Abstract:
In Rwanda, the traditional fired solid bricks embody high consumption of fuel and quantity of clay during their moulding. The traditional solid bricks are also heavy compared to perforated bricks. This study aimed at investigating the performance of perforated clay bricks made of clay soil (CS) mixed with charcoal waste (CW) as an additive. The physical, chemical and mechanical properties of CS mixed with 0, 10, 30, 40 and 50% of CW were determined at JKUAT laboratories. The bricks were extruded manually with inclusion of varied number of perforations: 0, 4, 8, 12 and 15 number perforations which correspond to the percentages of perforations 0%, 6.15%, 12.3%, 18.45%, and 23.06%, respectively. The chemical analysis included determination of organic carbon, exchangeable acidity and chemical components by X-ray diffractometer of soil matrix. The chemical analysis depicted an increase in calcium oxide proportions with increase of charcoal waste content. There was also an increase in amounts of exchangeable cations. The research found that with increase in perforations, there is reduced loss of weight. However, non-perforated bricks depicted least abrasion resistance followed by bricks with 4 perforations. As the CW content increased from 0 to 50%, bricks with 15 and 12 perforations displayed highest abrasion resistance. The research concludes that increase of charcoal waste led to increase in linear shrinkage of clay soil bricks due to the increase of calcium cation and reduction of magnesium cations in the soil. With an optimum of 30% of charcoal waste identified for linear shrinkage of clay soil bricks. Bricks having 12 perforations and below with 30% charcoal waste additive can be categorized as category I (load bearing) bricks.
