1、Standard Method of Test for Evaluation of the Tracking Resistance of Hot-Poured Asphalt Crack Sealant by Dynamic Shear Rheometer (DSR) AASHTO Designation: TP 126-18 1Technical Section: 4e, Joints, Bearings, and Geosynthetics Release: Group 2 (June) American Association of State Highway and Transport
2、ation Officials 444 North Capitol Street N.W., Suite 249 Washington, D.C. 20001 TS-4e TP 126-1 AASHTO Standard Method of Test for Evaluation of the Tracking Resistance of Hot- Poured Asphalt Crack Sealant by Dynamic Shear Rheometer (DSR) AASHTO Designation: TP 126-18 1Technical Section: 4e, Joints,
3、Bearings, and Geosynthetics Release: Group 2 (June) 1. SCOPE 1.1. This test method applies to hot-poured asphalt crack sealant used in the construction and maintenance of roadways as specified in MP 25 and PP 85. 1.2. This test method is used to determine the resistance of hot-poured asphalt crack s
4、ealant to tracking and deformation at summer temperatures. 1.3. This test method covers the determination of flow and shear thinning propensity in hot-poured asphalt crack sealant with the use of a dynamic shear rheometer and by means of creep-recovery tests. 2. REFERENCED STANDARDS 2.1. AASHTO Stan
5、dards: MP 25, Performance-Graded Hot-Poured Asphalt Crack Sealant PP 85, Grading or Verifying the Sealant Grade (SG) of a Hot-Poured Asphalt Crack Sealant T 315, Determining the Rheological Properties of Asphalt Binder Using a Dynamic Shear Rheometer (DSR) T 367, Accelerated Aging of Hot-Poured Asph
6、alt Crack Sealant Using a Vacuum Oven T 368, Measuring Low-Temperature Flexural Creep Stiffness of Hot-Poured Asphalt Crack Sealant by Bending Beam Rheometer (BBR) T 369, Evaluation of the Low-Temperature Tensile Property of Hot-Poured Asphalt Crack Sealant by Direct Tension Test T 370, Measuring Ad
7、hesion of Hot-Poured Asphalt Crack Sealant Using Direct Adhesion Tester 2.2. ASTM Standards: D5167, Standard Practice for Melting of Hot-Applied Joint and Crack Sealant and Filler for Evaluation E1, Standard Specification for ASTM Liquid-in-Glass Thermometers E77, Test Method for Inspection and Veri
8、fication of Thermometers 2018 by the American Association of State Highway and Transportation Officials. All rights reserved. Duplication is a violation of applicable law.TS-4e TP 126-2 AASHTO E145, Standard Specification for Gravity-Convection and Forced-Ventilation Ovens 3. TERMINOLOGY 3.1. Defini
9、tions: 3.1.1. hot-poured asphalt crack sealantPolymer- or rubber-modified asphalt materials most often formulated with mineral filler, used in pavement cracks and joints. Note 1Based on the references, hot-poured asphalt crack sealant is typically applied at a temperature of 160C or above. 3.1.2. cr
10、eepSlow deformation under a force. 3.1.3. flow coefficientEmpirical constant C in viscosity units in the OstwaldDeWeale equation. 3.1.4. limiting shear viscosityLow shear viscosity that tends towards the Newtonian viscosity. 3.1.5. Newtonian viscosityViscosity independent of the applied stress. 3.1.
11、6. recoveryElastic recoil after the removal of a stress. See creep. 3.1.7. shear thinningReduction in viscosity due to an increase in stress rate. 3.1.8. shear thinning exponentExponent P of the OstwaldDeWeale equation. 4. SUMMARY OF TEST METHOD 4.1. This standard contains the procedure to measure t
12、he flow coefficient and the shear-thinning exponent of a hot-poured asphalt crack sealant by means of a dynamic shear rheometer. 4.2. The hot-poured asphalt crack sealant material is placed between two parallel test plates in a dynamic shear rheometer and subjected to eight cycles of creep and recov
13、ery at increasing stresses and at a fixed temperature. The limiting shear rate is obtained from the end of the creep phase for each stress level. After the eight cycles, the stresses are plotted against the limiting shear rates and a power-law fit of the data provides two parameters to characterize
14、the asphalt crack sealant flow properties: C, the flow coefficient; and P, the shear thinning exponent. 4.3. Apparent viscosities between 0.1 kPas and 100 kPas are typically obtained between 46C and 82C when the applied shear stress varies from 25 Pa to 3200 Pa. 5. SIGNIFICANCE AND USE 5.1. This tes
15、t is intended for hot-poured asphalt crack sealant applied to roadway joints and cracks. 5.2. The test temperature for this test is related to the average 7-day maximum temperature experienced by the pavement surface in the geographical area for which the hot-poured asphalt crack sealant is intended
16、 to be used. 5.3. The asphalt crack sealant flow coefficient and shear thinning exponent are indicators of the resistance of hot-poured asphalt crack sealant to flow out of the crack or joint under loads simulating those from cars and trucks. 2018 by the American Association of State Highway and Tra
17、nsportation Officials. All rights reserved. Duplication is a violation of applicable law.TS-4e TP 126-3 AASHTO 5.4. This method is intended for unaged hot-poured asphalt crack sealant, which is relatively soft, but it could be applied to an aged hot-poured asphalt crack sealant that would become sof
18、ter with age. 6. APPARATUS 6.1. Dynamic Shear Rheometer (DSR)A DSR system that consists of parallel metal plates, an environmental chamber, a loading device, and a control and data acquisition system. The instrument must meet the requirements stated in T 315. 6.2. FreezerA calibrated freezer capable
19、 of maintaining a temperature of 23C 2C. 6.3. Specimen MoldMold with disk-shaped cavities of sufficient height and diameter to provide duplicate disks 2.0 mm thick and 25 mm in diameter after loading and trimming in the DSR. Note 2Flexible molds of silicone rubber, used in T 315, with a cavity of ab
20、out 2.2 mm in height and 19 mm in diameter work well for this purpose, but they could be aluminum, with a bottom plate and two arcs. 7. HAZARDS 7.1. Standard laboratory caution should be used in handling hot-poured asphalt crack sealant according to ASTM D5167. 7.2. This practice does not purport to
21、 address all of the safety concerns, if any, associated with their use. It is the responsibility of the user of this standard to establish and follow appropriate health and safety practices and to determine the applicability of regulatory limitations prior to use. 8. PREPARATION OF APPARATUS 8.1. DS
22、RFollow the procedures as expressed in T 315. Use 25 mm parallel test plates. 8.2. FreezerPrecool the freezer and set the temperature to achieve 23C 2C at the bottom of the freezer. 9. VERIFICATION, CALIBRATION AND STANDARDIZATION 9.1. DSRFollow the verification and calibration procedures as express
23、ed in T 315. 9.2. Oven and FreezerStandardize the temperature with a thermometer that meets the requirements of ASTM E1. The thermometer calibration can be verified according to ASTM E77. 10. PREPARATION OF SAMPLES AND TEST SPECIMENS 10.1. Sample and prepare hot-poured asphalt crack sealant accordin
24、g to ASTM D5167. Note 3It is recommended to homogenize about 500 g of hot-poured asphalt crack sealant and sequentially pour test specimens for all the hot-poured asphalt crack sealant grading tests, including the accelerated vacuum oven aging (VOA) (T 367) and the low-temperature tests (T 368, T 36
25、9, and T 370). 10.2. Pour hot asphalt crack sealant into a specimen mold and immediately store at 23C 2C. Prepare two replicates for each hot-poured asphalt crack sealant tested. 2018 by the American Association of State Highway and Transportation Officials. All rights reserved. Duplication is a vio
26、lation of applicable law.TS-4e TP 126-4 AASHTO Note 4Freezing is used to minimize molecular associations (steric hardening), as defined in T 315, and to help provide identical thermal histories for different test specimens, including polymer thermal degradation, if it occurs. 10.3. After 10 minutes
27、of cold storage, unmold the test specimen disks with minimal distortion while they are cold. Retrieve the mold to pour other asphalt crack sealant, if needed. Retain one test specimen for testing, and return the duplicate test specimen to the freezer for later testing. Note 5To protect and label tes
28、t specimen disks during cold storage, aluminum foil is convenient. 11. PROCEDURE 11.1. DSR Set-Up: 11.1.1. Install cleaned and inspected parallel test plates of 25 mm diameter according to T 315 in a DSR, and set-up instrument software for stress-controlled creep and recovery. 11.1.2. Bring the DSR
29、sample chamber to a stabilized test temperature 0.1C. Note 6Select test temperatures in accordance with the material specification MP 25. 11.1.3. Zero gap the instrument as stated in T 315. Load and trim the specimen to achieve a sample thickness of 2.0 mm. Allow 10 to 15 minutes for the hot-poured
30、asphalt crack sealant to equilibrate at the test temperature 0.1C. 11.2. Creep and Recovery Test: 11.2.1. Apply a shear creep stress of 25 Pa for 2 s to the asphalt crack sealant test specimen disk. Remove the stress and allow the specimen to recover for 18 s. Record the data for this 20 s cycle for
31、 later calculations. Pause 180 s before moving to the next higher load. This pause allows for the retrieving and setting-up of the next creep and recovery program with the next higher load. Double the load after each 20 s cycle until a stress of 3200 Pa is reached. The result is an 8-cycle test with
32、 a stress that increases from 25 Pa to 50 Pa, then to 100 Pa, 200 Pa, 400 Pa, 800 Pa, 1600 Pa, and 3200 Pa. 11.3. Repeat Sections 11.1 to 11.2.1 for the duplicate test specimen. 12. CALCULATION OF RESULTS 12.1. For each creep and recovery cycle, determine the shear rate ( ) at the end of the creep p
33、hase. Most rheometer software allows for a rapid collection and storage of the data. Typical results are shown in Figure 1. 2018 by the American Association of State Highway and Transportation Officials. All rights reserved. Duplication is a violation of applicable law.TS-4e TP 126-5 AASHTO Figure 1
34、Typical asphalt crack sealant response from 2 s of creep at a stress of 25 Pa followed by 18 s of recovery (left). The shear rate ( ) (shown as / t) is obtained from the linear portion of the creep phase (right). The stress and the creep rate can be used to measure the limiting viscosity L. 12.2. Pl
35、ot log against log ( ) to obtain the isotherm curve. Figure 2 shows isotherms obtained at several temperatures on an asphalt crack sealant. 12.3. Fit the isotherm to the OstwaldDeWaele power-law: = (1) where: = shear stress (kPa), C = flow coefficient proportional to viscosity (kPas), = shear rate (
36、1/s), and P = exponent that characterizes shear thinning. Note 7Newtonian behavior is a special case of the above power-law, where in the absence of shear thinning, P = 1 and C = 0, with 0 as the zero-shear viscosity. Newtonian behavior is characterized by a viscosity independent of shear rate. In c
37、ases of shear thinning, its extent is expressed by values of P between 0 and 1. The lower the value, the greater the shear thinning is. An asphalt crack sealants Newtonian and non-Newtonian behavior can be characterized by the parameters C and P in the OstwaldDeWaele equation. Figure 2Log-log plot o
38、f the shear stress against the shear rate for various temperatures. The OstwaldDeWaele power-law fit provides C and P. 0 2 4 6 8 0 5 10 15 20 Time/ sec Strain/ % 0 5 10 15 20 25 30 Stress/ Pa Strain Stress 0 2 4 6 8 0 1 2 3 4 Time/ sec Strain/ % t = /( / t) 10 100 1000 10000 0.0001 0.01 1 Shear rate
39、, 1/s Stress, Pa 46C 52C 58C 64C 70C 76C 82C 2018 by the American Association of State Highway and Transportation Officials. All rights reserved. Duplication is a violation of applicable law.TS-4e TP 126-6 AASHTO 13. REPORT 13.1. Report the following information: 13.1.1. Asphalt crack sealant identi
40、fication and supplier; 13.1.2. Lot number; 13.1.3. Date received; 13.1.4. Date sampled according to ASTM D5167; 13.1.5. Date tested for tracking resistance; 13.1.6. Test temperature, nearest 0.1C; 13.1.7. From the duplicates, report the average values for flow coefficient (C), to the nearest 0.1 kPa
41、s; and 13.1.8. Shear thinning coefficient (P), to the nearest 0.01 (unitless). 14. PRECISION AND BIAS 14.1. Single-Operator Precision (Repeatability)The results obtained in the same laboratory by the same operator using the same equipment, in the shortest practical period of time, should not be cons
42、idered suspect unless the difference in the two results, expressed as a percent of their mean, exceeds the value given in Table 1. Table 1Precision Estimates Condition Coefficient of Variation (1s%) aSingle-operator precision: Average C (kPas) 10 Average P 5 aThe precision estimate given in Table 1
43、is based on the analysis of test results from three asphalt crack sealants with a wide range of rheological properties at three different temperatures; 46C, 64C, and 76C. The data analyzed included results from one operator in the same laboratory who conducted each test in two replicates. 15. KEYWOR
44、DS 15.1. Crack; dynamic shear rheometer; fillers; hot-poured asphalt crack sealant; joint; pavement maintenance; shear thinning; tracking; viscosity. 16. REFERENCES 16.1. Mezger, T. G. The Rheology Handbook. Vincentz Network, Hannover, 2002. 16.2. Malkin, A. and A. Isayev. Rheology: Concepts, Method
45、s, and Applications. Chemtec Publishing, Toronto, 2006. 2018 by the American Association of State Highway and Transportation Officials. All rights reserved. Duplication is a violation of applicable law.TS-4e TP 126-7 AASHTO 16.3. Collins, P., M. Veitch, J. F. Masson, and I. L. Al-Qadi. “Deformation
46、and Tracking of Bituminous Sealants in Summer Temperatures: Pseudo-Field Behavior.” International Journal of Pavement Engineering, Vol. 9, No. 1, 2008, pp. 18. 1This provisional standard was first published in 2017. 2018 by the American Association of State Highway and Transportation Officials. All rights reserved. Duplication is a violation of applicable law.
