MECHANICAL PROPERTIES OF FOAMED CONCRETE REINFORCED WITH NATURAL FIBRE

Foamed concrete (FC) can withstand compressive loads but tends to produce numerous microcracks when subjected to flexural and tensile loads and is unable to endure further stress brought on by applied forces, particularly without any additional strengthening mechanism. Thus, this research was conducted to scrutinize the effectiveness of including natural fibre in FC to improve its mechanical properties. Three types of natural fibres were considered, namely coir fibre, mesocarp fibre, and jute fibre. FC specimens were reinforced with these fibres of 20mm in length at a volume fraction of 0.45%. Three densities of FC were explicitly cast, namely, 700 kg/m(3), 1100 kg/m(3), and 1500 kg/m(3), with a constant cement-to-sand ratio of 1:1.5, and a cement-water ratio of 0.45. The parameters evaluated were compressive strength, bending strength, and splitting tensile strength. The greatest compressive strength improvements were found with the presence of mesocarp fibre which attained a boost of 63%, 44%, and 24% for densities of 700 kg/m(3), 1100 kg/m(3), and 1500 kg/m(3), respectively at day56. For bending strength, the inclusion of coir fibre in 700 kg/m(3) density FC increased the bending strength by 116%, but when using the mesocarp fibre as an addition in FC, the bending strength was boosted by up to 144% compared to the control FC at day-180. This trend of improvement was also similar for the FC samples of 1100 kg/m(3) and 1500 kg/m(3) densities. Additionally, an increase of 133% in the tensile strength was also attained for the FC specimens with a density of 1500 kg/m3 as only a small amount of foam was needed to achieve this preferred density compared to densities of 700 kg/m(3) and 1100 kg/m(3). These natural fibres acted as fillers to bridge the gaps and micro-cracks within the FC, resulting in improved mechanical properties. The inclusion of coir, mesocarp and jute fibre facilitated in prevention of the propagation of cracks in the cement matrix in its plastic state.