Environmental and feasible analysis of recycling steel slag as aggregate treated by silicone resin

Abstract Steel slag is the desirable substitution of natural aggregate in asphalt mixture. Nevertheless, the high-water absorption and heavy metal ions pollution are the primary problems of recycling steel slag. This study involved silicone resin to process the steel slag for preventing it from water and improving heavy metal ions leaching problems. The sealing effect of silicon resin on steel slag was also verified by the micro measurement. The results show that the leaching concentrations of all heavy metal ions were generally reduced after treatment of silicone resin. The solid silicone resin formed the airtight membranous on the steel slag surface and effectively improved the heavy metal ions leaching problems. The boundary of elements distribution between steel slag and silicone resin area are obvious, which indicates that the silicone resin effectively and completely seals the steel slag surface. The water absorption rates, adhesion and microstructure of steel slag were also improved by silicone resin. The organic asphalt and silicone exhibit superior adhesion due to the rule of the likes dissolve each other, and it isolates steel slag from water, and reduces the stripping risk of asphalt binder.