Compressive Strength Characteristics of Kenaf Fibre Reinforced Cement Mortar

Abstract

This paper presents the findings of an investigation on the compressive strength properties of kenaf fiber composite mortar. Water–retted kenaf fibers were used as reinforcement in cement mortar. Fiber contents of 1%, 2% and 3 % (by weight of cement) with varying lengths of 10mm, 20mm and 30mm were used to produce 50mm mortar cubes. The Composite mortars were cured in water for 3, 7, 14, 21, and 28days. A total of 150 mortar cubes were used for the study. Density, water absorption and compressive strength tests were conducted on the composite mortar. Regression analysis was carried out on the compressive strength results using Minitab 15. The results showed that water absorption and density of the composite mortar increased as the volume of fiber and length increased. Compressive strength decreased with increasing fiber volume and length. However, there was increase in compressive strength of between 0.21%-22.3% for composite mortar containing 1-3% volume of fiber with 10mm fiber length. The fitted regression model showed a perfect relationship (R2=84.5%) between compressive strength, fiber volume, fiber length and curing age. Therefore, fiber volume, fiber length and curing are useful predictors of the selected model. Model adequacy test reveals that the fitted regression model is highly adequate. There was no statistically significant difference in the compressive strength of the control samples and those containing 1-3% fiber volumes with fiber length of 10mm.