Water cement ratio is generally expressed volume of water required per ………….
Correct Answer: C. Per 50 kg cement
📚 Detailed Explanation: W/C Ratio Convention in Indian Practice
In Indian construction practice, cement is supplied in standard 50 kg bags. Therefore, the water-cement ratio is conventionally stated as litres of water per 50 kg bag of cement, making it easy to measure on site without weighing water separately.
Why C (Per 50 kg cement) is correct: The 50 kg bag is the standard commercial unit for cement in India. Site engineers calculate water directly as: Water (litres) = w/c × 50 kg. For example, w/c = 0.45 → 22.5 litres per bag. This convention makes field measurement simple since 1 litre of water = 1 kg. Options A (10 kg), B (20 kg), and D (40 kg) are not standard bag sizes in India and are not used in this convention.
W/C Ratio Reference Table (50 kg bags)
| W/C Ratio | Water per 50 kg bag (litres) |
|---|---|
| 0.35 | 17.5 |
| 0.40 | 20.0 |
| 0.45 | 22.5 |
| 0.50 | 25.0 |
| 0.55 | 27.5 |
| 0.60 | 30.0 |
Key Concepts for Students
- W/C expressed as litres per 50 kg cement bag — the Indian site convention.
- Since 1 litre of water = 1 kg, the calculation is simply: litres = w/c × 50.
- This is distinct from the technical definition (mass ratio), but numerically equivalent since water density = 1.