Evaluation of the Mechanical and Durability Properties of Geopolymer Concrete Prepared with C-Glass Fibers

Abundant research on geopolymer concrete in the last two decades has provided worldwide acceptability in conventional structural applications. The high-impact applications of geopolymers are mostly limited because they are quasi-brittle in nature and show moderate crack resistance; hence, they require suitable reinforcing materials such as fibers. This paper reports a study to assess the strength and durability properties of fly ash-based geopolymer concrete (FA-GPC) prepared with novel C-glass fibers. The binder mix was comprised of Fly Ash (FA), Lime (L), Silica Fume (SF) and was activated by sodium hydroxide (12 M) and sodium silicate solution, followed by curing under ambient conditions. Glass fibers were utilized in varying proportions (0.125, 0.25, 0.375, 0.5, 0.625, and 0.75%), by weight of the binder mix. It was found that the incorporation of 0.5% glass fiber significantly increased the compressive strength, split tensile strength, and flexural strength properties. From the durability perspective, the samples exhibited good resistance against seawater, MgSO4 solution, and H2SO4 when compared with the control mix. Further, the Scanning Electron Microscope (SEM) analysis was employed to explore the nature of the geopolymer–fiber matrix. It was revealed that excellent interfacial bonding existed between fiber and the geopolymer matrix. The results indicate that addition of C-glass fibers significantly improves the overall mechanical performance of FA-GPC. The research presented here establishes the advantages of using C-glass fibers-based geopolymer concrete, thus encouraging its broader utilization.