Cement production is responsible for roughly 8% of global CO₂ emissions, mostly from the chemistry of making clinker. Carbon-negative concrete aims to flip this: by reducing clinker, using alternative binders, and permanently storing CO₂ inside the concrete, the net balance over the material's life becomes negative — it removes more carbon than it emits.
Working principle
Several levers combine. CO₂ mineralisation / curing injects captured CO₂ into fresh concrete, where it reacts with calcium to form stable carbonate minerals, permanently sequestering the gas while strengthening the mix. Supplementary cementitious materials (slag, fly ash, calcined clay) and alternative binders cut clinker. Pairing low-carbon production with carbon capture and storage pushes the lifecycle balance below zero.
| Strategy | Effect on CO₂ |
|---|---|
| Ordinary Portland cement | High emissions (baseline) |
| SCM blends (slag/fly ash) | Lower clinker, less CO₂ |
| CO₂ curing / mineralisation | Stores CO₂ in product |
| Capture + storage + low binder | Net-negative possible |
Key insightMineralised CO₂ is stored as a thermodynamically stable carbonate — permanent sequestration, unlike many temporary offsets — and it can improve early strength.
Applications
- Ready-mix and precast concrete with CO₂ curing
- Infrastructure and buildings targeting embodied-carbon limits
- Industrial CO₂ utilisation (CCUS) value chains
References & further reading
- Monkman & MacDonald, “On carbon dioxide utilization as a means to improve concrete,” J. Cleaner Production, 2017.
- Scrivener et al., “Eco-efficient cements,” Cement & Concrete Research, 2018.
- IEA, “Technology Roadmap — Low-Carbon Transition in the Cement Industry,” 2018.