The cement production is highly energy intensive & produces nearly one ton of co2 for production of one ton of cement which is greenhouse gas causing global warming. Hence Portland cement industry does not fit to the contemporary desirable picture of sustainable industry. So there is an urgent need of finding alternative to ordinary Portland cement which possesses satisfactory strength& durability. Production of fly ash & blast furnace slag in construction industry has been manipulated everywhere & demands new researches to use it more effectively. Ground granulated blast furnace slag has been used since 1960s in alkali activated slag cement which is also known as Geopolymer. Use of Ground granulated blast furnace slag & Fly ash at the same time decreases carbon footprint of construction. Geopolymer Concrete is an excellent alternative to ordinary Portland cement.