Question

What is the minimum duration required for curing of cement concrete for attaining good strength?

• A. 5 days
• B. 10 days
• C. 7 days
• D. 14 days

Hint:

Under standard civil engineering guidelines (IS 456), freshly cast concrete requires a minimum of 7 days of continuous wet curing to achieve satisfactory initial strength and durability.

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
Curing is the process of maintaining satisfactory moisture and temperature conditions in freshly cast concrete during its early stages.
This allows the cement to hydrate completely, which is essential for developing the concrete's target compressive strength, durability, and resistance to cracking.
If concrete dries out too quickly, the hydration reactions stop, leaving the concrete weak and porous.

Step 2: Detailed Explanation:
The hydration of cement is a slow chemical reaction that requires moisture.
The rate of strength development is highest during the first few days after casting.
According to standard civil engineering codes (such as Indian Standard IS 456), the minimum curing period is determined by the type of cement used and the environmental conditions.
For concrete made with Ordinary Portland Cement (OPC) under normal environmental conditions, the minimum curing duration is 7 days.
If the concrete contains mineral admixtures or is exposed to hot, dry weather, the minimum curing period is extended to 10 or 14 days to prevent rapid water evaporation.
Within 7 days of proper curing, concrete achieves approximately 65% to 70% of its ultimate 28-day compressive strength.
Therefore, 7 days is the standard minimum curing duration required for general construction.

Step 3: Final Answer
The minimum duration required for the curing of cement concrete under normal conditions is 7 days.