Sustainable management of autoclaved aerated concrete wastes in gypsum composites

Promoting the use of gypsum and gypsum-based materials in construction is a successful strategy from an environmental point of view; it allows a lower energy demand with a sensible reduction in carbon dioxide emissions. At the same time, the manufacturing of gypsum products can represent an interesting sector to redirect and manage the large amount of autoclaved aerated concrete (AAC) waste. In this paper a sustainable application of AAC granulate waste in gypsum-based building materials was proposed. The intrinsic compatibility derived their chemical composition and allowed it to partially substitute raw gypsum with the waste up to 30% without affecting the functional and structural properties of the final product. Physical characterization and sound absorption data confirmed that the addition of AAC waste does not significantly alter the typical porosity of the gypsum composite. Finally, all of the composites reached mechanical performances suitable for different building application as gypsum plaster.