Synthesis of Fly-ash and Slag Based Geopolymer Concrete for Rigid Pavement

Abstract

This research work describes the synthesis of fly-ash and granulated blast furnace slag (GGBS) based Geopolymer concrete (FSGC) for paving applications. The study looked at a total of 12 combinations comprising GGBS in proportions of 25%, 50%, 75%, and 100% as a fly-ash substitute, sodium hydroxide (NaOH) solutions of 8, 10, and 12 molars(M), and a fixed sodium hydroxide solution to sodium silicate (S/S) ratio of 2.5. The specimens were all cured outside in the open air. The investigation found that when the GGBS content and NaOH molar concentration increase, the mix's consistency stiffens, resulting in zero slumps and making it harder to work with. At the same time, as the GGBS content and NaOH molarity increased, the mechanical strengths of SFGC mixes improved. Maximum mechanical strengths were achieved using a mixture of 100 percent GGBS and 12 M NaOH solution. According to the findings of the study, the SFGC mix with GGBS content ranging from 25% to 30% and NaOH molarity ranging from 8 M to 10 M is adequate for meeting the criteria of paving grade concrete standards.