TLCat the conditioning period of 1 h. 2016 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-2b TP 122-3 AASHTO 3.2.11. TLCthe lower conditionin
19、g temperature, 10C warmer than the low-temperature grading designation, TLC= (10C + “-YY”). 3.2.12. TLTthe lower test temperature, 10C warmer than the low-temperature grading designation, TLT= (10C + “-YY”). 3.2.13. Tmthe calculated temperature where the m-value at 60 s loading equals 0.300. 3.2.14.
20、 TSthe calculated temperature where the creep stiffness (S) at 60 s loading equals 300 MPa. 4. APPARATUS 4.1. All equipment and material as noted in T 313. 4.2. Air-Cooled FreezerAir-cooled freezer that maintains the conditioning temperature requirements to within a temperature tolerance of 1.0C. 4.
21、3. Flat Aluminum PlateFlat aluminum plate of a size that will lie flat in the freezer and hold five samples. 5. PREPARATION OF MOLDS AND SAMPLES 5.1. Enough asphalt binder shall be aged according to T 240 (RTFO) and R 28 (PAV) to prepare ten samples according to T 313 procedures. 6. PROCEDURE 6.1. A
22、fter demolding, samples shall be conditioned and stabilized at the temperatures prescribed in this standard prior to testing. Conditioning shall be carried out in air-cooled freezers with the samples lying flat on their sides on a flat aluminum plate. Stabilization shall be carried out in the test b
23、ath. Note 1If required, a Teflon sheet can be placed between the sample and the aluminum plate to prevent the sample from sticking to the plate. Note 2A controlled-temperature fluid bath according to T 313 may be used in place of an air-cooled freezer for conditioning. 6.2. Five samples (A1, A2, B1,
24、 B2, and a spare) shall be conditioned at THC(shown as conditioning container I in Figure 1) and the other five samples (C1, C2, D1, D2, and a spare) shall be conditioned at TLC(shown as conditioning container II in Figure 2). 6.3. Condition samples for 50 to 55 min at the conditioning temperatures
25、indicated in step 6.2. 6.3.1. Transferring of each sample from a conditioning container to a test bath, and vice versa, shall be carried out as quickly as possible and in less than 10 s per sample per transfer, before physical hardening will reverse. 6.3.2. Stabilize samples A1 and A2 from condition
26、ing container I and samples C1 and C2 from conditioning container II for 10 2.0 min at THTin a test bath. Note 3The 50 to 55 min conditioning plus the 10 2.0 min is referred to as 1 h conditioning. 6.3.3. Test samples A1, A2, C1, and C2 following T 313 procedures at THT. Ensure that the test is vali
27、d as specified in A1.12 of T 313. 2016 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-2b TP 122-4 AASHTO Note 4For recovered asphalt binder, “-YY” in the calculation of THTis the actual low-temperature gr
28、ade obtained according to Section 6 of R 29. 6.3.4. Stabilize samples B1 and B2 from conditioning container I and samples D1 and D2 from conditioning container II for 10 2.0 min at TLTin a test bath. 6.3.5. Test samples B1, B2, D1, and D2 following T 313 procedures at TLT. Ensure that the test is va
29、lid as specified in A1.12 of T 313. Note 5For recovered asphalt binder, “-YY” in the calculation of TLTis the actual low-temperature grade obtained according to Section 6 of R 29. 6.3.6. Immediately after testing, in steps 6.3.3 and 6.3.5, samples shall be returned to their respective conditioning c
30、ontainers indicated in step 6.2. Note 6An example conditioning and testing matrix is shown in Table 1 for a specified asphalt binder performance grade of PG XX 34. 6.4. Condition samples for an additional t = (23 h 5.0 min) (referred to as 24 h conditioning), at the conditioning temperatures indicat
31、ed in step 6.2 and then repeat steps 6.3.1 to 6.3.6. 6.5. Condition samples for an additional t = (48 h 5.0 min) (referred to as 72 h conditioning), at the conditioning temperatures indicated in step 6.2 and then repeat steps 6.3.1 to 6.3.6. 6.6. If, during the testing sequence, sample A1, A2, B1, o
32、r B2 becomes damaged, the damaged sample shall be replaced with the spare sample in conditioning container I. If, during the testing sequence, sample C1, C2, D1, or D2 becomes damaged, the damaged sample shall be replaced with the spare sample in conditioning container II. Figure 1Samples Conditione
33、d at Temperature THC 2016 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-2b TP 122-5 AASHTO Figure 2 Samples Conditioned at Temperature TLCTable 1Example Conditioning and Testing Matrix for PG XX 34 Condi
34、tioning Container Sample Number Conditioning Temperature THC (20C+“-YY”) or TLC (10C+“-YY”) Test Temperature THT (16C+“-YY”) or TLT (10C+“-YY”) I A1 14C 18C I A2 14C 18C I B1 14C 24C I B2 14C 24C I SPARE 14C II C1 24C 18C II C2 24C 18C II D1 24C 24C II D2 24C 24C II SPARE 24C Note: This same test ma
35、trix is used for each of the 1 h, 24 h, and 72 h conditioning and testing periods. Spare samples are tested at the test temperature specified for the sample being replaced. An asphalt binder with a specified performance grading of PG XX 34 was used in this table. 7. CALCULATIONS 7.1. Using a table l
36、ike Table 3, for each combination of conditioning temperature and period: 7.1.1. Calculate, for each test temperature, the average m-value and average creep stiffness using the recorded m-values and creep stiffnesses at 60 s loading from a table like Table 2, “Extended BBR Test Results.” 7.1.2. Calc
37、ulate Tmwhere the m-value at 60 s loading equals 0.300 by interpolation or extrapolation using a linear scale between THTand TLTand the corresponding average m-values. 7.1.3. Calculate TSwhere the creep stiffness at 60 s loading equals 300 MPa by interpolation or extrapolation using a log scale betw
38、een THTand TLTand the corresponding average creep stiffnesses. 2016 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-2b TP 122-6 AASHTO 7.1.4. Calculate the limiting temperatures for m-value as Tm 10C and f
39、or creep stiffness as TS 10C. 7.1.5. Determine the limiting grade (TL), as the warmer of the two limiting temperatures. 7.2. Using a table like Table 3, calculate the following: 7.2.1. Determine the low-temperature limiting grade (LTLG), as the warmest of the limiting grades. 7.2.2. Determine TLBBR,
40、 the limiting grade at 1 h and TLC. 7.2.3. Calculate the grade loss as TLBBR LTLG. 8. REPORT 8.1. Report data using tables like Tables 2 and 3, including: 8.1.1. Sample identification; 8.1.2. Date test completed; 8.1.3. m-values, to the nearest 0.001; 8.1.4. Creep stiffnesses, to the nearest 0.1 MPa
41、; 8.1.5. average m-values, to the nearest 0.001; 8.1.6. average creep stiffnesses, to the nearest 0.1 MPa; 8.1.7. Tm, to within the nearest 0.1C; 8.1.8. TS, to within the nearest 0.1C; 8.1.9. Limiting temperatures at m-value equal to 0.300; 8.1.10. Limiting temperatures at creep stiffness equal to 3
42、00 MPa; 8.1.11. Limiting grades (LT); 8.1.12. Low-temperature limiting grade (LTLG); and 8.1.13. Grade loss. 2016 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-2b TP 122-7 AASHTO Table 2Extended BBR Test
43、 Results After 1 h Conditioning Sample Number Conditioning Temperature, C Stabilization and Testing Temperature, C m-value Creep Stiffness S (MPa) A1 THC(20C + “-YY”) THT(16C+ “-YY”) A2 THC(20C + “-YY”) THT(16C+ “-YY”) B1 THC(20C + “-YY”) TLT(10C+ “-YY”) B2 THC(20C + “-YY”) TLT(10C+ “-YY”) C1 TLC(10
44、C + “-YY”) THT(16C+ “-YY”) C2 TLC(10C + “-YY”) THT(16C+ “-YY”) D1 TLC(10C + “-YY”) TLT(10C+ “-YY”) D2 TLC(10C + “-YY”) TLT(10C+ “-YY”) After 24 h Conditioning Sample Number Conditioning Temperature, C Stabilization and Testing Temperature, C m-value Creep Stiffness S (MPa) A1 THC(20C + “-YY”) THT(16
45、C+ “-YY”) A2 THC(20C + “-YY”) THT(16C+ “-YY”) B1 THC(20C + “-YY”) TLT(10C+ “-YY”) B2 THC(20C + “-YY”) TLT(10C+ “-YY”) C1 TLC(10C + “-YY”) THT(16C+ “-YY”) C2 TLC(10C + “-YY”) THT(16C+ “-YY”) D1 TLC(10C + “-YY”) TLT(10C+ “-YY”) D2 TLC(10C + “-YY”) TLT(10C+ “-YY”) After 72 h Conditioning Sample Number
46、Conditioning Temperature, C Stabilization and Testing Temperature, C m-value Creep Stiffness S (MPa) A1 THC(20C + “-YY”) THT(16C+ “-YY”) A2 THC(20C + “-YY”) THT(16C+ “-YY”) B1 THC(20C + “-YY”) TLT(10C+ “-YY”) B2 THC(20C + “-YY”) TLT(10C+ “-YY”) C1 TLC(10C + “-YY”) THT(16C+ “-YY”) C2 TLC(10C + “-YY”)
47、 THT(16C+ “-YY”) D1 TLC(10C + “-YY”) TLT(10C+ “-YY”) D2 TLC(10C + “-YY”) TLT(10C+ “-YY”) 2016 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-2b TP 122-8 AASHTO Table 3Example Report for Extended BBR Test
48、9. PRECISION AND BIAS 9.1. PrecisionThe research required to develop precision estimates has not been conducted. 9.2. BiasThe research required to establish the bias has not been conducted. 10. KEYWORDS 10.1. Asphalt binders; bending beam rheometer; creep stiffness; extended BBR; grade loss; LTLG; m
49、-value; physical hardening. 1This provisional standard was first published in 2016. PG Grade: TLBBR: Date of Test: Sample: LTLG: Tested by: Grade Loss: Conditioning Temperature Conditioning Period Average m-values Average Creep Stiffnesses (MPa) TmTSLimiting Temperature at m = 0.300 Tm10(C) Limiting Temperature at S = 300 TS10(C) Limiting Grade TL(C) THTTLTTHTTLTTHC1 h 24 h
