ABSTRACT ANALYSIS OF STABILIZED ADOBE IN RURAL EAST AFRICA Grace Ying Yu Chen This project seeks to assist people in rural East Africa by proposing sustainable building methods which implement affordable and durable adobe bricks for construction. Adobe, one of the oldest sustainable building materials in the world, is strong when dry but lacks structural integrity when exposed to moisture. Chemical additives such as cement and lime are added into the adobe mix to protect the brick against moisture decomposition. Once the chemicals are added and the mix is formed into a brick, a stabilized adobe brick is formed. Cement, a stabilizer, is locally available in East Africa, but is generally unaffordable for families in rural areas. Lime is also locally available and costs about half the price of cement. This project investigates reducing the amount of cement to produce an economical and stabilized brick. The tested brick mixes, measured by volume, were • 10% cement • 5% cement • 5% cement+5% lime • 7% lime with sand • 7% lime with clay only • 10% lime with sand After testing these bricks by water jet, submersion, modulus of rupture, and compression, the 5% cement+5% lime mix and the 7% lime with clay mix proved to be viable options for economical and durable bricks. The second half of this project contains summaries of research related to stabilized adobe and other soil building methods. A literature search shows that lime mixed with soil containing small particles rich in calcium carbonate and quartz produces proper cementation in the mix called carbonation.

La presente investigación estudia el comportamiento de la resistencia a las inundaciones, de periodo corto y periodo largo, de los ladrillos de adobe convencionales y estabilizados, sustituyendo paja por virutas de Eucalipto en proporciones de 25%, 50% y 75%. La fabricación de los ladrillos se realizó con el procedimiento que utilizan los pobladores del distrito de Coracora, el cual representa a un pueblo típico de la sierra del Peru. Los resultados obtenidos para los ensayos de inmersión de una hora fueron en su totalidad moderados, mientras que los resultados obtenidos para los ensayos de inmersión de veinticuatro horas fueron en su totalidad severos. Con ello se concluye que los ladrillos estabilizados con sustitución de paja por virutas de Eucalipto resisten con dificultad a inundaciones con periodo corto. Sin embargo, la resistencia a las inundaciones de periodo largo es nula. Por lo cual, se recomienda que, para obtener una óptima resistencia a las inundaciones, se incorporen al procedimiento de fabricación estabilizantes impermeables. / The present investigation, studies the behavior of the resistance to floods of short and long period, of the conventional and stabilized adobe bricks, substituting straw for Eucalyptus shavings in proportions of 25%, 50% and 75%. The bricks were made applying the procedure used by the residents of the Coracora district, which represents a typical town in the Peruvian highlands. The results obtained for the one-hour immersion tests were entirely moderate, while the results obtained for the twenty-four-hour immersion tests were entirely severe. With this it is concluded that the stabilized bricks with substitution of straw by Eucalyptus shavings resist with difficulty to floods with a short period. However, resistance to long-period flooding is nil. Therefore, it is recommended that, in order to obtain optimum resistance to flooding, waterproof stabilizers are incorporated into the manufacturing process. / Trabajo de investigaciòn