cement

CEMENT

                        One of the most important and widely acceptable construction material. The binding property of the cement makes the cement this much important. cement have both cohesive and adhesive property this property of cement is helpfull or desirable to bind the ingrediant of mortar and concrete.

         The cement was first time manufactured by "Joseph Aspdin". The name given by him to the cement is portland cement because the the texture of harden cement mass resembles the stone quary of portland area in england. 

Cohesive property

                                   It is the property of cement which binds the particles of same nature that is when cement particles gets binded with another cement particle the it is referred as cohesive property.

Adhesive property

                                       It is referred as the property of cement where cement particles get binded with the particles of different nature. for example when cement particles get binded with the sand particles then it is referred as adhesive property of cement.

   MANUFACTURING OF CEMENT

The cement is a composition of calcareous component and argilaceous component, where the calcareous component is the one which has rich content of calcium(Ca) eg- lime stone, chalk. whereas the argilaceous component is the one which has rich content of alumina and silica  eg-sand stone, blast furnace slag and fly ash etc...

   The cement can be manufactured by...

• Wet process ( old method )
• Dry process ( new metod )

                                     DRY PROCESS

• Grinding 

                      When the grinding of lime stone and stand stone is done in the absence of moisture the it is known as dry grinding and the grinder used for grinding is ball mill and tube mill, ball mill offers greater grinding capacity when compared to tube mill.

• Mixing 

                 The calcareous and argilaceous component i.e lime stone and sand stone are mixed in a ratio 3:1 respectively
      The strength of cement is majorly governed by the content of lime therefore lime stone is kept on a higher side with respect to clay or sand.

• Burning

               The burning of dry mix involves the burning in preheater and post heater ( rotary kiln )

    Preheater Tempreture is less than 800 c

                  It removes the moisture from raw mix.

                  It certainely reduces the size of raw mix.

                  It make the raw mix pre heated

    Postheater Tempreture is between 801-1500 c ( rotary kiln )

               generally rotary kiln is divided in 3 parts virtually 

            1. Dry zone ( temp. 801-1000 c ) 

            2. Nodules zone ( temp. 1001-1200 c)

            3. Burning zone ( temp. 1201-1500 c)

                             In dry zone if the process is wet process then the moisture is removed from the slurry it is less significant for dry process.

In nodules zone raw mix converted in nodules  (lumps).

                              In burning zone the calcareous and argilaceous component ingredient get reacted with each other at a temp. 1200-1500 c to form the compound called bouge's compound. and this bouges compound is responsible for binding strength in cement.

                              The product obtain from rotary kiln is called clinker which has property of quick setting which is referred as flash set property. In order to prevent quick setting gypsum is added to it about ( 3-4 % of weight of clinker) 

            and finally the clinker and gypsum is grinding together in tubemill or ballmill to get cement....