Sustainable geopolymer concrete using ground granulated blast furnace slag and rice husk ash: Strength and permeability properties

The paper presents the utilization of industrial by-products such as ground granulated blast furnace slag (GGBS) and rice husk ash (RHA) for the development of sustainable geopolymer concrete. GGBS-based geopolymer concrete mixture was prepared and the effect of adding RHA as partial replacement of GGBS, on compressive strength, split tensile strength, chloride permeability and sorptivity were investigated up to the age of 90 days. In addition, SEM, EDS and XRD tests were also performed to observe the microstructure. The results indicate the development of geopolymer concrete using GGBS and RHA with high 3-day compressive strength of approximately 60 MPa, which can replace the conventional cement concrete and thus reduce carbon dioxide emissions. Also, the increase in compressive and split tensile strength, and reduction in chloride permeability and sorptivity was observed with the inclusion of RHA up to 15% at all ages. Beyond this optimum content of 15%, RHA inclusion showed negative results. In addition, the results of microstructure analysis showed more compact and dense micrograph of geopolymer concrete with 15% RHA, due to the coexistence of polymerization products with the additional calcium based hydration products.