COMPOSITION OF ORDINARY CEMENT
Composition of ordinary cement
The ordinary cement contain two main ingredients for argillaceous
and calcareous. in argillaceous materials the clay predominates and in
calcareous materials the calcium carbonate predominates.
The ordinary cement contents ratios
Ingredient
|
Percent
|
Lime Cao
|
62
|
Silica SiO2
|
22
|
Alumina Al2O3
|
05
|
Calcium sulphate Caso4
|
04
|
Iron oxide Fe2o3
|
03
|
Magnesia MgO
|
02
|
Sulphur
S
|
01
|
Alkalies
|
01
|
Total
|
100
|
Functions of ingredients of cement
Lime (cao)
This is the very important ingredients of cement .proportion
of lime is carefully maintained .because the excess of lime make the cement
soundness and make the cement expand .at the same time ,if the lime is deficiency , the strength
of the cement is decreased and its cause cement set to quickly
Silica (sio2)
Silica is also important component of cement .its give more strength to
cement due to formation of di-calcium and tri-calcium silicates .if the silica
is live more content in cement it caused the cement strength less .but at the same
time its setting time is increased
Alumina (Al2o3)
Alumina is used to quick setting time of cement .it act as a
flux and it lower the clinkering temperature temperature is the essential for the cement
.other hand live of excess of alumina it cause weakens of cement
Calcium sulphate (Caso4)
The ingredients is the form of gypsum and its function is to
increase the initial setting time of cement.
Iron oxide (fe2o3)
Iron oxide is to provide the color of cement .also this is
used to increase the strength and hardness of
cement.
Magnesia (Mgo)
Magnesia is present in very small amount of cement. It impart
hardness and colour to the cement .high
amount of magnesia make the cement soundness.
Sulphur (s)
Very small amount of sulphur is make cement sound. High
amount of sulphur make the cement soundness so the proportion of sulphur is very carefully maintained
Alkalies
Cement have very small amount of alkalies .if they present
in excess it cause the many troubles such as alkali aggregate reaction
,efflorescence and straining when used in concrete ,bricks or mortar .
