Performance and Life Cycle Assessment of Recycled Mixtures Incorporating Reclaimed Asphalt and Waste Cooking Oil as Rejuvenator: Emphasis on Circular Economy

Abstract

In the recent times, rejuvenators have been investigated as a potential solution to incorporate higher amounts of recycled asphalt (RA) in hot-mix asphalt (HMA). In this study, waste cooking oil (WCO) was used as rejuvenator to assess the performance of RA mixtures. A method was proposed to optimize WCO content in HMA with high RA content (>45%), balancing the performance in the high and intermediate temperatures. The optimized mixtures with high RA content depicted rut depth and cracking properties similar to HMA. Simultaneously, the recycled mixtures utilizing WCO dosages derived from a blending equation exhibited pronounced rutting, implying that the blending equations yielded WCO dosages that exceeded the necessary dosages. A life cycle assessment (LCA) study considering a cradle-to-gate approach indicated that incorporating 45%, 60%, and 75% RA would decrease total embodied energy (TEE) by 25.08%, 33.30%, and 41.17% compared with HMA. Further, a sensitivity study with distance as the parameter indicated that the permissible distance of RA source for 45%, 60%, and 75% was 500, 300, and 300 km, beyond which RA mixtures showed higher TEE than HMA. The incorporation of reclaimed asphalt pavements (RAP) using waste cooking oil as a rejuvenator presents significant practical implications for the asphalt industry and sustainability initiatives. By enabling the use of higher RAP content while maintaining the performance of traditional mixtures, this research offers a more environmentally friendly and cost-effective approach to road construction. Moreover, the life cycle assessment findings reveal substantial reductions in environmental impacts when including different RAP proportions, making a strong case for improved environmental sustainability. The sensitivity analysis regarding the distance between RAP sources and construction sites provides valuable insights for location-based decision-making, ensuring that the benefits of RAP utilization remain maximized. In summary, the potential application of the study emphasizes a greener and durable road infrastructure, with a focus on increasing RAP content using waste cooking oil as a rejuvenator in asphalt mixtures.