Improving the Strength of Adobe Units Using Eragrostis Teff Straw Fiber for Sustainable Construction, Wolaita Sodo, Ethiopia

The traditional rural house construction technique in Ethiopia, especially in Wolaita Sodo uses a lot of wood from the forests. A lot of woods taken from the forests lead to deforestation and causes global warming. And also, the modern construction material and techniques have gained some popularity in the rural areas; however, because of the high cost of modern construction materials like cement, aggregates, reinforcement bar and bricks, etc. many can’t afford it. To mitigate the risk of deforestation along with using a sustainable approach for building rural houses, Adobe houses perhaps can be the best-suited solution. Eragrostis teff straw is an agro-waste and abundantly available in Ethiopia has been considered to be used as fibers in the current research. The main objective of this research is providing a sustainable method of building rural adobe houses in the WolaitaSodo, Ethiopia, by utilizing the locally available fibers and binders for a better strength with a reduced cost of construction. So that, an attempt has been made to use a suitable binder of optimum quantity and locally available natural fibers of Eragrostis teff in different percentages to prepare various mixes of adobe units and test their strength properties. A total of 144 cubical adobe unit samples was prepared and tested according to different code of standards. The experimental tests conducted for clay soils are grain size analysis, Atterberg limit, natural moisture content, specific gravity and compaction tests, for Eragrostis teff straw fiber specific gravity, natural moisture content and water absorption for different hours, and strength (compressive and water strength) tests. Experimental investigations were carried out by using Eragrostis teff straw fiber reinforced and cement stabilized adobe unit specimens with a fiber proportion of 0.5%, 1%, 1.5%, 2% by weight and 3.5% cement by weight. Compressive strength tests were conducted after 14, 21 and 56 days of curing and drying periods. Water strength tests at different time rates of submersion were conducted after 28 days of curing and drying periods. The test results show that, both compressive strength and water strength were improved when adobe units reinforced with Eragrostis teff straw and stabilized with cement. The adobe unit specimens prepared using clay soil, 3.5% cement, and 1.5% Eragrostis teff straw is suggested for load-bearing walls. Improvement in adobe units promote acceptance of adobe units as a building material in Wolaita Sodo and reduce the use of woods in rural house construction which leads to deforestation.