Hydration of Portland Cement
CORRECT decreasing order of rate of hydration of Portland cement compounds
- C3A
- C4AF
- C3 S
- C2 S
C4AF > C3A > C3S > C2S
The setting and hardening of cement after addition of water is due to hydration of some of the constituent compounds of cement such as Tricalcium aluminate, Tricalcium silicate, Dicalcium silicate, and Tetra calcium aluminoferrite.
These compounds are known as Bogue’s Compounds.
Hydration of Bogues Compounds
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. The heat of hydration is 865 J/Cal.
Tricalcium silicate (C3S):
This is also called as Alite. This is also responsible for the early strength of the concrete. The cement that has more C3S content is good for cold weather concreting. The heat of hydration is 500 J/Cal.
Dicalcium Silicate (C2S):
This compound will undergo reaction slowly. It is responsible for the progressive strength of concrete. This is also called as Belite. The heat of hydration is 260 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.
For the rate of hydration is highest for C4AF and heat of hydration is highest for C3A.
From the above, the decreasing order of rate of hydration of Portland cement compounds is
C4 AF > C3 A > C3 S > C2 S.
For the heat of hydration, decreasing order of heat of hydration of portland cement is
C3 A > C3 S > C4 AF > C2S
Note: Heat of Hydration and Rate of Hydration is different
The setting and hardening of cement after addition of water is due to hydration of some of the constituent compounds of cement such as Tricalcium aluminate, Tricalcium silicate, Dicalcium silicate, and Tetra calcium aluminoferrite.
These compounds are known as Bogue’s Compounds.
Hydration of Bogues Compounds
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. The heat of hydration is 865 J/Cal.
Tricalcium silicate (C3S):
This is also called as Alite. This is also responsible for the early strength of the concrete. The cement that has more C3S content is good for cold weather concreting. The heat of hydration is 500 J/Cal.
Dicalcium Silicate (C2S):
This compound will undergo reaction slowly. It is responsible for the progressive strength of concrete. This is also called as Belite. The heat of hydration is 260 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.
For the rate of hydration is highest for C4AF and heat of hydration is highest for C3A.
From the above, the decreasing order of rate of hydration of Portland cement compounds is
C4 AF > C3 A > C3 S > C2 S.
For the heat of hydration, decreasing order of heat of hydration of portland cement is
C3 A > C3 S > C4 AF > C2S
Note: Heat of Hydration and Rate of Hydration is different
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