Civil Engineering - Building Materials - Discussion


The compound of Portland cement which reacts immediately with water and also sets first is

[A]. Tri-calcium silicate
[B]. Di-calcium silicate
[C]. Tri-calcium aluminate
[D]. Tetra calcium alumino ferrite.

Answer: Option C


No answer description available for this question.

Dipen Tilva said: (Jan 11, 2017)  
Tricalcium aluminate (C3A) is mostly related to the heat of hydration.

Functions of Dicalcium Silicate:-
1. Hardens slowly.
2. It effects on strength increases occurs at ages beyond one week.
3. Responsible for long-term strength.

Functions of Tricalcium Aluminate:-
1. Contributes to strength development in the first few days because it is the first compound to hydrate.
2. It turns out the higher heat of hydration and contributes to faster gain in strength.

Akki said: (Apr 17, 2017)  
Yes, C3A is the correct answer.

Dhananjay said: (Mar 4, 2019)  
No, the first compound to show the hydration when water is added is C4AF.

Gui said: (Mar 6, 2019)  
Answer is correct as we add gypsum in cement to slow down the reaction of c3A if gypsum is not added then cement would flash set in 5-10 mins.

Nehra said: (Jan 23, 2021)  
Option D is correct it's responsible for flash set.

Irfan Ali said: (Sep 7, 2022)  
I think Both option C and D are correct.

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