Self-healing behavior of rubberized asphalt modulated by the degradation of crumb tire rubber

The self-healing ability of rubberized asphalt, especially at low-temperatures, plays a vital role in extending the durability of pavements. Despite the wide use of rubberized asphalts, the impact of the degradation degree of crumb tire rubber (CTR) on self-healing behavior of rubberized asphalt remains unclear. In this study, we conducted a controlled degradation of CTR through screw extrusion to examine the effects of degradation degree and CTR dosage on the self-healing behavior of the rubberized asphalt. The self-healing ability of different rubberized asphalts was investigated by ductility tests and tensile tests conducted with a dynamic thermo-mechanical analyzer. The results revealed that the content of CTR and its degradation significantly affected the compositional structure and healing ability of the modified asphalt. The rubberized asphalt with highly degraded crumb tire rubber (DCTR) exhibited the best flow healing ability due to the fine dispersion of DCTR in asphalt and the highest value of loss factor at low temperatures. Conversely, the asphalt modified with the lightest DCTR exhibited higher healing efficiency at higher temperatures, attributed to more dynamic sulfur bonding and re-crosslinking of rubber molecular chains. This study provides a better understanding of the road healing performance of rubberized asphalts with different degradation degrees of CTR.