Lengths and Content Variation of Oil Palm Broom Fibre (OPBF) and Lime on the Physico-mechanical Properties of Compressed Earth Blocks

Abstract

The use of oil palm broom fibre (OPBF) which is usually burnt as waste contributes to carbon dioxide (CO2) emission in the atmosphere, as a sustainable reinforced construction material will provide both cost and environmental benefits. Combining OPBF and lime in compressed earth blocks as a construction material will further provide technical benefits in improving the mechanical properties of the blocks. This study investigates the physico-mechanical properties of compressed earth blocks stabilised with varying lengths and contents of OPBF and lime for housing provision. Laterite, 10% constant lime, and OPBF of 10, 20, and 30mm lengths, and 0.25, 0.5, and 0.75% by weight of laterite were used for preparing the blocks. The properties of the blocks were assessed between 7 and 28 days of curing. Compressive strength test, tensile strength test, water absorption test, and scanned electron microscopy (SEM) analysis were conducted on the OPBF and lime-stabilised compressed earth blocks. The 10mm and 0.5% OPBF and lime-stabilised compressed earth blocks achieved the lowest water absorption of 3.04% as compared to the highest water absorption of 9.78% recorded by the unstabilised blocks. The 20mm length with 0.5% content of OPBF achieved the optimum compressive strength of 6.641N/mm2 as compared to the ustabilised specimens of 5.976N/mm2, representing about 10% compressive strength increase. For the tensile strength, the 20mm length with 0.5% OPBF content specimens achieved the highest strength of 0.423N/mm2 as compared to the ustabilised specimens of 0.326N/mm2, representing about 23% increase in the tensile strength. The microstructural analysis of the specimen revealed micro-gaps at the periphery of the OPBF, and micro-cracks within the composite material. The study, therefore concludes that appropriate length and content of OPBF and lime enhance the physico-mechanical properties of compressed earth blocks. It is, therefore, recommended that 20mm length with 0.5% OPBF content should be used by practitioners to enhance the physico-mechanical properties of compressed earth blocks for use to provide housing accommodation.