Hydrothermal zeolitization: Towards a paradigm shift for producing stronger and more sustainable construction materials

The construction sector provides 14.8 million jobs in the European Union. However, it also accounts for 36% of greenhouse gas emissions and 35% of total waste. High-temperature ceramic manufacturing consumes substantial energy, yielding basic structural products. The alternatives presented, such as geopolymers, still do not replace traditional materials and are not as sustainable as believed. This innovative study combines hydrothermal zeolitization with kaolin-based ceramics fired at both conventional (900°C) and much lower temperatures (600°C), exploring varied conditions, including the use of microplastic wastes as pore-forming agents. Significant zeolite crystallization (15–74%) and mechanical strength increase (2–37-fold compared to untreated materials) is demonstrated in granular specimens, especially when adding microplastics. Geopolymerization appears as a secondary process during treatment. This innovative method offers energy-efficient lower temperatures, transforming fired specimens into zeolite-enriched, robust materials, adaptable to current technology. This study paves the way for further research, opening up a new field of study on hydrothermally manufactured Zeolitic Construction Materials.