Influence of ferrochrome ash on mechanical and microstructure properties of ambient cured fly ash-based geopolymer concrete

Earlier studies indicated that the reactive MgO reduces shrinkage crack and porosity, and accelerates the hydration and strength development. Ferrochrome ash (FCA), a waste generated from ferrochrome industry, is a rich source of MgO apart from the aluminosilicate compositions and hence can fulfil the need for added reactive MgO. With this objective, several geopolymer mixes are prepared by varying mix proportions of FCA and FA from 20 to 80% in the source mix. The alkaline solutions of sodium hydroxide and sodium silicate were used to activate these sources. The effect of FCA on resulting geopolymer concrete mix is evaluated through workability, compressive strength, microstructural and mineralogical analysis. Based on these extensive studies it is observed that a mix containing FCA and FA in 60:40 ratio can be best suited for geopolymerization that resulted in the 28-day compressive strength of 29.3 MPa under ambient curing condition.