Revised standards are set to bring about one of the most significant changes to the ingredients of concrete since the 1980s.
MPA UK Concrete, which represents the UK concrete industry, said the new standards could save a million tonnes of carbon dioxide emissions each year. Concrete and cement manufacturing currently accounts for 7.7m tonnes of carbon dioxide (CO2) emissions, equating to 1.5% of the UK’s total carbon emissions.
The new method of specifying concrete blends finely ground limestone from UK quarries with other materials such as fly ash and ground granulated blast furnace slag (GGBS).
As the majority of CO2 emissions in concrete is associated with the production of cement, using these supplementary materials helps to reduce the amount of traditional cement (CEM I) to create a lower carbon concrete.
The CEM I content in concrete can be replaced with up to 20% of limestone powder, a product widely available in the UK. For every 5% of limestone powder added, a 5% CO2 reduction can be delivered, according to MPA UK Concrete.
Elaine Toogood, director, architecture and sustainable design at the Concrete Centre, said: ‘In a climate emergency, this new approved standard is important to helping architects and engineers significantly lower embodied manufacturing emissions today and in the future, while delivering structural strength in buildings and infrastructure.
‘Providing a new generation of concretes are an important part of the UK concrete and cement industry’s roadmap to net zero alongside other technologies including the use of decarbonised transport, fuel switching and Carbon Capture, Usage or Storage (CCUS) technology.’
MPA UK Concrete said that GGBS and fly ash have been repurposed as an ingredient for concrete, but less of it is being produced, so the use of limestone fines is needed.
It said the new specification changes are part of a rigorous research and testing process over two years, with the results then independently assessed for inclusion into the standard by the BSI technical committee for concrete.
UK Concrete is part of the Mineral Products Association.
