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Ground granulated blast furnace slag (GGBS)

GGBS is primarily a binder used as an addition to cement which uses the latent hydraulic properties of GGBS to produce Portland blastfurnace cement (6-35% of GGBS) or blastfurnace cement (36-90% GGBS) produced by blending at the concrete mixer, or as a factory blend  at the cement factory. When produced at the concrete plant mixer these cements will have the designation CII or CIII, and when produced as a cement factory blend, they have the designation CEM II or CEM III.


GGBS is produced by grinding Granulated Blastfurnace Slag to a controlled fineness. There are a number of different methods of grinding granulated blastfurnace slag. Traditionally, standard ball mills have been used, but since the early 2000s the use of roller presses and vertical mills has increased.

Granulated blastfurnace slag is a very hard material and as a result necessitates the use of high wear resistant materials in the grinding process. The grinding process takes account of mean particle size, grading (particle size distribution), fineness and the particle shape in order to ensure that when used in concrete performance is maximised. Typically, GGBS is ground to a specific surface area of 450-550 m2/kg, similar to that of cement.


  • Ready mixed concrete
  • Precast concrete
  • Mortar
  • Grout
  • Hydraulic bound mixtures
  • Cut-off walls
  • Tile adhesive
  • Plaster
  • Nuclear waste encapsulation

Application & Description

GGBS is covered by European Standard BS EN 15167. For further information on the use of Ground granulated blast furnace slag refer to: CSMA - The Cementitious Slag Makers Association.