Microtexture Performance of EAF Slags Used as Aggregate in Asphalt Mixes: A Comparative Study with Surface Properties of Natural Stones

Steelmaking industries produce a large amount of solid wastes that need to be adequately managed in order to ensure environmental sustainability and reduce the impact of their disposal on earth pollution. Electric arc furnace (EAF) slags are those wastes deriving from secondary steelmaking production; these slags can be re-used and recycled in many industrial applications such as the production of asphalt mixes. In this paper authors investigate the surface performance of EAF slags used as second-hand aggregate in asphalt mixes. In particular, slags behavior under polishing is compared to other types of aggregate commonly used for asphalt concrete such as limestone, basalt, and kinginite. Several devices (skid tester, laser profilometer, polishing machine) were used to collect experimental data; the analysis of microtexture was carried out by comparing aggregate surface performance before and after polishing. Results show that EAF slags are positively comparable to basalt as concerns the polishing behavior; good correlations between skid resistance and some microtexture indicators are also carried out.