Low-carbon cement has a demand problem, not a chemistry problem. The science for cutting concrete’s carbon has existed for years; what’s missing is enough committed buyers to justify building plants at scale. Ozinga is betting that’s changing. Its East Chicago facility, which the company calls the largest low-carbon cement plant in North America, is on track to finish this quarter.
What the low-carbon cement plant produces
The plant is sized for a million tons a year of low-carbon cementitious material, including ASTM C989-compliant slag cement and proprietary blends. The headline figure is the embodied carbon cut: up to 80% below ordinary portland cement, depending on the mix. Run at full output, Ozinga says the facility would keep more than 700,000 metric tons of CO2 out of the air each year, which is roughly the annual footprint of a mid-sized town.
That 80% number deserves a caveat. Slag-based blends only work where the structural spec allows them, and slag itself is a finite byproduct of steelmaking, so this isn’t a drop-in fix for every pour. It’s a real tool for the projects that can use it, and that’s a growing share as embodied-carbon limits move from voluntary to mandatory under codes like the new LEED v5 framework.
Why buyers are organizing around offtake
Supply is only half the equation. The Sustainable Concrete Buyers Alliance is running a procurement push, with proposals due June 19, to lock multi-year offtake agreements covering up to 250,000 tons of low-carbon cement a year starting as early as 2027. That structure, guaranteed demand before a plant breaks ground, is how solar and wind got cheap. Cement is borrowing the playbook. If it works, the next East Chicago won’t need to gamble on whether the buyers show up.
External reference: World Resources Institute on low-carbon cement technology.