A New Approach to Concrete Could Prove Useful
Eliminating Portland cement and the heat of its manufacturing significantly cuts emissions.
A startup called C-Crete with several patents has claimed the pouring of a new round of concrete — this time granite-based and without the incorporation of Portland cement and any CO2 emissions, at a building site in Manhattan.
The pour at 270 Park Avenue was part of the construction of JPMorgan Chase’s new global headquarters, designed by architectural firm Foster + Partners and engineered by Severud Associates Consulting Engineers.
C-Crete has developed several versions of its concrete products without Portland cement, including ones based on zeolite and basalt. The search for carbon reduction in concrete is important because it is the source of a significant amount of carbon dioxide emissions in the world.
Portland cement is the cause of the emissions. A research paper in the journal Communications Materials said that in 2022, the category contributed about 8% of global CO2 emissions. The product requires significant amounts of heat. Remove the carbon footprint of the cement and concrete becomes a much friendlier building material at a time when many investors and regulators are asking about how to make buildings more climate-friendly.
What C-Crete offers is a Portland cement off-ramp. Although the explanation on the company’s website is thin, the story of the product seems to be a combination of a synthetic binding agent, possibly a nanotechnology product, and local sources of rock, hence the installed versions with granite, zeolite, and basalt.
The binder interacts with the minerals or industrial byproducts and locks everything together. There is no need to heat the mixture, saving the CO2 release. Additionally, the products absorb some amount of carbon dioxide from the air.
The research took a decade, with extensive time put into experimenting with about 2,000 binder formulas that didn’t work. According to a report from MIT News — an in-house publication at the school where C-Crete founder Rouzbeh Savary obtained his PhD — the binder meets the performance requirements of Portland cement.
As of last year, the company could produce several tons of the binder a day, although a typical Portland cement manufacturer can produce 2,000 tons daily.