Assessing structural performance of concrete blocks using sawdust as partial replacement for fine aggreagates
Charles, Alfred Okello
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Assessing the structural performance of concrete blocks using sawdust as partial replacement of fine aggregates was evaluated. The parameter adopted comprised analysis of the compressive strength according to the treatment applied to sawdust residue of the species Ginkgo trees. Blocks were composed by replacing fine aggregates by sawdust at 0,5,10,15 and 20% weight. Before mixing the wood residues to the concrete, sawdust underwent treatment so that wood residues could be compatible with the cement matrix. One treatment process was investigated. Treatment comprised the immersion of the residue in aluminum sulfate. Analysis was undertaken from compressive strength assays of the blocks on the 7th and 28th day. Results showed good performance in the aluminum sulfate-based treatment. The split tensile strength, compressive strength, masonry wallet compressive strength, density, water absorption and slump were evaluated. Where water absorption rate was found to increase with increase in sawdust content, dry density reduces with increase in sawdust quantity, compressive strength on blocks was found to be 5.3MPa at 10% with decrease in density with over 15%, where the compressive strength is greater than the minimum regulatory requirement of 3.6MPa for masonry unit and masonry wallets of 2.6MPa at 10% which can be classified as class 2 masonry unit according to BS5628. There was deduction in the general cost of producing concrete blocks using sawdust by 10%. And environmentally friendly as less energy is required during production as well as less CO2 released into the atmosphere during extraction and production of concrete blocks using plants.