Modelling constant displacement rate experiments of asphalt concrete using a thermodynamic framework

This study is concerned with the constitutive modeling of asphalt concrete mixtures. The response of the asphalt concrete pavement depends on its internal structure. The internal structure of the asphalt concrete mixture evolves during the loading process. Here, we develop a single constituent model for asphalt concrete mixture by associating different natural configurations (stress-free configurations) with distinct internal structures of the body. The evolution of the natural configurations is determined using a thermodynamic criterion, namely the maximization of the rate of dissipation. Making appropriate assumptions concerning the manner in which the body stores and dissipates energy, the constitutive relations for the stress is deduced. Constant displacement rate experiments are carried out at different confinement pressures on asphalt concrete specimens made of two different aggregates - granite and limestone. The efficacy of the model in predicting the mechanical response of asphalt concrete mixtures is shown by corroborating the model predictions with the experimental results.