A Review of Adhesion Mechanisms at the Crack Sealant/asphalt Concrete Interface

Existing adhesion theories and associated mechanisms are reviewed and applied to bituminous crack sealants and to the crack sealing of asphalt concrete (AC) roadways. As such, the possible contribution of each mechanism to the sealant-interface-AC system is critically assessed. Of six possible adhesion mechanisms, only sealant adsorption and interlock can explain adhesion between sealant and AC. In this regard, intrinsic sealant properties such as viscosity and composition are particularly important. In contrast, sealant failure can be explained best by the presence of defects at the sealant-AC interface such as dust, voids and microcracks. The existence of these defects is more closely related to sealant installation than to the sealant itself. In the end, the review allows for the identification of many factors that must be better understood if sealant adhesion and performance is to be enhanced significantly.