1、Standard Method of Test for Determining the Quality of Tack Coat Adhesion to the Surface of an Asphalt Pavement in the Field or Laboratory AASHTO Designation: TP 115-161 Release: Group 3 (August 2016) American Association of State Highway and Transportation Officials 444 North Capitol Street N.W., S
2、uite 249 Washington, D.C. 20001 TS-2c TP 115-1 AASHTO Standard Method of Test for Determining the Quality of Tack Coat Adhesion to the Surface of an Asphalt Pavement in the Field or Laboratory AASHTO Designation: TP 115-161Release: Group 3 (August 2016) 1. SCOPE 1.1. This test method covers the dete
3、rmination of the tack coat adhesion quality as measured by the tensile strength of tack coat materials on the free surface of asphalt pavement in the field or laboratory. 1.2. This test can be performed in the field on the surface of asphalt pavement or on 150-mm (6-in.) diameter, gyratory-compacted
4、 samples. 1.3. This standard may involve hazardous materials, operations, and equipment. This standard does not purport to address all safety concerns associated with its use. It is the responsibility of the user of this procedure to establish appropriate safety and health practices and to determine
5、 the applicability of regulatory limitations prior to use. 2. REFERENCED DOCUMENTS 2.1. AASHTO Standards: M 231, Weighing Devices Used in the Testing of Materials T 53, Softening Point of Bitumen (Ring-and-Ball Apparatus) 3. TERMINOLOGY 3.1. tack coat adhesion qualitya measure of the ability of a ta
6、ck coat material to bond to its underlying substrate as described by the adhesive tensile strength of the tack coat material. 4. SUMMARY OF METHOD 4.1. The standard test materials and test apparatus consist of the Louisiana Tack Coat Quality Tester (LTCQT), LTCQT software, computer, weights to hold
7、the LTCQT in place during testing, and an infrared reflective heating (IRH) device used to desiccate the emulsion and to adjust the tacked surface to the testing temperature. A thermometer should be used to determine the temperature. 4.2. The test procedure involves desiccating a tacked surface usin
8、g the IRH device, adjusting the temperature of the surface with the fan or heat gun to reach the testing temperature, and applying a compressive load to the tacked pavement surface for a given amount of time using the LTCQT device and software. At a prescribed displacement rate, the movement of the
9、loading plate away 2016 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-2c TP 115-2 AASHTO from the tacked surface results in tensile loading until failure. The maximum tensile strength reflects the qualit
10、y of the adhesion of the tack coat material. 5. SIGNIFICANCE AND USE 5.1. This test method is suitable for field or laboratory tests to determine the quality of tack coat adhesion as measured by the tensile strength. The knowledge of tack coat adhesion quality serves as a tool in characterizing the
11、tack coat material. 5.2. The tensile strength produced using this test method is influenced by the temperature at which the tacked surface is tested and the application rate of the tack coat material. 5.3. The tensile strength values measured by this test method, with the equipment and procedures st
12、ated herein, do not necessarily agree or correlate directly with other techniques of tack coat adhesion quality measurements. This test method is also suitable for research and development purposes, where direct comparisons between tack coat materials on a pavement surface are to be made within the
13、same test program. 6. APPARATUS 6.1. Louisiana Tack Coat Quality TesterThe device shall be equipped with a closed-loop servo motor actuator for precision control of the rate of displacement during testing. It shall be capable of measuring loads of up to 446 N (100 lbf) with an accuracy of 1 percent.
14、 The displacement of the actuator shall be measured using a position transducer that has a total travel of 100 mm (4 in.). The diameter of the loading plate shall be 100 mm (4 in.). The device is illustrated in Figure 1. Note: The tolerance for all dimensions is 0.005 in. Figure 1Illustration of the
15、 LTCQT Device 6.5 in.ActuatorMounting PlatePress PlateRamLoad CellWeightPlatform21.0 in.16.9in.Depth 12.0 in.(profile view not shown) 2016 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-2c TP 115-3 AASHTO
16、 6.2. Computer and SoftwareThe software shall be designed such that it displays the time, normal load, and displacement of the actuator continuously during testing while graphically illustrating the relationship of the normal load and time. It shall allow the user to input the required compressive l
17、oad, the time to hold the compressive load, and the displacement rate required. The actual holding time of the compressive load shall be displayed during testing as well as the actual displacement rate. In addition, the software shall allow the user to move the actuator manually. 6.3. Infrared Refle
18、ctive Heating SourceIt shall be equipped with a 250-watt, 120-volt bulb. It shall be designed such that it can be positioned 150 mm (6 in.) from the surface to be tested without making contact with the tacked surface. 6.4. ThermometerThe thermometer shall be suitable to measure the temperature of a
19、tacked surface without directly contacting the test area. It is recommended that an infrared thermometer be utilized. 6.5. WeightsThe weights used shall be equal to or greater than the expected maximum normal load. Note that the normal load applied by the machine cannot exceed 446 N (100 lbf). 6.6.
20、Temperature Control DevicesThe devices shall adjust the surface temperature to the required test temperature. It is recommended that a fan be used to cool the tacked surface and a heat gun be used to heat the tacked surface. 6.7. Weighing DeviceThe weighing device shall have sufficient capacity, be
21、readable to 0.1 percent of the sample mass or better, and conform to the requirements of M 231. 7. HAZARDS 7.1. Standard laboratory safety precautions must be observed when preparing and testing asphalt mixture specimens. 8. TEST SPECIMENS 8.1. Testing areas shall be cleaned prior to the tack coat a
22、pplication. 8.2. Tack coat material shall be applied using the appropriate method. For laboratory specimens, apply the tack coat material at the specified application rate using a 1-in. natural bristle brush. Utilize a laboratory scale to ensure that the correct amount of tack coat is applied. Field
23、 sections typically use a distributor truck for spray application of tack coat material. 8.3. For field testing, a 150 mm (6 in.) by 150 mm (6 in.) area of tacked surface shall be desiccated prior to testing by placing the IRH source 150 mm (6 in.) above the tacked surface for a minimum of 1 h. Note
24、 1The desiccation period may be extended for bulk application rates greater than 0.05gal/yd2. The maximum heating time will depend on the tack coat material used. 8.4. Number of Test AreasA single test shall consist of at least three test areas. Laboratory testing requires three samples prepared usi
25、ng a Superpave Gyratory Compactor (SGC). 8.5. The test areas shall be numbered and the locations shall be documented. 2016 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-2c TP 115-4 AASHTO 9. PROCEDURE 9.
26、1. Testing areas (specimen) shall be conditioned to the correct testing temperature using the IRH device. Determine the softening point of the tack coat material according to T 53, and use this result as the testing temperature. Note 2Rather than testing the tack coat material to determine the softe
27、ning point, the supplier of the asphalt material may provide that information. 9.2. Device PositioningPlace the LTCQT directly above the tacked surface to be tested. Lift up the front end of the device to verify that the loading plate is positioned directly above the tacked surface that will be test
28、ed. 9.3. A typical weight of 180 N (40 lbf) shall be placed on top of the LTCQT device. 9.4. The compressive load (89 N 20 lbf), time to hold the compressive load (3 min), and the displacement rate (0.2 mm/sec 0.008 in./sec) shall be entered into the computer by the user. 9.5. Zero the load reading
29、prior to the initiation of the test. It is also recommended that the plate be positioned as close as possible to the tacked surface prior to testing so as to minimize the change in temperature. 9.6. The compressive load shall be mechanically applied to the tacked surface for the specified amount of
30、time (3 min). Once the allotted time has ended, the loading plate shall automatically be raised away from the tacked surface at the prescribed displacement rate. The software shall by design record the normal load, vertical displacement, and time throughout the test. Record the ultimate tensile load
31、 (Pult) of the tack coat material. A graph of a typical test result is shown in Figure 2. Figure 2Typical Test Results 10. CALCULATIONS 10.1. Calculate the tack coat adhesion quality, TCQ, as follows: TensileLoad(lbf)00 2 4 6 8 10Time (s)Pult12510152025304035 2016 by the American Association of Stat
32、e Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-2c TP 115-5 AASHTO 24ultPTCQD=(1) where: TCQ = tack coat adhesion quality, Pa (psi) Pult= ultimate tensile load, N (lbf) D = diameter of the loading plate, m (in.) 11. REPORT 11.1. The report
33、must include the following parameters: 11.1.1. Test location. 11.1.2. Note the appearance of the tacked surface before and after testing, including any contaminants, milling striations, stripping, tack coat streaks, etc. 11.1.3. Softening point temperature, C (F). 11.1.4. Loading Plate DimensionsInc
34、luding the diameter and the cross-section area. 11.1.5. Test Results: 11.1.5.1. Ultimate tensile load, nearest 4.4 N (1 lbf). 11.1.5.2. Tensile strength, nearest 68.9 Pa (0.01 psi). 11.1.5.3. Corresponding vertical deformation, nearest 0.025 mm (0.001 in.). 11.1.5.4. Average and standard deviation o
35、f tensile strength for the set of tested areas. 12. PRECISION AND BIAS 12.1. The precision and bias statements for this method have not been determined. 13. KEYWORDS 13.1. Asphalt overlay; slippage failure; tack coat; tack coat adhesion quality; tensile strength. 1This provisional standard was first published in 2015. 2016 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.
