GGBS (Ground Granulated Blast-furnace Slag) is a cementitious material whose main use is in concrete and is a by-product from the blast-furnaces used to make iron. The major use of GGBS is in ready-mixed concrete, and it is utilised in the majority of UK ready-mix deliveries. GGBS is used to make durable concrete structures in combination with ordinary Portland cement and/or other pozzolanic materials. Two major uses of GGBS  are in the production of quality-improved slag cement, namely Portland. Sustainable construction alternative for Portland Cement. Ground granulated blastfurnace slag (ggbs) is subject in Europe to EN 15167-1: 2006100 with physical requirements for compressive strength (activity index),.