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
concreting and can also be used for plastering and single storied individual houses.

43 Grade Opc Cement

The 43 grade OPC is the most popular general-purpose cement in the country today. The production of 43 grade OPC is nearly 50% of the total production of cement in the country.

43 Grade OPC can be used for the following applications:

+ General Civil Engineering construction work.
+ RCC works(preferably where grade of concrete is up to M-30).
+ Precast items such as blocks, tiles, pipes etc.
+ Asbestos products such as sheets and pipes.
+ Non-structural works such as plastering, flooring etc.

53 Grade Opc Cement

53 Grade OPC is a higher strength cement to meet the needs of the consumer for higher strength concrete. As per BIS requirements the minimum 28 days compressive strength of 53 Grade OPC should not be less than 53 MPa. For certain specialized works, such as pre-stressed concrete and certain items of precast concrete requiring consistently high strength concrete, 53 grade OPC is found very useful. 53 grades OPC produce higher-grade concrete at very economical cement content. In concrete mix design, for concrete M-20 and above grades a saving of 8 to 10 % of cement may be achieved with the use of 53 grade OPC.

53 Grade OPC can be used for the following applications.

+ RCC works(Preferably where grade of concrete is M-25 and above)
+ Precast concrete items such as paving blocks, tiles building blocks etc.
+ Pre-stressed concrete components
+ Runways, concrete Roads, Bridges etc.

Portland Pozzolana Cement

Portland Pozzolana Cement is a kind of Blended Cement which is produced by either intergrinding of OPC clinker along with gypsum and pozzolanic materials in certain proportions or grinding the OPC clinker, gypsum and Pozzolanic materials separately and thoroughly blending them in certain proportions.

Pozzolana is a natural or artificial material containing silica in a reactive form. It may be further discussed as siliceous or siliceous and aluminous material which in itself possesses little, or no cementitious properties but will in finely divided form and in the presence of moisture, chemically react with calcium hydroxide at ordinary temperature to form compounds possessing cement properties. It is essential that Pozzolana be in a finely divided state as it is only then that silica can combine with calcium hydroxide (liberated by the hydrating Portland Cement) in the presence of water to form stable calcium silicates which have cement properties. The pozzolanic materials commonly used are:
+ Volcanic ash.
+ Calcined clay.
+ Fly ash.
+ Silica fumes.

Portland Pozzolana Cement is ideally suited for the following construction:
+ Hydraulic structures.
+ Mass concreting works.
+ Marine structures.
+ Masonry mortars and plastering.
+ Under aggressive conditions.
+ All other applications where OPC is used.
+ The compressive strength of PPC as per BIS code at present is equivalent to that of 33 grade OPC.

Rapid Hardening Portland Cement

Rapid Hardening Portland Cement is similar to OPC, except that it is ground much finer, so that on casting, the compressible strength increases rapidly.

Portland Blast Furnace Slag Cement

PBFSC consists of 45 per cent clinker, 50 per cent blast furnace slag and 5 per cent gypsum and accounts for 10 per cent of the total cement consumed. It has a heat of hydration even lower than PPC and is generally used in construction of dams and similar massive constructions.

Water Proof Cement

Water Proof Cement is similar to OPC, with small portion of calcium stearate or non- saponifibale oil to impart waterproofing properties.