Which vibrator is used for vibrating concrete test cubes in a laboratory?
Try it first: pick an option, then read the explanation.
Correct answer: C. Table vibrator
Detailed Explanation: Table Vibrator for Laboratory Concrete Cubes
Why C (Table vibrator) is correct: In a laboratory, test cubes or cylinders are compacted using a table vibrator (also called a vibrating table). The concrete-filled mould is clamped to the steel platform, and the vibrating mechanism beneath transmits vibration uniformly through the entire mould, producing well-compacted, void-free specimens.Types of Vibrators and Their Applications
| Type | Description | Application |
|---|---|---|
| Table vibrator | Steel platform on springs; vibrating mechanism below; mould clamped to table | Laboratory test cubes, cylinders, small precast panels |
| Internal vibrator (needle) | Vibrating probe inserted into concrete mass | In-situ beams, columns, deep slabs; most common on site |
| Surface vibrator (screed) | Vibrating plate or screed moved across surface | Slabs, road pavements, floors <20 cm deep |
| Form vibrator (external) | Clamps to outside of formwork | Precast elements, thin walls, congested reinforcement sections |
| Vibrating roller | Heavy roller on concrete surface | Roller Compacted Concrete (RCC) in dams, roads |
Table Vibrator Specifications
| Parameter | Value |
|---|---|
| Standard | IS 516 (method of tests for strength of concrete) |
| Frequency | Typically 50–60 Hz |
| Duration of vibration per layer | ~60 seconds per layer |
| Mould sizes used | 150 mm cube; 150×300 mm cylinder |
- Table vibrator = standard for compacting laboratory test cubes and cylinders (IS 516).
- On-site equivalent: internal (needle) vibrator for beams/columns; screed vibrator for slabs.