Hazardous characteristics and variation in internal structure by hydrodynamic damage of BOF slag-based thin asphalt overlay.

For the sustainable development of society, recycling of solid waste has received considerable attention worldwide. In this research, steel slag was used to replace natural aggregate in the thin asphalt overlay, and the hazardous characteristics and internal microstructure of this overlay were explored. The resistance to hydrodynamic damage of the overlay containing steel slag was also evaluated and compared with that of the traditional overlay. The results indicate that steel slag has potential leaching risk, which can lead to environmental hazards in long-term leaching processes. However, the recycling of steel slag in thin asphalt overlay inhibits the release of toxic heavy metals due to the encapsulation effect, thereby reducing the leaching concerns. Steel slag can significantly reinforce the skeleton structure and enhance the ability of the asphalt overlay to bear the load. The superior skeleton stability and moisture resistance of the steel slag asphalt overlay were observed after hydrodynamic treatment compared with overlays made of natural aggregate. The variations in the volumetric parameters and connectivity in the steel slag asphalt overlay are significantly less than those in conventional overlay after hydrodynamic treatment. This indicates that the volumetric characteristics of steel slag asphalt overlays are less affected by hydrodynamic pressure.