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Green cement production is scaling up – and it could cut the carbon footprint of construction

(The Conversation, 17 Apr 2024) Aside from water, concrete is the most-used material in the world, with about 14 billion cubic metres being used every year. Of that, 40% of that is used to build places for people to live.

If you were to pour that amount of concrete to make a paving slab ten centimetres thick, it would cover all of England and about half of Wales. In the US, the same amount would cover the state of New York.

But concrete production releases carbon dioxide (CO₂), one of the greenhouse gases that drives climate change. About 90% of emissions associated with concrete come from the production of Portland cement – this fine grey powder, the part that binds concrete ingredients together, was named after its resemblence to stone from the Isle of Portland, Dorset. Portland cement accounts for 7%-8% of the world’s direct CO₂ emissions.

Production of a more sustainable and cost-effective low-carbon cement, often nicknamed “green” cement, is scaling up. A new plant next to an existing cement plant in Redding, California, will produce about 15,000 tonnes of low-carbon cement every year. This could be used to make about 50,000 cubic metres of concrete, which is less than 0.0004% of the world’s concrete production.

At Redding, materials technology company Fortera turns CO₂ captured during conventional cement production into ready-to-use green cement, a form of calcium carbonate. This could reduce carbon emissions of cement by 70% on a tonne-for-tonne basis, according to Fortera.

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The Conversation, 17 Apr 2024: Green cement production is scaling up – and it could cut the carbon footprint of construction