The digital image processing techniques, including gray level transformation, image sharpening, image segmentation and edge detection, is applied to the study on the meso-structure image of shale. The results show that the digital image processing technique can extract useful information from the CT images and construct a model of meso-structure of shale. The model shows the spatial distribution of the different media in the rock. The process of the damage propagation can be seen IN the meso-structure image clearly. Asphalt concrete is a composite material which consists of asphalt cement, voids, fine particles, sand, and coarse aggregates. Previous investigations of asphalt concrete mixtures have mainly concentrated on the macroscopic properties of the composite materials based on the assumption that the mixtures are homogeneous and isotropic.