The hydration of ternary blended cements with Fe-rich slag from non-ferrous metallurgy and limestone

Abstract

Fe-rich slags originating from non-ferrous metallurgy have shown promising properties as a new type of supplementary cementitious material (SCM). However, their combined use with limestone has not yet been investigated in detail. The goal of this study is to elucidate whether this yields a positive effect as observed for aluminosilicate SCMs with limestone. Compressive strength, hydration kinetics and products as well as pore solution concentrations of ternary blended cements with at least 50 wt% replacement of PC by limestone and non-ferrous metallurgy slag are investigated up to 150 days. Although there is no significant change in the reaction degree of clinker or slag upon addition of limestone, a slight compressive strength enhancement and increased bound water content were observed, originating from formation of additional carbonate AFm phases. Finally, partial replacement of slag by limestone appeared to suppress the formation of siliceous hydrogarnet in favor of a (Fe, Mg)-Al-layered double hydroxide.