The primary objective is to comprehensively assess and analyze the influence of incorporating steel slag on the various durability aspects of cement-based materials, including but not limited to strength, thermal properties, and resistance to adverse environmental conditions. The investigation is conducted through a systematic series of laboratory experiments involving concrete specimens with varying percentages of steel slag replacement. The experimental setup includes standard tests such as compressive strength, flexural strength for different PH water condition and durability-related assessments to evaluate the performance of the modified cementitious mixtures. Based on the study, we can see when partial replace the cement and fine aggregate with steel slag then A better results shown in the term of strength and durability aspect. Optimum percentage for cement replacement is 10%, for fine aggregate replacement is 40%, with steel slag. When use optimum percentage then gives a higher value of compressive strength, flexural strength, and durability.