Nanomechanics Modeling of Interface Interactions in Asphalt Concrete: Traction and Shearing Failure Study

The interface bonding strength is critical for asphalt concrete performance under external load applications. A thorough understanding of the load transfer mechanism bridging the nanoscale interfacial details and the macroscale properties is required to accurately predict the performance of asphalt concrete. This research presents a multiscale analysis procedure for the modeling of interface behaviors, in which material properties are evaluated by atomic scale interactions, emphasizing the complex shearing and separation mechanisms under various loading modes. The representative model system was established based on multiscale experimental characterization of the tight-bonding interface between asphalt and aggregate. Interfacial load transfer and failure studies were conducted for investigating the effect of tension and compression on shearing mode separation. The cohesive zone model parameters, such as peak traction and energy of separation were evaluated for each loading mode. Different boundary conditions were applied to obtain the representative volume element (RVE) and connection to continuum level properties. Results indicated that depending on the various loading modes, the failure of the nanoscale interface system may occur within the asphalt phase or at the interface. These results set the basis for continuum length-scale micromechanical models which may be used to determine the bulk material response, incorporating interfacial phenomena. The findings presented in this paper are consistent with observations reported in previous studies and expand on the understanding of the relationship between molecular structures and combined shearing separation failure properties of asphalt concrete interfaces.