PERFORMANCE-BASED EVALUATION OF CASSAVA STARCH AND MAKUBA MATRIX FOR THE STABILISATION OF COMPRESSED EARTH BRICKS

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Author

Presented To

Department of Environmental Design

ABSTRACT
Although the major material(soil) for the production of Adobe or earth bricks isreadily available and affordable which,could provide a lasting solution to the need for affordable housing,it is not without some inherent problems.The problems associated with soil has led to drawback in the use of earth as a building material. These are lack of durability and need for frequent maintenance. Stabilising the earth with certain materials such as cement has helped a little however, many of these materials like lime and chemical stabilisers are limited in quantity some of them hazardous.Cementproduction highlycontributes to carbon dioxide emission, (a global concern) and it is majorly unaffordable to the common man. Cassava starch and makuba (CSM), are both applied for soil stabilisation in traditional building construction but no record of their usage exist in conventional construction. This Thesisexploresways to improve the strength and durability properties of Earth Bricks by utilising these locally available and affordable materials, CSM,to stabilise laterite soil. The work examined different techniques for soil stabilisation with CSM and various curing methods. Brick specimens with 0 to 20% content of CSM spaced at 5% intervalsas binder of laterite soil were produced. The specimens were subjected to tests of compressive strength, densification, abrasion resistance, moisture movements, elevated temperatures and a further confirmatory investigation in the form ofScanning Electron Microscopy. CSM Bricks (CSMBs) have shown improvements up to 64% in compressive strength beyond the minimum requirement of NBRRI and over 100% increased durability properties above un-stabilised laterite bricks. CSMBs could be utilised for application in building construction such as load bearing walls, partition walls, composite walls; parapets and for esthetic finishes as facing bricks since the surfaces of the bricks may not require finishing in the form of plastering, cladding or painting. This is due to the natural texture of laterite which is not altered by cassava starch paste but given additional red brownish tint by makuba.