Evaluation of Self-Healing Performance and Mechanism Analysis of Nano-Montmorillonite-Modified Asphalt

To evaluate and compare the self-healing properties of asphalt with different nano-montmorillonite (MMT) additions and from explaining the self-healing mechanism, the self-healing properties of base asphalt and Styrene Butadiene Styrene (SBS) modified asphalt with different MMT additions were tested using accompanying rest-time Dynamic Shear Rheometer (DSR) time-sweep test. Brookfield rotational viscosity test, sweeping electron microscope test, sessile drop test, Fourier transform infrared spectroscopy test, and gel permeation chromatography test were used to analyze the self-healing mechanism of the asphalt binder. Then, these indexes were correlated with the self-healing performance. The results showed that there were significant differences between the self-healing performance of base asphalt and SBS-modified asphalt binder. The intercalation structure formed by MMT in the binder increased the content of methylene and macromolecules, and increased the viscosity and surface free energy of the binder, thus increasing the active healing performance.