Ground Granulated Blast-furnace Slag powder is a fine white powder used in concrete. Slag is produced in iron and steel manufacturing process as a by-product. Molten slag is extracted from iron ore at elevated temperature (approximately around 1500ºC) and rapidly water quenched to obtain reactive granular slag particles. Currently slag is most widely used in concrete as a separate supplementary cementitious material or as part of a blended cement to enhance durability and long-term strength performance. Ground Granulated Blast Furnace Slag complies with Australian Standard AS 3582.2-2001-Supplementary cementitious materials for use with Portland cement.