Influence of GGBFS on the Mechanical Properties of the Water Cured Fly Ash Aggregate-Based Geopolymer Concrete

Abstract

Conventional concrete consists of cement, sand as fine aggregate and gravel, limestone or granite in various sizes and shapes as coarse aggregate including with water. In the present work, the feasibility of using industrial inorganic polymeric residues wastes as a total (100%) replacement to the traditionally used normal conventional concrete materials is examined in the preparation of the geopolymer concrete (GPC). In this GPC, the cement is totally replaced by the fly ash (class F) with ground granular blast furnace slag (GGBFS),
bottom ash is used in place of fine aggregate, water cured fly ash aggregates (WCA) were (prepared using the class C fly ash by adopting palletisation technique) used in place of coarse aggregate and the alkaline solution is used in place of water for polymerization purpose with binding material. A new design mix (volume batch) procedure was formulated for geopolymer concrete. The GPC mixes were cast with WCA at 0, 10, 20 and 30%replacement of fly ash (class F) by GGBFS at 8 molar ratios of NaOH solution. The concrete was cured at normal room/ambient temperature only to minimise the water in the water curing. The physical and mechanical properties of the GPC were studied. It was observed that the GPC mixes with WCA at 30% GGBFS with 8 Molar ratio of NaOH concentration attained maximum compressive strengths of 33.93 MPa cured at room temperature.

Keywords: bottom ash, fly ash, ground granulated blast furnace slag,palletisation, sodium hydroxide solution