Performance Characteristics of Microsurfacing Mixture Containing Basic Oxygen Furnace Steel Slag Powder as an Alternative to Natural Filler

Given the crucial importance of roads in connecting different areas, road maintenance has long been seen as a vital duty of road transportation/maintenance organizations. Microsurfacing is an important method of preventive maintenance for roads. The present research was aimed at investigating the use of basic oxygen furnace steel slag as filler in microsurfacing mix design in an attempt to evaluate its performance. For this purpose, we began by studying the physical and chemical properties of aggregates and steel slag filler. Subsequently, the performance of five different asphalt mixtures containing the steel slag filler at 0, 2.5, 5.0, 7.5, and 10.0 wt.% per total weight of aggregate was investigated. The microsurfacing specimens were evaluated using wet track abrasion, loaded wheel-displacement, loaded wheel-sand cohesion, and wet cohesion tests for 30 and 60-min testing times according to ISSA A143 and ASTM D6372. The results showed that the steel slag filler-containing mixtures tended to improve the performance of microsurfacing. Among other mixtures, the one containing the steel slag filler at 7.5 wt.% could improve the cohesion strength by 28 and 45% upon 30 and 60 min of testing, respectively, as compared to the control specimen. Moreover, this specimen exhibited 48.3% higher abrasion resistance, 29.3% lower bleeding, and increased resistance to vertical and lateral displacements by 47.6 and 40.0%, respectively. Compared to the control specimen, this specimen contained 1% higher bitumen emulsion, setting the scene for achieving an appropriate level of cohesion strength within a given time.