Compressive and Splitting Tensile Strengths of Coconut-Coir-Fibre-Reinforced Concrete: Effect of Fibre Volume

In light of the issues pertaining to the rising cost of raw materials and depleting natural resources resulting from the production of conventional construction materials, as well as that pertaining to disposal of wastes in the agricultural industry, reinforcement of concrete with organic fibres has to be further explored. Coconut coir fibre is an organic fibre that has a high tensile strength and can potentially be employed in fibre-reinforced concrete (FRC). In view of the potential of employing coconut coir fibre in FRC, in the present study, effect of fibre volume on compressive and splitting tensile strengths of coconut‑coir‑FRC was investigated. Four mix designs with varying fibre volume, which comprises 0, 0.5, 1.0 and 1.5% by volume of cement were adopted for preparation of concrete samples. Compressive and splitting tensile strength tests were performed on the samples. Compressive strength tests were conducted at 7 and 28 days of curing, while splitting tensile strength tests were conducted at 28 days of curing. Addition of fibre has increased the compressive strength and the maximum compressive strength of 33.83 MPa was obtained at fibre volume of 1.5%. The splitting tensile strength increased from 2.434 to 2.750 MPa as fibre volume was increased from 0.0 to 1.0% but, as fibre volume was further increased to 1.5%, the splitting tensile strength reduced to 2.699 MPa. Bridging activity of the fibres across the cracks effectively restricts crack development and contributes towards increasing the strength of coconut-coir-FRC samples.