Study on the Compressive Performance of High-strength Manufactured Sand Concrete with Steel-PVA Fibers

To mitigate the depletion of natural aggregates, this study aims to develop high-strength concrete by incorporating manufactured sand and fibers, and to investigate its axial mechanical properties. The effects of different manufactured sand substitution rates and PVA fiber contents on these properties are systematically explored. Based on tests of 25 mix proportions, the failure evolution characteristics under fiber-aggregate synergistic interactions are revealed, and the enhancement mechanisms of manufactured sand and fibers on compressive strength, peak strain, elastic modulus, Poisson's ratio, and compressive toughness are elucidated. The results demonstrate that PVA fibers effectively inhibit crack propagation through bridging effects, while the angularity of manufactured sand strengthens interfacial bonding and improves concrete compactness. A significant synergistic effect is observed between manufactured sand and fibers, with optimal compressive mechanical performance achieved at a 50% manufactured sand replacement ratio and 0.30% PVA fiber dosage. However, excessive fibers or high substitution rates can degrade performance due to fiber aggregation and poor aggregate grading. The synergy of manufactured sand and PVA fibers significantly improves the axial mechanical properties of high-strength concrete, offering a viable way to sustainably replace natural aggregates.