Effect of warm mix chemical additives on the binder-aggregate bond strength and high-service temperature performance of asphalt mixes containing electric arc furnace steel slag

Abstract

Warm Mix Asphalt (WMA) is a modified asphalt concrete, obtained by using organic, chemical or foaming additives, which can be produced and compacted at lower temperatures (100-140 °C). The environmental sustainability of WMA can be enhanced with the inclusion of steel slag in substitution of natural aggregates. Given this background, this paper illustrates an experimental research aimed at characterizing WMA containing steel slag. Rheological tests were carried out on asphalt binders in order to investigate the effect of the WMA additive on high-service temperature properties. Then, the bond strength between asphalt binders and aggregates (limestone and steel slag) was investigated. Finally, compactability and permanent deformation resistance of the studied mixtures were also evaluated. Results mainly showed that, regardless the presence of steel slag, the studied additive allowed adequate mixing and compaction at lower temperatures, improving the bond strength between binder and aggregates without affecting permanent deformation resistance of asphalt mixes.