Exploring the influence of silicone resin on the interfacial water stability of steel slag/asphalt: an experimental and molecular dynamics study

Steel slag, a common byproduct of industrial processes, is characterized by high alkalinity and a porous structure, which provide strong bonding properties with asphalt. However, its high-water absorption rate and porosity limit its application in asphalt pavements. This study focused on enhancing the hydrophobicity of steel slag by applying silicone resin to its surface, with the goal of improving the water stability of the steel slag/asphalt interface. The research identifies the optimal concentration of silicone resin-modified steel slag and evaluates the performance of both the asphalt and steel slag components. Additionally, the resistance of the interface to water-induced erosion is assessed. To elucidate the interaction mechanism, microscopic analysis and molecular dynamics simulations were employed to investigate how silicone resin infiltrates the pores of steel slag and enhances water stability at the interface. The results demonstrate a significant improvement in the water damage resistance of steel slag-asphalt mixtures modified with a 4% silicone resin concentration, resulting in a 5.94% increase in residual stability. The silicone resin formed a robust, dense film on the surface of the steel slag, contributing to a 49.57% increase in the contact angle between the steel slag and water, as well as an 83.89% reduction in the asphalt spalling rate from the aggregate surface. The formation of hydrogen bonds and stable Si-O-Si chemical bonds enhanced the hydrophobicity of the steel slag and strengthened the bonding interactions between the steel slag and asphalt. In conclusion, modifying steel slag with silicone resin significantly improves both the strength and interfacial water stability of asphalt mixtures, offering a promising approach for the effective recycling of steel slag.