In a UK first, Related Argent’s Brent Cross Town has seen the first use of a more sustainable concrete mix in a residential building
Calcined clay concrete is a lower-carbon alternative to traditional concrete, replacing some of the Portland cement with much more widely available thermally treated clay.
In the North London development, Midgard – the contractor working for Related Argent – has used a mix with 30% calcined clay in the cement, meaning an overall reduction of 10% embodied carbon in the concrete mix compared to what was used previously.
The new mix has gone into a residential building
The build-to-rent building makes up over 200 homes, and has seen the new calcined clay concrete utilised in a permanently suspended slab.
The practice is a first in the UK, but it is hoped that it will be adopted more. The construction industry accounts for about 37% of global emissions, and as concrete is the most-utilised material in construction by mass, it is no surprise that its production accounts for about 8% of global emissions per year.
The sheer availability of clay means that wider adoption of calcined clay concrete could save millions of tonnes of CO2 in the construction sector.
In this use, sustainability and the circular economy was also supported by the clay being sourced from waste bricks.
Tim Hoyland, environment manager at Related Argent said: “The successful application of calcined clay concrete in permanent works at Brent Cross Town is a significant step forward for sustainable construction in the UK. This material is a practical alternative to traditional cement replacement, enabling the industry to significantly reduce carbon emissions, support job creation and the circular economy.
“We are proud to lead by example and are committed to sharing our experience to encourage wider adoption of calcined clay concrete throughout the sector. A huge thank you to everyone who helped make this happen.”
Jack Sindhu, technical director at Capital Concrete, said: “By partially replacing traditional cement and GGBS with calcined clay, we’re able to review the amount of cement required in the mix, which in turn helps reduce embodied carbon and overall CO₂ emissions.”
The first CO2-neutral bridge was built this year
Revealed in January, Paebbl and Heijmans unveiled their world-first achievement, a seven metre-long bridge made from 75% circular raw materials, and no primary sand or gravel.
The Dutch construction company responsible said that nearly 66kg of CO2 has been sequestered within the bridge deck.
Nick Vervoort, innovation manager at Heijmans, commented: “This bridge proves that carbon-neutral structural concrete is not a future aspiration, it’s achievable today. For the first time, CO₂-neutral concrete has been poured using an innovative mix of materials: Paebbl, biochar and recycled concrete.
“This demonstrates what collaboration and ambition can achieve. We’re very proud that the concrete mix used in this bridge is fully CO₂-neutral and contains 75% circular raw materials.”
The post Calcined clay concrete used homes for first time appeared first on Planning, Building & Construction Today.
