Microstructure and physico-mechanical properties of Al2O3-doped sustainable glass-ceramic foams

Glass-ceramics foams (GCs foams) were manufactured with the aid of the replica method and from cheap and sustainable raw materials (waste glass bottle, bentonite, and alumina). In order to evaluate the Al2O3 effect on the microstructure and physico-chemical properties of the GCs foams, the precursor aqueous solutions were prepared with different contents of the waste glass bottles (30 wt% and 35 wt%), alumina (0 wt%, 2 wt%, 5 wt%, and 8 wt%), and sintered at temperatures 750 degrees C and 800 degrees C. The amorphous/crystalline nature of the GCs foams was investigated by XRD, and the calcium sodium silicate (Na2Ca3Si6O16), cristobalite, and corundum were the main crystalline phases identified. In general, the addition of alumina increased porosity and water absorption with a consequent reduction in flexural strength. The manufactured glass-ceramic foams showed average pore sizes in the range of 240-360 mu m, porosity between 52% and 85%, and flexural strength between 0.2 MPa and 3.7 MPa.