CarbonCure concrete poured at Calgary International Airport reducing 160 tonnes of carbon emissions. (CNW Group/CarbonCure Technologies)

CarbonCure process makes concrete stronger, sequesters carbon

This concrete (yes, concrete) is going high-tech

Cement is the glue that makes concrete strong, but the process of making cement requires superheating calcium carbonate, or limestone, and releases massive amounts of carbon dioxide into the atmosphere.

Cement is responsible for 7% of global man-made greenhouse emissions, making it the world’s second-largest industrial source of carbon dioxide, according to the International Energy Agency. Data from the United States Geological Survey — the scientific agency of the US government — reveals that global cement production was responsible for about 4 billion pounds of CO2 emissions in 2017 alone.

CarbonCure, a Canadian startup company, has devised a way to make concrete that also traps harmful CO2 emissions forever and makes the concrete stronger than traditional methods. CarbonCure’s system takes captured CO2, injects it into concrete as its being mixed, and then once it hardens, the carbon is sequestered forever. The CO2 is turned into a mineral as it reacts with the concrete during the process.

“The best thing about it is the mineral itself improves the compressive strength of the concrete,” Christie Gamble, director of sustainability at CarbonCure, said. “Because the CO2 actually helps to make the concrete stronger, concrete producers can still make concrete as strong as they need to but use less cement in the process.”
By using less cement, producers can drastically cut their emissions.

“We’re leading that movement right now [by] showing it is possible to take CO2 and turn it into something that makes financial sense,” Gamble said. “This concept of beneficial reuse of CO2 is expected to be a one trillion dollar industry by the year 2030.”

A new mixed-use development in one of Atlanta’s trendiest neighborhoods, called 725 Ponce, is a real-life example of the impact of building with greener concrete. When it opens in 2019, it will become the largest structure ever made with CarbonCure concrete.

Ultimately, the 360,000 sq. ft. office building, which will have a Kroger supermarket on the first floor, will save 1.5 million pounds in CO2 from being released into the air — the same amount 800 acres of forest would sequester in a year, according to Gamble.

The building is a step in the right direction, but CarbonCure is far from widespread adoption. Right now, only 90 concrete plants in the US and Canada are using their technology — a small fraction of the estimated 5,500 plants in the US alone.

CarbonCure’s Gamble noted if the industry can reduce 5% of its carbon footprint, that is a significant change from where it is right now. “If this technology is deployed across the globe, we could reduce about 700 megatons of CO2 each year. That’s the same as taking 150 million cars off the road every year,” Gamble said.

Although concrete isn’t going away anytime soon, it appears there is room to make all that grey a bit greener.

“Every time I see concrete being made, I see it as a missed opportunity to save CO2 emissions,” Gamble added. “Maybe it will take 20 years; maybe it will take 50 years. Maybe something crazy will happen and it will happen in five years. But we’re starting to see that process.”

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