What is the slump of pumped concrete used in heavily reinforced section if the degree of workability is medium as per IS 456-2000?
Correct Answer: D. 50 – 100 mm
📚 Detailed Explanation: Slump for Pumped Concrete (Heavily Reinforced)
Why D (50–100 mm) is correct: IS 456:2000 specifies the same slump range (50–100 mm) for both hand-placed and pumped medium-workability concrete in heavily reinforced sections. Pumped concrete requires this minimum workability to flow through the pump pipeline and still settle around reinforcement bars. Option B (100–150 mm) applies to high workability (tremie/very thin sections). Options A and C are too stiff for heavily reinforced sections.
IS 456 Slump vs. Placement Method
| Application | Method | Slump (mm) |
|---|---|---|
| Pavements | Hand/Machine | 25–75 |
| Normal RCC (beams, slabs, columns) | Hand | 50–100 |
| Heavily reinforced sections | Pumped | 50–100 |
| Tremie / Very thin walls | Tremie | 100–150 |
- Medium workability = 50–100 mm slump for heavily reinforced sections regardless of pumped or hand placement.
- Pumping requires a minimum slump of about 75 mm to avoid blockages in pump lines.