Evaluation of Rice Husks Stabilized Burnt and Unburnt Blocks: Affordable Housing

Low-income families in developing countries including Tanzania experience challenges on owning better houses appropriately constructed from locally available materials. Houses are either of low standard or low-quality materials. This project examined the use of rice husks, as agricultural wastes substance, in burnt and unburnt blocks commonly used for house construction in Mbeya, Tanzania. Blocks were cast by mixing the natural soil with water and 0, 1, 2, 3 or 4 percent rice husks. The cast blocks were air/sun-dried then half of them burnt. Tests performed on the blocks include compressive strength, flexural strength, relative density and water absorption. Although it constitutes further study, the efflorescence test were not available when writing this paper. Findings indicated that much as burnt blocks without rice husks have higher compressive strength compared to unburnt blocks, their water absorption is almost three times of the unburnt blocks. Therefore, unburnt blocks could have more potential to resist efflorescence than burnt blocks due to its low water absorption. Results also indicates that rice husks slightly increase the compressive strength of unburnt blocks but are not beneficial on burnt blocks.