Cement carbon capture

Berkeley University civil engineering student Cagla Meral is working to develop a greener form of Portland cement by sequestering CO₂ into it during the manufacturing process.

Up to 5 per cent of the globe’s climate-changing carbon dioxide emissions result from manufacturing the durable and popular construction material, and Meral believes that even if she can reduce emissions by a small percentage, it will have a tremendous impact on the environment.

Preliminary tests have shown that supercritical CO₂ infiltrates cement particles and chemically locks carbon dioxide back into the material.

'What we want to find out is how much CO₂ can be put back without losing the strength of cement-based materials,' said Meral, who is also studying how materials such as nanosilica or polymeric microfibres might fortify cement.

In another facet of her work, Meral is investigating the idea of replacing some of the cement typically used in concrete with greater quantities of industrial byproducts like fly ash and slag that might otherwise end up in landfills.

Here again, supercritical CO₂ processing might be helpful.

In this case, Meral is investigating whether supercritical CO₂ could eliminate heavy metals from fly ash and make it more chemically reactive.

To test her research, Meral has been working with an Irish materials processing company equipped with a specialised steel pressure chamber that can treat cement samples with supercritical CO₂.

If all goes well, Meral envisions installing CO₂ treatment units in cement factories to capture the emissions so they do not escape into the air.