A study on the effect of Binder Index on compressive strength of geopolymer concrete

Abstract

The use of alkali activated binders from granulated slags and siliceous fly ash in development of concretes is significant from the point of sustainability. Such concretes are called Geopolymer concrete (GPC). This paper presents an experimental investigation on the effect of ground granulated blastfurnace slag (GGBS) content and alkaline activated binder on the compressive strength of GPC. To study the combined effect of (GGBS) to fly ash ratio and the molarity of alkaline activator on the compressive strength of GPC a new parameter called the 'Binder Index (Bi)' has been introduced. The results have shown that the compressive strength of GPC is significantly influenced by varying the binder index.The experiments have shown that compression strength of GPC has increased with increase of GGBS to FA ratio for a particular molarity of activator used. As the molarity of activator increases the 28 day compressive strength of GPC also has increased. However the increase of strength is not in proportion to the increase in molarity. Both 7 days and 28 days compressive strength of GPC has increased with increase of the Binder Index.