Effect of surface modification on properties of steel slag aggregate and mixture

Industrial solid waste materials, especially steel slag, are hindered by porous structure and poor volume stability in the wide application of asphalt pavement engineering. This research aims to modify the steel slag aggregate with organosilicon-modified acrylic acid to reduce the surface pores, inhibit the expansion components, and achieve property control and environmental benefit optimization. The applicability of modified steel slag aggregate as an asphalt pavement surface course is evaluated by molecular dynamics simulation, steel slag aggregate property test, mixture performance test, and environmental benefit. The conventional properties results show that the modified steel slag aggregate reduces the water absorption by more than 70.3%, the expansion decreases by more than 35.2%, and the interfacial hydrophobic contact angle increases by 46.1°. The molecular dynamics simulation and microscopic properties result clearly show that the modified film has excellent physical–mechanical stability and thermal stability. Moreover, the high temperature performance and water stability of the modified steel slag AC-13 mixture are comparable with that of the diabase AC-13 mixture. Finally, the environmental benefit results show that the modified steel slag AC-13 mixture has the optimum environmental benefit among the three mixtures. This novel modification method is crucial to the resource utilization of steel slag aggregate in asphalt pavement infrastructure construction.