Effect of different heating rate on properties of fired brick produced from industrial waste and natural clay

Abstract

Gypsum waste is generated from the wastewater treatment plant activities from chemical industry. The environmental issues and secured landfill costs caused by this waste increasing every year. Therefore, this study is an attempted to reuse gypsum waste as a substitution material for natural clay in fired brick production. This study consisted of two stages where in the first stage, fired brick were produced from natural clay and gypsum waste with substitution of clay with 5%, 10%, 15% and 20% gypsum waste. The second stage was the investigation of the experimental when the brick samples were fired at different heating rates (1 °C/min, 2 °C/min and 3 °C/min). Next, the shrinkage, dry density, water absorption and compressive strength for each sample were examined and were compared to the control brick. Based on the results, the shrinkage and water absorption increased with the addition of gypsum waste in brick samples. In contrast, the density and compressive strength values were decreased in the brick samples containing gypsum waste. The mechanical properties met the conditions prescribed in the specified standards for all the samples and the optimization result showed that up to 10% of gypsum waste incorporation into fired brick (fired at 1°C/min heating rate) had a sufficient compressive strength over 20 MPa. The reclamation of gypsum waste was proved for the fired brick production insights reducing the environmental pollution. Gypsum waste can be used as a natural clay substitution whilst fulfilling the demand for fired brick requisition.