Mechanical properties and constitutive model of steel fiber reinforced manufactured sand concrete columns: Experimental, theoretical and numerical investigation

Le résumé fourni par la source

The intensive extraction of natural sand (NS) has created significant challenges related to resource depletion and ecological consequences, driving the need for manufactured sand (MS) as an eco-friendly substitute in construction applications. This research systematically examines the structural performance and deformation characteristics of steel fiber-reinforced manufactured sand concrete (FRMSC) columns subjected to eccentric loading, with particular focus on MS replacement percentage (0%, 50%, 100%), load eccentricity (20 mm, 40 mm, 60 mm), and steel fiber dosage (0%, 1%, 2%). The test results indicate that variations in the MS replacement ratio and reinforcement ratio had a minimal effect on concrete strain. In contrast, reducing the slenderness ratio and increasing the steel fiber content substantially enhanced deformation capacity. Furthermore, the incorporation of steel fibers improved the mechanical performance of MS concrete, effectively mitigated concrete cover spalling, and increased both load-bearing capacity and ductility. Although the fundamental failure mechanism of the columns remained unchanged, the fibers optimized internal stress redistribution by providing improved shear-frictional resistance. This mechanism consequently delayed the failure process and augmented energy dissipation. Additionally, a constitutive model for MS concrete was developed based on experimental data and validated through finite element simulation of the loading process. The numerical predictions correlated well with the experimental measurements, with minor errors of 4.84% in peak displacement and 1.40% in peak load.

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