Blue Circle

Ground Granulated
Blastfurnace Slag

GGBS (BS EN 15167-1)

Blue Circle

Ground Granulated
Blastfurnace Slag

A cementitious addition, typically mixed with CEM I at 30-50%, suitable for use in concrete:

- Large pours, to reduce the risk of early-age thermal cracking.

- Reducing attack on concrete in sulfate conditions.

- Improved surface finish of concrete.

Contact our Customer Service team

Tele: 0845 812 6300

Email: [email protected]

Regional Order Numbers:

Scotland & North East England – 0845 4700 300

North & Midlands – 0845 4700 400

South Wales & South West – 0845 4700 500

London & South East – 0845 4700 600

Technical Information

GGBS is available in bulk tankers in Southern England.


CEM I/GGBS concrete – when compared with Tarmac bulk Portland cement concrete at the same cement content – has the following properties:

Slower strength development and potentially higher long-term strength.

The appropriate cement content for concrete of a given 28 day cube strength and slump should be determined from trial mixes.

The cement content may differ from that of an equivalent Portland cement (CEM I) concrete in certain circumstances. In particular, where a high strength concrete is required, the cement content may be slightly higher than for CEM I.

Slower setting times.

Reduced water demand.

Improved placing and finishing.

Lighter in colour

Conditions for use:

Concrete, mortars and grouts containing Portland Cements and GGBS must be specified and used correctly for best performance.

The cement content must be correct and the water: cement ratio as low as possible consistent with satisfactory placing, thorough compaction and effective curing.

The final finish quality of this material will depend upon the operative having the required skills and a familiarisation with the materials and its application methods.

Tarmac cannot be held responsible where workmanship has not been carried out in accordance with good practice.


Strength gain after 28 days

Chloride Resistance

Enhanced resistance to chloride ingress

Reduces Alkali Risk

Reduces risk of Alkali-Silica Reaction


Enhanced sulfate resistance

Low CO2

Lower embodied CO2 than CEM I Portland cement

Quality Assurance

Quality is assured with independent third party certification and a CE Mark.

Product Data Sheet


Material Safety Data Sheet