Effect of addition of sawdust ash to clay bricks

This article presents a preliminary assessment of the effect of adding sawdust ash (SDA) to clay for the purpose of making bricks. Bricks are made with SDA, fired to temperatures of 200 degrees C, 600 degrees C and 1200 degrees C and cured for 1, 4 and 8 days, respectively. The purpose of curing is to allow the limestone (CaCO3) converted to quick lime during firing to hydrate without expansion in the volume of the bricks. Measurements taken on the comprehensive strength, water absorption and linear shrinkage show that the compressive strength of the bricks decreased as SDA was increased and maximum compressive strength was achieved at a firing temperature of 600 degrees C, curing for 1 day and at 10% SDA replacement. The low value recorded for the compressive strength may be attributed to low content of Al2O3 and the mullite content. Water absorption also increased as the SDA was increased but the values obtained were within the code specification of Indian Standard IS: 1077. Addition of SDA reduced the effect of shrinkage.