Effect of fibre aspect ratio of palm bunch fibre on some physical and strength properties of concrete

Abstract

The natural fibres, abundantly available in nature and also generated as agricultural waste, can be used advantageously in improving certain physical and strength properties of cement matrix and concrete. As compared to fibres widely used in construction activities viz. steel, glass carbon synthetic etc., these are advantageous in the sense that they are renewable, non-abrasive, cheaper, comparatively more flexible etc. Also, the health and safety concerns during their handling, processing and mixing are less. Several natural fibres have been used in experimental studies and construction activities to investigate and improve upon the mechanical properties of cement and concrete matrices which are brittle in nature. This research examines the effects of fibre aspect ratio of palm bunch fibre on the physical and strength properties of concrete. Experimental studies on compressive strength in accordance with BS 1881: Part 116 (1983), split tensile strength in accordance with BS1881, Part 117 (1983) and flexural strength in accordance with BS 1881: Part 118: (1983) were conducted with fibre aspect ratios of 75, 100, 125 and 150. The addition of palm bunch fibres significantly improved many of the engineering properties of the concrete, notably toughness, split tensile and flexural strengths. The ability to resist cracking and spalling were also enhanced. However, compressive strength was adversely affected. The toughness or energy-absorbing capacity increased, but there is an optimum aspect ratio (125), beyond which the toughness started to decrease. Overall the study has demonstrated that addition of palm bunch fibre to concrete leads to improvement of its engineering properties. Further work is however, required to assess the long term durability of concrete enhanced with palm bunch fibre.