Variation In The Strength Properties Of Cement Mortar Made With Sawdust

Abstract

The behavior of building blocks with the partial replacement of fine aggregates by sawdust is evaluated. The parameter adopted comprised analysis of the compressive strength according to the treatment applied to sawdust residue. Blocks were composed by replacing fine aggregates by sawdust at 5% weight. Before mixing the wood residues to the concrete, the former underwent treatment so that wood residues could be compatible with the cement matrix. Two treatment processes were investigated. The first treatment comprised the washing of residues in an alkaline solution (lime) at a 5% proportion (weight / weight). The second 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 low efficiency in the alkaline-based treatment (lime) and good performance in the aluminum sulfate-based treatment. The production of masonry blocks with a replacement of 5% fine aggregates for this type of treatment and species studied is possible. This paper reports on experimental investigations on the effect of replacing sand with sawdust on the properties of concrete. A concrete mix of 1:2:4 was used as control while sawdust was used to replace 25%, 50%, 75% and 100% of sand by volume. The percentage reduction in density is 5.96%, 12.44%,13.56% and 17.93% respectively while the corresponding percentage reduction in compressive strength were 57.5%, 68.1%, 83.7%, and 87.3% respectively[1]. The results of the study indicate that both the density and compressive strength of concrete decreased as the percentage replacement increased but replacement of sand by sawdust produced a higher percentage reduction in compressive strength than in density. Sawdust can potentially be used as aggregate in the production of both non-structural lightweight concrete and structural concrete. However, further research should be conducted to establish its suitability as aggregate in concrete [1