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Cement is made by heating limestone (calcium carbonate) with small quantities of other materials (such as clay) to 1450°C in a kiln. The resulting hard substance, called ‘clinker’, is then ground with a small amount of gypsum into a powder to make ‘Cement’, the most commonly used type of cement. This cement is called Ordinary Portland Cement.
Ordinary Portland Cement (OPC) is the most common cement used in general concrete construction when there is no exposure to sulphates in the soil or groundwater.
Portland cement is the most common type of cement in general use around the world, used as a basic ingredient of concrete, mortar, stucco, and most non-speciality grout. It was developed from other types of hydraulic lime in England in the mid 19th century and usually originates from limestone.
Also Read: Differences Between Ordinary Portland Cement And Portland Pozzolana Cement
To retard the faster setting time of cement resulted from (C3A) compound a percentage of raw gypsum(selenite) is added during the grinding of the clinker.
OPC is environment friendly as well as economical.
Ordinary Portland Cement (OPC-53, OPC-43, OPC-33).
The 43 grade OPC is the most popular general-purpose cement in India. The OPC can be used for following applications:
- General Civil Engineering construction work
- RCC works(preferably where grade of concrete is up to M-30)
- Pre-cast 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 inter grinding 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.
Portland Pozzolana Cement also commonly known as PPC cement. These types of cement are manufactured by using pozzolanic materials as one of the main ingredient. The percentage of pozzolanic material used in the preparation should be between 10 to 30. If the percentage is exceeded, the strength of cement is reduced.
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 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 to form stable calcium silicates which have cementitious properties.
The pozzolanic materials commonly used are:
- Volcanic ash
- Calcined clay
- Fly ash
- Lica fumes
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Article Sorce: Quora
