According to Civil Engineering material books there are more that 13 type of cements available in construction world. But in Indian cement industry produce its product as per construction need. Generally 4 type of cement production going on at cement plant or grinding unit.
For construction practice 4 types of cement used as Ordinary Portland Cement(OPC), Portland Pozzolana Cement(PPC), Portland Slag Cement(PSC) and Composite Cement.
There are three grade of OPC available in cement industry are 33 Grade, 43 Grade and 53 Grade but conservation of lime stone ,the use of OPC decrease. Government restricted cement companies to produce OPC until its urgency. In case of structure demand ,production of OPC generated as non trade(Not For Sale).OPC contain 95% of lime and 5% of gypsum.
Many cement company provide OPC as Non Trade cement category directly to construction site. Now a days OPC only used at construction site by licensed contractor or building.
Mostly PPC used at construction project. Many cement dealer sells PPC at their shop due to is dark colour and initial high strength. PPC contain not less than 15% and not more than 35% of flyash ,5% gypsum and rest % of lime.
Portland Slag Cement used in massive structure and its provide later strength. But this Portland Slag Cement gain more strength than Portland Pozzolana after 7 days of casting. Portland Slag Cement contain not less than 25% and not more than 65% of slag,5% of gypsum and rest % of lime.
To reduce the use of lime stone in cement and utilize the fly ash and slag ,many cement brand launch their composite cement now a days. Composite cement provide required minimum 33 MPa strength in 28 days of casting. Composite cement contain not less than 15% and not more than 35% of flyash, not less than 25% and not more than 65% of slag,5% of gypsum and rest % of lime. Its a good quality cement for our environment.
As we know PPC and PSC are generally used in construction practice, but now most of cement company comes with its composite cement which provide same strength as compare to other and cement industries gain more profit by use using this civil engineering technology.