ASTM C150/C150M
Standard Specification for Portland Cement
What may be sold as portland cement in the United States, and the meaning of the familiar Type I through Type V designations.
Who needs it
Cement producers, ready-mix batch plants, mix designers, and specifiers choosing a cement for sulfate exposure or heat-sensitive placements.
What the test involves
It is a prescriptive specification: it constrains the chemical makeup and physical performance of the finished cement rather than describing how the concrete made from it must behave. The types separate general-purpose cement from versions optimized for moderate or high sulfate resistance, low heat of hydration, and high early strength. Air-entraining variants of some types carry an 'A' suffix.
Common misconceptions
- Type II is not simply 'better' Type I. It is a sulfate-resistance and heat choice, and specifying it where it is not needed adds cost without benefit.
- Type III gains strength faster but does not end up meaningfully stronger. It shifts the strength curve earlier, and it generates more heat while doing so.
- Many bags and silos now hold a blended or performance cement rather than straight portland, so the label matters more than the habit of calling everything 'portland'.
Official source
We summarize scope and purpose only. The full text belongs to the issuing body — read it at the official source. ASTM International