Performance analysis of coloured microsurfacing with electric arc furnace steel slag as an aggregate replacement: a laboratory evaluation

Coloured microsurfacing is a preventive maintenance method that, if used correctly, is well known to bring about economic and environmental benefits. The present work seeks to examine the possible use of electric arc furnace steel slag (EAF-SS) aggregates as a substitute for part of the conventional aggregates in the microsurfacing mix design to improve its performance. Beginning with an assessment of the steel slag (SS) properties both chemically and physically, the slag was incorporated in microsurfacing mixtures to replace control sample aggregates at five different dosages, namely 0, 10, 20, 30 and 40% (based on the total weight of aggregate), to determine the proper dosage. Specimens were examined using cohesion, loaded wheel and wet track abrasion tests. The results showed that the SS-bearing mixtures performed well, especially when the slag dosage was 30%. Experimental outcomes further indicated acceptable compatibility of the blends with SS aggregates and the asphalt emulsion, thanks to their good physical, chemical, and mechanical characteristics. These advantages enahanced the microsurfacing performance in terms of adhesion of asphalt binder to aggregates (by up to 36.3%), abrasion resistance (by up to 47.7%), bleeding potential (down by up to 48.0%) and vertical displacement (down by up to 45.9%).