With the aim of simultaneously achieving proper performance, high strength and high density in conventional concrete, the use of self-compacting concrete (SCC) was inevitable for the diaphragm walls of the second phase of the Shahid Rajaee Port Development Project.These three characteristics, both in fresh and hardened concrete, were crucial for the implementation of the main T-shaped wall of this project. For this purpose, the effect of fly ash and silica fume pozzolans on self-compacting concrete to achieve high performance and maintain its fluidity for a maximum of 6 hours and the 28-day compressive strength of the design (at least 450 kg/cm2) was investigated by preparing 8 mixing plans. For assessing the concrete’s flowability, the standard slump flow test according to ASTM C143 was employed. This test was repeated 7 times, with initial slump measurements taken at the time of production for each mix design, and subsequently at hourly intervals to monitor workability retention, up to a maximum of 6 hours. For compressive strength, four 15x15x15 cm cubic specimens were prepared for each mix design based on BS 1881 and ASTM C31. The results ultimately indicated that all mix designs incorporating 24% fly ash performed better in terms of 28-day compressive strength and slump compared to designs containing 5% to 7.5% silica fume. Among these, Mix Design B achieved the best results with a 13% increase in strength and 50% improvement in workability and slump retention (which was of particular importance to the project), demonstrating excellent compatibility with the operational requirements for casting the diaphragm wall of the Shahid Rajaee Port.