Study on thermal properties of steel slag asphalt concrete for snow-melting pavement

Abstract The utilization of steel slag in asphalt concrete can improve the thermal conductivity of steel slag asphalt concrete. The thermal conductivity of asphalt concrete largely affects the surface temperature distribution of asphalt pavement, which in turn affects the mechanical characteristics of asphalt pavement and the temperature of the environment near the surface pavement. In this study, the thermal properties of asphalt concrete with different steel slag volume contents were investigated in a laboratory. The thermal conductivity was tested using a parallel hot-wire and transient plane source method, and the uniformity and surface temperature were studied through infrared thermal imaging. Next, a 3D infrared image was analyzed based on regional statistics, image binarization, and the coefficient of variation evaluation. The practical snow melting efficiency of thermally conductive asphalt concrete was evaluated using an electrical-thermal system. Experimental results indicate that the thermal conductivity, heating distribution uniformity, and surface temperature of asphalt concrete are first increased, before decreasing with an increase in the steel slag replacement. Regardless, the thermal properties of steel slag asphalt concrete were shown to be better than those of conventional asphalt concrete. The most effective steel slag volume in asphalt concrete was shown to be 60 vol. %. The snow melting efficiency of thermal conductivity asphalt concrete can be improved using an electrical-thermal system. The results of this study will help mitigate a shortage of natural resources and improve the temperature distribution of pavements.