| Abstract | This study introduces three laboratory tests aimed to assess the bond property of hot-poured crack sealant topavement crack walls. The three tests are designed to serve the respective needs of producers, engineers, andresearchers. The first test implements the principle of surface energy to measure the thermodynamic work of adhesion, which is the energy spent in separating the two materials at the interface. The work of adhesion is reported as a measure of material compatibility at an interface. The second test is a direct adhesion test, a mechanical test which is designed to closely resemble both the installation process and the crack expansion due to thermal loading. This test uses the Direct Tensile Test (DTT) machine. The principle of the test is to apply a tensile force to detach the sealant from its aggregate counterpart. The maximum load, Pmax, and the energy to separation, E, are calculated and reported to indicate interface bonding. The third test implements the principles of fracture mechanics in a pressurized circular blister test. The apparatusis specifically designed to conduct the test for bituminous crack sealant, asphalt binder, or other bitumen-based materials. In this test, a fluid is injected at a constant rate at the interface between the substrate (aggregate or a standard material) and the adhesive (crack sealant) to create a blister. The fluid pressure and blister height are measured as functions of time; the data is used to calculate Interfacial Fracture Energy (IFE), which is a fundamental property that can be used to predict adhesion. The stable interface debonding process makes this test attractive. This test may also provide a means to quantify other factors, such as the moisture susceptibility of a bond. In addition, the elastic modulus of the sealant and its residualstresses can be determined analytically. While the direct adhesion test is proposed as part of a newly developed performance-based guideline for the selection of hot-poured crack sealant, the blister test can be used to estimate the optimum annealing time and installation temperature. |
|---|
