Investigating rheological and healing properties of asphalt binder modified by disulfide-crosslinked poly(urea-urethane) elastomer

Abstract

• Dynamic covalent bonds are introduced to asphalt binder for endowing healing property. • Disulfide-Crosslinked polyurethane shows positive effect in the rheological properties. • Disulfide bonds significantly enhance the early-stage healing properties for cracks. The deployment of self-healing materials to asphalt can increase the service life of the asphalt pavement. This study proposed a novel self-healing asphalt binder modified by the polyurethane elastomer containing disulfide bonds. Micro-chemical characterization, rheological tests, fatigue-healing-fatigue test, and fracture-healing-fracture test were used to evaluate the rheological and healing properties of disulfide-crosslinked poly(urea-urethane) elastomer modified asphalt binder. Micro-chemical analysis shows the poly(urea-urethane) elastomer containing disulfide bonds was stably introduced to the asphalt binder and dispersed regularly. Rheological analysis indicates positive effects of poly(urea-urethane) elastomers in the rutting resistance at high temperatures and cracking resistance at low temperatures of asphalt binder, which enhanced by maximum 66% and 65% with the addition of 4% and 6% poly(urea-urethane) elastomer, respectively. Fatigue-healing-fatigue test and the fracture-healing-fracture test shows that the polyurethane elastomer significantly enhances the healing capability of asphalt binder, especially at the early healing stage. Results of the healing tests suggest that 6% is recommended as the optimum dosage of poly(urea-urethane) elastomer for self-healing asphalt due to its sound healing effects for fatigue cracking and macroscopic cracks. This study provides a comprehensive investigation on the rheological and healing properties of self-healing asphalt binder based on dynamic chemistry.