Properties Improvement of Metakaolin-Zeolite-Diatomite-Red Mud Based Geopolymers

Addition of pozzolanic materials increases the mechanical characteristics of construction materials and contributes towards a higher durability. Metakaolin is an artifical pozzolan obtained by calcination of kaolinitic clays at an adequate temperature. Geopolymers are inorganic materials from mineral origin, composed of a precursor, an alkaline activator and a solvent. New geopolymer formulations were designed by sodium silicate/NaOH/KOH activation of metakaolin, zeolites, diatomites and red mud mixtures. The effects of source materials on the microstructure and mechanical properties were studied. Mineralogical and chemical compositions were assessed as well as microstructure, specific surface area, compressive strength and adsorption. In general, incorporation of red mud, zeolite filler and diatomites to metakaolin in medium of alkali activators of low concentration provided formation of more eco-friendly materials with high mechanical resistances and water treatment capabilities.