Preparation and dynamic mechanical properties of fiber-reinforced high-strength all-coral-sand seawater concrete

High-strength all-coral-sand seawater concrete (HCSC) has been widely used in marine engineering. However, the dynamic mechanical properties of HCSC has been rarely studied. Here, an orthogonal design method is employed to optimize the mix ratio of polyvinyl alcohol (PVA) fibers and copper-coated steel (CCS) fiberreinforced HCSC. The quasi-static and dynamic mechanical properties of HCSC, as well as the strain rate effect and dynamic reinforcement mechanism, are intensively investigated using a universal testing machine and Hopkinson pressure bar. The results show that blending PVA and CCS fibers can significantly improve the quasistatic compressive strength (fcs) and impact compression compressive strength (fcd) of HCSC. The spatial structure formed by blending PVA and CCS fibers affords an excellent toughening effect on the mechanical properties of HCSC. As the strain rate increases to 37.28-184.29/s, the dynamic strength increase factor (DIF) and fcd become positively correlated, where both increase gradually and then stabilize. Conversely, the DIF is negatively correlated with the curing time under the same conditions. The incident energy, reflected energy, absorbed energy, and energy dissipation density of the HCSC specimens exhibit a significant positive linear relationship with the strain rate. Optimizing the volume content of the PVA and CCS fibers can significantly enhance the absorbed energy and improve the impact resistance of the HCSC.

Automated summary

The dynamic mechanical properties of high-strength all-coral-sand seawater concrete (HCSC) were studied by optimizing the mix ratio of polyvinyl alcohol (PVA) fibers and copper-coated steel (CCS) fibers. The results showed that blending PVA and CCS fibers improved the compressive and impact compression strength of HCSC. The study also revealed the correlation between strain rate and dynamic strength increase factor (DIF), as well as the relationship between energy properties and strain rate. Optimizing the volume content of PVA and CCS fibers enhanced the impact resistance of HCSC.