As per ASTM, cement is designated as Type I, Type II, Type III, Type IV, Type V and other minor types like Type IS, Type IP and Type IA IIA and IIIA.
According to ASTM regulations cement is described as:
Portland Cement ASTM C150
Blended Cement ASTM C595
ASTM C150 Standard Specification for Portland Cement covers the following cement types:
For use in general concrete construction where the special properties specified for Types II, III, IV and V are not required (Ordinary Portland Cement). It contains fairly high C3S content for high early strength development.
Used where concrete is not subjected to specific exposures such as sulphate attacks from soil or water or to objectionable temperature rise due to the heat of hydration
C3A content is less than 8%. For use in general concrete construction exposed to moderate sulphate action, or where moderate heat of hydration is required. Due to less heat generation, it can be used in hot weather.
It is grounded more finely, may have slightly more C3S. For use when high early strength is required (Rapid Hardening Cement).
It is used where formwork is to be removed quickly or sufficient strength for further construction is required. It has a high heat of hydration and achieves its design strength in 7 days or less. Due to high heat generation, it should not be used in mass concreting or a large structural section. Though in cold climate it may serve well.
It has a low content of C3S (less than 30%) and C3A. For use when low heat of hydration is required (Low Heat Cement).
This type of cement is used in mass concrete because it generates less heat, though sets slowly but becomes much stronger after curing.
C3A content is lesser than 5 %. For use when high sulphate resistance is required (Sulphate Resisting Cement). ASTM standard also has cement of the type IS. This consist of an intimate and uniform blend of Portland Cement of type I and finely granulated slag. The slag content is between 25 and 70 per cent of the weight of Portland Blast-Furnace Slag Cement.
Type IA, IIA and IIIA
These are type I, II or III cement in which air-entraining agent is underground where air entrainment in concrete is desired.
ASTM C 595 Standard Specification for Blended Hydraulic Cement:
It covers blended hydraulic cement for both general and special applications, using slag or pozzolana, or both, with Portland cement or Portland cement clinker or slag with lime.
This consist of an intimate and uniform blend of Portland Cement (or Portland Blast Furnace Slag Cement) and fine pozzolana in which the pozzolana content is between 15 and 40 per cent of the weight of the total cement.
Type IS Portland blast-furnace slag cement
Type IT Ternary blended cement
For more information watch this video