Effect of rice husk ash on the properties of bricks made from fired lateritic soil-clay mix

The effects of rice husk ash (RHA) on the various properties of lateritic soil-clay mixed bricks were studied. The effect of firing duration (at a firing temperature of 1000°C) on the properties of bricks was also studied. The measured properties were linear shrinkage, unit weight, compressive strength, 24-hour immersion water absorption and 5-hour boiling water absorption. Both linear shrinkage and unit weight of bricks decreased with increase in the percentage of RHA content. The compressive strength of lateritic soil-clay mixed bricks increased almost linearly with increase in the percentage content of RHA. The bricks which received a 4-hour at 1000°C attained maximum compressive strength. Both 24-hour immersion and 5-hour boiling water absorptions of the bricks were within the permissible limits. The strengths of the bricks were compared with British statutory minimum compressive strengths of bricks for various walls. The bricks are recommended or load-bearing walls.