Utilization of waste from steel and iron industry as replacement of cement in mortars

Abstract

The viability of combining waste slag produced from steel (Basic Oxygen furnace) and iron (Blast Furnace) industry as replacement of cement in cement mortars was investigated. The impacts on the normal consistency, setting times, soundness, compressive strength, microstructure, and durability of cement paste/mortar were studied. The results revealed that the water requirement and the setting time of cement paste increased by the addition of steel slag powder. The optimum content of steel slag and GGBS (ground granulated blast furnace slag) as a combined admixture was 40%. The 28 day compressive strength was comparable, whereas it exceeded the strength of control mortar after 90 days of curing. The microstructure of samples was studied using SEM micrographs, which indicated denser structures of ternary mortars. The durability tests of accelerated carbonation, sulphuric acid resistance, and electrical resistivity showed acceptable results. Life cycle assessment (LCA) of ternary mortar indicated visible decrease in environmental impacts in all categories. Response Surface Methodology (RSM) was adopted to find relation between partial replacement of cement by steel slag and GGBS in ternary blend and compressive strength. This research bestows a new understanding of how industrial wastes can be managed sustainably with imparting additional benefits to the concrete economically.