Photo: Collected
Researchers on Wednesday (22 May) said they were a step closer to solving one of the trickiest problems in tackling climate change -- how to keep making cement despite its enormous carbon footprint.
In a world first, engineers from Britain's University of Cambridge have shown that cement can be recycled without the same steep cost to the environment as making it from scratch.
Cement binds concrete together but the whitish powder is highly carbon-intensive to produce, with the sector generating more than triple the emissions of global air travel.
Demand for concrete -- already the most widely used construction material on Earth -- is soaring, but the notoriously polluting industry has struggled to produce it in a less harmful way to the climate.
The team at Cambridge believes it has a solution, pioneering a method that tweaks an existing process for steel manufacturing to produce recycled cement without the associated CO2 pollution.
This discovery, published in the journal Nature, could provoke "an absolutely massive change" by providing low-cost and low-emission cement at scale, said Julian Allwood, who co-authored the research.
"It is an extremely exciting project... I think it's going to have a huge impact," said Allwood, an expert on industrial emissions and key contributor to reports from the UN's scientific panel on climate change.
To produce cement, the basic ingredient in concrete, limestone must be fired in kilns at very high temperatures usually achieved by burning fossil fuels like coal. On top of that, limestone produces significant additional CO2 when heated.
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