The process of maintaining moisture and temperature conditions of concrete so that it develops hardened properties over time is called:
Correct Answer: D. Curing
📚 Detailed Explanation: Curing — Definition and Purpose
Why D (Curing) is correct: Curing is precisely defined as the process of maintaining satisfactory moisture content and a favourable temperature in concrete during the early stages of hardening, so that it can develop its intended hardened properties — primarily strength, durability, and impermeability.
Distinguishing Key Concrete Terms
| Term | Definition | Duration |
|---|---|---|
| Setting | Transition of cement paste from plastic/fluid to rigid solid state; initial set and final set | Initial: ~30–45 min; Final: ~600 min (OPC) |
| Hardening | Gain of strength after setting through continued hydration; a result of curing | Days to months |
| Curing | Deliberate process of providing moisture and temperature control to promote hydration and hardened properties | 7–28 days minimum |
| Softening | Reduction in strength/stiffness (due to heat, chemical attack, etc.) — undesirable | N/A (damage process) |
IS 456:2000 Minimum Curing Periods
| Cement Type | Min. Curing Duration |
|---|---|
| OPC (M20 and below) | 7 days |
| OPC (above M20) | 10–14 days |
| Blended cements (PPC, PSC) | 14 days minimum |
| Hot weather conditions | Up to 28 days |
- Curing = maintaining moisture and temperature conditions for concrete to develop hardened properties.
- Curing starts after final setting (typically 10–24 hours after placement).
- Uncured concrete may achieve only 50–60% of its design strength.