Evaluation of mortars produced with Baosteel slag short flow (BSSF) steel slag as fine aggregate

Abstract

The objective was to evaluate the influence of Baosteel slag short flow (BSSF) steel slag, a byproduct of a Brazilian steel mill, as a fine aggregate on the properties of fresh state and on the compressive strength of mortars. The experimental work was to characterize the BSSF steel slag and to produce simple mortars (only cement) and mixed mortars (cement and lime), replacing the natural sand with the slag aggregate in 20%, 40%, and 60% by volume. The fresh state tests were specific mass, incorporated air, water retention, and squeeze-flow, while in the hardened state, compressive strength at 28 days was investigated. It was verified that mortars with higher slag contents required greater amounts of water to obtain the spread (consistency) on the flow table, which was fixed at 260±5 mm. The mortars with slag presented higher specific mass since the slag had a higher density than natural sand and less water retention in the case of simple mortars. In addition, it was verified that the mortars with BSSF steel slag presented lower values of maximum displacement in the squeeze-flow test, which negatively affected its workability in the fresh state, besides the properties of mortar adherence. In addition, it was verified through the analysis of variance that the substitution of natural sand by BBSF steel slag did not significantly influence the compression strength of mortars.