There are many times of cement but the below are commonly used:

1.     OPC (ORDINARY PORTLAND CEMENT). 

This is  one of the commonly used cement. This is the basic cement for all construction activities. By adding some additives with this cement, we can produce some other cement types.

PPC (PORTLAND POZZOLLONA CEMENT OR POZZOLLANA CEMENT)

This is the only cement that can be  used in areas where cement is exposed to water or in under water areas ie., bridges across rivers, seas and dams etc.,

Other types of cements tends to crack if used at these places.

This cement remains harder even under water, but has a lower strength compared to other grades of  OPC cements like 43 grade and 53 grade cements . A defined quantity of flyash / ash (15 - 35%) added to OPC cement is called pozzollana cement.

That is, OPC cement becames PPC cement after mixed with flyash/ash.    
 (Image of flyash in hand) 
                                               

SLAG CEMENT :


A defined quantity of blast furnace slag (30 - 70%) added to OPC cement is called slag cement. Slag is a by product from iron industry.

(Image of blast furnace slag)


Blast furnace is used for smelting iron in iron industry from where slag was obtained as a by product. So slag was also called blast furnace slag.  

Slag cement was used in building concretes as it has less tendency to crack. Also slag cement provides good resistance to corrosion attacks and chemical attacks with low permeability. So it was widely used in industries like toxic waste treatment plants.

 WHITE CEMENT :

 A OPC cement produced with low iron levels makes cement white. It was used in decoration and white wash purpose.