TYPES OF CEMENT AND THEIR USES

Following are the different types of cement used in construction work:

1. RAPID HARDENING CEMENT:

Rapid hardening cement is very similar to ordinary portland cement. It contain higher percentage of tricalcium silicate C3S to the extent about 56%. Burning at high temperature and very fine grinding is also necessary. It obtain strength in a short period. The compressive strength at the end of one day is about 11.50 N/mm2 and at the end of 3 days is about 21 N/mm2. Similarly the tensile strength at the end of one day is about 2 N/mm2 and at the end of 3 days is about 3 N/mm2.

It is light in weight and not damaged easily.The structural member constructed with this cement may be loaded earlier and requires short period of curing. The formwork can be removed earlier and reused in other area which save the cost of formwork.

Rapid hardening cement is used in prefabricated concrete construction, road work etc.
(IS:8041-1990)

2. QUICK SETTING CEMENT:

Quick setting cement produced by reducing the percentage of gypsum adding a small amount of aluminium sulphate during the manufacture of cement. The addition of aluminium sulphate and fineness of grinding are responsible for accelerating the setting action of cement. The setting action of quick setting cement starts with in five minutes after addition of water and it becomes hard like stone in less than 30 minutes or so.

The extreme care is to be taken when this cement is used as mixing and placing of concrete are to be completed in a very short period. this cement is used where work is be completed in very short period and for concreting under static water or running water.

3. LOW HEAT CEMENT:

Low heat cement is manufactured by increasing the proportion of C2S and by decreasing the C3S and C3A content. This cement posses less compressive strength. The initial setting time is about one hour and final setting time is about 10 hours. This cement is less reactive and used mostly used in mass concrete construction.

(IS:12600-1989)

4. SULPHATE RESISTING CEMENT:

It is a cement cement with low C3A content and comparatively lower C4AF content. The percentage of tricalcium aluminate (C3A) is kept below 5%. and it results in the increase in resisting power against sulphate attack.

Sulphate resisting cement is used in construction exposed to sever sulphate action by soil and water in place likes canal lining, culvert, retaining walls, siphons etc.

(IS:12330-1998)

5. BLAST FURNACE SLAG CEMENT:

This cement is produced by clinker of cement with about 50-60 percent of Slag. Slag is a waste product in the manufacturing process of pig iron and it contains the basic elements of cement namely alumina, silica, and lime. The properties of this cement are more or less same as ordinary cement. It is cheap cement because of the utilization of waste for its production. This cement is durable but it gains strength slowly and hence needs longer period of curing.

Blast furnace slag cement is used in mass construction works such as making dams, retaining walls, foundations and abutment of bridge, construction in sea water.

6. HIGH ALUMINA CEMENT:

High alumina cement is a special cement, manufactured by mixing of bauxite and lime at a certain temperature. This cement also known as calcium aluminum cement. The initial setting time of this cement is about 3.5 hours and final setting time is about 5 hours. The compressive strength of this cement is very high and more workable than ordinary portland cement. It can stand high temperature and resists the action of acid in a better way. It is used for under water works.

(IS:6452-1989)

7. WHITE CEMENT:

White cement is a type of ordinary portland cement which is pure white in colour and has same composition and same strength as ordinary cement. This cement is manufactured from the materials that contain very little amount of iron oxide and manganese oxide. The raw material used in this cement are lime stone and china clay.

It is costlier and used for architectural purposes such as precast curtain wall and facing panels, terrazzo surface etc and for interior and exterior decorative work like external renderings of buildings, facing slabs, flooring, ornamental concrete products, paths or gardens, swimming pools etc.

(IS:8042-1989)

8. COLOURED CEMENT:

This cement is produced by adding 5 - 10% mineral pigments with portland cement during the time of grinding. This cement is widely used for interior and exterior decorative works such as giving finishing touch to floors, walls, roof, window shills etc. It is used for making artificial marble.

9. POZZOLANA CEMENT:

Pozzolana is a volcanic powder found in Italy near Vesuvius. It can also be processed from shales and certain types of clays. The percentage of pozzolana material should be between 10 to 30.

It gains high compressive strength with age.
It release less heat during setting.
It impart higher degree of water tightness.
It can resist action of sulphates.
It offers great resistance to the expansion and posses higher tensile strength.

It is used in marine structures, sewage work and for laying concrete under water such as bridge, piers, dams and mass concrete works.

(IS:1489-1991)

10. AIR ENTRAINING CEMENT:

Air entrainment is process of creating air bubbles by adding some air entraining agents. Air entraining cement is produced by adding indigenous air entraining agents such as resins, glues, sodium salts of sulphates etc during grinding of clinker. The main purpose of these types of cement is to fill the gap produced in concrete because of excessive water during casting. The enrained air produced separate cavities in the cement paste and fills the channel created due to passage of water. It increase the durability of concrete structures. It is used in cold countries for the construction of concrete structures.

11. EXPENDING CEMENT:

This types of cement is produced by adding an expending medium like sulpho-aluminate and a stabilising agent to the ordinary cement. Hence, this cement expands whereas other cement shrink. The expending cement is used for the construction of water retaining structures and also for repairing the damage concrete surfaces.

12. HYDROPHOBIC CEMENT:

Hydrophobic cement is manufactured by adding water repellant chemicals like petrolatum and naphthalene soap to ordinary portland cement in the process of grinding. It has high workability and strength. These types of cement does not get spoiled even during mansoon season because of water repelling property.

It is used to construct hydraulic structures such as dames, spill way, water tanks, water retaining structures etc.

(IS:8043-1991)