Experimental study and molecular simulation on regeneration feasibility of high-content waste tire crumb rubber modified asphalt

The application of crumb rubber modified asphalt (CRMA) in road engineering can not only improve pavement performance, but also solves the environmental pollution problems caused by the accumulation of waste tires, producing economic and environmental benefits. This study aims to investigate feasible methods of regenerating CRMA with 35% content of waste tire crumb rubber (CR) through molecular dynamics and experimental methods. Three regeneration approaches were studied and compared, including using a rejuvenator, virgin binder and CR, and a mixture of the above two. Results show that the regeneration of short-term aged CRMA is the converse process of aging, while the regeneration of long-term aged CRMA is the process of repairing internal structural damage and improving its integrity and thermal stability. Although the traditional rejuvenator only restores the asphalt properties in CRMA, it can improve the compatibility of long-term aged CRMA and other components in the regeneration system. The self-aggregation of asphaltene in the aged CRMA is alleviated after regeneration. Besides, the light components are closely attracted by the asphaltene for better lubricating the asphaltene micellar. The colloidal structure of aged CRMA is more ordered after regeneration.