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)
