Determination of moisture damage mechanism in asphalt mixtures using thermodynamic and mix design parameters

Abstract

The shortcoming of the available laboratory methods for determining the moisture susceptibility of asphalt mixtures has led researchers to think about providing new methods based on effective parameters on moisture damage process. Accordingly, this research is an attempt to provide a prediction model using thermodynamic and mix design parameters that can predict and analyze the performance of asphalt mix against moisture. T he results of this study indicate that the use of anti-stripping additives can generally improve the performance of asphalt mixtures against moisture; however, the type and percentage of these additives should be determined according to the type of aggregate, the type of bitumen and the properties of the mixing plan of the asphalt mix. Based on the proposed model, it can be stated that an increase in cohesion free energy, adhesion free energy, aggregate wettability by bitumen, surface area of aggregates, and apparent asphalt film thickness on the aggregate surface improve the moisture resistance of mixtures. On the other hand, debonding energy, saturation percentage, and permeability negatively affect the asphalt mixture’s resistance to moisture damage.