Temperature and humidity sensitivity of graphene/rubber composite modified asphalt-aggregate interface adhesion based on molecular dynamics

To investigate the evolution of adhesion properties at the interface between graphene/rubber modified asphalt and aggregates under the coupled effects of water and temperature, this study employed molecular dynamics simulations to systematically analyze the influence of water molecule intrusion and temperature variation on asphalt-aggregate interface adhesion, and revealed its mechanism of action at the atomic scale. The results indicate that intruding water molecules form a molecular layer and ‘water column’ structure on the oxide surfaces of aggregates, which obstructs direct contact between asphalt and aggregate and significantly reduces the interfacial adhesion work. Among the three asphalt systems studied, the graphene/rubber composite modified asphalt exhibited the smallest reduction in adhesion work, demonstrating superior resistance to moisture damage. Furthermore, the coupled effects of ambient temperature and water temperature exerted a more pronounced influence on the asphalt-acidic oxide (e.g., SiO2) interface system. The variation in adhesion work between the graphene/rubber composite modified asphalt and SiO2 under changing temperatures was significantly smaller than that observed for rubber-modified asphalt and matrix asphalt, indicating its lower temperature sensitivity. This study provides a theoretical basis for optimizing the interface properties between modified asphalt and aggregates at the micro-mechanistic level.