North Carolina Building Contractor License Practice Exam

Which method is NOT commonly used for curing concrete?

1. Water spraying

2. Covering with wet burlap

3. Using curing compounds

4. Adding gravel on top

The correct answer is: Adding gravel on top

Adding gravel on top is not a common method used for curing concrete. Curing concrete involves maintaining adequate moisture, temperature, and time to allow the concrete to gain strength and durability after it has been poured. Water spraying, covering with wet burlap, and using curing compounds are widely recognized practices for curing. Water spraying helps to keep the surface of the concrete moist, which is crucial for hydration. Covering with wet burlap retains moisture and provides a consistent, humid environment, reducing the risk of cracking due to rapid evaporation. Curing compounds, which form a membrane on the surface, prevent moisture loss by creating a barrier to evaporation, ensuring that the hydration process continues effectively. In contrast, adding gravel on top would not provide the necessary moisture retention required for proper curing and could impede the concrete's ability to cure evenly. Instead, it may create a barrier that traps moisture in a way that is not beneficial for the concrete curing process.