Metakaolin and Red-Mud Based Geopolymer: Resistance to Sodium and Magnesium Sulfate Attack

Abstract

This paper aims to study strength properties, UPV, and weight changes exposed to sulfate attack, andmicrostructural properties of geopolymer mortar prepared using metakaolin and red-mud as bindermaterials by mixing with river sand replaced partially by limestone, marble and basalt powder withdifferent ratios (25%, 50%, and 75%) as filler materials, the mix proposed were activated by sodiumsilicate and sodium hydroxide solutions (12mol). The proposed samples were exposed to 10% ofmagnesium and sodium sulfate solutions for various periods of 60, 120, and 180 days to investigate thedurability properties of the manufactured geopolymer mortar. The experimentally obtained resultsuncover that the prepared geopolymer mortar’s strength properties increase at 60 days for all the proposedmixes, while at 180 days; the geopolymer mortar suffers a significant loss. Change in weight increaseobviously between 10.83% and 13.65% for 60 days and decrease gradually for 120 days between 9.22%and 10.19% to reach a stable value between 120 and 180 days. Furthermore, to evaluate this work, theScanning Electron Microscopy and X-ray Diffraction methods were investigated.