Engineering Materials·MCQ explained

The process of maintaining moisture and temperature conditions of concrete so that it develops hardened properties over time is called:

Try it first: pick an option, then read the explanation.

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

TermDefinitionDuration
SettingTransition of cement paste from plastic/fluid to rigid solid state; initial set and final setInitial: ~30–45 min; Final: ~600 min (OPC)
HardeningGain of strength after setting through continued hydration; a result of curingDays to months
CuringDeliberate process of providing moisture and temperature control to promote hydration and hardened properties7–28 days minimum
SofteningReduction in strength/stiffness (due to heat, chemical attack, etc.) — undesirableN/A (damage process)

IS 456:2000 Minimum Curing Periods

Cement TypeMin. Curing Duration
OPC (M20 and below)7 days
OPC (above M20)10–14 days
Blended cements (PPC, PSC)14 days minimum
Hot weather conditionsUp 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.