I hope You all like it. I hope It is very beneficial for you all. I really thought that you all get enough knowledge from this presentation. This presentation is about materials and their classifications. After you read this presentation you knowledge is not as before.

2. Cement:
Cement is the mixture of
calcareous, siliceous, argillaceous and
other substances. Cement is used as
a binding material in mortar, concrete,
etc.

3. Chemical Composition of cement
is:
Lime 63%
Silica 22%
Alumina 06%
Iron oxide 03%
Gypsum 01 to 04%

4. MANUFACTURING OF CEMENT:
(1) Mixing and crushing of raw materials
a. Dry process
b. Wet process
(2) Burning
(3) Grinding

5. (a) Dry process:
In this process calcareous material such as
lime stone (calcium carbonate) and
argillaceous material such as clay are ground
separately to fine powder in the absence of
water and then are mixed together in the
desired proportions. Water is then added to it
for getting thick paste and then its cakes are
formed, dried and burnt in kilns. This process
is usually used when raw materials are very
strong and hard.
In this process, the raw materials are changed
to powdered form in the absence of water.

6. (b) Wet process:
In this process, the raw materials are changed
to powdered form in the presence of water.
In this process, raw materials are pulverized by
using a Ball mill, which is a rotary steel cylinder
with hardened steel balls. When the mill rotates,
steel balls pulverize the raw materials which
form slurry (liquid mixture). The slurry is then
passed into storage tanks, where correct
proportioning is done. Proper composition of
raw materials can be ensured by using wet
process than dry process. Corrected slurry is
then fed into rotary kiln for burning.

7. (b) Wet Process: Continued------
This process is generally used when raw
materials are soft because complete mixing is
not possible unless water is added.
Actually the purpose of both processes is to
change the raw materials to fine powder.

8. (2) Burning:
Corrected slurry is feed to rotary kiln,
which is a 150-500 feet long, 8-16 feet in
diameter and temperature arrangement
is up to 1500-1650 degree C.At this
temperature slurry losses moisture and
forms into small lumps, after that
changes to clinkers. Clinkers are cooled
in another inclined tube similar to kiln but
of lesser length.

9. (3) Grinding:
Now the final process is applied which is
grinding of clinker, it is first cooled down to
atmospheric temperature. Grinding of clinker
is done in large tube mills. After proper
grinding gypsum (Calcium sulphate Ca SO4)
in the ratio of 01-04 % is added for
controlling the setting time of cement.
Finally, fine ground cement is stored in
storage tanks from where it is drawn for
packing.

10. TYPES OF CEMENT:
1. Ordinary Portland Cement
2. Sulphate Resisting Cement
3. Rapid Hardening Cement (or) High
Early Strength cement
4. Quick Setting Cement
5. Low Heat Cement
6. High Alumina Cement
7. Air Entraining Cement
8. White Cement

11. (1) ORDINARY PORTLAND CEMENT:
It is the variety of artificial cement. It is
called Portland cement because on
hardening (setting) its colour resembles to
rocks near Portland in England. It was first
of all introduced in 1824 by Joseph Asp din,
a bricklayer of Leeds, England.

12. Chemical Composition of O.P.Cement:
O.P.C has the following approximate chemical
composition:
The major constituents are:
1. Lime (CaO) 60- 63%
2. Silica (SiO2) 17- 25%
3. Alumina (Al2O3) 03- 08%

13. Chemical Composition of O.P.Cement:
Continued-------
The auxiliary constituents are:
1. Iron oxide (Fe2O3) 0.5- 06%
2. Magnesia (MgO) 1.5- 03%
3. Sulphur Tri Oxide (SO3) 01- 02%
4. Gypsum 01 to 04%

14. Functions of Cement ,
Manufacturing
and
Constituents

15. (i) Lime (CaO):
Lime forms nearly two-third (2/3) of the
cement. Therefore sufficient quantity of
the lime must be in the raw materials for
the manufacturing of cement. Its
proportion has an important effect on the
cement. Sufficient quantity of lime forms
di-calcium silicate (C2SiO2) and tri-
calcium silicate in the manufacturing of
cement.
Lime in excess, causes the cement to
expand and disintegrate.

16. (ii) Silica (SiO2):
The quantity of silica should be
enough to form di-calcium
silicate (C2SiO2) and tri-calcium
silicate in the manufacturing of
cement. Silica gives strength to
the cement. Silica in excess
causes the cement to set slowly.

17. (iii) Alumina (Al2O3):
Alumina supports to set quickly to
the cement. It also lowers the
clinkering temperature. Alumina in
excess, reduces the strength of the
cement.

18. (iv) Iron Oxide (Fe2O3):
Iron oxide gives colour to the cement.

19. (v) Magnesia (MgO):
It also helps in giving colour to the cement.
Magnesium in excess makes the cement
unsound.

20. (vi) Calcium Sulphate (or) Gypsum (Ca
SO4) :
At the final stage of manufacturing,
gypsum is added to increase the setting of
cement.

21. (2) SULPHATE RESISTING CEMENT:
It is modified form of O.P.C and is specially
manufactured to resist the sulphates. In certain
regions/areas where water and soil may have
alkaline contents and O.P.C is liable to
disintegrate, because of unfavourable chemical
reaction between cement and water, S.R.C is
used. This cement contains a low %age of C3A not
more than 05%.
This cement requires longer period of curing. This
cement is used for hydraulic structures in alkaline
water and for canal and water courses lining. It
develops strength slowly, but ultimately it is as
strong as O.P.C.

22. (3) RAPID HARDENING CEMENT:
This cement contains more %age of C3S and less %age of
C2S. This is infact high early strength cement. The high
strength at early stage is due to finer grinding, burning at
higher temperature and increased lime content. The
strength obtained by this cement in 04 days is same as
obtained by O.P.C in 14 days. This cement is used in
highway slabs which are to be opened for traffic quickly.
This is also suitable for use in cold weather areas. One
type of this cement is manufactured by adding calcium
chloride (CaCl2) to the O.P.C in small proportions.
Calcium chloride (CaCl2) should not be more than 02%.
When this type of cement is used, shuttering material can
be removed earlier.

23. (4) QUICK SETTING CEMENT:
When concrete is to be laid under water,
quick setting cement is to used. This cement
is manufactured by adding small %age of
aluminum sulphate (Al2SO4) which
accelerates the setting action. The setting
action of such cement starts with in 05
minutes after addition of water and it
becomes stone hard in less than half an
hour.

24. (5) LOW HEAT CEMENT:
In this cement the heat of hydration is
reduced by tri calcium aluminate (C3 A )
content. It contains less %age of lime than
ordinary port land cement. It is used for
mass concrete works such as dams etc.

25. (6) HIGH ALUMINA CEMENT:
This cement contains high aluminate %age
usually between 35-55%. It gains strength
very rapidly with in 24 hours. It is also
used for construction of dams and other
heavy structures. It has resistance to
sulphates and action of frost also.

26. (7) AIR ENTRAINING CEMENT:
This type of cement was first of all developed in
U.S.A to produce such concrete which would
have resistance to weathering actions and
particularly to the action of frost. It is found that
entrainment of air or gas bubbles while applying
cement, increases resistance to frost action. Air
entraining cement is produced by grinding minute
air entraining materials with clinker or the
materials are also added separately while making
concrete. Entrainment of air also improves
workability and durability. It is recommended that
air contents should be 03-04 % by volume.
Natural resins, fats, oils are used as air entraining
agents.

27. (8) WHITE CEMENT:
This cement is called snowcrete. As iron
oxide gives the grey colour to cement, it is
therefore necessary for white cement to
keep the content of iron oxide as low as
possible. Lime stone and china clay free
from iron oxide are suitable for its
manufacturing. This cement is costlier
than O.P.C. It is mainly used for
architectural finishing in the buildings.

28. TO CHECK THE QUALITY OF CEMENT
IN THE FILED:
1.Colour greenish grey.
2.One feels cool by thrusting one’s hand
in the cement bag.
3.It is smooth when rubbed in between
fingers.
4.A handful of cement thrown in a bucket
of water should float.

29. QUALITY TESTS OF CEMENT:
(1) Fineness Test,
(2) Consistency test / setting time
test
(3) Setting Time Test
(4) Compressive strength test