Micromechanical Behaviour of Asphalt Concrete Based on X-ray Computed Tomography Images and Random Generation of Heterogeneous Aggregates Skeleton

摘要

The main objective of this work is to investigate the influence of the micro structure characteristics on the mechanical behaviour of asphalt concrete. The heterogeneous microstructure of an asphalt concrete is influenced by the aggregate content, shape, orientation and contacts. In previous works, the asphalt concrete is treated as homogeneous material and its heterogeneous microstructures are ignored. While the distribution of its heterogeneous microstructure can strongly influence the intensity of deformation at local scale. Therefore, it is important to create more precisely a micromechanical model containing information on heterogeneous microstructure. A comparison study has been done between the microstructure issues from X-ray computed tomography (CT) and digital models of random aggregate generation. The dynamic modulus of the viscoelastic matrix and elastic properties of aggregates are used as input parameters in the numerical simulations. The obtained results at global scale (complex modulus and phase angle) and at local scale (local strain intensity) of each model are compared. This comparison leads to confirm the feasibility of the proposed heterogeneous random generation of aggregate skeleton at global and local scales. These results provide the basis for an interesting discussion on material design optimization in order to increase the durability of the road pavement materials.