A comparative study of steel reinforced concrete and flax fibre reinforced polymer tube confined coconut fibre reinforced concrete beams

Abstract

This paper experimentally investigates the flexural behaviour of circular steel rebar-coconut fibre reinforced concrete and flax fibre reinforced polymer tube-confined coconut fibre reinforced concrete composite beams. Conventional steel reinforced concrete beam and flax fibre reinforced polymer tube-confined plain concrete were considered as reference. A total of 18 beams were tested under 4-point bending. For flax fibre reinforced polymer-confined concrete specimens, two different tube thicknesses were used, i.e. 2-layers and 4-layers fabric. The effect of coconut fibre inclusion on the flexural behaviour of steel rebar-coconut fibre reinforced concrete and flax fibre reinforced polymer tube confined coconut fibre reinforced concrete beams were evaluated. In addition, the performance of flax fibre reinforced polymer tube-confined plain concrete and flax fibre reinforced polymer tube-confined coconut fibre reinforced concrete composite beams were compared with steel reinforced concrete and steel rebar-coconut fibre reinforced concrete beams. The test results indicate that coir inclusion slightly increased the load-carrying capacity but significantly enhanced the energy absorption of the steel rebar-coconut fibre reinforced concrete beam, compared to the steel reinforced concrete beam. For both flax fibre reinforced polymer-confined plain concrete and coconut fibre reinforced concrete, an increase in tube thickness provides a larger ultimate load, deflection and ductility of the beams. In comparison with the brittle failure of flax fibre reinforced polymer tube-confined plain concrete, coconut fibre inclusion modified the failure modes of flax fibre reinforced polymer tube-confined coconut fibre reinforced concrete to be ductile. The comparative study showed that 4-layer flax fibre reinforced polymer plain concrete and flax fibre reinforced polymer tube-confined coconut fibre reinforced concrete beams experienced lower deflection, higher ultimate load and higher energy absorption than the steel reinforced concrete beam.

Keywords

Flax fibre reinforced polymer coconut fibre reinforced concrete ductility reinforced concrete

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