Alternatives for improving the compressive strength of clay-based bricks

In this work three alternatives to improve the compressive strength of clay-based bricks were evaluated. Four mixtures were prepared: The control with only CLAY (without any treatment), one single mixture with the ground and screened clay (CLAYGS), one binary mixture in which CLAYGS was partially replaced by fly ash (FA) and one ternary mixture in which CLAYGS was partially replaced by FA plus Sugar Cane Bagasse Ash (SCBA). Apparent densities and porosities (ASTM C-20), initial rates of absorption (ASTM C-67) and compressive strengths (ASTM C-67) were determined. The results showed that the use of CLAYGS has positive effects on the density, porosity and compressive strength of bricks made with this material. Bricks made with CLAYGS were 23.08% denser, 20% less porous and 64.41% more resistant to compression than control bricks. According to the ASTM C-62 standard, the bricks obtained correspond to the MW grade. The partial replacement of CLAYGS with 20% FA improves the quality of bricks made only with CLAYGS and with CLAY. According to the ASTM C 62 standard, the bricks made with binary mixture (CLAYGS+FA) have the compressive strength required to be considered SW grade bricks. The addition of SCBA in binary bricks negatively affects their compressive strength.