Sulfate resistance of ferrochrome slag based geopolymer concrete

This paper presents the study of the performance of a new geopolymer binding material exposed to sulfate attack. Geopolymer binding material was obtained by alkaline activating FS with chemical materials (NaOH and Na2SiO3). Geopolymer concrete samples were produced by mixing this binding material with river sand and crushed sand aggregates. Test specimens were immersed in magnesium sulfate solutions (by weight 3%, 5% and 7%) for various periods of time and the durability of geopolymer concrete was investigated. The residual compressive strength (90 and 180 days), change in weight and length of samples, pH variation of solution and visual appearance of these samples were obtained experimentally. It was concluded that compressive strength of both geopolymer and Ordinary Portland Cement (OPC) based concrete samples decreases with increasing in MgSO4 content and exposure duration. After exposed to 7% MgSO4 solution for 180 days, the minimum decrease in compressive strength was seen 25% in geopolymer concrete samples with crushed sand aggregates.