Mechanical Characteristics of Fly Ash, GGBS, and GBFS Used Geopolymer Concrete: A Sustainable Cement Alternative

Abstract

This research examines the feasibility of Geopolymer Concrete (GPC) utilizing fly ash and ground Granulated Blast Furnace Slag (GGBS) as sole binders, thereby eliminating the need for standard cement. Classes F fly ash and GGBS were utilized as primary cementitious materials, with Ground Blast Furnace Slag (GBFS) replacing fine aggregate. The mix proportions were designed for M30 concrete, maintaining a constant water to binder ratio of 0.5. Alkaline activators, comprising sodium hydroxide (98% purity) and sodium silicate in a 2:1 ratio, were used at a binder to activator ratio of 0.40. The preparation process involved thorough mixing of dry materials, followed by incorporation of a pre prepared alkaline solution, with the final mix cured under a hybrid regime of oven curing at 100°C and subsequent air curing at room temperature. Mechanical properties, including compressive, tensile, and flexural strengths, were evaluated at 7 and 28 days using standard procedures. Results suggest that GPC made with fly ash and GGBS provides substantial promise as an ecologically friendly alternative to traditional cement based concrete, attaining appropriate mechanical characteristics and durability. The results emphasize the appropriateness of GPC for structural applications, contributing to decreased carbon emissions and increasing the use of industrial by products in buildings.