Ordinary portland cement (OPC ) is a hydraulic cement produced by pulverizing clinker consisting essentially of hydraulic calcium silicates, usually containing one or more of the forms of the calcium sulfate as an interground addition.
Ordinary Portland cement (type I) is for use when the special properties specified for any other type are not required.
The product is conforming to ASTMC 150 specifications as follows:
| Magnesium Oxside (Mgo) max% | 6 |
| Sulfur Trioxside (So3) max% | |
| When C3A is 8% or less | 3 |
| When C3A is more than 8% | 3.5 |
| Loss on ignition max% | 3 |
| Insoluble residue max% | 0.75 |
The product is conforming to the American Standards. ASTMC 150 requirement as follows:
| Air Content of Morter volume % | Max 12 |
| Fineness, Specific surface, M2/kg by air per meability test to minimum | 280 M2/kg |
| Autoclave expansion max % | 0.8 |
Strength not less than the values shown for the ages indicated as follows:
| 3 Days | 12 (1740) |
| 7 Days | 19 (2760) |
Time of setting using vicat test:
| Initial set, not less than | 45 minutes |
| Final set, not more than | 375 minutes |
