Application of aluminum industry solid waste in asphalt mixtures and its impact on performance: Current research and future perspectives

Aluminum industrial solid waste represents a highly abundant yet underutilized resource. Its incorporation into asphalt pavement applications can effectively reduce the exploitation of natural resources and mitigate environmental issues caused by waste accumulation. This paper focuses on typical solid waste resources generated by the aluminum industry, summarizing the latest research progress in their application within the asphalt pavement industry and proposing key directions for future attention. The physicochemical properties of red mud (RM), spent aluminum electrolytic cathode materials, and secondary aluminum dross (SAD) are reviewed. The effects and mechanisms of RM, spent aluminum electrolytic cathode materials, and SAD on the performance of asphalt and its mixtures are elaborated. RM significantly enhances the aging resistance of asphalt, the high-temperature rheological properties of asphalt mastic, and the rutting resistance of asphalt mixtures. Spent aluminum electrolytic cathode materials require the removal of fluorides and cyanides before further application in asphalt pavement. SAD effectively improves the dynamic stability of asphalt mixtures. This review presents the first systematic summary of key scientific challenges and technical bottlenecks in the application of aluminum industrial solid waste in asphalt pavements. It clarifies that future research should prioritize waste pretreatment technologies, performance regulation mechanisms, and life cycle environmental impact assessments. These contributions provide essential theoretical foundations and technical guidance for advancing the resource utilization of aluminum industrial solid waste, holding substantial significance for promoting the development of green transportation infrastructure.