This project was aimed at determining the effects of wood ash admixture on the engineering properties of burnt clay bricks. Sieve analysis and Atterberg’s limits tests were carried out to classify the clay soil used. These tests indicated that it was poorly graded clay soil of intermediate upper plasticity. The clay soil had a liquid limit of 45.1%, Plastic Limit of 13.4% and Plastic Index of 31.7 %. Bricks were made with partial replacement of clay using wood ash in percentages of 0%, 5%, 10%, 15% and 20%. These bricks were tested for water absorption, dry compressive strength, wet compressive strength and density. Density was observed to gradually decrease with increase in wood ash content. Maximum density was observed at 1833 kg/m3. A maximum dry compressive strength of 14.3 N/mm2 and maximum wet compressive strength of 9.7 N/mm2 were observed at 5% clay soil replacement with wood ash. The lowest water absorption of 14.78% and highest softening coefficient of 0.68 were also observed for bricks of 5% wood ash content. Bricks made with 5% wood ash content had the highest dry and wet compressive strength, lowest water absorption, highest softening coefficient and were less dense than the control (normal) bricks. We recommend that these bricks be adopted for use in the construction industry since they have improved engineering properties as compared to the normal bricks. Using these bricks can help reduce damages that occur due to breakages during transportation, handling and construction.

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