Use of Oil Palm Broom Fibres for Eco-friendly Concrete

The use of vegetative fibres in reinforcing concrete is void of the high carbon footprint associated with use of conventional reinforcements like steel. Until recently, the rib of the leaflets of the oil palm tree was only used for making brooms. These ribs referred to as Oil Palm Broom Fibres (OPBF) however potentially have mechanical characteristics similar to steel and can be incorporated in concrete to improve its mechanical properties. With a specific gravity of 0.84, an average length of 800mm and diameter varying between 0.20mm (at the tail) and 4.00mm (at the head), maximum tensile strength of 900MPa was recorded in the study, hence making the fibres superior to steel in terms of strength-to-weight ratio. Optical microscopy of fibre cross sections reveals randomly dispersed xylem cavities, a densely packed core but lightly packed cortex. This radial and longitudinal density gradient is responsible for the phenomenon whereby towards the cap of the fibres, the fibres are stiffer in bending but reduces in tensile strength. Investigation of mechanical properties of concrete incorporating OPBF as random fibre-reinforcement was carried out. Although the inclusion of OPBF in concrete reduces its compressive strength, the post-yield behaviour shows that energy absorption of the composite is enhanced, making OPBF-concrete a potential material for low-cost seismic construction.