For a 50 kg cement bag, water required is ………..
Correct Answer: C. 20.5 liters
📚 Detailed Explanation: Water per 50 kg Cement Bag
IS 456:2000 Table 9 specifies nominal mix proportions for M10 to M20 grades. The water quantity per 50 kg bag is a site-level practical value that directly encodes the target w/c ratio.
Why C (20.5 liters) is correct: For standard nominal mix proportioning per IS 456:2000 Table 9:
20.5 litres per 50 kg bag = w/c = 20.5/50 = 0.41
This corresponds to M20 grade nominal mix target (approximate). Some references cite this as the “standard” water quantity for general structural concrete. Option D (22.5 L = w/c 0.45) is also common for other grades; option B (18.5 L = w/c 0.37) is typical for higher-strength mixes. The specific answer 20.5 L is the value most cited in Indian textbook problems for the standard 50 kg bag reference.
20.5 litres per 50 kg bag = w/c = 20.5/50 = 0.41
This corresponds to M20 grade nominal mix target (approximate). Some references cite this as the “standard” water quantity for general structural concrete. Option D (22.5 L = w/c 0.45) is also common for other grades; option B (18.5 L = w/c 0.37) is typical for higher-strength mixes. The specific answer 20.5 L is the value most cited in Indian textbook problems for the standard 50 kg bag reference.
Water per 50 kg Bag for Different W/C Ratios
| W/C Ratio | Water per 50 kg bag | Approx. Grade |
|---|---|---|
| 0.37 | 18.5 L | M25–M30 |
| 0.41 | 20.5 L | M20 (nominal) |
| 0.45 | 22.5 L | M15–M20 |
| 0.50 | 25.0 L | M10–M15 |
Key Concepts for Students
- 20.5 litres per 50 kg bag ≡ w/c = 0.41 — the standard reference value for this type of MCQ.
- Nominal mix proportions from IS 456 Table 9 are for small jobs; designed mixes per IS 10262 are used for M25 and above.