Evaluation of asphalt-aggregate adhesive property and its correlation with the interaction behavior

The performance of the asphalt binder-aggregate interface is an essential guarantee of the stability and durability of asphalt pavements. The objectives of this paper are to investigate the effects of various factors (test conditions, material properties) on the interfacial adhesive properties of asphalt binder-aggregate systems and to analyze the correlation between the bond strength and interface interaction. For this purpose, the improved pull-off tests under various temperatures, loading frequencies and asphalt film thickness were carried out to determine the test conditions for interfacial adhesion failure. The interfacial bond strength of various asphalt binders-aggregates and the corresponding interaction values were tested according to the determined test conditions and the correlation between them was analyzed. The results show that the bond strength between asphalt binder and aggregate was negatively correlated with temperature and positively correlated with loading rate, and there was an optimal film thickness. Among the selected minerals and aggregates, calcite and limestone presented the best bonding properties with asphalt binder respectively. Asphaltenes and resins enhanced the bond strength of asphalt binder-aggregate, while saturates and aromatics weakened the bond strength of asphalt binderaggregate. The short-term aging of asphalt binder was beneficial to the bonding of binder and aggregate, whereas the long-term aging of asphalt binder was detrimental. Among the material properties factors, the SARA composition had the most significant effect on interfacial bond strength. A significant correlation was found between the C value (the preferred interaction parameter) and the bond strength of the asphalt binder-aggregate interface.