1、TS-4e TP 87-1 AASHTO Standard Method of Test for Measure Low-Temperature Flexural Creep Stiffness of Bituminous Sealants and Fillers by Bending Beam Rheometer (BBR) AASHTO Designation: TP 87-10 (2013) 1. SCOPE 1.1. This method applies to bituminous sealants used in the construction and maintenance o
2、f roadways. 1.2. The method is used to determine the bituminous sealant flexural stiffness. It can be used on unaged material or on material aged using TP 86. The test apparatus is designed for testing within the temperature range from 4 to 40C. 1.3. The values stated in SI units are to be regarded
3、as the standard. 1.4. This standard covers the determination of flexural stiffness in bituminous sealants using the bending beam rheometer and by conducting the creep test. 2. REFERENCED DOCUMENTS 2.1. AASHTO Standards: T 313, Determining the Flexural Creep Stiffness of Asphalt Binder Using the Bend
4、ing Beam Rheometer (BBR) TP 86, Accelerated Aging of Bituminous Sealants and Fillers with a Vacuum Oven 2.2. ASTM Standards: D 5167, Standard Practice for Melting of Hot-Applied Joint and Crack Sealant and Filler for Evaluation E 1, Standard Specification for ASTM Liquid-in-Glass Thermometers E 77,
5、Standard Test Method for Inspection and Verification of Thermometers 2.3. Sealant Consortium (SC) Standards:1 SC-1, Guidelines for Graded Bituminous Sealants SC-2, Test Method for Measuring Apparent Viscosity of Hot-Poured Crack Sealant Using Brookfield Rotational Viscometer RV Series Instrument SC-
6、3, Test Method for Accelerated Aging of Bituminous Sealants SC-4, Sealant Flow and Deformation SC-5, Test Method to Measure Low-Temperature Sealant Flexural Creep Stiffness at Low Temperature by Bending Beam Rheometer SC-6, Test Method to Evaluate Sealant Extensibility at Low Temperature by Direct T
7、ension Test 2013 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-4e TP 87-2 AASHTO SC-7, Test Method for Measuring Adhesion of Hot-Poured Crack Sealant Using Direct Adhesion Tester 3. TERMINOLOGY 3.1. bitu
8、minous sealantshot-poured modified asphaltic materials used in pavement cracks and joints. 3.2. Definitions of Terms Specific to This Standard: 3.2.1. contact load, nthe load, Pc , required to maintain positive contact between the test specimen, supports, and the loading shaft, 35 10 mN. 3.2.2. flex
9、ural creep compliance, D(t), nthe ratio obtained by dividing the maximum bending strain in a beam by the maximum bending stress. The flexural creep stiffness is the inverse of the flexural creep compliance. 3.2.3. flexural creep stiffness, S(t), nthe creep stiffness obtained by fitting a second orde
10、r polynomial to the logarithm of the measured stiffness at 8.0, 15.0, 30.0, 60.0, 120.0, and 240.0 s and the logarithm of time. 3.2.4. measured flexural creep stiffness, Sm(t), nthe ratio obtained by dividing the measured maximum bending stress by the measured maximum bending strain. Flexural creep
11、stiffness has been used historically in asphalt technology, while creep compliance is commonly used in studies of viscoelasticity. 3.2.5. average creep ratethe average creep rate obtained by fitting the power law model of the logarithm of the strain versus the logarithm of time. The average creep ra
12、te is the absolute value of the exponents of the power law model. 3.2.6. test load, nthe load, Pt , of 240 s duration is used to determine the stiffness of the crack sealant being tested, 980 50 mN. 4. SUMMARY OF PRACTICE 4.1. The bending beam rheometer is used to measure the midpoint deflection of
13、a simply supported prismatic beam of bituminous crack sealant subjected to a constant load applied to the midpoint of the test specimen. The device operates only in the loading mode. 4.2. A prismatic test specimen is placed in the controlled temperature fluid bath and loaded with a constant test loa
14、d for 240.0 s and unloaded for 480.0 s. The test load (980 50 mN) and the midpoint deflection of the test specimen are monitored versus time using a computerized data acquisition system. 5. SIGNIFICANCE AND USE 5.1. This test is intended for bituminous sealants applied to roadway joints and cracks.
15、5.2. The test temperature is determined as the lowest temperature experienced by the pavement surface in the geographical area for which the sealant is intended. 2013 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicab
16、le law.TS-4e TP 87-3 AASHTO 5.3. The flexural creep stiffness or flexural creep compliance, determined from this test, describes the low-temperature stress-strain-time response of crack sealant at the test temperature. 5.4. The average creep rate determined from this test gives an indication of the
17、rate of deformation of crack sealant at the test temperature. 5.5. Sealants must be homogenized before being used to conduct this test. 6. APPARATUS 6.1. A crack sealant bending beam rheometer (CSBBR) test system consists of the following: (1) a modified bending beam rheometer with a controlled temp
18、erature liquid bath that maintains the test specimen at the test temperature, (2) test specimen molds, and (3) items for verifying and calibrating the system. 6.2. Modified Bending Beam RheometerA CSBBR is modified from a typical BBR. The CSBBR has a modified loading frame system that can accommodat
19、e a specimen 12.7 mm in height to operate a three-point bending beam test that applies a constant test load for 240.0 s and unloads for 480.0 s. The specification required by the CSBBR system is in accordance with T 313. The updated version software can be obtained from the instrument manufacturer.
20、6.3. Test Specimen MoldsTest specimen molds with interior dimensions of 12.70 0.05 mm wide by 12.70 0.05 mm deep by 102.0 0.5 mm long and fabricated from aluminum or stainless steel (Figure 1). 6.3.1. The thickness of the two spacers used for each mold (small end pieces used in the metal molds) shal
21、l be measured with a micrometer and shall not vary from each other in thickness by more than 0.05 mm. Note 1Small errors in the thickness of the test specimen can have a significant effect on the calculated stiffness because the calculated stiffness is a function of the thickness, h, raised to the t
22、hird power. 2013 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-4e TP 87-4 AASHTO Figure 1Dimensions for Crack Sealant Bending Beam Rheometer Mold and Modified Specimen Support 6.4. Items for CalibrationI
23、tems remain the same as in T 313 except for the thickness dimension of the stainless steel beam used for calibration. The new calibration kits can be obtained from the instrument manufacturer. 6.5. Calibrated ThermometersCalibrated liquid-in-glass thermometers to verify the temperature transducer of
24、 suitable range with subdivisions of 0.1C. 6.6. Laboratory OvensTwo standard laboratory ovens capable of producing and maintaining a temperature of 200 0.5C. ITEM QTY DESCRIPTIONABC221Side BarSpacer BarBottom PlateABCAABBA-AB-BC-CCC19.00 mm19.00 mm19.00 mm12.70 mm12.70 mm12.70 mm165.00 mm177.00 mm6.
25、00 mm5.25 mm13.00 mm 2013 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-4e TP 87-5 AASHTO 7. REAGENTS AND MATERIALS 7.1. Bath FluidA bath fluid that is not absorbed by or does not affect the properties o
26、f the crack sealant being tested. The bath fluid shall be optically clear at the test temperature. 7.2. Binder ClipA binder clip is used to hold the aluminum mold to maintain the size of the sample to prevent shrinkage during sealant cooling. 7.3. Release AgentA proper release agent prevents bitumin
27、ous crack sealant from sticking to the mold. Using a spray type silicon-based release agent is recommended. 7.4. SolventA solvent can properly clean the molds, end tabs, and plates. The parts cleaned by the solvent shall be submerged in the ethanol prior to use. Cleaning ensures the proper bond betw
28、een sealant and end tabs. 7.5. Cleaning ClothsCloths for wiping molds, end tabs, and plates. 8. HAZARDS 8.1. Standard laboratory caution should be used in handling hot bituminous sealant in accordance with ASTM D 5167, and required safety procedures should be followed when chemical agents are used.
29、9. VERIFICATION AND CALIBRATION 9.1. Bending Beam Rheometer (BBR)Follow the procedure as stated in T 313. 9.2. Oven and FreezerCalibrate the temperature with a thermometer that meets the requirements of ASTM E 1. The thermometer calibration can be verified according to ASTM E 77. 10. SAMPLES PREPARA
30、TION 10.1. Preparation of Molds: 10.1.1. Spread a very thin layer of release agent on the interior faces of four mold sections to prevent the crack sealant from sticking to the metal end pieces. Assemble the mold and use binder clips to hold the pieces of the mold together. 10.1.2. Preheat the oven
31、to a temperature 50C lower than the recommended pouring temperature at least 1 h before testing. Place the mold on the ceramic tiles into the oven 15 m before pouring the crack sealant. 10.2. Preparation of Test Specimens: 10.2.1. Laboratory-aged samples shall be obtained in accordance with appropri
32、ate test methods. 10.2.2. Heat four cans of bituminous crack sealant, which contain 35 g of bituminous sealant each, in an oven set at the sealant manufacturer-recommended pouring temperature until the sealant is sufficiently fluid to pour. (Do not heat the sealant more than 30 min.) Each can of sea
33、lant will be poured into its own mold. 2013 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-4e TP 87-6 AASHTO 10.3. Molding Test SpecimensPrepare four replicates for each tested sealant. Prior to pouring t
34、he sealant, take one preheated mold and one ceramic tile from the oven. With the preheated mold on the ceramic tile, firmly stir the sealants prior to pouring into the molds to ensure the homogeneity of the sealant. Begin pouring the sealant from one end of the mold and move toward the other end, sl
35、ightly overfilling the mold. When pouring, hold the sample container 20 to 30 mm from the top of the mold, pouring continuously toward the other end in a single pass. Repeat the same procedure for the other three molds. With the filled mold still on the preheated ceramic tile, allow to cool for 1 h
36、to room temperature. After cooling to room temperature, trim the exposed face of the cooled specimens even with the top of the mold using a hot knife. 10.4. Storing and Demolding Test Specimens: 10.4.1. Store all test specimens in their molds at room temperature prior to testing. Testing shall be co
37、mpleted within 4 h after specimens are poured. 10.4.2. Just prior to demolding, cool the molds containing the test specimens in a cold fluid bath that has the same temperature as the selected test temperature for no longer than 5 min and only long enough to stiffen the test specimen so that it can b
38、e readily demolded without distortion. A 15-min interval between each sample is desired prior to placing the sample into the cold chamber bath. Do not cool the molds containing the specimens in the test bath because it may cause temperature fluctuations in the bath to exceed 0.2C. 10.4.3. Immediatel
39、y demold the specimen when it is sufficiently stiff to demold without distortion, by disassembling the mold. To avoid distorting the specimen, demold the specimen by sliding the metal side pieces from the specimen. Note 2During demolding, handle the specimen with care to prevent distortion. Full con
40、tact at specimen supports is assumed in the analysis. A warped test specimen may affect the measured stiffness. 11. PROCEDURE 11.1. All sealants to be tested must undergo the aging process. Follow the procedure described in TP 86. It is recommended that a minimum of 150 g of bituminous sealant be pr
41、epared for a set of tests. 11.2. Select the appropriate test temperature for the crack sealant specimen. After demolding, immediately place the test specimen in the testing bath and condition it at the testing temperature. The test specimen shall remain submerged in the bath fluid at the test temper
42、ature 0.1C for the entire 60 5 min. 11.3. Check the adjustment of the contact load and test load prior to testing each set of test specimens. The 12.7-mm thick stainless steel beam shall be used for checking the contact load and test load. 11.3.1. Place the 12.7-mm steel beam in position on the beam
43、 supports. Using the test load regulator valve, gently increase the force on the beam to 980 50 mN. 11.3.2. Switch from the test load to the contact load and adjust the force on the beam to 35 10 mN. Switch between the test load and contact load four times to ensure that the load is stable. 11.3.3.
44、When switching between the test load and contact load, watch the loading shaft and platform for visible vertical movement. The loading shaft shall maintain contact with the steel beam when switching between the contact load and test load; the contact load and test load shall be maintained at 35 10 m
45、N and 980 50 mN, respectively. 2013 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-4e TP 87-7 AASHTO 11.4. Enter the specimen identification information, including the elapsed time the specimen has been c
46、onditioned in the bath at the test temperature, and other information, as appropriate, into the computer that controls the test system. 11.5. After conditioning, place the test specimen on the test supports and gently position the back side of the test specimen against the alignment pins. Initiate t
47、he test. 11.6. The bath temperature shall be maintained at the selected test temperature 0.1C during the test; otherwise the test shall be rejected. 11.7. The contact load shall be applied by gently increasing the load to 35 10 mN. While applying the contact load, the load on the beam shall not exce
48、ed 45 mN, and the time to apply and adjust the contact load shall be no greater than 10 s. 11.8. With the contact load applied to the test specimen, activate the automatic test system, which is programmed to proceed as follows: 11.8.1. Apply a 980 50 mN seating load for 1 0.1 s. 11.8.2. Reduce the l
49、oad to the 35 10 mN contact load, and allow the test specimen to recover for 480 0.1 s. At the end of the test, the operator shall monitor the computer screen to verify that the load on the test specimen returns to 35 10 mN. If it does not, the test shall be rejected. 11.8.3. Apply a 980 50 mN test load to the test specimen. The software shall record the test load at 0.5-s intervals from 0.5 to 240 s and calculate the average of the recorded load values. Between 0.5 and 5 s, the test lo
