Finnish startup turns CO2 into carbon-negative concrete blocks that can trap emissions


Carbonaide, a spin-out from VTT Technical Research Centre of Finland, has come up with a solution to reduce carbon footprint by transforming CO2 into carbon-negative concrete blocks that eventually become a carbon sink, or an object that is able to absorb carbon dioxide from the atmosphere.

Carbonaide says that concrete may capture carbon dioxide through a process called carbonation. The technique causes the iron reinforcements to rust, which, in turn, breaks the concrete structures.

“We turned this disadvantage into an advantage. The Carbonaide method makes the calculated carbon footprint of concrete manufacturing carbon negative: -60 kg per cubic metre of concrete. The carbon footprint of conventional concrete is approximately 250–300 kg per cubic metre,” says Carbonaide CEO Tapio Vehmas.

Carbonaide technology is based on carbonation, which binds carbon dioxide into precast concrete using an automated system at atmospheric pressure. By lowering the cement content and mineralizing CO2 into concrete, the method can cut CO2 emissions by up to 50%, Carbonaide claims.

When industrial byproducts such as slags, green liquor dregs, and bio-ash are used in the binding process, the result is carbon-negative concrete, and CO2 can be permanently stored and eliminated from the carbon cycle.

Vehmas says that the team has already demonstrated its technology can reduce the CO2 emissions of conventional concrete by 45% during its pilot-batch production in the autumn of 2022.

“Our goal at Carbonaide is to create a more sustainable future with cutting-edge tech that doesn’t just reduce the carbon emissions of construction materials like concrete, but that traps more CO2 than they emit throughout their lifetime. It is very natural that the constructed environment becomes a CO2 sink as it is the largest volume of man-made material,” he adds.

The concrete industry is responsible for approximtely 8% of the global carbon emissions, with most of the emissions coming from cement manufacturing. With legislation increasingly enforced and observed in construction materials, the industry seeks to generate an alternative block that can withstand the standards of environmental laws on carbon neutrality and reducing emissions.

VTT claims that it has studied concrete structures throughout its 80-year history and founding Carbonaide poses as an extension of its research, the area that finally churns out a tangible result from its decades-long exploration.

As of March 28th, 2023, Carbonaide has secured EUR 1.8 million in seed funding led by Lakan Betoni and Vantaa Energy. The round was completed with public loans and in-kind contributions from Business Finland and other Finnish concrete companies and strategic investors.

The company will use the funding to scale operations and integrate its CO2 curing technology into an automated production line of its precast concrete factory in Hollola, Finland.

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