What is the primary action to take in order to preserve freshly laid concrete?

• A. Mix it with sand
• B. Keep it moist
• C. Expose it to sunlight
• D. Cover it with plastic sheets

Answer: (B)

To preserve freshly laid concrete, the primary action is to keep it moist. This step is critical because concrete undergoes a curing process that requires hydration to develop its strength and durability. When concrete is kept moist, it allows the chemical reactions necessary for curing to occur effectively, leading to a stronger bond within the material.

If concrete dries out too quickly, which can happen in hot weather or dry wind conditions, it can lead to surface cracks, reduced strength, and an overall compromised structure. Maintaining moisture not only aids in strength development but also helps to prevent shrinkage cracks and other potential defects that could arise from an improper curing process.

While covering concrete with plastic sheets can help retain moisture, the primary focus should be on ensuring adequate hydration. Mixing concrete with sand or exposing it to sunlight does not support the preservation of its integrity; in fact, both can be detrimental to the curing process. Thus, the practice of keeping concrete moist is essential for achieving optimal results.