ASSESSMENT OF THE IMPACT RESISTANCE BEHAVIOUR OF RHA BASED KENAF FIBROUS CONCRETE

Abstract

Waste materials utilization is one of the central concerns of waste management approaches in recent years. The developments in cement and concrete technology towards the production of sustainable concrete by using waste materials and cellulosic fibre is gradually attaining acceptance because of its technological, economic and ecological advantages. This research investigated the potential use of a natural fibre known as Kenaf fibre and Rice Husk Ash (RHA) from agricultural waste towards achieving a bio fibrous concrete with enhanced impact resistance and strength properties. Four mixes with varying percentage of RHA from 0% to 15% at an interval of 5% without fibre was used as a basis for comparison against another four mixes made with 50 mm length fibre of 0.5% volume fraction and RHA of 0% to 15% as supplementary cementing material. The drop weight impact test method was adopted in determination of the impact resistance strength and energy absorption of the RHA based kenaf fibrous concrete. It was found that the addition of Kenaf fibre decreased the slump values and increased the VeBe time of fresh concrete. Also, the inclusion of RHA at varying percentage had a reducing effect on the workability of both the fibreless and the fibrous concrete. At later ages, the compressive strength of the fibrous concrete mixtures containing RHA significantly increased and the obtained values were higher than the mix with OPC alone. The positive interaction between Kenaf fibres and RHA leads to high tensile strength, flexural strengths and impact resistance, thereby increasing the concrete ductility with higher energy absorption and improved crack distribution. The study established that Kenaf Fibre (KF) at 5% and 10% Rice Husk Ash (RHA) resulted in; 12%, 26.3%, 30.8% and 3.9% in compressive strength, splitting tensile strength, flexural strength and energy absorption values respectively compared to the control. It is concluded that Kenaf fibre and rice husk ash can be used as building materials in the construction of sustainable concrete.