Constitutive Modeling of the Coupled Moisture-Mechanical Response of Particulate Composite Materials with Application to Asphalt Concrete

A novel continuum damage mechanics-based framework is proposed to model the detrimental effect of moisture on the response of particulate composite materials. This framework extends the well-known Kachanov's effective (undamaged) configuration and the concept of effective stress space to moisture-susceptible materials by introducing wet-undamaged and wet-damaged natural configurations. Physically based moisture-induced damage internal variables are introduced within the proposed framework to consider the moisture aggravation effect and to couple moisture-induced damage with mechanical responses. Constitutive relationships are proposed for the time-dependent evolution of adhesive and cohesive moisture-induced damage to explicate the fundamental processes associated with the moisture-induced damage phenomena. The material properties associated with the moisture-induced damage constitutive relationship are determined based on the available experimental data from asphalt concrete materials. Comparison of the model predictions with independent experimental measurements illustrates the capabilities of the model in capturing the coupled moisture-mechanical response of asphalt concrete. (C) 2014 American Society of Civil Engineers.