Punching shear behavior of two-way coral-reef-sand concrete slab reinforced with BFRP composites

The basic mechanical properties of coral reef sand (CRS) concrete and the punching shear behavior of two-way CRS concrete slab reinforced with basalt fiber-reinforced polymer (BFRP) composites including bars and grids were investigated. A total of 54 CRS concrete cubes were designed for compression tests. The test parameters include water-cement ratio, cement grade, and aggregate gradation. Further, five two-way CRS concrete slabs reinforced with steel/BFRP bars/BFRP grids were produced to investigate the failure modes, the effects of the BFRP reinforcement ratio and type on the punching behavior. Finally, the punching capacities of the BFRP-reinforced CRS concrete slabs were predicted with different models. The results shows that the CRS concrete fails in the fracture of the coral reef aggregates. Compared with the steel-reinforced slab, no evident punching surface appears during the failure of the BFRP-reinforced slabs. The BFRP grid-reinforced slab exhibits a higher post-cracking stiffness and lower energy consumption than the BFRP bar-reinforced slab owing to the integrity of the BFRP grid. Moreover, the models of CAN/CSA S806-12 and EI-Gamal et al. (2005) reasonably predict the punching capacities of two-way CRS concrete slabs reinforced with BFRP. (C) 2019 Elsevier Ltd. All rights reserved.