Effect of rejuvenating oil type on the synthesis and properties of alginate-based polynuclear capsules for asphalt self-healing

Encapsulated rejuvenating agents for self-healing of bituminous materials have gained significant interest within the road scientific community, turning these enhanced materials into a hot topic. In this study, virgin cooking oil, waste cooking oil, and virgin engine oil were used as encapsulated rejuvenators to restore properties of aged bitumen and their capacity for asphalt self-healing. The alginate-based capsules and their components were characterised by chemical, physical, morphological, thermal stability, and mechanical tests. Self-healing recovery tests of cracked long-term aged bitumen by the effect of oil release were also performed. Main results showed that all rejuvenating oils presented functional groups contributing to the chemical restoration of aged bitumen. Encapsulation of stable O/W emulsions was achieved. Capsules presented uniform size, multicavity microstructure, high encapsulation efficiency, thermal and mechanical stability. Finally, all rejuvenating oils were successfully diffused into an aged bitumen, although virgin cooking oil presented the highest healing capacity.