The constituent of cement which is responsible for all the undesirable properties of cement is
A. Di-calcium silicate
B. Tri-calcium silicate
C. Tri-calcium aluminate
D. Tetra calcium alumino ferrite
Answer: Option C
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Explanation:
Tri-calcium aluminate (C3A)
It rapidly reacts with water and is responsible for the flash set of finely grounded clinkers.
The rapidity of action is regulated by the addition of 2-3% of gypsum at the time of grinding the cement.
It is most responsible for the initial setting, the high heat of hydration, and has a greater tendency to volume changes causing cracking.
Raising the C3A content reduces the setting time, weakens resistance to sulfate attack, and lowers the ultimate strength, heat of hydration, and contraction during air hardening.
When Tri-calcium aluminate is in excess in cement then it is responsible for most of the undesirable properties.
The heat of hydration of 865 J/g.
Explanation:
Tri-calcium aluminate (C3A)
It rapidly reacts with water and is responsible for the flash set of finely grounded clinkers.
The rapidity of action is regulated by the addition of 2-3% of gypsum at the time of grinding the cement.
It is most responsible for the initial setting, the high heat of hydration, and has a greater tendency to volume changes causing cracking.
Raising the C3A content reduces the setting time, weakens resistance to sulfate attack, and lowers the ultimate strength, heat of hydration, and contraction during air hardening.
When Tri-calcium aluminate is in excess in cement then it is responsible for most of the undesirable properties.
The heat of hydration of 865 J/g.
tri calcium alluminate is fast reactive with water and responsible for initial setting time...
Tetra calcium alumino ferrite