The development of an affordable Kgalagadi Sand building block (KSBB)—a position paper
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About ¾ of Botswana is covered by Kgalagadi Sands (KS). KS are invariably closely graded, consist of medium to fine sub-rounded particles and contain insignificant amounts of silty and clayey fractions. As a result of these physical and chemical properties, KS lack packing and therefore compactibility, have very high voids ratios and are cohesionless. Consequently, the wet and dry strengths (compressive, shear and flexural), dimensional stability, durability and aesthetics of building blocks moulded with KS alone, in the very rare cases where they occur with silts and clays of the right quantities and quality, are well below acceptable values.
This position paper describes the extensive experimental work currently underway at Botswana’s major multi-disciplinary Research and Development (R&D) Centre—Botswana Technology Centre. The work seeks to render this immensely abundant and widely available, but hitherto unusable resource, utilizable in construction. The affordability of the resultant KSBB shall derive from the local availability of KS as a raw material, usage of locally manufactured manually operated equipment and exploitation of local, largely unskilled labour force under supervision by semi-skilled artisans.
KeywordsOrdinary Portland Cement Pozzolanic Reaction Tricalcium Silicate Particle Size Distribution Curve Dicalcium Silicate
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