If the slump of a concrete mix is 60 mm, its workability is:
Correct Answer: C. medium
📚 Detailed Explanation: Slump 60 mm = Medium Workability
Why C (medium) is correct: IS classification of workability by slump:
Very low: 0–25 mm | Low: 25–50 mm | Medium: 50–100 mm | High: 100–150 mm
60 mm falls squarely in the 50–100 mm medium range. Options A and B (very low, low) correspond to 0–25 mm and 25–50 mm respectively — less than 60 mm. Option D (high) applies to 100+ mm slump.
Very low: 0–25 mm | Low: 25–50 mm | Medium: 50–100 mm | High: 100–150 mm
60 mm falls squarely in the 50–100 mm medium range. Options A and B (very low, low) correspond to 0–25 mm and 25–50 mm respectively — less than 60 mm. Option D (high) applies to 100+ mm slump.
IS Slump Classification
| Slump (mm) | Workability | Application |
|---|---|---|
| 0–25 | Very low | Dry mixes, road base |
| 25–50 | Low | Mass concrete, pavements |
| 50–100 (incl. 60 mm) | Medium | Slabs, beams, columns |
| 100–150 | High | Thin sections, pumped, tremie |
- 60 mm slump → medium workability.
- Medium workability (50–100 mm) is the most common range for normal structural RCC.