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This study reports the fabrication of novel glass-ceramic foams for thermal insulation to minimize the energy consumption in the buildings. Different combinations of zeolite-poor rock/eggshell powders (with eggshell content varying from 0 to 20 wt%) have been used to produce the foams through alkali-activation and reactive sintering techniques. The produced glass-ceramic foams were characterized based on their structural, thermal, and mechanical characteristics. The heat treatment process and the foaming patterns are examined by a heating microscope, and the findings reveal an excellent foamability of the utilized alkali-activated mixture in the range of 800–950 °C. The microstructure and the pore size of the acquired foams are investigated using a scanning electron microscope (SEM) and computed tomography (CT) analysis. The crystallinity and phase composition of the prepared samples were investigated via X-ray diffraction (XRD). The experiment findings reveal that raising the eggshell content is favorable to gas production, but it affects the liquid phase creation resulting in inconsistent pore size distribution. The appropriate eggshell content is 4%, and the optimal heat treatment temperature is 900 °C. The produced ceramic foams possess a density ranging from 0.54 to 1 g/cm3, thermal conductivity around 0.07–0.4 W/mK, and compressive strength values between 1.2 and 6.7 MPa. The results indicate that the ceramic foams created could be a feasible choice for applications in constriction as thermal insulation materials. [ABSTRACT FROM AUTHOR]

• Zeolite-poor rock incorporated sawdust was used as an alternative for clay. • The addition of sawdust creates lightweight bricks with enhanced thermal insulation. • The water absorption and porosity increase with increasing sawdust addition. • The optimum quantity of sawdust in the bricks should be less than 10% by weight. • The produced samples have a good potential for practical application. The production of innovative building bricks from new materials has drawn a huge interest lately, targeting sustainability-related problems. This research investigates the utilization of zeolite-poor rock and sawdust as an alternative for clay to produce new and eco-friendly bricks. Ceramic specimens were prepared using uniaxial dry pressing and firing at a temperature range of (950–1250 °C) for three hours. Sawdust was added as a partial replacement of zeolite-poor rock in the specimens. The replacement percentages were 0%, 2%, 4%, 6%, 8% and 10% by mass of zeolite-poor rock. The raw materials were characterized based on their chemical composition, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), X-ray fluorescence (XRF), thermogravimetric (TG), differential thermal analysis (DTA), BET (Brunauer, Emmett and Teller) and particle size distribution. The topographical features, microstructure, phase identification and the characteristic of the produced ceramic bricks were investigated using different characterization techniques such as SEM, EDS and XRD. Moreover, the technical properties (e.g., bulk density, open porosity, volume shrinkage, water absorption, compressive strength and thermal conductivity) of the specimens were also investigated and compared to the control samples' results. The results confirmed that the inclusion of 8% sawdust to zeolite-poor rock minimizes the bulk density of the specimens down to 1.45 from 1.6 g/cm3. It has been noted that their porosity increased up to 37.37 from 31%. In contrast, their compressive strengths declined from 14.5 to 6.7 MPa. However, their strengths were greater than those desired by the standards. The thermal conductivity of the samples contains 8% sawdust reduced from 0.37 to 0.14 W/mK, which corresponds to a decrease of 37% compared to the blank. The mechanical and physical characteristics of bricks were also influenced by the sintering temperature. This research confirms the potential use of zeolite-poor rock together with sawdust as environmentally-friendly building materials. [ABSTRACT FROM AUTHOR]