Effects of RAP Pretreatment Methods on Durability and Carbon Reduction in High-Proportion Plant-Produced Hot-Recycled Asphalt Mixtures

To address the poor performance of plant-produced hot recycled asphalt mixtures with high recycled asphalt pavement (RAP) content, this study employed a refined separation technology to treat RAP materials. The effectiveness of this technology in enhancing the durability of high-RAP-content recycled asphalt mixtures was verified through trial pavement construction and performance testing. In addition, the carbon reduction potential as well as the economic and social benefits of the refined separation technology were analyzed. The results demonstrate that the refined-separation recycled asphalt mixture performs significantly better than conventional crushed-and-screened recycled asphalt mixtures in terms of water-temperature cycling resistance, long-term aging resistance, high-temperature and moisture damage resistance, and fatigue resistance, while exhibiting comparable durability to virgin asphalt mixtures. From an economic and social perspective, the total cost of refined-separation recycled asphalt pavement decreases by 33% and 50% compared to conventional crushed-and-screened recycled asphalt pavement and virgin asphalt pavement, respectively. Furthermore, its energy consumption and carbon emissions decrease by 25% and 32% compared to virgin asphalt pavement, and by 25% and 24% compared to conventional crushed-and-screened recycled asphalt pavement. This technology not only achieves significant energy conservation and emission reduction but also substantially enhances the durability of high-RAP-content recycled asphalt pavements.