Numerical prediction of elastic modulus of asphalt concrete with imperfect bonding

Air voids and interfacial bonding strength between asphalt mastic and rigid aggregates have a significant effect on the overall mechanical behavior of asphalt concrete. However, almost little numerical modeling has considered these two factors. In the present research, a spring layer model will be introduced to account for the interfacial bonding strength, and the effects of the size and content of the air voids will also be considered in the geometrical model of asphalt concrete. A new numerical method, fast multipole boundary element method, which has the advantages of higher efficiency, higher accuracy, lower storage of data, and simpler grid discretization, will be firstly adopted to simulate the elastic behavior of asphalt concrete. Tests on asphalt mixture with various microstructures are conducted to verify the proposed approach. It is shown that the imperfect interface effect and air voids effect should be considered when establishing any micromechanical or numerical model of the asphalt concrete.