UK scientists have developed a method to recycle the cement from concrete. Until now, the concrete from demolished buildings, would at worst go to landfill and at best get a second use, crushed in to aggregate for a road subsurface or as a building foundation supporting material.

The production of cement is a massive contributor to climate change. Limestone is heated over 1500 degrees centigrade releasing carbon dioxide (CO2). This industry alone is responsible for over 5% of human produced CO2.

An estimated tonne of CO2 is released for every tonne of cement produced. CO2 is emitted from the limestone itself and from the burning of fossil fuels to heat the limestone.

The new process involves heating the used cement again, reactivating it for a further use. Since the cement does not contain CO2, there is no CO2 emissions from this reclaimed cement.

The Cambridge University, England, UK scientist team also looked in to combining the recycling of cement with the steel industry. Using the heat from the molten steel to heat the cement. The layer of slag on top of the molten steel protects the steel from the oxygen in the air. The team used cement as a slag, thereby reducing the amount of energy required to heat the cement.

If this will ever have a commercial application, has yet to be decided. It seems like a good idea, but would need to be undertaken on a massive scale to make any difference. The process is in the very early stages of development and could ultimately prove too resource intensive compared with creating fresh cement. Also, the resulting cement has not been tested long term on an actual building or in harsh weather.

About The Author
Jane Duncan
Chewells Contributor

Jane is passionate about the environment, she is our main contributor for the renewable industry blogs. She... »

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