Make the switch: save carbon now

Recent updates to the BS 8500 concrete standard mean that there are now more lower carbon options available for use, helping architects and engineers decarbonise buildings and infrastructure.

What are the changes outlined in the updated standard?

Traditional concrete is made up of CEM I, which mostly consists of Portland cement clinker. Until recently it could be combined with Fly Ash or ground granulated blast-furnace slag (GGBS), by-products from the power and steel industries.

In the most significant update to concrete mixes since the 1980s, limestone fines can now be added as a third component.

Approved by BSI, the business improvement and standards company, after rigorous research and testing, the new multicomponent mixes can replace up to 65% of CEM I.

What are limestone fines and why are they now being added to concrete?

Limestone fines are finely ground limestone, abundant in the UK.

They provide an important alternative to Fly Ash and GGBS, the availability of which is declining as the UK moves away from coal-fired power stations and traditional steel manufacturing.

How do limestone fines affect the performance of concrete?

Testing has shown that concrete containing up to 20% limestone fines as part of a multicomponent mix delivers the same high strength, durability and fire protection as CEM I concrete.

Why should engineers and designers embrace the updates?

Reducing embodied carbon is a priority for the construction industry and adoption of the new standard could save around 1 million tonnes of carbon dioxide emissions each year.

For every 5% of limestone fines used, a 5% CO2 reduction can be delivered per cubic metre of concrete. Similarly, the maximum replacement of 20% limestone provides around 20% carbon saving.

Potential project level savings are significant, with successful trials on the Environment Agency’s Hexham flood alleviation scheme delivering carbon savings of 64% compared to CEM I concrete.

What else is the industry doing to decarbonise?

This revision to the standard is one of many ongoing activities to develop lower carbon cements and concretes but is an important milestone in the UK Concrete and Cement sector’s commitment to decarbonise.

The industry’s roadmap has set out how the use of decarbonised transport, fuel switching and carbon capture, usage or storage technology will also help to deliver its targets with good progress being made in all areas. The concrete and cement industry has delivered a 53% reduction in absolute carbon emissions since 1990, decarbonising faster than the UK on the whole.

How can the new concrete standard be used now?

Speak to your supplier today to find out what options and specifications are available for use.

For more information, download the Concrete Centre ‘How to’ guide for designers on implementing the new concrete standard here.

Find out more about the updated standard here

28th February 2024