Porcelain stoneware scraps recycling in alkali bonded insulating panels

Ground porcelain stoneware scraps were recycled as main component (up to 80 wt%) in alkali bonded insulating panels. Sandwich panels were prepared by varying the scraps dimension and amount in the core and skins. The alkali bonding was realized by using highly reactive metakaolin powder and alkali KOH/K2SiO3 aqueous solution. The setting was performed at 80°C for 24 h. The thermal conductivity of the panel at room temperature was 0.7 W/(m.K). Water capillary absorption and water release investigations indicated the possibility to exploit the water retention properties of the porous geopolymer for cooling by water evaporation.