Putting the squeeze on C02 emissions
The environmentally minded among us know we're in dire need of a concrete solution — that is, a way to reduce the carbon dioxide (CO2) emissions from the ubiquitous grey building material.
Concrete is the most used manmade material in the world, and cement (an ingredient in concrete made of sand, paste and gravel or crushed stone) gives off about eight per cent of the planet's CO2 emissions, according to think-tank Chatham House.
What's more, BBC News reports that if the cement industry were a country, it would be the third largest emitter in the world — after China and the U.S.
Enter Carbicrete, a Montrealbased company that can sequester carbon in concrete, allowing its product to capture more carbon than it emits.
“It's negative emissions,” CEO Chris Stern told Dezeen. “We're taking CO2 out of the system every time we make a block.”
To make cement, you typically need to heat calcium carbonate (usually in the form of limestone) to roughly 1,480 C so you can extract calcium oxide. That's when carbon dioxide is released into the air, not to mention the additional emissions that come from the fossil fuels that power the process.
Carbicrete, however, takes cement out of the equation. Instead, it blends waste slag from the steel industry with carbon gathered from industrial plants that would otherwise have gone into the atmosphere.
“We're taking it from there and then injecting it into concrete and getting rid of it forever,” Stern said.
The whole process captures more carbon in the production procedure than the manufacturing process gives off, he explained, making for carbon-negative concrete.
The method only goes so far, though. Since it needs emissions produced by other industries, it's not actually removing carbon dioxide from the air — it's just helping reduce additional CO2 from being emitted. That's where direct air capture (DAC) companies, which can capture CO2 from the sky, come in. Once their products are more affordable and more widely used, concrete could aid in actively lowering global CO2 emissions.
Carbicrete is aiming to eventually produce 25,000 concrete masonry units (CMUS) per day.