Pre-industrial production of recycled ceramic tiles using construction and demolition waste: Exploring their technological feasibility

Abstract

Annually, construction and demolition waste (CDW) represents one-third of the EU's waste generation. Due to its sheer volume and low-value applications, there is growing interest in its valorisation for new building products. One promising avenue is the incorporation of CDW in recycled ceramic tile production, though this remains largely unexplored at the pre-industrial level. This research examines the viability of pre-industrial-scale production of recycled ceramic tiles with a high content of CDW. CDW materials from a management plant, including ceramic waste (tiles) and mixed debris (construction ceramics and concrete), were processed to create compositions containing up to 10 wt% mixed debris. Virgin clay was added in different proportions, resulting in 55, 70, and 100 wt% CDW compositions. Results show that spray-dried characteristics allow tile production with up to 70 wt% recycled content. The compositions containing 70 and 55 wt% CDW were tested pre-industrially, fired at 1145–1155 °C. The 55 wt% CDW mixture achieves characteristics comparable to those of pre-industrial ceramic tiles, producing novel recycled products with high waste content. These tiles had a flexural strength of >41 N/mm², surpassing the market standard for porcelain stoneware (35 N/mm²), and water absorption of 12%, meeting wall tile specifications. An economic and environmental assessment highlights the benefits of using CDW in ceramic tiles, highlighting the potential for an environmentally responsible and resource-efficient approach within the tile industry, while minimising environmental impact and preserving natural resources.