Carbon-Negative Concrete Binder Ratio Calculator

Determine the supplementary cementitious material fraction that satisfies aggressive carbon budgets, including mineralization credits and low-carbon binder blends.

Desired cradle-to-gate footprint after credits. Negative values indicate net removal.
Combined mass of Portland cement and supplementary cementitious materials per cubic metre.
Process + calcination footprint for the cement component.
Lifecycle emission factor for the supplementary cementitious material blend.
Captured CO₂ permanently mineralised per cubic metre. Defaults to 0 if blank.

Preconstruction estimation aid. Validate mix designs with laboratory testing, lifecycle inventory data, and structural engineering review before certification filings.

Examples

  • Target -20 kg CO₂e/m³, binder 600 kg/m³, cement EF 0.85, SCM EF 0.05, credit 204.27 ⇒ Required SCM fraction 67.86%, equating to 407.16 kg SCM and 192.84 kg cement.
  • Target 205.8 kg CO₂e/m³, binder 500 kg/m³, cement EF 0.82, SCM EF 0.12, credit blank ⇒ SCM fraction 58.34%, or 291.71 kg SCM and 208.29 kg cement.

FAQ

Which SCM emission factor should I use?

Use supplier-specific environmental product declarations for the fly ash, slag, calcined clay, or ternary blend you intend to deploy. Blended SCMs should be mass-weighted by component.

How do I incorporate aggregate carbonation?

Treat additional carbonation pathways as part of the mineralization credit. Document measurement protocols so auditors can verify the claimed removals.

Does the calculator handle binder performance constraints?

The output addresses carbon intensity only. Before issuing specifications, verify that the computed SCM fraction satisfies strength, durability, and curing requirements with laboratory mix designs.

Additional Information

  • Result unit: SCM share reported as a percentage plus mass split in kg/m³.
  • Mineralization credits default to zero to avoid overstating removals when monitoring data are unavailable.
  • Feasibility checks ensure the target intensity sits between all-cement and all-SCM bounds before solving the ratio.

Related calculators