Functions of ingredients of cement

 1. Lime:

 Lime is the important ingredient of cement and its  proportion is to be  maintained carefully. Lime in excess  makes the cement unsound and causes the cement to expand and disintegrate. On the other hand, if lime  is  in  deficiency  the strength  of the cement is  decreased and it causes cement to set quickly 

2. Silica: 

This also an important ingredient of cement and it gives or imparts quick setting property  to imparts strength to cement. 

3.Alumina:  

This ingredient imparts quick setting properly to cement. Express alumina  weakens the cement.   

4. Calcium Sulphate: 

This ingredient is in the form  of gypsum  and its function is to increase the initial setting time  of cement. 

5. Magnesia: 

The small amount of this ingredient imparts hardness and colour to cement. 

6. Sulphur: 

A very  small amount of sulphur  is useful in making sound cement. If it is in excess, it causes the cement to become  unsound. 

7. Alkalies: 

Most of the alkalies present in  raw  material are carried away by  the flue gases during heating and only  small quantity  will be left. If they  are in excess in cement, efflorescence is caused.