Type IL vs Type I/II cement
Type IL portland-limestone cement performs equivalently to ordinary portland for most work, produces up to about 10% less CO₂, and is approved by all 50 state DOTs plus DC.
The full comparison
| Factor | Type IL | Type I/II |
|---|---|---|
| Specification | ASTM C595 | ASTM C150 |
| Composition | Portland clinker with ground limestone | Portland clinker |
| CO₂ footprint | Up to ~10% lower | Baseline |
| Performance | Equivalent for most applications | Baseline |
| DOT approval | All 50 states plus DC | All 50 states plus DC |
| US market share | Surpassed ordinary portland in June 2023 | Declining |
| Availability | Default supply in many markets | Widely available |
Type IL: When it wins
Almost all general construction. If your specification calls out Type I/II, it is worth asking whether Type IL is acceptable, because in many cases it already is and it may be what the plant supplies anyway.
Type I/II: When it wins
Where a specification or an agency explicitly requires C150 cement and has not yet accepted C595 blended cements. Sulfate-resistant work may call for Type II or V specifically.
About these figuresUS producers avoided over 4 million metric tons of CO₂ in 2023 through PLC and blended cements.