Recycling of porcelain stoneware scraps in alkali bonded ceramic composites

Ground porcelain stoneware scraps were recycled as partially reactive filler in alkali bonded ceramic composites. 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 alkaline KOH/K2SiO3 aqueous solution. The setting was performed at 80°C for 24 h. The thermal conductivity of the panels at room temperature was 0.7 Wom-1oK-1. Investigations on the extent of capillary water absorption and water release indicated the possibility to exploit the water retention properties of the binder for cooling by water evaporation.