INDIAN CEMENT INDUSTRY

In the most general sense of the word, a cement is a binder, a substance which sets and hardens independently, and can bind other materials together. The word "cement" traces to the Romans, who used the term "opus caementicium" to describe masonry which resembled concrete and was made from crushed rock with burnt lime as binder. The volcanic ash and pulverized brick additives which were added to the burnt lime to obtain a hydraulic binder were later referred to as cementum, cimentum, cäment and cement. Cements used in construction are characterized as hydraulic or non-hydraulic.

The most important use of cement is the production of mortar and concrete - the bonding of natural or artificial aggregates to form a strong building material which is durable in the face of normal environmental effects. Cement should not be confused with concrete as the term cement explicitly refers to the dry powder substance. Upon the addition of water and/or additives the cement mixture is referred to as concrete, especially if aggregates have been added.

It is uncertain where it was first discovered that a combination of hydrated non-hydraulic lime and a pozzolan produces a hydraulic mixture (see also: Pozzolanic reaction), but concrete made from such mixtures was first used on a large scale by Roman engineers . They used both natural pozzolans (trass or pumice) and artificial pozzolans (ground brick or pottery) in these concretes. Many excellent examples of structures made from these concretes are still standing, notably the huge monolithic dome of the Pantheon in Rome and the massive Baths of Caracalla. The vast system of Roman aqueducts also made extensive use of hydraulic cement. The use of structural concrete disappeared in medieval Europe, although weak pozzolanic concretes continued to be used as a core fill in stone walls and columns.

India is today the second largest producer of cement in world with an installed capacity of close to 155 million tonnes per year. 95 % is consumed domestically and only 5% is exported. Demand is growing at more than 10 % per annum. More than 90 % of production comes from large cement plants. There are a total of 130 large and more than 350 small cement manufacturing units in the country. More than 80% of the cement-manufacturing units use modern environment friendly “dry” process.

There are around 11 different types of cement that are being produced in India. The production of all these cement varieties is according to the specifications of the BIS (Bureau Of Indian Standards).

Some of the various types of cement produced in India are:

* Clinker Cement
* Ordinary Portland Cement
* Portland Blast Furnace Slag Cement
* Portland Pozzolana Cement
* Rapid Hardening Portland Cement
* Oil Well Cement
* White Cement
* Sulphate Resisting Portland Cement

India’s per capita cement production: 130 kg per annum. World average of per capita cement production: More than 280 kg per annum.