Review of advances in understanding impacts of mix composition characteristics on asphalt concrete (AC) mechanics

The overall performance of an asphalt concrete (AC) mixture is dependent on its composition including the properties, proportions and distributions of the ingredients. For existing asphalt mix design methods, however, there is a missing link between the mix composition and the overall properties and performance. To improve the fundamental understanding of AC mixtures, this paper presents a comprehensive review of the advances in understanding the mix composition characteristics and their impact on AC mechanics. This review focused on the links between the mix composition and the overall properties. The review contains a brief background of this study, followed by a discussion of four typical mixture composition characteristics, namely aggregate size, aggregate morphology, asphalt matrix time-dependent properties and anisotropic AC microstructural characteristics. Furthermore, three types of methods were reviewed for understanding the links between the composition characteristics and the AC behaviours: the experiment-based methods, multiphase micromechanical models and numerical models. The numerical models include discrete element models and finite element models. Finally, a brief summary and further research needs are provided.