ICETETM 25: a Review of Thermal Insulation Bricks From Kaolin and Aluminum Oxide for Sustainable Construction

Recent advancements in eco-friendly building materials have highlighted kaolin-Al₂O₃)composites for its thermally insulated bricks. Because of its low thermal conductivity (0.15–0.25 W/m·K), refractory characteristics, and natural obtainability, kaolin is ideal for producing eco-friendly bricks. Because of improved particle bonding, kaolin bricks with 10–30% Al₂O₃)reinforcement have a 30–50% increase in compressive strength. Nevertheless, high levels of Al₂O₃ (>30%) decrease workability and increase sintering costs . Sawdust and other organic additives can add 30–50% porosity, which lowers thermal conductivity to 0.18–0.30 W/m·K. However, when porosity surpasses 50%, mechanical strength below 5 MPa may be compromised . Inorganic additives such as perlite and vermiculite provide even better insulation (0.05–0.10 W/m·K), but their production costs increase by 20–25%. Energy comparisons have indicated that kaolin-AlO3 bricks have 30–50% less embodied energy and support superior thermal insulation performance when compared with burnt clay bricks.. Not with standing these benefits, significant obstacles still exist, such as durability and increased expenses, necessitating more study into hybrid composites and nano-Al₂O₃ integration .