Engineering Materials·MCQ explained

Curing concrete for a long period ensures better:

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

Correct answer: D. All options are correct

Detailed Explanation: Long Curing Period Improves Volume Stability, Strength, and Water Resistance

Why D (All options) is correct: All three properties improve with extended curing because they all arise from the same fundamental process: continued cement hydration producing C-S-H gel that fills the capillary pore network.

How Extended Curing Improves Each Property

PropertyHow Curing Improves ItPractical Impact
StrengthMore C-S-H gel formed → denser paste matrix → higher compressive and tensile strength28-day cured concrete can be 30–50% stronger than 3-day cured at same w/c
Water resistanceCapillary pores progressively filled with hydration products → lower permeabilityLess water, chloride, and sulfate ingress → slower corrosion and chemical attack
Volume stabilityHydrated paste shrinks less than unhydrated paste on drying; pores filled with solid products reduce net shrinkageFewer shrinkage cracks; more dimensionally stable structure

Curing Duration vs. Concrete Quality (Approximate)

Curing DurationStrength (%)PermeabilityShrinkage Risk
0 days (no curing)~50%Very highHigh
7 days~85%ModerateModerate
14 days~95%LowLow
28 days100%+Very lowMinimal
  • Long curing improves all three: volume stability, strength, and water resistance.
  • The common root cause: more complete hydration → denser, more stable, less permeable concrete.