Self-healing of asphalt binder with cohesive failure: Insights from molecular dynamics simulation

Abstract

Self-healing behavior of asphalt binder is of great interest for development of high performance material. This study presented a novel method to investigate intrinsic self-healing behavior of asphalt binder through molecular dynamics (MD) simulation. The proposed method provided the insights on crack development and strength recovery during the failure-healing-failure process of asphalt binder. The cohesive failure trend obtained from the tensile test simulation was consistent with the findings from macroscopic experiments. Through the observation of cracked surfaces and tensile strength over healing time, the self-healing process were described as two separate phases that were consistent with previous experimental findings: (1) a rapid recovery phase with short duration, namely the surface wetting stage; and (2) a slow recovery phase, representing the surface diffusion stage. The strength of asphalt binder may not be fully recovered with the disappearance of nano-crack and the restoration of density at the end of surface wetting stage. The healing ratio was found significantly affected by the initial damage of asphalt binder. The effect of temperature on self-healing of asphalt binder was observed with variations. The proposed method shows the potential to investigate the chemo-mechanical relationship of asphalt binder regarding cohesive failure and self-healing behavior.