The Impact of the Particle Size Distribution of Organic Additives on the Microstructure of a Clay Ceramic and Its Thermal and Mechanical Properties

In this study, the structure-property relationships of a clay ceramic with calibrated particles (10 or $50\mathrm{\mu m}$) of polymethyl methacrylate (PMMA) were investigated to improve both the thermal and mechanical properties of fired clay bricks incorporating organic wastes. The structure was characterized using differential thermal, thermomechanical, and computed tomography analysis. It was found that the addition of 10- or $50–\mathrm{\mu m}$ particles of PMMA resulted in a same 11% decrease of the thermal conductivity during the extrusion process. The Young’s modulus also increased by 23% during the extrusion process with the addition of $50–\mathrm{\mu m}$ particles. However, the addition of $10–\mathrm{\mu m}$ particles resulted in a greater increase of the Young’s modulus by 34%. The calibrated particles of PMMA were then found to transform into porosity during firing of the clay ceramic. Typically, the pore size of the clay ceramic corresponded to the particle size of the calibrated particles of PMMA. The improvement of the thermal and mechanical properties that was obtained during the extrusion process was conserved in the form of porosity with a reduction of the median pore size after the firing process. Hence, the current results indicate that the thermal and mechanical properties of fired clay bricks can be improved at the same time using a wide range of organic wastes if the organic wastes are subjected to grinding prior to incorporation in the mixture. They also suggest that organic wastes can reduce the environmental impact of fired clay bricks with an energetic contribution of 73.8%.