This series highlights the companies Carbon Drawdown Initiative has invested in.

Can we use carbon emissions to build our cities?

That’s the question Co-reactive is answering with a bold new approach: turning CO₂ into high-performance cement substitutes that store carbon permanently—and improve the materials they go into.

It’s carbon removal and better concrete, in one process. And it’s working.

From PhD research to carbon-negative concrete

Co-reactive’s journey began with founder Andreas Bremen’s doctoral research into carbon mineralization. While the science was well established, most reactor technology couldn’t scale. So, together with co-founder Orlando Kleineberg, they designed a solution from scratch: a continuous tubular reactor that efficiently mineralizes CO₂ using minerals like olivine and industrial by-products.

The result? A supplementary cementitious material (SCM) that locks carbon into a usable powder, called CO-SCM, ready to replace carbon-intensive clinker in cement.

Why this matters for the construction industry

The cement sector is responsible for 8% of global CO₂ emissions. And the industry’s main decarbonization strategies — carbon capture and clinker substitution — are hitting limits:

Fly ash and blast furnace slag, traditional SCMs, are becoming scarce due to a shift in production methods.
New alternatives like calcined clays require high heat and offer only partial decarbonization.

Co-reactive’s CO-SCM solves both issues. It sequesters ~330 kg of CO₂ per ton of material, and it boosts the performance of cement. In pilot tests, mortars with 25% CO-SCM reached the same strength as 100% Ordinary Portland Cement.

Evidence that it works

Co-reactive has built and validated a semi-continuous pilot reactor producing 10 tons per year, with full industry-standard testing of the output. Early partners include top cement manufacturers and concrete mix designers, who are exploring applications ranging from low-carbon blends to advanced geopolymers.

Their process has three major advantages:

High yield: Up to 95% CO₂ conversion efficiency
Energy efficiency: Reactor design recycles exothermic heat
Continuous output: Enables industrial-scale production without batch limitations

The vision: Cement that stores carbon, at scale

Co-reactive’s plan is to commission its first-of-a-kind (FOAK) commercial plant in 2027, scaling from lab prototype to 10,000 tons/year in under 30 months. With each ton of product locking away up to one-third of its weight in CO₂, this approach could turn cement plants from climate liabilities into carbon sinks.

That’s the kind of innovation we need: practical, scalable, and grounded in science.

Why we are backing them

We don’t need perfect. We need progress. And Co-reactive is showing what it looks like when deep science meets industrial ambition. Their work doesn’t just “offset” emissions; it uses them to build the infrastructure of tomorrow.

We are excited to support this team as they turn CO₂ from waste into resource, and help the construction sector decarbonize from the inside out.

To learn more about their work, visit: https://www.co-reactive.com/

Portfolio Spotlight: Co-reactive decarbonizes construction