Crack resistance of asphalt mixture with steel slag powder

Abstract

Steel slag is a kind of industrial waste generated during steelmaking. It has been widely used in asphalt mixtures as aggregate in previous research. The utilisation of steel slag in asphalt mixtures as filler is rarely reported. The primary objective of this research was to evaluate the effect of steel slag powder (SSP) on the crack resistance of asphalt mixtures. Two types of fillers – namely, SSP and limestone powder (LP) – were used, and LP functioned as the control group. The characteristics of SSP and LP, including surface texture, chemical composition and particle size gradation, were first investigated. Then, asphalt mixtures containing SSP and LP were designed by the Superpave procedure. Finally, the indirect tensile strength (ITS) and fracture energy of asphalt mixtures were determined to evaluate the crack resistance of asphalt mixtures. Results suggest that the particles in SSP and LP both possess obvious edges and corners and coarse surface textures. The average chemical compositions indicate that SSP is a high-alkalinity slag filler. Determining the crack resistance of asphalt mixtures by ITS value is not sufficient because of the similar results caused by SSP and LP. The fracture energy parameter suggests that SSP improves the crack resistance of asphalt mixtures.