Development of a combined micromechanics & damage mechanics model for the design of asphalt pavements

Asphalt is a complex, heterogeneous material that is composed of differently sized aggregates, binder and air voids: in other words, it is a particulate reinforced composite. The focus of the present work is to investigate the structural effectiveness of this material composition following the introduction of recycled asphalt pavement (RAP) into the mix. The virgin mortar mix (i.e., matrix) consists of an asphalt binder, sand and crushed rock fines (CRF), while the RAP-containing mix additionally includes fine aggregates ranging in size from fine dust (< 75μm diameter) up to small particles (< 3.35mm diameter). The stress distribution throughout such a material and the resulting mechanical response is strongly related to the interaction between the mix constituents. Previous work has shown that this performance is less influenced by the presence of larger aggregate than it is by the mortar composition and it is for this reason that the present work attempts to model damage evolution in various mortar mixes.