Investigation into the strength and toughness of polyvinyl alcohol fiber-reinforced fly ash-based geopolymer composites

Abstract

This study investigates the influence of polyvinyl alcohol (PVA) fiber dosage and length on the porosity, mechanical strength, and toughness of fly ash-based geopolymer composites. The experimental data are analyzed to examine the deflection-load relationship in the flexural toughness tests of fiber-reinforced geopolymer composites (FRGPC) with different PVA fiber parameters. The results indicate that the addition of a certain amount of PVA fibers effectively enhances the flexural resistance of FRGPC. Particularly, the optimal performance is achieved with the addition of 2.0 vol% of 9 mm PVA fibers, where the 28-day flexural strength reaches 13.16 MPa, representing a 150.95 % increase compared to the control group, and the deflection at peak load increases by 308.00 %. However, the compressive strength of FRGPC with PVA fiber dosage at 1.6 vol%, 2.0 vol%, and 2.4 vol% decreases by 0.89 %, 6.39 %, and 10.13 %, respectively. Microscopic observations of FRGPC indicate that an increase in fiber dosage and length results in larger pores and uneven distribution of fibers. Notably, 12 mm PVA fibers exhibit significant aggregation, confirming the findings from mechanical property tests. This study, through an in-depth exploration of the mechanical properties of PVA fiber-reinforced fly ash-based geopolymer composites, provides crucial experimental data and a theoretical foundation for the development of sustainable construction materials.