The search for a green alternative to cement

Cement is a component of concrete, but its production has been known to create high carbon emissions. Concrete manufacturers, therefore, have begun looking for greener cement alternatives.

Slag is a by-product of steel production and is used to reduce the quantity of cement that is in concrete. However, there is an ongoing general move by the steel industry away from fossil fuel blast furnaces to electric arc furnaces, which generate a type of slag unsuitable as a cement substitute.

A start-up company, Cocoon have found a method to take by-products from electric arc furnaces and convert them to slag replacements that can be used instead of cement. They claim that their slag alternative can replace half of the cement used in concrete.

The company is conducting initial tests of the process in UK and USA steel plants and plans to operate a pilot steel plant before the end of 2025. The founder of Cocoon, Eliot Brooks, said:

“We’re turning a by-product with little use into a valuable product that the market badly needs and can be easily integrated into existing supply chains.”

The Cocoon technology, as well as meeting the low carbon requirements of the concrete industry, will provide extra income for steel makers that use arc furnaces.

The World Economic Forum has predicted that the global floor area of construction projects will double by 2060. As most floors are made from concrete, if viable alternatives to cement can be developed, this will significantly reduce the carbon emissions associated with concrete flooring.