A constitutive model for simulation of water to ice phase change in asphalt mixtures

Frost damage is one of the major concerns in pavement design particularly in cold regions. During their service life, asphalt pavements are continuously exposed to various environmental conditions such as oxidation, ultraviolet radiation and moisture. The joint effects of mechanical and environmental loading progressively degrade the mechanical properties of asphalt pavements, resulting thus to frost damage when ice crystals form in the asphalt concrete. In this contribution a 3D energy based micromechanical finite element model is presented for simulation of the volume expansion that occurs during the water- To-ice phase change in the macro pores of the mixture. For the simulations, the internal microstructure of asphalt mixtures was captured with X-Ray Computed Tomography (CT) imaging techniques. The analyses enable the quantification of the contribution of asphalt mixture characteristics such as air voids and pore connectivity in the damage developed in the asphalt binder due to the volume change of water- To-ice in the pores.