Determination of thermal properties in the frequency domain based on a non-integer model: Application to a sample of concrete

A technique for determining thermophysical properties is proposed and applied to a sample of concrete by taking advantage of pseudo-random signals. Data are treated in the frequency domain. A new approach is developed for estimating the thermal impedance based on the formalism of non-integer order models. An experimental setup consisting of a heat flux and temperature sensor arranged in contact with a material assuming a semi-infinite boundary condition is studied. The theoretical expression for such a thermal impedance takes into account the thermal capacity of the sensor and the contact resistance and emphasizes fractional orders in the behavior model.