Microstructure Characterization for Modeling HMA Behaviour using Imaging Technology

ABSTRACT The properties of hot mix asphalt (HMA) highly depend on the microstructure. The ability to experimentally characterize the microstructure is fundamental in describing the macroscopic behavior of HMA. It improves our understanding of the influence of the microstructure distribution on the macroscopic response of the material, which is at the heart of constitutive modeling of granular materials. This paper is an attempt to summarize the recent advances in imaging technology and its applications to the characterization of HMA microstructure including aggregate orientation distribution, aggregate contact, aggregate shape properties, air void distribution, permeability, crack distribution, three-dimensional (3-D) microstructure reconstruction, and microstructure evolution. The microstructure of HMA is linked to the macroscopic behavior of the material within the framework of continuum modeling via microstructure tensors that are incorporated in the continuum modeling formulations. It is envisioned that this link will fill in the gap that has always been present between interpreting laboratory results and the reality of the interior behavior of HMA.