Critical review on waste cooking oil rejuvenation in asphalt mixture with high recycled asphalt

Waste cooking oil (WCO) as a rejuvenator is gaining attention in the pavement industry to incorporate higher reclaimed asphalt (RA) in asphalt mixture. This review article provides a comprehensive review on the current state and the feasibility of turning WCO and RA into cleaner and sustainable asphalt pavement material. Considering the advancements in research related to the utilization of WCO in RA mixture, it was necessary to critically review the past and recent studies to provide a methodological scope for future research. The review discusses a plethora of characteristics focusing on chemical, rheological, simulation, environmental, and economical findings related to the utilization of WCO in RA mixtures. Based on the review, WCO can be adjudged as a potential material to rejuvenate asphalt mixtures with higher recycled asphalt content. Furthermore, although WCO enhances low-to-intermediate temperature performance, studies indicated that moisture damage and higher temperature properties are compromised. Future research scope exists in understanding the rejuvenation capabilities of different WCOs and blends of different types of WCO, optimizing the transesterification process of WCO to improve its quality, molecular dynamic simulations focusing on transesterified WCO, quantification of environmental and economic benefits of recycled asphalt mixtures with WCO, and field performance studies.