A State-of-the-Art Review on Warm Mix Asphalt with Recycled Asphalt: Sustainable Approach to Utilize High RAP Contents

This review article explores the synergistic benefits and challenges of incorporating Warm Mix Asphalt (WMA) with Reclaimed Asphalt Pavement (RAP) in asphalt pavements. WMA’s lower production temperature offers energy savings and reduced greenhouse gas emissions, while RAP utilization conserves virgin materials. Despite individual limitations, combining WMA and RAP overcomes these drawbacks, enhancing mixture performance. The literature reveals that specific WMA additives and RAP percentages distinctly influence high-temperature resistance, low-temperature performance, and moisture susceptibility. Optimal WMA-RAP mixtures demonstrate improved rutting resistance and cracking resilience at low and intermediate temperatures. This comprehensive review synthesizes laboratory and field studies, and mixture design strategies, and addresses high RAP content challenges. It underscores the economic and environmental advantages of WMA-RAP mixtures and outlines future research directions, aiming to guide pavement engineers in designing more sustainable asphalt mixtures.