Effect of Recycling Chicken Eggshell Waste as a Pore-Forming Mineral Source in Low-Water-Absorption Bi-Layered Red Ceramic Tiles

This work evaluated the effects of incorporating chicken eggshell waste in a low-water-absorption bi-layered red ceramic tile composition, focusing on its porosity. Red ceramic tile formulations were prepared with incorporations of 0, 5, 10, 15, 20 and 25 wt.% of chicken eggshell waste. The bi-layered red floor tile processing method consisted of dry powder granulation, double uniaxial pressing and firing at 1220 °C using a fast-firing cycle. The physical properties and microstructural development of the tile specimens were investigated. It was found that chicken eggshell waste exhibited good chemical compatibility for use in red ceramic tile formulations, enabling its recycling. The novel bi-layered red ceramic tiles presented water absorption between 0.34 and 0.97% and apparent density between 2.09 and 2.14 g/cm3. The results demonstrated that chicken eggshell waste, when incorporated up to 15 wt.%, can be used as an efficient pore-forming carbonate source to manufacture low-water-absorption bi-layered red ceramic tiles (BIa and BIb groups—ISO 13006), which allows use in ventilated façades. It was concluded that the proposed approach is suitable for recycling chicken eggshell waste into red ceramic tile formulations, with relevant repercussions for the circular economy.