Micromechanical characteristics of the asphalt mixture in bending condition

Abstract

The characteristics of asphalt mixtures are associated with the key features of the mixed material when it is not damaged. Two-dimensional (2D) microstructure images of asphalt mixture bending beam specimen were captured by a CCD camera. After image processing, such as noise elimination, boundary identification, image binarization and vectorization, the images were imported into finite element (FE) software in order to set up the micromechanical finite element (FE) model. The simulation results show that the displacement contours spectrum is not a smooth curve since the mixed material is heterogeneous. Also, the largest strain value exists at the bottom of the specimen between two coarse aggregates, and it is the point where the fracture starts. The stress values of aggregates are larger than those of the asphalt matrix. Different from the strain of asphalt matrix, the strain of aggregates is close to zero because the aggregates have higher capability to resist self-deformation. The difference in deformation between aggregate and asphalt matrix can lead to an interface crack as a final result. All these results can be improved by three-point bending test of asphalt mixture beam.