Effects of anti-stripping agents on the microscopic strength of mineral aggregate contact surface

This study investigated the effects of types I and II anti-stripping agents on the microscopic strength of the mineral aggregate contact surface of mixture. Panjin70# bitumen and SBS-modified bitumen were used as binders and granite acid stone was used as the aggregate. Microscopic strength covers the total strength of the contact surface, adhesion strength between the aggregate and bitumen, and the cohesive strength of the bitumen binder. Microscopic strengths were tested after short-term aging (RTFOT) and long-term aging (RTFOT + PAV). Results show that the enhancement effect of type I anti-stripping agents on adhesion was weakened after aging treatment, but anti-stripping agents exert no remarkable influence on cohesive strength under such treatment. Short-term aging treatment has slightly influence on enhancement effect of type II anti-stripping agents on adhesion, but the enhancement effect on adhesion was not obvious after long-term aging treatment and cohesive strength of bitumen significantly decreased at low temperature, thereby markedly diminishing total strength. Anti-stripping agents may influence adhesive and cohesive strengths of bitumen, choosing the anti-stripping agents should seriously considering the compatibility between anti-stripping materials and bitumen.