Cement is commonly used as a binding material in construction. It is manufactured through either natural or artificial processes by burning limestone and clay at high temperatures, which produces clinker. In the wet process, limestone and clay are mixed as slurry and burned in a rotary kiln to produce clinker, while the dry process avoids slurry formation. The clinker is then ground with gypsum to produce cement powder. Cement sets due to hydration and provides cohesion and strength in structures.

1. Cement is an important building material.
It is commonly used as binding material.
It is manufactured either from natural stones or by
artificial methods.
Natural cement: Obtained by burning and crushing
the stones containing Clay, carbonate of lime and
magnesia.

2. It is brown in color and has lesser
strength.Eg:Roman cement.
Artificial cement: Manufactured by burning
a mixture of calcareous and argillaceous
materials at high T.
Eg:Ordinary portland cement(OPC)

5. i. Excellent building material.
ii. Attains early setting.
iii. It has higher strength.
iv. Easily workable.
v. Offers good resistance to moisture.
vi. Possesses good plasticity.

6. I. Most commonly used building material.
II. Used to prepare cement mortar.
III. Cement mortar is used for masonry works,
plastering,…..
IV. Used to prepare cement concrete.
V. Used for laying floors, Structural components
such as beam,Column, lintel, roof, etc…

7. VI. Used to make precast products such as slabs.
VII. Used in construction
bridges,culverts,dams,tunnels,
tanks,roads,wells,etc.Used for making joints for
drains, pipes,etc.
IX. Used for special applications such as
expansive
X. cement for repair of cracks,white cement for
ornamental finish, quick setting cement for
structures under water, etc.

8. Ordinary cement contains two
basic ingredients:
A. Calcareous materials (Eg:
limestone,Chalk)
B. Argillaceous materials(Eg:clay)

9. Chemical composition of OPC
Ingredient Chemical form
1)Lime
2)Silica
3)Calcium sulphate
4)Alumina
5)Iron oxide
6)Magnesia
7)Sulphur
8)Alkalies
1)Cao(62%)
2)SiO2(27%)
3)CaSO4(4%)
4)Al2O3(5%)
5)Fe2O3(3%)
6)MgO(2%)
7)S(1%)
8)(1%)

10.  Lime: Imparts strength and
soundness to the cement.
 Silica: Imparts strength due to
formation of dicalcium and tricalcium
silicates.
 Alumina: Imparts quick setting
property.

11. Calcium sulphate: Present in the form
of GYPSUM which increase the initial
setting time of cement.
 Iron Oxide: Imparts and strength to
cement.
 Magnesia: Imparts hardness and
color.
 Sulphur and Alkalies: Imparts
hardness.

12. Cement is manufactured by
1. Wet process
2. Dry process
Manufacture of cement involves 3 steps:
1. Mixing of raw materials
2. Burning
3. Grinding

13. DRY PROCESS

14. WET PROCESS

15. Raw materials:
a. Limestone
b. Clay

16. Manufacture of cement by wet process:
MIXING OF RAW MATERIALS:
Limestone is crushed and stored in silos.
Clay is washed with water and stored
In basins.
The crushed limestone and wet clay are mixed
in correct proportion.
It is made into slurry with the help of grinding
mills.
It is then taken to correcting tank to achieve
correct chemical composition. It is then stored in
storage tanks.

17. BURNING:
It is carried out in ROTARY KILN.
The slurry is fed into the rotary kiln and is
heated by using coal dust.
Due to this the slurry losses its moisture
and forms into small lumps.
The temperature is kept b/w 1500-
1650deg.

18. The lumps are converted into small hard
stones known as CLINKERS.
The size of clinkers varies b/w 5-10mm.
It is then cooled in clinkers and stored in
containers.

20. GRINDING:
Cooled clinkers are ground in Ballmills
and Tubemills.
During grinding 3-4% of gypsum is
added to control the initial setting time of
cement.
Gypsum acts as retarder.
The finely grounded cement is stored
and then weighed and packed in bags.

21. QUALITIES OF GOOD CEMENT:
1) Color should be uniform.
2) It should be of uniform fineness and free
from lumps.
3) Cement if thrown in water should sink.
4) When tested in accordance with IS
specification,the average compressive
strength at the age of 3days and 7days
should not be less than 11.5MPa and
16MPa.

22. 5) The average tensile strength at the age of
3and7days should not be less than 2N/mm2 and
2.5N/mm2.
6) Initial setting time: < half an hour .
Final setting time: around 10hrs.
7) Insoluble residue should be < 1.5%
8) Magnesia content: < 5%0
9) Expansion of cement should not be greater than
10mm during soundness test.
10) When the cement is sieved in 90micron sieve,
the residue should not exceed 10%.

23. Presented by.,
Aravinth M
Thank you .,