Forterra turns muck to brass with SCM from brick dust

Forterra has partnered with LKAB Minerals, part of the Swedish state-owned mining company Luossavaara-Kiirunavaara Aktiebolag, to pioneer the repurposing of crushed brick waste to produce calcined clay as a low-carbon alternative to traditional cement.

Derived from recycled brick waste, calcined clay can be used as a supplementary cementitious material (SCM) in accordance with international cement standards.

Among its advantages, SCM contributes to the concrete’s strength by increasing the strength-producing compounds and, in doing so, reducing the porosity of the concrete, Forterra says.

Conventionally, calcined clay is produced by heating raw clay at temperatures of between 700-800°C to drive off volatile compounds like water and carbon dioxide – a process called calcination. However, the combustion process is emissions heavy, resulting in high embodied carbon. Forterra’s approach avoids the high-temperature calcination process: the waste bricks have already been fired and the carbon accounted for. The embodied carbon of the final product is thus reduced and the entire process contributes towards a circular economy.

To produce the calcined clay product, waste from Forterra’s Kings Dyke brickworks near Peterborough is crushed and delivered to LKAB Minerals’ sites in the UK, where it is fine-milled to an agreed specification, processing it into a reactive calcined clay material. Initial use of the calcined clay at one of Forterra’s aggregate block plants in 2024 has already resulted in the avoidance of approximately 2,000 tonnes of CO₂ emissions, Forterra says.

Forterra and LKAB Minerals plan to produce approximately 35,000 tonnes of calcined clay per year.

Forterra chief executive Neil Ash, said: “Forterra is proud to be the first in the industry to commercialise the use of calcined clay as a sustainable, low-carbon cement alternative.

“We’re ambitious in our targets to reduce CO₂ emissions within our operations and value chain, so being at the forefront of innovations such as this partnership shows the level of our aspirations, while also underpinning our commitment to the environment.

“Leading the way in sustainable and circular industry practices allows us to reduce our emissions and add value to our business. But it also has wider benefits. By offering high-quality, low-carbon products, we help to reduce the embodied carbon in construction, cutting emissions across the industry as a whole.”

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