Investigation of Adhesion Property between Asphalt Binder and Aggregate Using Modified Boiling Methods for Hot and Wet Area

For long-term hot and rainy climate areas, the moisture susceptibility of asphalt pavement is the most serious issue during the service of pavement, which primarily depends on the adhesion between asphalt binder and aggregate. To explore the adhesion between different asphalt binders and aggregates, two types of asphalt binders and three kinds of aggregates were selected in this study. The water boiling test was modified by increasing the boiling time, quantifying the stripping rate and increasing the sample weight. The contact angle test and the energy dispersive spectrometer test were also conducted. The results showed that longer boiling time, longer aging time for asphalt binder, and higher Si content in aggregates will increase the stripping rate between the asphalt binder and the aggregate. For base asphalt, the stripping rate of sandstone is about 35.76% at long-term aging. The stripping rate calculated by boiling loose mixture for 30 min has the good correlation with the silicon content in the aggregates, with R-square about 98.77%, which indicates a good indicator to evaluate the asphalt-aggregate adhesion.