Determining the Properties of Unfired Stabilized Kaolinitic Clay Brick for Sustainable Construction

Abstract

Kaolin is one of the most vital industrial minerals whose application is reliant on its chemistry and structural makeup. This research attempts to determine the properties of unfired kaolinitic clay bricks for sustainable construction. Samples of the material were pre-treated and analyzed to obtain their physical and refractory properties, such as chemical composition, microstructure, moisture content, dry density, linear shrinkage, plastic index, and crushing strength. The results revealed that the clay comprises high percentages of silicon and alumina oxides being 75.6% and 17.0% of the total oxide composition respectively. The clay also contained some residual impurities in the form of metallic oxides i.e., oxides of iron, sodium, calcium, potassium, manganese, and lead. Characterization tests on the clay presented a specific gravity of 2.66, liquid limit of 38, plastic limit of 25.9, and plasticity index of 12.1 which classifies the clay as low-plasticity clay based on the Unified Soil Classification System. The river sand used was distributed between 0.06 – 3 mm falling within the category of medium and fine sand. The aggregate fineness modulus was obtained as 3.03%. The coefficient of uniformity was lower than 4.0 and thus classified as being uniformly graded. Stabilization of the clay with sand and lime resulted in decreased compression and flexural strength but increased durability. The results imply that kaolinitic clay can be used in an unfired form for earth construction.