This deliverable presents the results of long-duration and cyclic thermal tests conducted on waste ceramic materials and industrial by-products — including clinker, roof tiles, hollow bricks, and ashes — to evaluate their suitability as high-temperature Thermal Energy Storage (TES) media. It assesses material structural and weight stability under prolonged exposure at 800°C and repeated thermal cycling between 400°C and 800°C, and provides final recommendations for material selection and enhancement techniques to support the integration of upcycled TES materials into commercialised TES systems.