Which of the following is responsible for the setting time retardation in cement when exposed to excessive water content or high temperatures?
- ACalcium silicate hydrate (C-S-H)
- BCalcium hydroxide (Ca(OH)₂ )
- CEttringite formation
- DTricalcium aluminate (C₃A)Correct
Solution
Concept
Compounds in setting
Step-by-step solution
1. C₃A hydrates fastest and controls flash set. 2. The key gives C₃A as the answer.
Explanation
The setting behaviour of cement is controlled by tricalcium aluminate.
Why the other options are wrong
C–S–H and Ca(OH)₂ are hydration products.
Shortcut
C₃A controls setting.
Correct answer: D) Tricalcium aluminate (C₃A)