Experimental investigation on geopolymer concrete

Abstract

Increase in emission of carbon dioxide due to different industrial and non-industrial activities are posing a severe threat to global atmosphere. Cement industry contributes significantly in emission of carbon dioxide gas during its production. On the other hand, industrial by-products such as GGBS, fly ash, etc. poses a serious waste disposal problems thus affecting the economy of the town or nation leading to global environmental impact. Geopolymer concrete is a solution to this problem. Geopolymer is a class of aluminosilicate binding material synthesized by thermal activation of solid aluminosilicate base material such as GGBS and fly ash. Geopolymer concrete is produced due to alkalination of materials rich in aluminium and silicon with an alkali solution, an aqueous solution of sodium hydroxide and sodium silicate. Alkali solution was varied in different molar concentration as 16 M, 18M, 20M and 22 M with hydroxide to silicate ratio of 2.5. Two different set of concrete specimens were casted which were viz. fly ash based only and GGBS together with fly ash in the proportion to 70:30. All the specimens were cured at 60 °C in oven and accelerated curing tank for 3 days and atmospheric curing in lab till 28th day. It was observed that, oven dried curing showed a slight higher strength than steam cured and it was a successful.