The major use of GGBS is in ready-mixed concrete, and it is utilised in the majority of UK ready-mix deliveries.
Specifiers are well aware of the technical benefits, which GGBS imparts to concrete, including:
Considerable sustainability benefits
Lower early-age temperature rise, reducing the risk of thermal cracking in large pours
Minimizes the risk of damaging internal reactions such as Alkali Silica Reaction (see factsheet) and Delayed Ettringite Formation (see factsheet)
High resistance to chloride ingress (see factsheet) thus reducing the risk of steel reinforcement corrosion
High resistance to attack by sulphates and other chemicals (see factsheet)
Better workability, making placing and compaction easier
Pleasing off-white colour
In the production of ready-mixed concrete, GGBS replaces a substantial portion of the Portland cement component, generally about 50%, but sometimes up to 70%.
The higher the proportion, the better is the durability. The disadvantage of the higher replacement level is that early-age strength development is somewhat slower.
