Performance of a hybrid concrete structure with natural fibre reinforcements

Abstract

The use of natural fibres as reinforcement of concrete will be a significant step to have a sustainable construction industry. In this study, a hybrid concrete structure reinforced with natural fibre and natural fibre reinforced polymer composite was introduced, namely, flax fabric reinforced polymer composite (FFRP) tube encased coir fibre reinforced concrete (CFRC), termed as FFRP-CFRC. The compressive and flexural performance of this natural FFRP-CFRC structure were investigated under axial compression and four-point bending. In addition, the effect of ultraviolet radiation and water spray ageing (1500 h exposure) on the mechanical properties of FFRP composites was investigated to study the durability of FFRP composites for civil engineering application. The test results indicate that in axial compression, the use of natural FFRP tube increased the compressive strength and ductility of concrete remarkably. In flexure, the FFRP tube enhanced the lateral load carrying capacity concrete significantly. Coir fiber inclusion changed the failure mode of concrete to be ductile. The ageing conditions cause severe degradation in the tensile and flexural properties of FFRP composites, which was induced by the degradation in flax fibre and polymer matrix interfacial bonding. Overall, this study shows that the hybrid structure has the potential to be light and environmentally-friendly structure for infrastructure application. However, how to improve the durability of FFRP composites is a critical issue which should be considered in the future study.