Durability Studies on Alkali Activated Fly Ash and GGBS-Based Geopolymer Mortars

Abstract

The present scenario in the growth of infrastructure development led to the production of high amount of concrete. Cement being the major binding material to make concrete imperatively causes the release of high amount of carbon dioxide (CO₂) into atmosphere. The thought about sustainable environment arose a strong concern towards development of geopolymer concrete (GPC) that can be produced with alternative cementitious materials (Fly ash, GGBS, micro-silica, etc.). The research work presented in this paper explained the development of mortar specimens with fly ash and GGBS as binders. Nowadays, the construction industry requires the replacement of cement mortar with the novel type material, i.e. geopolymer mortar. It can be produced by using fly ash and GGBS as binders; and alkaline solution (combination of NaOH and Na₂SiO₃) as activator. Generally, heat treatment is necessary for curing geopolymer materials which becomes a drawback in practical applications. This study includes the development of geopolymer mortars under outdoor curing and suggests the attainment of strength with proper proportions of GGBS and Fly ash. Research work was carried out on fly ash and GGBS-based geopolymer mortar subjected to acidic solutions (Sulphuric and Nitric). The main parameters considered in this study were mass loss and strength loss. An experimental study was conducted to analyse the acid attack resistance of geopolymer mortar, considering five different mixes with varying the fly ash and GGBS (100FA-0GGBS, 75FA-25GGBS, 50FA-50GGBS, 25FA-75GGBS and 0FA-100GGBS) for different acid exposure periods of 7 and 28 days. The performance of geopolymer mortar of 100FA-0GGBS when exposed to acid environment was found to be superior compared with the other mixes.