Due to the rapid growth of the population in the world, the need for infrastructure is also on the increase. Because of this, meeting the global demand for reinforced concrete is now becoming more challenging as the resources on earth are limited. Despite this, the expensive material of new mixed concrete is still composed of cement. In concrete, cement is the primary ingredient. Therefore, it is essential to investigate the feasibility of using by product or waste materials as cement to maintain the concrete construction industry. Ground granulated blast furnace is the most significant solid waste generated from steel processing factories. Hence, this study investigated the possibility of using GGBFS as replacement of cement in concrete. In the study an attempt is made to understand the variation in compressive strength by replacing up to 40 % of cement by GGBFS under aggressive environment for 7, 28, 56 and 90 days testing. There were five different sets of mixes including the control mix used for investigations with constant water-cement ratio of 0.49 and slump ranging between 75- 100 mm for concrete having a compressive strength of 25 MPa. The research used XRD test to identify the phase of the material and also comparative analysis was made using ultra-sonic pulse velocity (UPV) in addition to compressive strength test. The results of the study show that, GGBFS can be considered as pozzolanic material since the percentage sum of lime, silicate aluminate and ferrite is greater than 80%. Concrete containing GGBFS waste as cement replacement shows high compressive strength than the conventional at an optimum replacement rate of 31% under acidic environment and 23% under normal tap water and marine water curing and it can also save up to 11.6% of the total cost of concrete. Concrete with partial replacement of cement with GGBFS under aggressive environment showed increment as ultra-sonic pulse velocity (UPV) increases. In general partially replacing cement with ground granulated blast furnace slag will have a significant environmental and economic impact to the construction industry. Key Words: Compressive strength, Workability, XRD, UPV, Ground granulated blast furnace slag, Marine solution, Acidic solution