Experimental study of flax FRP tube encased coir fibre reinforced concrete composite column

The use of natural fibres as building materials is benefit to achieve a sustainable construction. This paper reports on an experimental investigation of a composite column consisting of flax fibre reinforced polymer (FFRP) and coir fibre reinforced concrete (CFRC), i.e. FFRP tube encased CFRC (FFRP-CFRC). In this FFRP-CFRC, coir fibre is the reinforcement of the concrete and FFRP tube as formwork provides confinement to the concrete. Uniaxial compression and third-point bending tests were conducted to assess the compression and flexural performance of the composite column. A total of 36 specimens were tested. The test variables were FFRP tube thickness and coir fibre inclusion. The axial stress–strain response, confinement performance, lateral load–displacement response, bond behaviour and failure modes of the composite column were analysed. In addition, the confined concrete compressive strength was predicted using existing strength equations/models and compared with the experimental results. Results indicate that the FFRP-CFRC composite columns using natural fibres have the potential to be axial and flexural structural members.