Siliceous fly ash and blast furnace slag based geopolymer concrete under ambient temperature curing condition

Abundance of industrial by-products along with its disposal issues and exploitation of the natural resource of limestone for cement production creates a huge problem throughout the globe. Geopolymer technology could be a worthy solution to these problems by producing concrete utilizing industrial by-products and resisting the exploration of the natural source of limestone and limiting the greenhouse gas emission. This article presents the observations achieved by replacing siliceous fly ash with ground granulated blast furnace slag (GGBFS). Different mix proportions were prepared to measure the mechanical strength. GGBFS was added in replacement of fly ash in different percentages from 0% to 30%. Two different types of molarity of NaOH solution was used to observe the effect of molarity with the addition of GGBFS. By-product binders were mixed with alkaline solution by keeping the ratio of mixing of Sodium silicate (Na2SiO3) to sodium hydroxide (NaOH) solution equals to 1.5. Slump cone test, compressive and flexural test was conducted to examine the workability and mechanical strength, respectively. Microstructural analysis was conducted to understand the surface morphology and minerology. Current study shows that with the inclusion of GGBFS to siliceous fly ash based geopolymer concrete compressive and flexural strength equals to 43.61 and 5.45 MPa, respectively, can be achieved at ambient condition which may be feasible for cast-in situ applications.