Types / Grades of Cement

Types of Cement - CEM

There are 5 types of cement : CEM I, II, III, IV, V

For general construction use only types I and II are relevant.

CEM I is pure (100%) OPC (Ordinary Portland Cement)
CEM II is a mixture of OPC and additives such as fly ash, slag or limestone, up to a maximum additive content of 35%.

Grades of Cement - 28-Day Strength

Within each type there are three grades, based on the 28-day strength of the concrete that they produce. The grades are 32.5, 42.5 and 52.5 (sometimes written 33, 43, 53).

Classes of Cement - Strength Gain

Each grade consists of 3 classes which describe the speed at which the concrete made from them gains strength:
R = early strength gain
N = normal strength gain
L (or S) = low/slow strength gain.

Additives in CEM II

In the case of CEM II type there are further sub-classifications as follows:
A = additive content <20%
B = additive content 21 to 35%

Furthermore, the type of additive is indicated by letters:
V = fly ash
S = slag
L = limestone

The letter M is used to indicate that it is multi-additive, for example it contains both ash and slag.

Markings / Nomenclature

Typical markings are, for example

  • CEM I 42.5 N
  • [pure OPC giving strength of 42.5 MPa with 'normal' strength gain.]
  • CEM I 52.5 R
  • [pure OPC giving strength of 52.5 MPa with 'early' strength gain.]
  • CEM II /A-V 42.5 N
  • [fly ash content <20% ... of 42.5 MPa with 'normal' strength gain.]
  • CEM II /B-M(S-V) 32.5 S
  • [slag plus fly ash content <35% ... 32.5 MPa with 'slow' strength gain.]