Utilization of gneiss coarse aggregate and steel slag fine aggregate in asphalt mixture

Natural resource shortage and environmental pollution issue have promoted the recycling of inferior natural resources and solid wastes in asphalt pavement. While steel slag fine aggregate and inferior gneiss aggregate are rarely used in asphalt mixture in China due to some poor performances. The primary objective of this research was to explore the feasibility of simultaneously using gneiss coarse aggregate and steel slag fine aggregate in asphalt mixture. A new method to improve the quality of steel slag fine aggregate was proposed first. Raw material characteristics directly related to asphalt adhesion and absorption were fully detected then. Performances of asphalt mixture including Marshall stability and quotient, crack resistance, moisture susceptibility, volume stability and deformation resistance were evaluated finally. Results showed that modified WSFA (Weathered Steel Slag Fine Aggregate) presented lower asphalt absorption than original WSFA. Asphalt mixture consist of gneiss coarse aggregate and modified WSFA obtained better crack resistance, moisture resistance, volume stability and deformation resistance.