Axial compression performances of concrete filled flax-basalt hybrid fibers reinforced FRP tubes

Flax fiber reinforced polymer (FFRP) composites could be used in civil engineering as structural materials. To improve the mechanical properties and durability of FFRP, flax-basalt hybrid fiber reinforced polymer (HFRP) composite was developed. In the present study, unidirectional HFRP tubes were prepared with a winding process, and the compression performances of the concrete filled HFRP tubes were investigated. HFRP coupon was prepared and tested in tensile properties. The tensile results of the HFRP plate coupons shows linear in stress-strain, and hybrid with basalt fiber enhances the elongation at break remarkably. The tensile strength and modulus of the HFRP follow the rule of mixture. The concrete filled HFRP tubes exhibited much improved ultimate strength and ductility compared to those with the flax fiber tubes. The axial compression stress-strain curves were analyzed with the existing models. The coefficients of confinement of HFRP were higher than those of glass or carbon fiber based FRPs.