Development of glass-ceramic foams from natural zeolite and silica fume: Advancing low-carbon thermal insulation materials for sustainable construction

High-performance sustainable thermal insulation materials play a significant role in the development of energy efficiency and net-zero building technologies. In this study, a new energy efficiency building material is proposed for sustainable constructions. Novel light weight glass-ceramic foams were designed and developed using natural zeolite, silica fume, and carbon soot. Prior to sintering, the materials used were subjected to mechanical activation to improve the reactivity and facilitate the formation of glass-ceramic foams. The properties of the fabricated materials were identified by using X-ray diffraction analysis (XRD), scanning electron microscopy coupled with energy dispersive spectroscopy analysis (SEM-EDS), and Fourier transform infrared spectroscopy (FTIR). The analysis reveals that soot content and sintering temperatures strongly influence foam expansion, morphology, physical and technical characteristics. Optimized compositions (ZSS₄–ZSS₆) sintered at 870 °C exhibited uniform cellular structures, low bulk density (0.24–0.25 g/cm³), and low thermal conductivity (0.061–0.068 W/m·K). XRD analysis revealed the presence of thermally stable crystalline phases including α-cristobalite and albite embedded within a glass matrix. SEM analysis also confirmed the presence of homogeneous and finely distributed pore structure, predominantly composed of small and closed cells, which is beneficial for suppressing heat transfer and enhancing thermal insulation performance. Along with reduced density and good compressive strength, the excellent insulation performance of the foams highlights their potential as sustainable wall insulation materials. Moreover, the integration of natural minerals and industrial by-products also helps to reduce embodied carbon, making the developed materials good candidates for sustainable energy-efficient construction applications.