ORDINARY PORTLAND CEMENT 53 & 43 Grade
OPC 53 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 prestressed concrete and certain items of precast concrete requiring consistently high strength concrete, the use of 53 grade OPC is found very useful. 53 grade OPC produces higher-grade concrete at very economical cement content. 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.
- Prestressed concrete components
- Runways, concrete Roads, Bridges etc.
purpose cement in the country today. The production of 43 grade OPC is nearly 50% of the total production of cement in the country. The 43 grade OPC can be used for 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.
PORTLAND POZZOLANA CEMENT (PPC)
The 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 and aluminous material which 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 cementitious 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 toform stable calcium silicates which have cementitious properties. The pozzolanic materials commonly used are:
- Volcanic Ash
- Calcined clay
- Fly Ash
- Silica Fumes
The Indian Standards for Portland Pozzolana Cement have been issued in two parts based on the type of pozzolanic materials to be used in manufacturing of Portland Pozzolana Cement as given below:
- IS 1489 (Part 1) 1991, Portland Pozzolana Cement ? specification (fly ash based)
- IS 1489 (Part 2), Portland Pozzolana Cement ? specification (Calcined clay based)
- The quality of flyash or calcined clay to be used in manufacturing of PPC is also specified by BIS in the following standards:
- IS 3812 1981 - specification for flyash as pozzolana and admixture
- IS 1344 1981 - specification for calcined clay pozzolana
The 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 application where OPC is used.
The compressive strength of PPC as per BIS code at present is equivalent to that of 33 grade OPC.