Development and Characterization of Fly Ash Based PVA Fiber Reinforced Engineered Geopolymer Composites Incorporating Metakaolin

Abstract This work focused on the development and characterization of fly ash based polyvinyl alcohol fiber reinforced Engineered Geopolymer Composites incorporating Metakaolin (MFA-EGC). Both mechanical properties and microstructural characteristics were studied. The optimal mix design of the MFA-EGC was selected using the Taguchi method. The tensile strain capacities of the optimal mix at 3d, 7d and 28d can reach 6.8%, 6.4% and 5.2%, respectively. Multi-cracking is a pronounced phenomenon of the MFA-EGC. The cracks are uniformly distributed, with the spacing of 2-5 μm and the average crack width of only ∼25 μm. It was demonstrated that the MFA-EGC can meet both the energy and the strength criteria required to achieve tensile strain hardening behavior, and saturated multi-cracking is expected. The microstructural analyses using XRD, FT-IR and SEM indicate that the reaction products of the hardened MFA-EGC were mainly amorphous aluminosilicate phases, while new crystalline phases were concluded insignificant.