Application of tack coat is known to enhance the performance and durability of the pavement structure by improving the bond between pavement layers. Although the most common mechanisms for tack coat failure in pavement interlayers are shear and tensile modes, the tensile failure mode has not been thoroughly investigated. In this study, a modified version of the bitumen bond strength (BBS) test was introduced for measuring the tensile bond strength between tack coat and an asphalt surface. Also, the effects of curing, moisture, and aging on the tensile bond strength of the tack coat were studied. A cationic tack coat containing polymer was applied at its optimum application rate to the surfaces of the cylindrical asphalt samples. One set of the samples was prepared with different curing times at 25°C in dry condition as well as after moisture-conditioning. The samples of the second set were long-term aged in an oven at 85°C, simulating an in-service aging equivalent to 5 to 7 years. Samples of both sets were tested using the modified BBS test at 25°C. The findings of this study clearly exhibited the effect of curing time, moisture, and aging on the tensile bond strength of the tack coat applied to the surface of an asphalt pavement. The application of the BBS test was found to be a time- and cost-effective method for determining the tensile bond strength of the tack coats.
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