A novel molecular modeling approach for simulating asphalt-aggregate debonding: Considering interfacial moisture migration

Abstract

The asphalt-aggregate debonding behavior in moisture environments is a fundamental but unresolved issue in pavement engineering. In this study, a novel molecular dynamics (MD) modeling method was developed to address this challenge. Compared with previous layered modeling methods, the new method considers the moisture diffusion and migration at the interface, which better reflects the real debonding process. Based on the results, we found a layered diffusion phenomenon at the interface, which significantly affects the efficiency of moisture migration and interfacial debonding. The strong interactions between water molecules and alkaline aggregates (represented by calcite) restrict the interfacial moisture diffusion and migration, making it more resistant to moisture damage than acidic aggregates (represented by quartz). This study highlights the limitations of energy-based parameters obtained from the layered modeling method and resolves a long-standing controversy over whether calcite or quartz is more susceptible to water damage. Findings from this research contribute to comprehending the fundamental debonding mechanisms and provide an atomic-level perspective to investigate moisture damage in pavement engineering.