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

Abstract

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.