Use of surface free energy properties to predict moisture damage potential of Asphalt concrete mixture in cyclic loading condition

The synergistic effects of microdamage due to repeated loading in Asphalt-Aggregate system at a high temperature (40°C) and moisture damage analysis based on surface free energy theory are presented in this paper. The introduction of moisture in either a liquid or vapor state during cyclic loading may well be more damaging than simply moisture conditioning an asphalt concrete sample prior to testing. This difference may be due to the presence of a dynamic “network” of adhesive fracture, which potentially provides a channel for moisture movement within the sample. The percentage of the surface area of aggregate that has been exposed to water was used as a significant index to quantify the level of adhesive fracture. This index is calculated with the surface free energies of aggregate and asphalt which are measured by two methods, the universal gas adsorption and the Wilhelmy plate, respectively. The relation between the percentage of the surface area of the aggregate exposed to water and the number of cycles of loading assists in quantifying adhesive fracture in the asphalt-aggregate mixture.