GGBFS

Slag cement or GGBFS is granulated blast-furnace slag that has been finely ground and that is hydraulic cement. When slag cement is mixed with water, however, the initial hydration is much slower than Portland cement mixed with water; therefore, Portland cement or salts of alkali metals, principally sodium and potassium or lime, are used to increase the reaction rate of slag cement (ACI 233R). The ASTM C989 slag-activity index is often used as a basic criterion for evaluating the relative cementitious potential of slag cements.

GGBFS is formed when granulated blast furnace slag (GBFS) is further processed or ground using conventional cement clinker grinding technology. On a casual examination, GGBFS can be off-white in appearance and could pass for a powder fineness typically between 380m2/kg - 420m2/kg. After molten slag has been quenched rapidly by passing it through a trough of high pressure, high volume water sprays, the heat energy contained in the molten slag causes it to explode and instantly form granulated blast furnace slag (GBFS).

GGBFS is typically used in activation of granular pavement materials and as a cementitious material in the manufacture of concrete, particularly where resistance to aggressive ground, water and aggressive environmental conditions are present.