Investigation of Adhesion and Stripping Properties in Asphalt–Aggregate Systems: Impact of NaCl Solubility and Freeze–Thaw Cycles

Abstract

The water stability of asphalt pavements has been a focus of attention in coastal municipal areas. This work thoroughly examined the adhesion and stripping properties of the asphalt–aggregate system under salt solution freeze–thaw cycle conditions. The investigation was conducted utilizing the differential capillary rise test, surface free energy (SFE) theory, and modified water boiling test. The experimental findings suggest that the surface tension of asphalt increases in a linear manner as the temperature exceeds 100°C. The asphalt surface layer experiences irreversible fatigue degradation after completing five freeze–thaw cycles, resulting in a complete breakdown of adhesion capabilities. During the third freeze–thaw cycle, the proportion of asphalt binder that was stripped off the slide rose by 83% due to the NaCl solubility surpassing 21%. Upon reaching seven freeze–thaw cycles, the asphalt’s stripping area ratio on the slide increased by approximately 50%. The correlation study indicates that the adhesion of asphalt to the surface of the slide cannot be explained by the work of adhesion. These findings offer valuable insights for future research in this area.