Lightweight gypsum composites: Design strategies for multi-functionality

Two technological solutions for the preparation of lightweight gypsum composites are analyzed involving low-density foamed gypsum matrix with higher-density aggregates and higher-density matrix with low-density aggregates. In the design process, lightweight gypsum composites are considered as multi-functional materials which are supposed to have both load bearing function and thermal insulation capability. The design strategy with higher-density matrix and low-density aggregates appears to be more successful. The most favorable material resulting from this strategy contains expanded perlite in the amount of 5% of mass of gypsum. It has a bulk density of 547 kg m−3, thermal conductivity of 0.12 W m−1 K−1 and compressive strength of 2.0 MPa. On the other hand, the designed composites with low-density foamed gypsum matrix and higher-density aggregates are found to have good thermal insulation properties but insufficient compressive strength. Nevertheless, this strategy is potentially viable if mechanical properties of the basic foamed-gypsum paste are improved, for instance by a moderate increase of bulk density.