The recommended slump range (mm) as per IS 456:2000, for hand placed pavement quality concrete is:
Correct Answer: D. 25 – 75
📚 Detailed Explanation: IS 456 Slump Requirements for Pavement Concrete
Pavement Quality Concrete (PQC) must be stiff enough to maintain shape during compaction and finishing, yet workable enough for manual placement. IS 456:2000 Table 2 specifies different slump ranges for different applications.
Why D (25–75 mm) is correct: Pavement concrete must: resist deformation during screeding and finishing; maintain tight joints and precise grades; develop high flexural strength (typically M30–M40). A slump of 25–75 mm achieves this balance — stiff enough for shape retention but workable enough for hand placement. Options A (50–100mm) and B (100–150mm) are too fluid for pavement and would lead to surface settlement. Option C (75–100mm) applies to different structural elements.
IS 456:2000 Table 2 — Slump Ranges
| Application | Degree of Workability | Slump (mm) |
|---|---|---|
| Pavements (hand placed) | Low | 25–75 |
| Mass concrete / foundations | Low | 25–75 |
| Beams, slabs, walls (normal RCC) | Medium | 50–100 |
| Heavily reinforced sections | Medium–High | 75–100 |
| Pumped / tremie concrete | High | 100–150 |
- Pavement concrete slump = 25–75 mm (low workability) per IS 456:2000.
- Low slump prevents surface cracking, rutting, and ensures adequate flexural strength.