Mineral coal bottom ash, a residue from power plants, is an under-exploited industrial waste in Niger despite its interesting properties, notably its low density. This study aims to add value to this material by developing an economical, high-performance composite combining bottom ash powder (≤80 microns) and construction plaster, intended for interior applications such as false ceilings, wall coverings and decorations. Mortars with different proportions of clinker (0-70%) were formulated to assess their mechanical strength and thermal conductivity. The results show that replacing plaster with 20-35% clinker optimizes technical performance, with a 1.32-fold increase in compressive strength for 20% clinker. Thermal properties are also unaffected. This composite material offers an economically advantageous solution, by reducing the cost of construction materials and valorizing the large stocks of bottom ash accumulated, notably at the SONICHAR company in Niger. This approach contributes to the sustainable management of industrial waste while meeting the needs of the construction sector.
