Study on the echelon utilization and recycling performance of recycled asphalt pavement based on physical and chemical separation

This paper addresses the issues of agglomeration and variability in reclaimed asphalt pavement (RAP) materials generated from road infrastructure. These problems can lead to both environmental and economic impacts. An innovative method that combines physical and chemical separation techniques (PCST) is proposed to improve the recycling rate of RAP aggregates and enhance the performance of reclaimed asphalt mixtures (RAM). In this method, RAP is first classified by particle size using a vibrating screen. The aggregates and asphalt are then separated and recycled through a combination of physical and chemical processes. The recovered materials are used to produce new RAM. The results show that the maximum separation efficiency reaches 83.12% for coarse aggregates and 88.52% for fine aggregates. The combined separation method significantly reduces RAP agglomeration and variability, improving the adhesion between aggregates and asphalt. RAM produced with the separated aggregates demonstrates a 13.35% improvement in low-temperature stability, a 1.28% increase in residual stability, and a 5.39% enhancement in freeze-thaw splitting strength compared to the refined separation method (RCS). These findings provide a new approach for the efficient recycling of RAP materials and support the development of more sustainable and cost-effective road construction practices.