Performance of Fe-Rich Alkali-Activated Materials in Na2SO4 Solution: Role of MgO/(MgO + CaO) in the Slag

Abstract

: To enable the usage of non-ferrous metallurgy slags in alkali-activated materials (AAMs), the influence of the chemical composition of slags on durability must be better understood. In this work, two slags were synthesized with different MgO/(MgO + CaO) weight ratios to investigate the effect on the sulfate resistance (Na 2 SO 4 ) of AAMs. Experimental results suggested that a higher MgO/(MgO + CaO) ratio does not lead to higher strength, but the trend of the mass change and compressive strength change of two AAMs is quite similar upon Na 2 SO 4 exposure for 24 weeks. The leaching of elements (Na, Al, and Si) during Na 2 SO 4 exposure is more significant in the early stage, while Ca leaching is more pronounced in the late stage.