Research and Application of High RAP Content Warm Mix Recycled SMA Mixture Performance

Traditional plant-mixed hot recycling technology faces significant challenges due to the severe aging of RAP (Reclaimed Asphalt Pavement) during high-temperature heating, which typically limits its incorporation rate to between 20% and 30%, making it difficult to meet the demand for high-volume reuse. Additionally, the high-temperature heating process consumes substantial energy and generates significant carbon emissions, which contradicts the requirements of green and low-carbon development. To address the issues of limited RAP incorporation rates and high carbon emissions in current plant-mixed hot recycling technology, this paper proposes the application of warm-mix recycling technology to the surface layer of SMA (Stone Mastic Asphalt) pavements. By reducing the mixing and construction temperatures, the aging of asphalt is minimized, thereby exploring the feasibility of increasing RAP incorporation rates and reducing carbon emissions. Through systematic research on the selection of raw materials, mix design, pavement performance, and construction techniques for high-RAP warm-mix recycled SMA asphalt mixtures, the successful implementation of a 40% high-RAP warm-mix recycled SMA asphalt mixture was achieved and applied in actual engineering projects. The results from the practical application demonstrate that the pavement using this technology is in good condition with no significant defects, while also reducing material costs and construction energy consumption, yielding notable economic benefits. This study holds significant importance for promoting green road construction and sustainable development.