Performance (recommended first)
Concrete shall achieve the specified f′c and shall not exceed [X] kg CO₂e/m³ (A1–A3), demonstrated by EPD and trial batch tested per ASTM C39.
Write the carbon and the strength into the same concrete spec.
Producers stop at 30–40% SCM because a failed pour is their risk. A performance specification gives the producer room to use the materials already in the plant, while the trial batch protects the engineer, schedule and owner's carbon target.
Field performance first
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Trident: design strengthUntreated: design strength
1 week instead of 4.
| Age | Untreated | Trident |
|---|---|---|
| 1 d | 1,220 PSI | 1,470 PSI |
| 7 d | 4,350 PSI | 7,030 PSI |
| 14 d | 5,540 PSI | 8,990 PSI |
| 28 d | 7,090 PSI | 9,940 PSI |
Producer QC lab · ASTM C39 · poured control cast alongside the same mix · breaks Jul 30–Aug 26, 2026.
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Trident: design strengthUntreated: design strength
Design strength in week 1.
| Age | Untreated | Trident |
|---|---|---|
| 3 d | 3,118 PSI | 4,104 PSI |
| 7 d | 3,596 PSI | 5,177 PSI |
| 28 d | 5,133 PSI | 6,699 PSI |
3rd party gov't accredited laboratory · M30 · Trident 1.2 L/m³ (≈31 fl oz/yd³) · Oct 2026.
Choose the lever that serves the project
| Priority | Write | Expected outcome |
|---|---|---|
| Carbon + speed | GWP cap plus early-age strength | Deep SCM replacement without waiting 28 days |
| Carbon + cost | GWP cap plus performance | About 9–13% lower materials cost at equal strength across 50–80% SCM |
| Exposure-limited | ACI 318 exposure limit plus GWP cap | 50% slag for F3; deeper replacement elsewhere |
Sample clauses
Draft for review with counsel and the engineer of record.
SCM minimum
Concrete shall contain at least [X]% supplementary cementitious material by mass of total cementitious material, subject to exposure-class limits and trial-batch validation.
Schedule
The trial batch shall demonstrate the project release strength at the required age and the specified 28-day compressive strength.
Set the carbon limit from published data
Published M30 series · 380 kg/m³ binder
337
equal-strength standard 80/20
117
target kg CO₂e/m³ · -65%
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tonnes avoided for volume
Binder model, A1–A3. Published EPD factors: OPC 922, slag 147 and fly ash 10 kg CO₂e/t. Equal-strength baseline: 439 kg/m³ standard 80/20; Trident mixes: 380 kg/m³. Trident adds a Pipedream estimate of 2 kg CO₂e/m³. Estimates, not an EPD.