Correct option is A
Vibrating concrete before grouting improves its quality by:
1. Removing air voids: Ensures that trapped air bubbles are eliminated, reducing porosity.
2. Increasing compaction: Promotes better compaction, ensuring that the concrete fully fills the formwork and surrounds the reinforcement.
3. Improving strength and durability: Proper vibration leads to a denser and stronger concrete structure, enhancing its overall durability and resistance to environmental factors.
