Slag cement, often referred to as ground granulated blast-furnace slag (GGBFS), is a hydraulic cementitious material created by grinding blast-furnace slag, a byproduct of steel production, to a fine powder. The slag is granulated using high-pressure water jets, which rapidly cool the molten slag to form glassy granules. When mixed with water, slag cement reacts with it to form calcium silicate hydrate, much like Portland cement, contributing to the concrete’s strength and durability. The mechanism of action in slag cement involves both the hydration of calcium silicates and the pozzolanic reaction, where the silicates in the slag react with calcium hydroxide to produce additional cementitious material.