Study of mixtures using simplex design for the addition of chamotte in clay bricks

Abstract The red clay ceramic industry is associated with several environmental damages, from the extraction of natural resources as raw materials to the generation of high amounts of waste. This study proposed the incorporation of the ceramic bricks waste (chamotte) in ceramic mixtures for the production of clay bricks. In order to define the greater content of chamotte, which can be added maintaining the technical qualities required for the product, the experimental design of mixtures was used, with the production of bricks containing the chamotte and two other clayey materials. The compositions were subjected to firing at 850, 950, and 1050°C. The properties of firing linear shrinkage, apparent specific mass, water absorption, apparent porosity, and axial compressive strength were evaluated. It was observed that chamotte (C) contributed to the improvement of some of these properties, such as linear shrinkage. Overlapping the response surfaces obtained in the statistical analysis, the optimal chamotte (C) content was determined for each firing temperature. It was concluded that the incorporation of up to 30% chamotte (C) is technically feasible considering the evaluated temperature range. In this way, there is a product that adds both sustainability and technical performance to the ceramic industry.