Construction materials. Alkali-activated cementitious material and concrete. Specification (PAS 8820:2016)

Why has PAS 8820 been developed?

The UK’s Construction 2025: Industrial strategy for construction – government and industry in partnership sets out a range of targets including lower emissions, lower costs, faster delivery and improvement in exports. Low carbon cements using alkali activators have been and continue to be developed in the UK and using these cements can assist in reaching all of the targets in the strategy by:
- Reducing the quantity of carbon dioxide released during the manufacture of cement and concrete
- Avoiding increasing costs associated with energy sources and the capture and storage of carbon from cement production processes and potentially reducing other production costs
- Providing an alternative range of materials for precasting products, as this mode of production can enable faster delivery
- Helping UK product developers bring their products to market and develop exports.

The concrete produced using alkali-activated cementitious materials (AACM) can have performance benefits such as improved chemical and fire resistance and/or lower permeability to water and aggressive agents. However, these new AACM products are not fully covered in other British Standards for cement and concrete.

PAS 8820 has been developed to fill this gap and encourage the use of AACMs in the construction industry.

What does PAS 8820 cover?

PAS 8820 specifies:
- The performance requirements for AACM comprising aluminosilicate main constituents and an alkali activator.
- A means of assessing concrete obtained through the use of such cementitious material for performance and durability
- Requirements for the alkali-activating component and the aluminosilicate powder component of these concretes

This PAS does not:
- Set detailed requirements for the composition of the AACMs
- Specifically address applications for such materials as renders, screeds, mortars or repair materials, although it does not exclude the possibility that such materials could be used for such purposes
- Cover the use of any material classified as hazardous waste

- Manufacturers of alkali-activated cementitious material
- Producers of prefabricated concrete elements containing alkali-activated cementitious material
- Producers of concrete containing alkali-activated cementitious material which is to be precast, delivered ready-mixed, or mixed in situ
- Designers and specifiers