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1. CarbonBuilt reduces emissions by replacing cement in concrete with industrial byproducts and embedding captured CO₂ into the concrete itself.
2. Their Flagstaff, AZ pilot aims to permanently remove up to 600 tonnes of CO₂ annually, with the potential to scale to millions of tonnes by 2030.
3. With 4 Corners support, this project proves that low-carbon concrete can be both cost-effective and scalable for small manufacturers.
In 2024, 4 Corners awarded $150,000 in catalytic funding to CarbonBuilt, a California-based company rethinking how we make concrete—a material responsible for a significant share of global greenhouse gas emissions. Through their DAC-to-Concrete Pilot Project in Flagstaff, Arizona, CarbonBuilt is taking a bold step: turning captured CO₂ into a core ingredient for durable, low-carbon building materials.
Traditional concrete relies heavily on cement, a material that emits large amounts of CO₂ during its production. CarbonBuilt’s innovative approach cuts or even eliminates cement from the mix. Instead, they use calcium-rich industrial byproducts combined with captured CO₂, which is mineralized into calcium carbonate—a stable, long-lasting form of carbon storage.
This process doesn’t just reduce emissions—it locks CO₂ away for over 1,000 years while maintaining the strength, performance, and cost that concrete producers need. It’s a drop-in solution, meaning producers don’t need new equipment or big operational changes.
With help from the 4 Corners program, CarbonBuilt is launching a first-of-its-kind project with Block-Lite, a family-owned masonry company in Flagstaff. The project retrofits Block-Lite’s plant to replace traditional steam curing with a system that uses captured atmospheric CO₂ to cure the concrete.
The pilot will include six modular DAC units, each capable of capturing 100 tonnes of CO₂ per year. Together, they will enable the removal and mineralization of up to 600 tonnes of CO₂ annually. When combined with 1,500–2,500+ tonnes of avoided emissions, this adds up to 2,000–3,000+ tonnes of CO₂ savings every year.
By 2030, CarbonBuilt aims to scale this model, with a target of removing 2.5 to 3 million tonnes of CO₂ annually.
CarbonBuilt places a strong emphasis on rigorous tracking and verification. They monitor CO₂ inputs and mineralization using flow meters and thermogravimetric analysis (TGA). To validate their carbon savings, they work with ClimateEarth to conduct third-party Environmental Product Declarations (EPDs), ensuring transparency for customers and stakeholders alike.
“Without the support of 4 Corners, this collaboration between early-stage climate tech and a small, family-run manufacturer wouldn’t be possible,” says Cindy McLaughlin, Head of Product at CarbonBuilt.
The funding helps cover upfront costs, making this project a model for replication in other regions. It shows that even small manufacturers can lead on climate action—and that decarbonizing heavy industries like concrete doesn’t have to come at the expense of profitability or performance.
By using CO₂ as a resource, CarbonBuilt is helping to create a circular economy—one where we can build the future while cleaning up the past.
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