The details about the quality of water to be used for concreting are given in
Correct Answer: A. IS 456
📚 Detailed Explanation: IS 456 and Water Quality for Concrete
The quality of water used in concrete significantly affects the setting, strength, and durability of the mix. Too many dissolved salts, organic impurities, or suspended solids can interfere with cement hydration or corrode reinforcement. Indian Standards address this through IS 456:2000.
Why A (IS 456) is correct: IS 456:2000 (Plain and Reinforced Concrete — Code of Practice) contains Clause 5.4 on “Water,” which specifies permissible limits for all relevant impurities in mixing water. The other standards serve different purposes: IS 269 is the specification for Ordinary Portland Cement (OPC); IS 2386 governs testing methods for aggregates; IS 383 specifies coarse and fine aggregates for concrete. Water quality requirements are specifically a code-of-practice concern, addressed in IS 456.
IS 456:2000 Water Quality Limits (Clause 5.4)
| Impurity | Maximum Permissible (mg/l) |
|---|---|
| Organic solids | 200 |
| Inorganic solids | 3000 |
| Sulphates (as SO3) | 400 |
| Chlorides (for RCC) | 500 |
| Chlorides (for plain concrete) | 2000 |
| Suspended matter | 2000 |
Key Concepts for Students
- IS 456 governs water quality — always the reference for water specifications in concrete mixing and curing.
- Potable water conforming to IS 10500 is automatically acceptable for concrete without further testing.
- Sea water, trade effluent, or water with oil/acid/sugar should never be used without full analysis.