A micromechanical model to evaluate the impact of air void content and connectivity in the oxidation of asphalt mixtures

Asphalt oxidation is a chemical reaction between asphalt binders and oxygen that causes irreversible changes in the properties of asphalt materials used in pavement structures. This paper explores the influence of the air void phase of asphalt mixtures on oxidation. Microstructures of an asphalt mixture with probable internal air void structures were generated and implemented in finite elements, and they were used in combination with oxygen diffusion and chemical kinetics models to estimate the changes generated in the mechanical properties of the material. The results confirm that the air void phase strongly impacts the stiffening processes caused by oxidation in asphalt mixtures.