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

Abstract

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.

KEYWORDS:

• Rejuvenators
• alginate biopolymer
• polynuclear capsules
• aged bitumen
• asphalt self-healing

Acknowledgements

The first author wishes to thank the financial support given by the University of Bío-Bío for his internal PhD scholarship granted. Authors thank the Carbon and Catalysis Laboratory (CarboCat) of the University of Concepción for providing access to their analytical capabilities. The authors gratefully acknowledge the financial support for the sixth and seventh authors from the Royal Society (United Kingdom) through the Project International Exchanges 2019 Round 1 (Ref. IES/R1/191015). The authors also thank Dr. Andrea Guadarrama-Lezama from the Autonomous University of Mexico State for her help with the antioxidant activity measurements, and Professor Rodrigo Delgadillo of the Laboratory LEMCO from the Universidad Técnica Federico Santa Maria at Valparaiso-Chile for his technical support during the bitumen ageing tests. Finally, the authors thank Jaime Zamorano from Gelymar S.A. for his help in the chemical characterisation of the alginate biopolymer used in this study.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

The authors express their gratitude for the funding given by the National Research and Development Agency (ANID) through the Research Projects FONDECYT [grant number 1190027] and CONICYT PIA/Apoyo [grant number CCTE 170007].