Correct Answer - Option 2 : Dicalcium Silicate
Concept
There are four compounds (Called Bogue's Compounds) formed as a result of hydration of cement:
Alite: C3S, or Tricalcium Silicate
Belite: C2S, or Dicalcium Silicate
Aluminate phase: C3A, or Tricalcium Aluminate
Ferrite phase: C4AF, or Tetracalcium Aluminoferrite
Bogue Compounds:
Dicalcium Silicate (C2S): This compound will undergo reaction slowly. It is responsible for the progressive strength of concrete. This is also called as Belite.
A higher percentage of C2S results in slow hardening, less heat of hydration, and great resistance to chemical attack.
The heat of hydration is 260 J/Cal.
Tricalcium silicate (C3S): This is also called as Alite. It undergoes hydration within one week and helps in the development of strength in the early stages of concrete (aka hardening).
It has the best cementitious property among all the other Bogue's Compounds. Tricalcium Silicate (C3S) hardens rapidly and is largely responsible for the initial set and early strength.
The cement that has more C3S content is good for cold weather concreting. The heat of hydration is 500 J/Cal.
Tricalcium aluminate (C3A): Celite is the quickest one to react when the water is added to the cement. It is responsible for the flash setting. The increase of this content will help in the manufacture of Quick Setting Cement.
It provides weak resistance against sulphate attack and contribution to the development of strength is significantly less than above two bogue compounds.
The heat of hydration is 865 J/Cal.
Tetra calcium Alumino ferrite (C4AF): This is called as Felite. The heat of hydration is 420 J/Cal. It has the poorest cementing value but it responsible for long term gain of strength of the cement.
