Mechanical and dynamic properties of coconut fibre reinforced concrete

Coconut fibres have the highest toughness amongst natural fibres. They have potential to be used as reinforcement in low-cost concrete structures, especially in tropical earthquake regions. For this purpose, the mechanical and dynamic properties of coconut fibre reinforced concrete (CFRC) members need to be well understood. In this work, in addition to mechanical properties, damping ratio and fundamental frequency of simply supported CFRC beams are determined experimentally. A comparison between the static and dynamic moduli is conducted. The influence of 1%, 2%, 3% and 5% fibre contents by mass of cement and fibre lengths of 2.5, 5 and 7.5 cm is investigated. To evaluate the effect of coconut fibres in improving the properties of concrete, the properties of plain concrete are used as a reference. Damping of CFRC beams increases while their fundamental frequency decreases with structural damage. CFRC with higher fibre content has a higher damping but lower dynamic and static modulus of elasticity. It is found that CFRC with a fibre length of 5 cm and a fibre content of 5% has the best properties.