Innovative Cement Process Uses Demolished Buildings to Cut Down Carbon Emissions in Construction

Cement production is the leading source of carbon emissions in the construction industry. To address this, a new innovative process incorporates materials from demolished buildings into cement manufacturing, significantly reducing carbon emissions and making construction more sustainable.

(Photo : Pexels/Rakib Hasan Redoan )

Carbon Emissions in the Production of Cement

Over 4.7 million tonnes of carbon dioxide are reportedly emitted annually during the cement manufacturing process, with the blending phase accounting for 60% of those emissions. Amid the nation's pursuit of a net-zero emissions target by 2050, the industry has labored in vain for years to find a viable, environmentally friendly alternative to the material that comprises the nation's fundamental building elements.

A research team affiliated with Cambridge University announced this week that they had solved the mystery by developing a method that modifies an existing steel manufacturing process to generate recycled cement without emitting carbon dioxide.

Julian Allwood, a professor who was a co-author on the paper, stated that the discovery, published in the journal Nature, had the potential to bring about a massive change' by delivering cement that is both low in cost and low in emissions on a large scale.

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Recently Innovated Cement Process

Through the reuse of cement paste from demolished structures, Allwood and his associates have devised an alternative method for producing clinker. The chemical composition of this material is precisely the same as that of lime flux, which is employed to eliminate impurities from recycled steel.

As mentioned, slag accumulates on recycled steel as the flux composed of used cement evaporates during the steel's melting process. Once clinker has been ground into a powder, there is no difference between them. Thus, it can then be utilized in the production of Portland cement, the most widely used type of cement. If recycled steel and cement are produced in an electric furnace driven by nuclear or renewable energy, the process can be almost entirely emission-free. As per Allwood, the concept is quite simple to execute.

Moreover, the technique has been demonstrated to be effective through laboratory tests. Based on the team's calculations, a global transition to this process may save up to three gigatonnes of carbon dioxide per year. It provides a solution that can be implemented with standard machinery due to its "drop-in" compatibility.

The research team is conducting industrial trials through a spin-off company called Cambridge Electric Cement. These trials are undertaken with various construction companies, including Balfour Beatty and Tarmac. Allwood claims that the researchers will begin a series of experiments over the next several weeks and that these experiments will be capable of creating batches of thirty tonnes every hour.

On the other hand, researchers have also recently disclosed their intention to utilize solar heat in producing construction materials, including glass, steel, ceramics, and cement. This development demonstrates that generating heat at 1,000°C is feasible without relying on fossil fuels. Nevertheless, through hundreds of sun-tracking mirrors, they have discovered a method to enhance the efficiency of solar receivers, which concentrate and grow heat.

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