Behavior of BFRP strips confined PVC tubes with internal fillers under axial compressive load

Poly Vinyl Chloride (PVC) material, which exhibits high tensile capacity, economical cost, and excellent corrosion resistance, has attracted the interest of many researchers for using in con-struction engineering. Existing studies reveal that fiber-reinforced polymer (FRP) confinement is a high-efficiency method for strengthening concrete columns, which can be divided into FRP sheets fully and partially wrapped columns. In recent years, the combination of PVC tubes and FRP as a hybrid confinement system can effectively improve the mechanical properties of concrete col-umns. Rubberized concrete, which incorporates rubber waste as a partial replacement for con-ventional aggregates, can improve the ductility, and energy absorption, while lowering other qualities such as compressive strength, tensile strength, and elastic modulus. In order to overcome these shortages, this paper proposes a new type of composite column aimed for new construction, that rubberized concrete is filled into PVC tubes externally wrapped by basalt fiber-reinforced polymer (BFRP) strips. Its compression performance was investigated, and the test variables included the replacement percentage of rubber waste (i.e. 10% and 60%) and the net-spacing of FRP strips (i.e. 25 mm and 50 mm). The test results demonstrated that the PVC-FRP system considerably improved the load capacity and deformation capacity of rubberized concrete col-umns. The peak axial stress and axial strain increased obviously with the shortened net distance of FRP strips. Besides, the promotional effect of PVC-FRP confinement became more apparent when the mixture of rubber particles in concrete was enhanced. A modified efficiency coefficient was given at the end of this paper which can provide a comparative accurate prediction of the compressive strength for PVC-FRP confined rubberized concrete.