Types of Cement
- Ordinary Portland Cement
- Rapid Hardening Cement
- Extra Rapid Hardening Cement
- Sulfate Resisting Cement
- Portland Slag Cement
- Quick Setting Cement
- Super Sulphated Cement
- Low Heat Cement
- Portland Pozzolana Cement
- Air En training Cement
- Co-loured Cement: White Cement
- Hydrophobic Cement
- Masonry Cement
- Expansive Cement
- Oil Well Cement
- Rediset Cement
- Concrete Sleeper grade Cement
- High Alumina Cement
1. Ordinary Portland Cement
Ordinary Portland cement (OPC) is by far the most important type of cement.
All the discussions that we have done in the previous chapter and most of the discussions that are going to be done in the coming chapters relate to OPC.
Prior to 1987, there was only one grade of OPC which was governed by IS 269-1976.
After 1987 higher grade cements were introduced in India.
The OPC was classified into three grades, namely 33 grade, 43 grade and 53 grade depending upon the strength of the cement at 28 days when tested as per IS 4031- 1988.
If the 28 days strength is not less than 33N/mm, it is called 33 grade cement, if the 2 strength is not less than 43N/mm, it is called 43 grade cement, and if the strength is not less 2 then 53 N/mm, it is called 53 grade cement.
2. Rapid Hardening Cement
This cement is similar to ordinary Portland cement.
As the name indicates it develops strength rapidly and as such it may be more appropriate to call it as high early strength cement.
It is pointed out that rapid hardening cement which develops higher rate of development of strength should not be confused with quick-setting cement which only sets quickly.
Rapid hardening cement develops at the age of three days, the same strength as that is expected of ordinary Portland cement at seven days.
3. Extra Rapid Hardening Cement
Extra rapid hardening cement is obtained by inter-grinding calcium chloride with rapid hardening Portland cement.
The normal addition of calcium chloride should not exceed 2 per cent by weight of the rapid hardening cement. It is necessary that the concrete made by using extra rapid hardening cement should be transported, placed and compacted and finished within about 20 minutes. It is also necessary that this cement should not be stored for more than a month.
4. Sulfate Resisting Cement
Ordinary Portland cement is susceptible to the attack of sulfates, in particular to the action of magnesium sulfate.
Sulfates react both with the free calcium hydroxide in set- cement to form calcium sulfate and with hydrate of calcium illuminate to form calcium sulfate alumina, the volume of which is approximately 227% of the volume of the original illuminate.
5. Portland Slag Cement (PSC)
Portland slag cement is obtained by mixing Portland cement clinker, gypsum and granulated blast furnace slag in suitable proportions and grinding the mixture to get a thorough and intimate mixture between the constituents.
It may also be manufactured by separately grinding Portland cement clinker, gypsum and ground granulated blast furnace slag and later mixing them intimatel
6. Quick Setting Cement
This cement as the name indicates sets very early. The early setting property is brought out by reducing the gypsum content at the time of clinker grinding.
This cement is required to be mixed, placed and compacted very early. It is used mostly in under water construction .
7. Super Sulphated Cement
Super sulphated cement is manufactured by grinding together a mixture of 80-85 per cent granulated slag, 10-15 per cent hard burnt gypsum, and about 5 per cent Portland cement clinker.
The product is ground finer than that of Portland cement. Specific surface must not be less than 4000 cm per gm.
8. Low Heat Cement
It is well known that hydration of cement is an exothermic action which produces large quantity of heat during hydration.
Formation of cracks in large body of concrete due to heat of hydration has focused the attention of the concrete technologists to produce a kind of cement which produces less heat or the same amount of heat, at a low rate during the hydration process.
Cement having this property was developed in U.S.A. during 1930 for use in mass concrete construction, such as dams, where temperature rise by the heat of hydration can become excessively large.
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