Abstract

This study aimed to investigate the changes in adhesion performance between recycled asphalt pavement (RAP) materials and aggregates by the regeneration process. The oil-rich RAP fine aggregate was utilized to assess the adhesion performance and its improvement between recycled asphalt mortar and aggregates. Various testing methods, such as contact angle test, dynamic shear rheometer (DSR), atomic force microscopy (AFM), and water stability tests, were employed to comprehensively analyze and evaluate the adhesion performance of oil-rich RAP fine aggregate in the regeneration process of recycled asphalt mortar at multi-scale. The results show that alkaline aggregate limestone and SBS-modified asphalt exhibit higher adhesion work by surface-free energy theory. The anti-stripping agents XTA2 and LQ20 can improve the adhesion area between recycled asphalt and aggregates. Under the same influencing factors, SBS-modified asphalt, aggregate, and additive type can all improve adhesion performance between recycled asphalt mortar and aggregates. The recycled asphalt mixture prepared from SBS-modified asphalt has a freeze-thaw splitting tensile strength ratio (TSR) increase of 3.5∼10 % compared to matrix asphalt, limestone can increase TSR by 2∼6 % compared to basalt, and TSR increases by 7∼10 % before and after adding anti stripping agents. The mechanism of adhesion performance enhancement in recycled asphalt mortar was analyzed from a micro/nano perspective. That provides a reference for the durability development of RAP recycled asphalt pavement.