Types of Cement
Cement is a building material that is used in the construction industry. Cement sets well underwater and hardens quickly and attain strength. Cement contains hydraulic properties to a great extent and acquires more strength in the setting. In actual cement is a Calcareous substance that is used in mortar or concrete for construction.
A wide variety of cement types are available, which are suitable for use under certain conditions due to its unique properties. They are as follows.
- Ordinary Portland cement (OPC)
- Portland pozzolana cement (PPC)
- Rapid hardening Portland cement
- Extra rapid hardening Portland cement
- Low heat Portland cement
- Sulphate-resisting Portland cement
- Supersulphated cement
- High alumina cement
- Portland blast furnace
- White Portland cement
- Air-entraining cement
- Hydrophobic cement
- Quick setting cement
- Coloured cement
Ordinary Portland Cement (OPC)
It is used for making concrete used in general construction. It has a low resistance to chemical attack, and it has a medium rate of hardening. The colour of ordinary Portland cement is grey or greenish-grey. Chemical compositions are silica-alumina, iron oxide, magnesia, Sulphur trioxide, soda and potash. It comes with grades 33,43 and 53.
Uses: Commonly used for all type of construction works. Widely, used in residential construction where a particular type of cement properties is not required.
Portland pozzolana cement (PPC)
It is produced by grinding together a mixture of 20 to 40% pozzolana material (which may be a naturally active material like fly ash, Volcanic tuff, clay and shale and rice husk ash) and 60 to 80% Portland cement. It has a higher resistance to chemical disintegration and sulphate attack.
Uses – This cement is especially useful in marine and underwater constructions. This cement produces less heat of hydration and offers more excellent resistance to the attack of water than ordinary Portland cement.
Rapid hardening Portland cement
It develops strength rapidly, so as it is called as High early strength cement. This cement develops strength rapidly due to the higher fineness of grinding and high C3S and lowers C2S content.
Uses – This type of cement is used where high strength is needed to be achieved in the initial stage quickly. It is mainly used for the construction of underwater work.
- Road Pavement Work
- Precast concrete casting (Beam, column etc.)
Extra rapid hardening Portland cement
It contains calcium chloride ground with it, which accelerates the chemical reaction, it results in increasing the initial rate of gain of strength and the evolution of heat.
Uses – It is used in cold weather conditions. It has 25% higher strength than rapid hardening cement at a period of 1 to 2 days and 10 to 20% higher at seven days.
Low heat Portland cement
A cement which produces less amount of heat is called low heat cement. It is evolved by reducing the content C3S and C3A, which are the compounds developing the maximum heat of hydration and increasing C2S.
Uses – This type of cement is used in mass constructions like the dam and where high wear resistance is required.
- Mass construction (Dams, Marine construction)
- Hydraulic engineering concrete
- Retaining wall construction
Sulphate-resisting Portland cement
To remedy the sulphate attack, the use of low C3A content found to be effective. Such cement with low C3A and comparatively low C4A content is known as sulphate resisting cement. This cement contains a high percentage of silicate.
Uses – This type of cement is used in foundation basement where soil infected with sulphate. It is also used in case of construction of sewage treatment works and even in the marine structure.
- Pile foundation
- In coastal area works
- Sewage and water treatment plants
It is made by grinding together blast furnace slag, calcium sulphate and an activator, usually, Ordinary Portland cement. It is highly resistant to sulphate attack and can withstand attack from acid having a pH value as low as 3.5. It has a very low evolution of heat.
Uses – Due to the low heat of hydration, it is suitable for mass concreting and Dam construction.
High alumina cement
It is produced by fusing a mixture of limestone and bauxite. It has an exceptionally high proportion of aluminate (33 to 44%), resulting in the rapid development of strength and high evolution of heat.
Uses – It is used in massive concrete construction and works of furnaces and chemical plants.
Portland blast furnace or Slag Cement
It is manufactured grinding together a mixture of Portland cement, clinker and blast furnace slag with a small quantity of gypsum. The proportion of slag is limited to 65% of the total. It has a lower rate of hardening, lower heat of hydration and is more resistant to chemical attack, especially in seawater, than ordinary Portland cement.
Uses – It is used in mass concreting work like Dams, Foundations which need low heat of hydration. It is also used in areas which are susceptible to chloride attack.
White Portland cement
It has the same properties as of Ordinary Portland cement except that strength is little lower than the ordinary Portland cement. White cement is available in the market in 5kg, 10Kg, 20 kg and 50 kg bags.
- It is used for aesthetic purpose.
- Used as a base coat before painting.
- Used to cover the hairline cracks on the concrete surface to give a smooth finish.
It is ordinary Portland cement to which an air-entraining agent has been inter ground during the manufacturing process. These material have the property of entraining more air in the concrete in the form of air bubbles of diameter 0.075 mm to 1.25 mm. It is more resistant to freezing.
Uses – It is used to fill up the gap in concrete which are produced by an excessive amount of water during casting (later evaporated and leave the opening), used in frost resistance concrete (frost also make a gap in concrete).
It is Ordinary Portland cement to which additive is mixed which give a protective coating to the cement particles. Thus inhibiting hydration of the cement This enables the cement to be stored in damp or buried conditions for a much more extended period than is possible for ordinary Portland cement.
- It is useful in wet climatic conditions.
- Applicable when cement is stored for longer duration in wet climatic condition.
Quick setting cement
This type of cement sets very early. This property is brought out by reducing the gypsum content at the time of clinker grinding.
Uses – This cement is used where the works need to be done quickly.
- In underwater construction.
- In cold and rainy weather conditions.
Coloured cement is manufactured by grinding 5 to 10% of suitable colour pigment with ordinary portland cement. It is used for any aesthetic purpose, artificial marble and flooring finishing.
Uses – It is used for external surfaces, finishing of floors, decorative work etc.
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