Strength and Microstructural Characterization of Ferrochrome Ash- and Ground Granulated Blast Furnace Slag-Based Geopolymer Concrete

Abstract

The paper evaluates the possibility of developing open-air cured geopolymer concrete using the mixture of two metallurgical wastes such as ferrochrome ash (FCA) as the primary and ground granulated blast furnace slag (GGBFS) as the secondary source material. Several concrete mixes are prepared with varying combinations of the source materials, and sodium hydroxide and sodium silicate solution as the alkali activator; and characterized to understand their strength development, microstructure properties, and environmental impact. It is observed that the mixture containing 80% FCA and 20% GGBFS provides a compressive strength of 30.2 MPa, suitable for general construction works. At the same time, it requires 44.26% less embodied energy and releases 39.28% less carbon dioxide (CO2) gas than cement-based concrete of similar strength. The characterization of the resulting geopolymer concrete through scanning electron microscopy, X-ray diffraction, and Fourier-transform infrared spectroscopy indicated the participation of primary oxides available in the FCA for strength development.