Study of the design process and thermomechanical properties of a low carbon porous fired clay-cork composite for building insulation

This study develops and evaluates a fired clay–cork composite with improved thermal insulation for sustainable construction. The composite is fabricated by incorporating cork particles into clay and firing at 780 °C, generating a porous structure from cork combustion. Thermal conductivity, diffusivity, and effusivity are measured using flash and asymmetrical hot plate methods and compared to theoretical models. Mechanical performance is assessed through compressive and flexural strength tests. Results show that increasing cork content (2–10 % by mass) significantly enhances porosity (16–59 %) and reduces bulk density (1261–620 kg/m³), with thermal conductivity decreasing from 0.356 to 0.130 W/m·K. However, mechanical strength drops with higher porosity, ranging from 5.64 MPa to 0.09 MPa in compression. The Schiller and Hasselman models best describe the strength–porosity behavior. Thermal simulations demonstrate energy and environmental savings up to 37 %, with a cork content of 3.68 % identified as the structural threshold for 4 MPa compressive strength. These findings support the development of low-carbon, thermally efficient building materials using cork, an industrial by-product, and contribute to sustainable construction solutions.