Moisture Damage of Asphalt Based on Adhesion, Microsurface Energy, and Nanosurface Roughness

To explore the influence of water on the multiscale adhesive behavior between asphalt binder and aggregate, the nanosurface morphology and microsurface energy of asphalt binder and the macrobonding force between the asphalt binder and aggregate over different soaking times were examined using atomic force microscopy (AFM) and the pull-off test. Relationships between the macrobonding and the nanosurface roughness as well as the microsurface energy were analyzed. The results demonstrated that the effect of water on the surface morphology of asphalt binder was important. After immersion in water, water-induced bulges occurred on the asphalt binder surface, which further changed the nanosurface roughness and the surface energy of asphalt. As per the sensitivity results, it can be concluded that the surface energy of asphalt and the effective contact area between asphalt and aggregate were reduced because of moisture, thus resulting in the failure of adhesion.