As part of the valorization of local materials and the search for energy efficiency in the building sector, a thermophysical study was carried out on a new clay-based composite material from the Atlas region reinforced by peanut shells, which constitute an abundant ecological and untapped waste. In this study, a series of samples (100×100×26 mm3) of this composite are elaborated at different mass fractions of peanut shells. The thermal parameters are estimated by metrological methods such as the steady-state hot plane method and the flash method. The results showed, in addition to the lightness offered by peanut shells to these composites, that the thermal conductivity and thermal diffusivity vary respectively from values 0.623 W.m−1.K−1 and 4.8 m2.s−1 for raw clay to the values 0.323 W.m−1.K−1 and 3.5 m2.s−1 for the mass fraction of peanut shells to ϖ = 9%, which give this material the quality of the insulating walls.

Most of the energy savings in the building sector come from the choice of the materials used and their microphysical properties. In the present study, through numerical simulations a link is established between the thermal performance of composite materials and their microstructures. First, a two-phase 3D composite structure is modeled, then the RSA (Random Sequential Addition) algorithm and a finite element method (FE) are applied to evaluate the effective thermal conductivity of these composites in the steady-state. In particular, building composites based on gypsum and clay, consolidated with peanut shell additives and/or cork are considered. The numerically determined thermal conductivities are compared with values experimentally calculated using the typical tools of modern metrology, and with available analytical models. The calculated thermal conductivities of the clay-based materials are 0.453 and 0.301 W.m −1 .K −1 with peanut shells and cork, respectively. Those of the gypsum-based materials are 0.245 and 0.165 W.m −1 .K −1 with peanut shells and cork, respectively. It is shown that, in addition to its dependence on the volume fraction of inclusions, the effective thermal conductivity is also influenced by other parameters such as the shape of inclusions and their distribution. The relative deviations, on average, do not exceed 6.8%, which provides evidence for the reliability of the used approach for random heterogeneous materials.