Wednesday, December 15, 2021

Quebec company's concrete alternative absorbs rather than emits carbon dioxide

Good news is in short supply these days, so lets celebrate the possibility that concrete, one of the most carbon-intensive and ubiquitous building materials we have, might be approaching its end-days.

Concrete is everywhere, and it's manufacture is responsible for at least 8% of the world's greenhouse gases. If the global concrete industry were a country, it would be the third largest carbon dioxide emitter, after only China and the USA. Most of concrete's carbon footprint comes from the manufacture of its binding agent, cement, which involves heating limestone to 1,400°C (usually using a fossil fuel). As the limestone breaks down, it releases another dose of carbon dioxide. Double whammy!

What, though, if we could do away with cement completely? Well, Quebec start-up Carbicrete's product not only eliminates cement completely (and its GHG emissions in the process), but it uses steel slag, a by-product of the steel-making process, as a binding agent, which can be injected with carbon dioxide from industrial plants, thereby converting it into a mineral (a kind of carbon capture and storage process). So, it turns the manufacture of concrete from a CO2-emitting process into a CO2-saving one - negative carbon emissions! - while, at the same time, utilising the steel slag waste. What's more, Carbicrete is 30% stronger and 10-20% less expensive than traditional concrete. Win-win-win!

Carbicrete's process can easily be incorporated into any existing concrete production plant, and a collaboration with Quebec comcrete manufacturer Patio Dummond is already going ahead. Let's hope this one takes off.

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