Thermal Properties of Lightweight Cement–Sand–Natural Pozzolan Moroccan Composites

Thermal insulation is a key research topic due to its role in improving passive thermal comfort in buildings and reducing carbon emissions. This study investigates the development of a low-cost, thermally insulating concrete incorporating natural pozzolan aggregates (NPA) derived from a locally available mineral resource. Concrete mixtures containing different NPA proportions (0–6 wt%) were prepared and experimentally evaluated. Thermal conductivity and thermal diffusivity were measured using the Hot Disk technique. The results showed that the incorporation of 6 wt% NPA reduced thermal conductivity by 15.79%, thermal diffusivity by 20.55%, and density by 5.29%. These results demonstrate the effectiveness of natural pozzolan aggregates in enhancing the thermal performance of concrete. Consequently, natural pozzolan represents a promising and environmentally friendly material for producing thermally efficient concrete for sustainable building applications.