Large amounts of steel slag (SS) stockpiled and buried leads to land occupation, and is prone to cause soil and water contamination. Partially replacing natural minerals in pavement construction can contribute to the rapid consumption of stockpiled SS, but its poor volume stability limits its widespread adoption into engineering applications. Meanwhile, the potential leaching of hazardous substances (HS) should also be emphasized. This study prepared different pretreated SSs and asphalt mixtures. The differences and improvement mechanisms of the pretreatment on the SS properties were investigated through micro-morphology and chemical composition analyses. The physical properties of different SS and the long-term volume stability and moisture damage resistance of the steel slag asphalt mixture (SSAM) were tested. Moreover, a revised HS leaching test method for the SSAM was proposed, and the effectiveness of various pretreatment methods in reducing HS leaching was evaluated. The results revealed that the porous characteristics and free oxides contained in SS were the main obstacles to their large-scale application in pavement engineering. Natural aging, thermal immersion, and acid modification alter the composition of SS through chemical reactions and accelerate the consumption of free oxides. The polymer film formed by the silane coupling agent on the SS surface mitigated the environmental effects on the performance. The long-term performance of the SSAMs was improved, and the amount of HS precipitated was significantly reduced. Acetic acid modification and surface treatments are recommended because they are more effective in improving moisture damage resistance and reducing potential adverse environmental impacts. The findings are significant for reasonable pretreatment and application of converted SS as well as for contributing to the sustainable development of transportation infrastructure.

来源平台：CHEMICAL ENGINEERING JOURNAL