1、Standard Method of Test for Determining Asphalt Binder Bond Strength by Means of the Binder Bond Strength (BBS) Test AASHTO Designation: TP 91-151American Association of State Highway and Transportation Officials 444 North Capitol Street N.W., Suite 249 Washington, D.C. 20001 TS-2a TP 91-1 AASHTO St
2、andard Method of Test for Determining Asphalt Binder Bond Strength by Means of the Binder Bond Strength (BBS) Test AASHTO Designation: TP 91-1511. SCOPE 1.1. This test method quantifies the tensile force needed to remove a pull-off stub adhered to a solid substrate with asphalt binder. Samples are p
3、repared at controlled environmental and moisture conditions (i.e., temperature and humidity). After conditioning, a pneumatic load is applied to a pull-off stub using an ASTM D4541 Type IV adhesion tester until failure. The pull-off tensile strength and mode of failure are used to describe the bondi
4、ng properties of the asphalt binder and compatibility between aggregates and asphalt binders. 1.2. The values stated in SI units are to be regarded as the standard. 1.3. This test may involve hazardous materials, operations, and equipment. This standard does not purport to address all of the safety
5、concerns associated with its use. It is the responsibility of the user to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. 2. REFERENCED DOCUMENTS 2.1. AASHTO Standards: M 140, Emulsified Asphalt M 208, Cationic Emulsified Asph
6、alt M 316, Polymer-Modified Cationic Emulsified Asphalt R 66, Sampling Asphalt Materials T 315, Determining the Rheological Properties of Asphalt Binder Using a Dynamic Shear Rheometer (DSR) 2.2. ASTM Standards: D4541, Standard Test Method for Pull-Off Strength of Coatings Using Portable Adhesion Te
7、sters D4753, Standard Guide for Evaluating, Selecting, and Specifying Balances and Standard Masses for Use in Soil, Rock, and Construction Materials Testing E77, Standard Test Method for Inspection and Verification of Thermometers E145, Standard Specification for Gravity-Convection and Forced-Ventil
8、ation Ovens 2015 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-2a TP 91-2 AASHTO 3. TERMINOLOGY 3.1. Definitions: 3.1.1. failure modeindicator of the weakest component of the asphalt/surface system. In a
9、pplications to this test procedure failure can occur at three locations: within the asphalt binder, at the asphalt binder/substrate interface, or in a mixed mode. 3.1.2. pull-off tensile strengththe pressure required to remove a pull-off stub attached to a prefabricated surface by asphalt binder, wi
10、th force applied in the normal direction. Used in this procedure as a parameter to evaluate the quality of the bond. 3.1.3. saturated surface-dry (SSD) conditionin this condition, the void structure of the aggregate is filled with moisture, while the main surface area of the aggregate particles rema
11、ins dry. 4. SUMMARY OF METHOD 4.1. The adhesion tester applies a pneumatic load via a pressure ring to a pull-off stub fixed to a rigid substrate with asphalt binder, as shown in Figure 1. The binder is adhered to the substrate and subjected to different curing conditions. For curing emulsified bind
12、ers, fixed levels of temperature and humidity are used. Moisture conditioning is used for both hot-applied binders and emulsion residues to evaluate the effects of moisture damage. Pressure and time are monitored during the test and the load is applied until failure. The output of the test is pressu
13、re at failure. The surface is also inspected visually to determine the nature of failure. Figure 1Schematic Representation of the Testing Assembly for the Binder Bond Strength Test 5. SIGNIFICANCE AND USE 5.1. Pull-off tensile strength values measured over a range of environmental conditions and cur
14、ing times provide information related to the bond strength at the interface between a substrate and hot-applied or emulsified asphalt binders. 5.2. Evaluation of pull-off tensile strength on different aggregate substrates provides a measure of asphalt-aggregate compatibility. 5.2.1. Applications to
15、emulsified binders include assessment of curing rate and ultimate tensile strength. 2015 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-2a TP 91-3 AASHTO 5.2.2. Applications to hot-applied asphalt binders
16、 and recovered emulsion residues include evaluation of the effects of application temperature and moisture conditioning on pull-off tensile strength. 6. APPARATUS 6.1. Molds: 6.1.1. Emulsified BindersFor emulsified asphalt binders, use a silicone mold measuring approximately 20 mm (0.79 in.) in diam
17、eter, 5 mm (0.20 in.) in width, and 5 mm (0.20 in.) in thickness. The mold has no backing and is used to contain the emulsion on the aggregate surface. A diagram of the mold is shown in Figure 2a. 6.1.2. Hot-Applied Asphalt Binders and Emulsion Residues Use a silicone mold measuring approximately 40
18、 mm by 40 mm (1.6 in. by 1.6 in.) with an 8-mm (0.32-in.) diameter cavity and a 2.0-mm (0.08-in.) depth. This mold is similar to the molds used to prepare Dynamic Shear Rheometer (DSR) test samples in T 315. A diagram of the mold is shown in Figure 2b. 40408(a) (b) Figure 2Mold Dimensions (mm) for E
19、mulsified Binders (a) and Hot Binders (b)Drawings Not to Scale 6.2. SubstrateComposed of solid aggregate or aggregate composite with dimensions as defined in Section 9. 6.3. Testing MachineUse a Type IV adhesion tester as defined by ASTM D4541 for all tests. At a minimum the device must consist of t
20、he components detailed in Sections 6.3.1 through 6.3.3. An example of a testing machine is shown in Figure 3. Note 1 The testing apparatus shown in Figure 3 is a commercially available device produced by GARDCO, Inc. The F-4 piston depicted in the figure has a diameter of 73.0 mm (2.88 in.). Other d
21、evices meeting the requirements of this procedure can be used. 6.3.1. Control ModuleCapable of controlling the air pressure load range from 7 to 35,000 kPa (1 to 5000 psi), and equipped with a digital or analog display, loading rate control, and data acquisition software capable of monitoring air pr
22、essure over time. 6.3.2. Load AssemblyConsists of a piston, reaction plate, gasket and air hose. 2015 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-2a TP 91-4 AASHTO 6.3.2.1. Piston and Reaction PlateSel
23、ect a piston and reaction plate assembly with sufficient diameter to allow for loading of the sample until failure. Air pressure at failure is a function of test temperature, loading rate, and asphalt binder stiffness. Application of the device to asphalt binders and mastics indicates that a minimum
24、 piston/reaction plate diameter of 57.2 mm (2.25 in.) is required. 6.3.2.2. GasketComposed of polymer or other material with properties and dimensions capable of providing an air-tight seal between the piston and reaction plate. The gasket must be inspected regularly to ensure the air-tight seal is
25、maintained and replaced when the gasket is no longer functioning. 6.3.2.3. Air HoseRated for a maximum kPa (psi) value that exceeds the air supply specified in Section 6.3.3. Figure 3General Representation of Binder Bond Strength Test Apparatus 6.3.3. Air SupplyCapable of producing a consistent air
26、pressure of at least 0.7 MPa (100 psi) as read on the supply gauge. Self-contained air cylinders, shop (bottled) air, or air from an automatic pump can be used. 6.4. Pull-off StubsStainless steel or any other suitable material, with dimensions as shown in Figure 4. Stub edges are beveled to reduce t
27、he amount of binder trapped between the stub edge and substrate and to ensure a uniform film thickness. Inspect the pull-off stub edges frequently to verify that the edge is consistent along the diameter of the stub with no visible chips or dents. Discard damaged stubs. The stub surface is roughened
28、 to increase the surface area in contact with the asphalt binder. Note 2The dimensions presented in Figure 4 are specific to the device used in the development of this test procedure. If another device is used adjust the dimensions to match the pull-off stub with the load assembly of the device. Pul
29、l-off stub diameter (20 mm (0.8 in.) in Figure 4) is an 2015 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-2a TP 91-5 AASHTO input to the calculation of pull-off tensile strength (POTS). Maintain a toler
30、ance of 0.025 mm (0.001 in.) in stub diameter to ensure consistent results. The procedure was developed based on a pull-off stub diameter of 20 mm; it is recommended the user maintain this dimension for testing. Roughened Stub Surface Profile View (mm) Bottom View (mm) Dimensional Equivalents mm 0.8
31、 5 6 7 15 20 22 40 in. 0.03 0.2 0.24 0.28 0.6 0.8 0.9 1.6 Figure 4Pull-off Stub Dimensions for Binder Bond Strength Test 6.5. Ring SupportProvides support to the piston and reaction plate support; also provides space between the substrate and load assembly to minimize the risk of eccentric loading.
32、The ring support (e.g., a shaft collar) has minimum dimensions of 12.5 mm (0.5 in.) in height and a 25.4-mm (1.0-in.) inside diameter. An example of a ring support is shown in Figure 5. Figure 5Pull-off Stub Metal Ring support 6.6. Forced-Draft OvenCapable of maintaining temperatures of at least 150
33、 3C (302 6F) for preparing all aggregate and binder samples. Use as many temperature-controlled ovens of Type IIA or IIB as defined in ASTM E145 as necessary to accommodate different heating conditions required in the sample preparation process detailed in Section 10. 6.7. Environmental ChamberCapab
34、le of maintaining temperatures between 15 and 75 1C (60 and 167 2F) and a relative humidity between 20 and 80 percent 1 percent, for curing all emulsified asphalt samples. 2015 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation o
35、f applicable law.TS-2a TP 91-6 AASHTO 6.8. ThermometerFor tests performed at 25C (77F), use an ASTM Thermometer No. 17C (17F) to measure the temperature of the substrate surface prior to testing. For tests performed at other temperatures, use ASTM thermometers of an appropriate range and accuracy eq
36、ual to that of the No. 17 thermometer. Since the accuracy of the test results is dependent upon closely controlled temperature conditions, calibrate thermometers in accordance with ASTM E77. Thermometric devices with the same accuracy as ASTM thermometers may also be used. 6.9. ContainerAny suitable
37、 container may be used to hold the hot-applied asphalt binder material while it is being melted. For emulsified asphalt binders, the container may be plastic, nonmetal, or, if metal, epoxy-lined. 6.10. Ultrasonic CleanerNeeded to remove residual particles from substrate surfaces prior to testing. Ca
38、pable of maintaining bath temperatures of 60 1C (140 2F) and with a sufficiently large chamber to allow for complete submersion of the substrate. 6.11. 280-Grit Silicon Carbide MaterialOn a standard lapidary wheel to ensure uniform roughness on the substrate. 6.12. Bench ScaleCapable of meeting GP2
39、requirements as specified in ASTM D4753. 6.13. Water Bath Capable of maintaining a minimum temperature of 40 3C (104 6F) and with sufficient dimensions to allow for complete submersion of asphalt-aggregate systems in water during moisture conditioning. 7. SAFETY PRECAUTIONS 7.1. Observe standard lab
40、oratory safety precautions when preparing and testing hot-applied asphalt binders and emulsified asphalts. 8. CALIBRATION OF TESTING EQUIPMENT 8.1. Verify the operating condition of all physical components in the testing system (i.e., air supply, pressure ring, software, and connections) prior to te
41、sting. 8.2. Calibration of Loading Rate: 8.2.1. Turn on the adhesion testing equipment, computer, and data acquisition system per the manufacturers instructions. 8.2.2. Insert the gasket into the piston and place the reaction plate over the piston, as indicated in Figure 3. Clamp the top (reaction p
42、late) and bottom (piston) of the loading assembly using an appropriately sized C-clamp. 8.2.3. Set the loading rate to the predetermined setting, noting the position of the loading rate setting relative to the position that corresponds to the minimum or zero loading rate. 8.2.4. Apply air pressure f
43、or a maximum of 3 s. Monitor the air pressure versus time through the data acquisition system or manual readings. For electronic sampling devices, this step also verifies that the data acquisition system is functioning. 8.2.5. Calculate the loading rate based on the slope of the “air pressure versus
44、 time” curve between 20 and 80 percent of the maximum pressure. Verify that the actual loading rate is within 10 percent of 2015 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-2a TP 91-7 AASHTO the pre-se
45、lected target value. If the measured value falls outside the target range, adjust the pressure setting, and repeat Sections 8.2.2 through 8.2.4. 8.3. Conduct the verification of testing equipment and calibration of loading rate procedures specified in Sections 8.1 and 8.2 prior to each day of bond s
46、trength testing. 9. AGGREGATE TEST SPECIMENS 9.1. Solid Aggregate SubstratesCut aggregate substrates from either quarried rocks or cored rock samples using standard rock saws such that the plate faces are parallel. Lap all substrates using a 280-grit silicon carbide material on a standard lapidary w
47、heel to remove saw marks and ensure a consistent surface roughness. Once cut and lapped, clean the samples for 60 min in an ultrasonic cleaner containing distilled water at a temperature of 60 1C (140 2F) to remove residual particles on the plate surface. Limit the use of the same solid aggregate su
48、bstrate to five times per cut surface. 9.2. Composite SubstratesComposite substrates contain aggregate chips and a rapid-setting cement compound. Prepare composite substrates by casting samples in portland cement concrete cylinder molds measuring 15.2 cm (6 in.) in diameter and 35.4 cm (13.9 in.) in
49、 height. Cure samples according to the cement compound manufacturers instructions. After curing, cut, lap, and clean the composite substrates according to the procedures provided in Section 9.1 for aggregate substrates. Limit the use of the same composite substrate to five times per cut surface. 9.3. Substrate DimensionsCut solid aggregate or aggregate composite substrates to a minimum thickness of 20 mm (0.8 in.) and dimensions that provide sufficient surface area for placement of f
