Overview
How this pathway works
Fresh concrete — a mixture of cement, water, and aggregate — is naturally alkaline, and calcium silicate hydrate (the primary binding phase formed as cement hydrates) reacts readily with CO₂ to form calcium carbonate. CO₂ Concrete Curing exploits this chemistry deliberately: captured CO₂ gas is injected into concrete during mixing, at a dedicated curing chamber for precast products, or into fresh cement paste before or during the hydration reaction, accelerating and directing carbonate mineral formation throughout the concrete matrix rather than relying on the slow, superficial carbonation that occurs naturally as hardened concrete is exposed to atmospheric CO₂ over decades.
Under the Teravent Technology-Based Carbon Standard (TTS v1.0) Annex J, CO₂ Concrete Curing projects earn Teravent Technology Credits for verified net tonnes of CO₂ permanently mineralised within the cured concrete product, net of full lifecycle project emissions. This pathway carries a mixed credit type designation (TTC-D / R) — the specific type depends on the origin of the CO₂ injected. Where the CO₂ source is captured atmospheric or biogenic carbon, the project earns Removal credits (TTC-R); where the source is industrial flue gas, it earns Reduction credits (TTC-D), following the same source-based logic applied throughout TTS v1.0.
Three methodology variants are approved under Annex J, differentiated by the concrete production format — precast products, ready-mix cast-in-place concrete, and cement replacement material treatment. Each specifies its own injection point, curing process, and mineralisation confirmation protocol.
📌
Class III — Mineral permanence. All credits issued under TTS Annex J carry Class III permanence, reflecting the >1,000-year stability of the calcium carbonate mineral phase formed within the concrete matrix. Buffer pool contributions of 2–8% of gross verified credits apply, among the lowest in the Teravent system, reflecting the very low reversal risk of mineralised carbon locked within a solid, widely used structural material.
Governing Standard
TTS v1.0 — Annex J
This pathway is governed exclusively by the Teravent Technology-Based Carbon Standard (TTS v1.0). No external registry, standard, or methodology is referenced or incorporated. All requirements — additionality, quantification, durability, safeguards, and credit issuance — are defined within TTS v1.0 and Annex J specifically.
TCR›
TTS v1.0›
Annex J — CO₂ Concrete Curing›
COC-M01 through COC-M03
M02
Three-test additionality with TRL-based screening applied ahead of common practice test
M03
Quantification and MRV — Net TTC formula, CO₂ uptake metering at ±2% accuracy, carbonate mineral confirmation
M04
Class III Mineral permanence · Buffer pool 2–8% · CO₂ source determines credit type (TTC-D or TTC-R)
M05
Environmental and social safeguards — worker exposure to CO₂ injection systems, product quality assurance
M06
Ten-stage registration process; 17-element PDD including product distribution and end-use tracking
M07
TTC serial: TCR–TTS–[R/D]–COC–[Country]–[ProjectID]–[Vintage]–[Unit]
Teravent Technology Credit — Serial Number Format (TTS Annex J · Mixed Credit Type)
TCR
–
TTS
–
D / R
–
COC
–
MX
–
00073
–
2025
–
000112
💡
Credit type is determined by CO₂ source, not methodology: The same COC-M01 precast curing methodology can issue either TTC-D or TTC-R credits depending on whether the injected CO₂ originates from industrial flue gas or from atmospheric/biogenic capture. Projects must document and verify CO₂ source at registration, and this classification is fixed for the life of the project unless the source materially changes.
Methodologies Accepted
Three approved methodology variants
TTS v1.0 Annex J approves three discrete methodology types for the CO₂ Concrete Curing pathway, differentiated by the point in concrete production where CO₂ is injected and the resulting curing process.
Precast concrete products — masonry blocks, pavers, structural panels — are cured in dedicated chambers where CO₂ concentration, humidity, and temperature can be tightly controlled, making this the most mature and widely deployed methodology in the pathway. CO₂ is introduced during the early curing window when calcium silicate hydrate formation is most reactive, maximising both carbonate uptake and the resulting compressive strength gain.
Permanence
Class III · Mineral
Buffer Pool
2–6% (by SIRR)
CO₂ Uptake Metering
Curing chamber gas analysis, ±2%
Typical Uptake Rate
5–15% of cement mass as CO₂
Product Applications
Masonry blocks, pavers, structural panels
Credit Type
Determined by CO₂ source (fossil vs. biogenic/DAC)
Key Monitoring Indicators
- CO₂ gas uptake within curing chamber via calibrated gas analysis, ±2% accuracy
- Carbonate mineral content of cured product confirmed by thermogravimetric analysis (TGA) at representative sampling frequency
- Compressive strength testing per batch, confirming the co-benefit performance improvement alongside carbon uptake
- CO₂ source documentation and chain-of-custody, determining TTC-D versus TTC-R credit type classification
- Product distribution and end-use tracking to prevent double counting of embodied-carbon claims by downstream purchasers
Ready-mix concrete destined for cast-in-place applications — foundations, slabs, walls poured on-site — receives a metered CO₂ dose during batching at the concrete plant, before the mix is transported to the pour site. Because curing occurs after transport and pour rather than in a controlled chamber, this methodology requires more conservative uptake assumptions and additional field verification relative to precast curing, but addresses a substantially larger share of total global concrete production.
Permanence
Class III · Mineral
Buffer Pool
3–8% (by SIRR — field conditions add variability)
CO₂ Uptake Metering
Batching plant dosing system, ±2%
Field Verification
Core sampling from poured structures required
Product Applications
Foundations, slabs, cast-in-place walls
Credit Type
Determined by CO₂ source (fossil vs. biogenic/DAC)
Key Monitoring Indicators
- CO₂ dosing rate at the batching plant via calibrated metering, ±2% accuracy
- Core sampling from a representative subset of poured structures to confirm carbonate mineral content via TGA
- Compressive strength testing per batch and, where feasible, on cured field samples
- CO₂ source documentation and chain-of-custody, determining TTC-D versus TTC-R credit type classification
- Pour site and structure-level record keeping to support the product's end-use tracking obligation
Rather than treating the finished concrete, this methodology applies CO₂ curing to supplementary cementitious materials (SCMs) — fly ash, ground granulated blast furnace slag, or other alkaline industrial byproducts — before they are blended into the cement mix, reducing the overall clinker content required (a further embodied-carbon benefit) while achieving carbonate mineralisation in the SCM component itself. Where the SCM feedstock is also registered under Industrial Waste Mineralisation (Annex F), projects must confirm no double registration of the same mineralised tonnes.
Permanence
Class III · Mineral
Buffer Pool
2–7% (by SIRR)
CO₂ Uptake Metering
Reactor/curing process gas analysis, ±2%
Cross-Pathway Check
Must not overlap with Annex F (Industrial Waste Mineralisation)
Additional Benefit
Reduced clinker content lowers embodied carbon further
Credit Type
Determined by CO₂ source (fossil vs. biogenic/DAC)
Key Monitoring Indicators
- CO₂ gas uptake at the SCM treatment reactor or curing process, via calibrated gas analysis, ±2% accuracy
- Carbonate mineral content of treated SCM confirmed by TGA or XRD prior to blending into cement
- Clinker substitution ratio documented to substantiate the additional embodied-carbon reduction claim
- CO₂ source documentation and chain-of-custody, determining TTC-D versus TTC-R credit type classification
- Confirmation the same mineralised SCM tonnes are not separately registered under Annex F
Project Boundary & GHG Accounting
Which emission sources must be counted
TTS v1.0 Module 3 requires a full lifecycle GHG emissions inventory within the project boundary, deducted from gross mineralised CO₂ to arrive at the Net TTC figure.
Required
Mineralised CO₂ (Gross)
Primary benefit quantity. CO₂ gas uptake metered at the curing chamber, batching dosing system, or SCM reactor, confirmed as converted to carbonate mineral phase via TGA analysis.
Required
CO₂ Source Capture & Transport
Where CO₂ is captured from a separate facility and transported to the concrete plant, associated capture and transport emissions must be assessed unless already fully accounted under a separate registered capture pathway.
Required
Curing Process Energy
Electricity and thermal energy consumed by curing chamber operation, batching plant CO₂ dosing systems, or SCM treatment reactors, applying the applicable grid emissions factor per TLP v1.0.
Excluded
Underlying Cement & Aggregate Production
Emissions from cement clinker production, aggregate mining, and other conventional concrete input materials are excluded from this pathway's boundary — only the CO₂ mineralisation benefit is credited, addressed separately from any facility-level cement production emissions accounting.
Excluded — Prevents Double Counting
Overlapping Product-Embodied Carbon Claims
Where the concrete product is separately marketed with an embodied-carbon or green building material claim, that portion of mineralised CO₂ is excluded from Teravent credit issuance to prevent double counting across value chains, and where SCM feedstock overlaps with Annex F registration.
MRV Confidence
Measurement, reporting
& verification
Teravent's Science Advisory Board assesses each pathway against four MRV dimensions. Precast curing (COC-M01) benefits from a fully controlled process environment giving very high measurement confidence; ready-mix curing (COC-M02) carries somewhat lower confidence given field pour conditions.
CO₂ Uptake QuantificationVery High
Mineralisation ConfirmationVery High
Permanence ConfidenceVery High
Additionality ClarityHigh
🔬 Measurement Requirements — TTS Module 3
CO₂ uptake is quantified via calibrated gas analysis at the curing chamber, batching plant dosing system, or SCM reactor, accurate to ±2%. Mineralisation is directly confirmed through thermogravimetric analysis (TGA) or X-ray diffraction (XRD) of representative product samples, quantifying the carbonate mineral content formed. Ready-mix curing (COC-M02) additionally requires core sampling from a representative subset of poured structures given the field conditions between batching and final cure. Compressive strength testing, conducted as standard concrete quality assurance practice, provides a secondary corroborating indicator of successful carbonation. All laboratory analyses must be conducted by an accredited facility, and gas metering instrumentation calibrated by an accredited VVB.
Additionality
Demonstrating additionality
TTS v1.0 Module 2 requires all projects to pass a three-test additionality framework, with a Technology Readiness Level (TRL) screen applied ahead of the common practice test. Because CO₂ curing also improves compressive strength — a commercially valuable property independent of carbon credit revenue — the financial additionality test requires particular care to isolate the CO₂ injection system's incremental cost from the underlying commercial benefit of a stronger product.
1
TRL-Based Common Practice Screen
Projects deploying CO₂ curing technology at TRL 7 or below automatically satisfy the common practice test. Precast facilities using increasingly mature commercial CO₂ curing systems (approaching TRL 8-9 in some markets) must instead complete a full common practice survey of comparable regional precast producers.
2
Regulatory Surplus Test
The CO₂ curing activity must not be mandated by any legally binding building code, embodied-carbon regulation, or green building certification requirement. Where a jurisdiction mandates a minimum embodied-carbon reduction for concrete products, projects must demonstrate the achieved mineralisation exceeds the mandated minimum.
3
Financial Additionality Test
Carbon revenue must be necessary for the CO₂ injection system specifically — not merely for the underlying concrete production business. Developers must submit a discounted cash flow analysis isolating the CO₂ dosing equipment and CO₂ procurement costs, net of any strength-improvement commercial benefit already captured in product pricing, net of any government grants (disclosed under Module 8), demonstrating these incremental costs exceed available revenue absent carbon credit income.
ℹ️
Government incentive disclosure: Where a project receives direct government grants, capital cost subsidies, or per-tonne carbon utilisation tax credits for the same mineralised CO₂, this must be disclosed to the TSA at registration under Module 8. Double-claiming the same carbon benefit under both a government incentive programme and Teravent credits is prohibited.
Leakage Assessment
Leakage types & deductions
TTS v1.0 Module 3 defines three leakage types applicable across all engineered pathways. CO₂ Concrete Curing carries relatively limited leakage exposure given its contained industrial process, primarily energy-source leakage and a CO₂ source double-counting consideration.
Energy-Source Leakage
Grid Electricity Displacement
Where curing chamber, batching dosing, or SCM reactor equipment draws electricity from a constrained grid, its consumption may increase marginal fossil generation elsewhere. Facilities without a dedicated renewable power purchase agreement must apply the regional marginal emissions factor.
Deduction: applicable regional grid factor, TLP v1.0
CO₂ Source Double-Counting Risk
Overlap with Registered Capture Pathways
Where the CO₂ source is a co-located capture facility already registered under a separate Teravent pathway (e.g. DAC, CCUS), chain-of-custody documentation must confirm the same captured CO₂ is not credited twice — once at capture and again at concrete curing.
Zero-tolerance exclusion · verified each period
Product Overlap Leakage
SCM Cross-Registration Risk
Where a supplementary cementitious material used under COC-M03 has already been credited as mineralised waste under Industrial Waste Mineralisation (Annex F), the mineralised tonnes must not be double registered.
Zero-tolerance exclusion · verified at PDD stage
Permanence & Storage Integrity Risk
Buffer pool & reversal risk
All Annex J credits carry Class III Mineral permanence (>1,000-year storage horizon). Because mineralisation is confirmed directly through laboratory analysis of the finished concrete product, reversal risk for this pathway is very low once carbonation is verified. Buffer rates are set by the project's Storage Integrity Risk Rating (SIRR).
| Methodology |
SIRR Rating |
Buffer Pool Rate |
Primary Reversal Risks |
| COC-M01 Precast |
Very Low |
2–6% |
Incomplete curing prior to product sale; product misclassification at end use |
| COC-M02 Ready-Mix |
Low |
3–8% |
Field pour conditions introduce curing variability relative to controlled chambers |
| COC-M03 SCM Treatment |
Very Low |
2–7% |
Cross-registration overlap risk with Annex F; incomplete curing prior to blending |
⚠️
Reversal notification: Project proponents must notify the TSA within 72 hours of discovering a reversal event — for example, laboratory re-analysis revealing lower-than-reported carbonate content in a sampled batch. Because the finished concrete product is a durable, widely dispersed structural material, physical reversal of already-mineralised carbon is exceptionally rare once curing is confirmed; the primary risk lies in overstated initial mineralisation reporting rather than subsequent degradation.
Eligibility Requirements
Key registration criteria
Projects must meet all of the following minimum requirements to qualify for registration under TTS Annex J. Additional methodology-specific requirements are detailed in the Annex J methodology tables for each COC-M code.
✓
Calibrated CO₂ gas uptake metering installed at the curing chamber, batching dosing system, or SCM reactor, accurate to ±2%
✓
CO₂ source documentation establishing whether the injected CO₂ is fossil, biogenic, or atmospheric-derived, determining TTC-D or TTC-R credit type classification
✓
Ten-stage registration process completed, from technology eligibility assessment through validation to ongoing verification, per TTS Module 6
✓
Seventeen-element Project Design Document submitted, including product distribution and end-use tracking methodology
✓
Three-test additionality demonstrated, isolating the CO₂ injection system's incremental cost from the strength-improvement commercial benefit
✓
Post-curing product testing by TGA or XRD confirming carbonate mineral content, at a minimum sampling frequency specified per methodology
✓
Storage Integrity Risk Rating (SIRR) assessed by an accredited VVB at validation; buffer pool contribution of 2–8% applied to gross verified credits
✓
Chain-of-custody documentation confirming no double counting where CO₂ source is a separately registered capture facility, or where SCM feedstock overlaps with Annex F
✓
Standard concrete quality assurance testing (compressive strength) provided as a corroborating carbonation indicator
✓
Government production incentive or capital grant disclosure submitted at registration and updated at each verification period
Co-Benefits & SDGs
Sustainable Development
Goal alignment
All Teravent registered CO₂ Concrete Curing projects must complete an SDG impact assessment at registration and at each verification period. Three SDGs are systematically tracked for this pathway. Projects may apply for co-benefit quality labels where independently verified indicators are met.
SDG 9 · Industry, Innovation & Infrastructure
SDG 11 · Sustainable Cities & Communities
SDG 13 · Climate Action
Permanent Removal
Projects verified to use atmospheric or biogenic CO₂ (issuing TTC-R credits) with an unqualified mineralisation confirmation are eligible for the Teravent Permanent Removal label.
Circular Feedstock+
SCM treatment projects (COC-M03) that put industrial waste materials to productive climate and construction use are eligible for the Circular Feedstock co-benefit label.
Zero Fossil Input+
Facilities powered entirely by verified renewable or nuclear electricity for curing chamber and dosing system operation are eligible for the Zero Fossil Input co-benefit label.
Community Benefit+
Facilities demonstrating lower-embodied-carbon construction materials for local affordable housing or public infrastructure projects are eligible for the Community Benefit+ label.
Deployment scope: Global — precast and ready-mix concrete production facilities exist wherever construction activity occurs, making this one of the most geographically flexible and scalable pathways in the Teravent system given concrete's status as the world's most-consumed manufactured material.