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 126-171Technical Section: 4e, Joints, Bearings, and Geosynthetics Release: Group 2 (June 2017) American Association of State Highway and Trans
2、portation 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 126-171Technical Section: 4e, Joints
3、, Bearings, and Geosynthetics Release: Group 2 (June 2017) 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
4、crack sealant 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. AASH
5、TO Standards: 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-Pour
6、ed Asphalt 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, Measu
7、ring Adhesion 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 a
8、nd Verification of Thermometers 2017 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.
9、 Definitions: 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.
10、1.2. creepSlow 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 stres
11、s. 3.1.6. 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 me
12、asure the 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 an
13、d recovery 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 charac
14、terize the asphalt crack sealant flow properties: C, the flow coefficient; and P, the shear thinning exponent. 4.3. Apparent viscosities between 0.1 kPa.s and 100 kPa.s 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.
15、 This test 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
16、 intended 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. 2017 by the American Association of State Highwa
17、y and Transportation 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 b
18、ecome softer 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 freeze
19、r capable 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 cav
20、ity of about 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 p
21、urport to 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 APPARATU
22、S 8.1. DSRFollow 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 a
23、s expressed 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
24、 according 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
25、368, T 369, and T 370). 2017 by the American Association of State Highway and Transportation Officials. All rights reserved. Duplication is a violation of applicable law.TS-4e TP 126-4 AASHTO 10.2. Pour hot asphalt crack sealant into a specimen mold. With a hot knife, trim the crack sealant flush wi
26、th the mold and immediately store at 23C 2C. Prepare two replicates for each asphalt crack sealant tested. 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 polyme
27、r thermal degradation, if it occurs. 10.3. After 10 minutes 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 t
28、he freezer for later testing. Note 5To protect and label test 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
29、stress-controlled creep and recovery. 11.1.2. Bring the DSR 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 thi
30、ckness of 2.0 mm. Allow 10 to 15 minutes for the hot-poured 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
31、to recover for 18 s. Record the data for this 20 s cycle for 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 stre
32、ss of 3200 Pa is reached. The result is an 8-cycle test with 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 c
33、ycle, determine the shear rate( ) at the end of the creep phase. Most rheometer software allows for a rapid collection and storage of the data. Typical results are shown in Figure 1. 2017 by the American Association of State Highway and Transportation Officials. All rights reserved. Duplication is a
34、 violation of applicable law.TS-4e TP 126-5 AASHTO Figure 1Typical 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
35、 can be used to measure the limiting viscosity L. 12.2. Plot 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 coe
36、fficient proportional to viscosity (kPa.s), = shear rate (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 0as the zero-shear viscosity. Newtonian behavior is cha
37、racterized by a viscosity independent of shear rate. In cases 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
38、 P in the OstwaldDeWaele equation. Figure 2 Log-log plot of the shear stress against the shear rate for various temperatures. The OstwaldDeWaele power-law fit provides C and P. 024680 5 10 15 20Time/ secStrain/ %051015202530Stress/ PaStrainStress024680 1 2 3 4Time/ secStrain/ %t = /(/t) 101001000100
39、000.0001 0.01 1Shear rate, 1/sStress, Pa46C52C58C64C70C76C82C 2017 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 cra
40、ck sealant identification 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 th
41、e nearest 0.1 kPa.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,
42、should not be considered 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 (kPa.s) 10 Average P 5 aThe precision estimate
43、 given in Table 1 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 repl
44、icates. 15. KEYWORDS 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
45、: Concepts, Methods, and Applications. Chemtec Publishing, Toronto, 2006. 2017 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-Q
46、adi. “Deformation 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. 2017 by the American Association of State Highway and Transportation Officials. All rights reserved. Duplication is a violation of applicable law.
