Abstract High-performance concrete (HPC) is widely recognised for its superior strength and durability, making it suitable for advanced infrastructure applications. However, the high cement content in HPC significantly contributes to CO2 emissions, emphasizing the need to develop sustainable alternatives. This study investigates the mechanical performance, durability characteristics, microstructural behavior, and eco-efficiency of HPC incorporating ultrafine fly ash (UFFA) and silica fume (SF).