The Effects of Nano-Montmorillonite on the Key Healing Factors of Asphalt Binders

摘要

The effects of nano-montmorillonite (MMT) on the key healing factors of base asphalt and styrene-butadiene-styrene (SBS)-modified asphalt binder were investigated. The flow behavior of the nano-modified asphalt binder was measured using the viscosity-frequency sweep test, and the power law equation was calculated to determine the value of the optimum healing temperature. The healing performance of asphalt at different healing temperatures and healing times was examined using the fatigue-rest-fatigue test, and the full healing time was derived by fitting the healing function. In addition, the healing mechanism of the MMT-enhanced asphalt binder was analyzed from the perspective of surface free energy theory. The results demonstrated that increasing the MMT dose enhanced the healing performance under various healing situations, as well as the softening point and optimal healing temperature of binders. The higher binder healing efficiency was caused by the decrease in full healing time. The nanoparticles increased the surface free energy of the asphalt binder, which hastened the wetting of the microcrack interface and facilitated the healing process.