Molecular dynamics simulation of adhesion at the asphalt-aggregate interface: A review

Interfacial adhesion at the molecular level is a complex process, where the key players (asphalt, aggregates, water, and air) are in a dynamic state of structural equilibrium, varying rapidly under different environments and conditions. Most experimental tests, while capable of providing crucial information for practical application, are ill-suited to characterize molecular-level behavior of these materials. Molecular dynamics (MD) simulation provides a unique perspective into the dynamic world of asphalt-aggregate interfaces. It allows to directly monitor physiochemical processes that depend on the structural distribution, molecular composition, external load, and atomic mobility. Over the past decade, MD simulation has provided important insights into the dynamical processes that control interactions at asphalt-aggregate interfaces, including adhesion, cohesion, diffusion, aggregation, binding, distribution, and aging, among others. This review covers both theoretical models and practical methods which provide a reliable and computationally efficient tool to incorporate certain microscopic details and correlations. This review also provides a comprehensive account of applications of MD to asphalt-aggregate interfaces and the advances it has enables in adhesion property of asphalt, with an emphasis on insights into model construction and performance of interfaces evaluation methods.