Hybrid basalt/flax fibers reinforced polymer composites and their use in confinement of concrete cylinders

Abstract

Flax fiber–reinforced polymer composites were determined to be effective in confinement of concrete cylinders. Flax fibers exhibit strong intrinsic hydrophilic properties and relatively inferior mechanical properties; therefore, combining them with mineral-based natural fiber (i.e. basalt fibers) was proposed. In the present study, unidirectional flax–basalt hybrid fiber reinforced polymer plates and tubes were prepared using a filament-winding process. The mechanical properties of the fiber-reinforced polymer plates and compressive properties of the concrete-filled fiber-reinforced polymer tubes were studied. Compared to those of flax fiber–reinforced polymer, hybrid fiber–reinforced polymers exhibited linear rather than bilinear stress–strain curves and enhanced tensile properties. The lateral–axial relationship of the hybrid fiber reinforced polymer–confined concrete cylinders can be well predicted by the classic model for glass- or carbon-based fiber-reinforced polymer-confined concrete cylinders, however, the axial stress–strain cannot. In addition, the lateral–axial relationship of the hybrid fiber reinforced polymer–confined cylinders depends on the arrangement of the fiber layers.