An engineered alternative brick masonry unit for the poor inhabitants at Hawassa village, Ethiopia

The southern rural regions of Hawassa village, Ethiopia customarily practices Chika-pet and adobe masonry houses. They use soil, wood and teff straw adobe bricks in house construction, due to its extreme poverty and unsophisticated manner of living. These houses are unsustainable and flimsy due to its inclusion of easily degradable raw materials, non-engineered construction practice, poor earthquake resistance and rapid climatic uncertainties. Moreover, the soil utilized for the adobe brick making is consumed from far away distant regions by ignoring their native Hawassa soil due to its unsuitable brick making characteristics. This impacts the economical expenditure of the poor income inhabitants. Therefore, this research is intended to facilitate the Hawassa village inhabitants by improving their native soil characteristics on adding lime and considers it for brick unit formation. In addition, an alternative reinforcement called pineapple leaf fibre is introduced for the adobe brick making which enriches compressive and tensile strength at a satisfactory rate according to the California Building Standard Code (CBC) requirement. The maximum compressive strength is recorded as 4.1 MPa which is 6 times greater than the conventional specimens and flexural strength is recorded at an improved rate of 0.78 Mpa. It ensures the standard requirement according to the CBC code. As a result, a sustained residual tensile load is recorded which indicates an efficient improvement in the ductility failure of brick. The bending test data is processed to estimate young's modulus in tension highlighting the bi-modularity of the earthen composite material. The experimental correlation between various mechanical properties is presented and modelling design equations are proposed in the engineered manner of design/assessment purposes. A comparative study and cost analysis of the existing and proposed approach is discussed to validate the superiority of the proposed concept.