Evaluation of Moisture Damage of Cold Patch Asphalt Using the Surface Free Energy Method

Cold patch asphalt is more preferable in pavement construction compared to hot mix asphalt from the perspective of environmental conservation. However, the cold patch asphalt mixture is prone to moisture damage for production at lower temperatures and the presence of a diluent. The objective of this paper is to evaluate the moisture induce damage potential of cold patch asphalt mixture based on surface free energy theory. Three kinds of cold patch asphalts were synthesized by base asphalt, abietic resin, diesel, and anti-stripping agent, while the aggregates consisted of limestone and basalt. The surface free energy components of cold patch asphalt and aggregates were measured using the high-precision automatic Tensiometer System and Gravimetric Sorption Analyzer, respectively. The analytical computation to assess cohesive bond energy, wettability, adhesion bond energy, and energy ratio was obtained after surface free energy calculations. The results showed that the mixture of additives decreased the surface free energy of cold patch asphalt. Moreover, diesel can increase the surface free energy of pure asphalt. However, the abietic resin and anti-stripping agent have an adverse effect. Therefore, it can be concluded that the cold patch asphalt synthesized in this study has better resistance to water damage ability than base asphalt. More cold patch asphalt and aggregates are strongly suggested to validate the findings of this research.