Assessing the structural potential of cement stabilized rammed earth walls as an alternative to burnt clay brick walls for low-cost housing construction in Uganda.

Abstract

Uganda, as a developing country in Africa is suffering from an enormous housing deficit that currently stands at about 2.4 million units per year, with a projection of up to about 3 million units by 2022(UN-HABITAT, 2017) .These numbers reflect the rapid population growth, being the fourth highest in the world (World Bank, 2018). In addition, the costs for conventional construction methods are very high owing to the fluctuations in the prices of clay bricks and cement. This has made it significantly difficult for the 34% of Uganda’s population who are living below the poverty line as of 2013(World Bank, 2016) to build a decent residential house. Earth as the main walling material is an abundant resource, which is not the same for the Burnt Clay Bricks. While the prices of Burnt Clay Bricks on the market is affected by the demand from the construction industry, earth remains a free resource readily accessed by everyone regardless of their income levels. This opens up opportunities of using earth as a walling material to help every Ugandan achieve their dream of building a house. This however is met with concerns such as the load bearing capacity of earth walls, which has been considered to be low. Therefore, this research comparatively analyses the compressive strength and durability of small sized Burnt Clay Brick and CSRE wall panels at 21 days. The Rammed Earth wall panels were built with two soils sourced around Makerere University stabilized with Tororo Portland Pozzolana cement across percentages of 6%, 8% and 10%. The BCB panels were built with bricks sampled from a brick laying site in Mpererwe, a residential area in Uganda. In addition, a comparative cost study of both walls is carried out to determine any cost savings available when each of the walling materials is used for a typical two-bedroom house model in Uganda.