Applications, performance characteristics and environmental benefits of alkali-activated binder concretes

BRE (The Building Research Establishment) is an independent, research-based consultancy, testing and training organisation, operating in the built environment and associated industries.

On 5 June 2013, BRE published, Applications, performance characteristics and environmental benefits of alkali-activated binder concretes (DG 530), written by Andrew Dunster and Keith Quillin.

Approximately 5% of human-generated CO2 emissions result from cement production. There is a need therefore to develop alternative, low-carbon cements and binders suitable for use at scale in concrete production. Alkali-activated binders (AA binders) and concretes produce less CO2 in their manufacture than conventional Portland Cement (PC). They also offer flexibility in materials sourcing and can give better durability to sulfates and acid than PC.

Alkali-activated binder (AA binder or alkali-activated material) concretes use a single mineral binder, or blend of binders, that are chemically activated by the addition of a highly-alkaline activator solution, generally based on sodium silicate.They encompass a range of finely-divided silicate and aluminosilicate materials including:

• Fly ash (pulverised fuel ash or pfa).
• Thermally treated clays.
• Ground granulated blastfurnace slag (ggbs), in combination or alone.

The BRE digest summarises the state of the art in this emerging area and provides an introduction to the use of these new binders in concrete production, their performance and durability. It is intended for specifiers of concrete products, concrete product producers and those with an interest in low-carbon concrete products.

The contents of the digest are:

• A brief introduction to alkali-activated binder concretes
• Raw materials

1. Binders
2. Chemical activators

• Concrete production
• Strength development, durability and performance

1. Efflorescence
2. Alkali–aggregate reaction

• Codes and standards
• Environmental impact (LCA) of AA binder concretes
• Conclusions
• References
• Further reading

Click here to see the digest in the BRE Bookshop.

--BRE Group

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