One significant source of emitting greenhouse gases is the creation of cement., primarily through the burning of fuel and the calcination of raw materials, accounting for approximately 7% of total greenhouse gas emissions. It has been bring to light that the majority of CO2 emissions from commercially available concrete mixes come from Portland cement, accounting for 74–81% of all emissions. It was discovered that, in common concrete mixtures, Ground granulated blast furnace slag (GGBFS) might cut CO2 emissions from concrete by 22%. It was discovered that, in common concrete mixtures, fly ash might reduce CO2 emissions from concrete by 13–15%. In efforts to mitigate emissions, experimental studies are exploring the utilization of factory-made by-products being like Flyash and GGBFS. This study explores use of Flyash and GGBFS in M-40 Concrete as a part-substitution of cement. Experiments show that GGBFS mixes offer better resistance to chloride permeability, lower calcium hydroxide levels, and higher calcium silicate hydrates. Replacing Ordinary Portland Cement with GGBFS can decrease compressive strength, but both mixes show resistance to water permeability. High-volume GGBFS concrete offers a sustainable alternative to conventional concrete.