A comprehensive evaluation of steel slag asphalt mixtures: performance, functional applications, and ecological considerations

Steel slag offers a sustainable alternative to traditional aggregates in road construction. This review highlights the performance, environmental risks and economic benefits of steel slag asphalt mixture. Key findings indicate that steel slag-asphalt adhesion surpasses that of natural aggregates, enhancing the road performance of steel slag asphalt mixtures. Physical treatments provide only temporary control over volume expansion, while chemical treatments offer permanent solutions. Furthermore, steel slag asphalt mixtures exhibit superior heating and self-healing capabilities under microwave conditions compared to induction heating. Steel slag’s inherent surface porosity and electrical conductivity afford them enhanced functionality over conventional aggregates. Despite their environmental advantages and economic viability, challenges persist concerning the long-term leaching of heavy metals, high specific gravity, and increased asphalt content. Future research should prioritize the development of cost-effective chemical treatments to address volume expansion and optimize asphalt content. In addition, establishing comprehensive testing for heavy metal and gaseous emissions in trial sections and conducting detailed life cycle assessments (LCAs) are recommended to facilitate the broader adoption of steel slag asphalt pavements.