English

Abstract

In Rwanda, the traditional fired solid bricks embody high fuel consumption and quantity of clay during their molding. 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. The bricks were extruded manually with the inclusion of a varied number of perforations: 4, 8, 12 and 15 number perforations. The chemical analysis included the determination of organic carbon, exchangeable acidity and chemical components (through XRD) in the soil matrix. The chemical analysis depicted an increase in CaO proportions with an increase in charcoal waste content. There was also an increase in the amounts of exchangeable cations. The research found that with an increase in perforations, weight loss is reduced. However, non-perforated bricks depicted the 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 the highest abrasion resistance. The research concludes that an increase in charcoal waste led to an increase in the linear shrinkage of clay soil bricks due to increased calcium cations and reduced magnesium cations in the soil. An optimum of 30% of charcoal waste was identified for the 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.