Concrete and its grades

Concrete is a construction material that consists of cement (commonly Portland cement), aggregate (generally gravel and sand), water and admixtures.

Engineers usually specify the required compressive strength of concrete, which is normally given as the 28 day compressive strength in mega pascals (MPa) or pounds per square inch (psi). Twenty eight days is a long wait to determine if desired strengths are going to be obtained, so three-day and seven-day strengths can be useful to predict the ultimate 28-day compressive strength of the concrete.

cement and its grade

33 Grade Opc Cement

This cement is used for general civil construction work under normal environmental conditions. The compressive strength of cement after 28 days test as per BIS specification is 33 MPa. Due to low compressive strength, this cement is normally not used where high grade of concrete viz, M-20 and above is required. The availability of higher grades of OPC in the market impacts the usage of 33 grade OPC as these days 43 grade OPC is normally used for general construction work. This grade of cement is more useful for mass concreting and plain cement