Effect of Calcium Hydroxide on Compressive Strength and Microstructure of Geopolymer Containing Admixture of Kaolin, Fly Ash, and Red Mud

The current study aims to investigate the effect of calcium hydroxide on geopolymer derived from an admixture natural mineral (kaolin) and industrial by-products (fly ash, red mud). compressive strength microstructure were studied using tests, X-ray diffraction, infrared spectroscopy, BET method, scanning electron microscopy. For investigated NaOH activator concentrations ranging 4 M 10 M, first increases, then decreases with increase content. optimal content hydroxide, which can give highest prepared, is about 13% wt. solid raw materials. materials produced at 8 have higher than those prepared 6 NaOH. There a coexistence geopolymerization gel C-S-H/C-A-S-H in prepared. Both porosity formation N-A-S-H/C-S-H/C-A-S-H during polymerization process are important for mechanical properties