Development and Validation of an Experimental Method for the Thermophysical Characterization of Thermal Conductivity in Porous Building Materials: Application to Stone in the Context of Sustainable Construction

The thermophysical characterization of construction materials is a fundamental area of research in building physics and energy efficiency. Over the years, various experimental techniques have been developed to determine key thermal properties such as thermal conductivity, diffusivity, and heat capacity. While these methods have provided valuable results, their accuracy and applicability remain limited in many cases due to uncertainties in the input parameters and assumptions regarding material homogeneity and saturation levels. These limitations often require researchers to implement additional experimental protocols to refine the measurements and adapt them to real-world conditions. This paper proposes a new experimental method that builds on two well-established techniques: the "hot wire" method and the "guarded hot probe" method. The proposed technique is specifically designed for the characterization of unsaturated porous construction materials, which pose particular challenges due to their complex structure and moisture content. It enables the reliable measurement of apparent thermal conductivity under variable saturation conditions and offers greater adaptability in laboratory and field settings. Experimental thermal tests were performed on a typical construction material to validate the method. The results show that the new technique improves the precision of thermophysical parameter estimation and provides a more accurate reflection of material behaviour under realistic conditions. This approach contributes to the on-going development of energy-efficient construction practices by supporting the selection and optimization of materials based on scientifically validated thermal performance criteria.