Strength of Concrete MCQ with answer and solution

Concept

Infrared radiation curing gives faster strength gain than steam curing without loss of final strength.

Step-by-step solution

1. Normal methods like water sprinkling and membrane curing give slow, normal strength gain. 2. Accelerated methods are steam curing (low and high pressure), electrical curing and infrared curing. 3. Standard texts (M.S. Shetty) say infrared radiation curing gives much more rapid gain of strength than steam curing. 4. Its quick early heating also does not reduce final strength, unlike steam curing at 100°C. 5. So the answer is (D).

Explanation

Infrared radiation heats the concrete quickly, so cement hydration becomes very fast. It gives faster early strength than steam curing and does not lower the final strength. So it is preferred for rapid strength gain.

Why the other options are wrong

A: Water sprinkling only keeps concrete moist, so strength gain is normal and slow. B: Membrane curing only stops loss of moisture and does not speed up hydration. C: High-pressure steam curing is also fast, but texts say infrared curing is even faster and has no loss of final strength.

Shortcut

Rapid gain + no loss of ultimate strength = Infrared curing.

Common mistake

Choosing steam curing because it is the best known accelerated curing method.