Thermal diffusivity measurements of building materials based on 2D models

This paper presents the results and experimental procedure used for obtaining the thermal diffusivity of building materials like cement, sand, expanded polystyrene, silicone and concrete. The determination of this important physical property is based on the solution of the 2D cartesian and cylindrical Fourier equation adapted to high surface conductances. Material samples are shaped as rectangular prisms or cylinders to accomplish these simple geometries. The measurement technique is based on the sample thermal response when it is suddenly submitted to baths of constant temperature. The uncertainty associated with this method is systematically estimated in both cases. Thermal diffusivity is obtained with a precision of about 6% using a simple proving bench. Such precision is good enough taking into account the typical low values of this property for such kind of materials and their strong dependence with temperature.