Synthesis and characterization of geopolymer from metakaolin and sugarcane bagasse ash: Fid-Bau Portal

Synthesis and characterization of geopolymer from metakaolin and sugarcane bagasse ash

Yadav, Ankur Laxman / Sairam, V. / Srinivasan, K. / Muruganandam, L.

Highlights • Geopolymer from sugarcane bagasse ash and metakaolin. • Physico-chemical characterization of sugarcane bagasse ash and metakaolin. • Morphology characterization of sugarcane bagasse ash and metakaolin. • Effect of silica/alumina ratio. • Effect of alkaline activator/binder ratio. • Effect of sodium silicate/sodium hydroxide ratio.

Abstract Many researchers are using sugarcane bagasse ash as a pozzolanic admixture. Pozzolanic admixture is an amorphous aluminosilicate materials, which may not be naturally cementitious, but react with calcium hydroxide (Ca(OH)2) ande water to form cementitious compounds. Mostly Fly ash and other pozzolanic materials have been utilized as raw materials in Geopolymer concrete. However, sugarcane bagasse ash is also rich in aluminosilicate source, which is a primary requirement for the geopolymer concrete. This experimental study was to synthesize geopolymer from sugarcane bagasse ash and metakaolin in order to effectively utilize both these low cost and easily available materials. In this study physico-chemical and morphology characterization of sugarcane bagasse ash and metakaolin were studied and observed that sugarcane bagasse ash needed mechanical as well chemical treatment in order to enhance its pozzolanic reactivity. In the chemical processing of sugarcane bagasse ash, calcination has been carried out at 700 °C for 90 min. while in mechanical treatment grinding has been done for 2 h grinding in ball mill. For synthesizing geopolymer three parameters were considered i.e. effect of silica/alumina ratio, effect of alkaline activator/binder ratio and effect of sodium silicate/sodium hydroxide ratio, while the molarity of sodium hydroxide was fixed i.e. 6 M. In silica/alumina ratio, four ratios were considered i.e. 2.0, 2.5, 3.0 and 3.5. In alkaline activator/binder ratio 0.45, 0.50, 0.55 and 0.60 ratios were taken. Lastly in sodium silicate/sodium hydroxide ratio 2.0, 2.5 and 3.0 were considered. Finally the optimal mix proportion was defined based on the 28 day compressive strength and it was observed 2.5 silica/alumina ratio was the optimum ratio among the other silica/alumina ratios. In alkaline activator/binder ratio and sodium silicate/sodium hydroxide ratio 0.50 and 2.5 ratio respectively was the optimal ratio.