North Carolina Building Contractor License Practice Exam

What is the minimum concrete cover for No. 9 rebar?

1. 15%

2. 20%

3. 25%

4. 30%

The correct answer is: 25%

The minimum concrete cover for No. 9 rebar is 25%. Concrete cover is crucial in construction, as it protects the rebar from environmental factors such as moisture, which can lead to corrosion, and it helps ensure sufficient fire resistance. The specific requirement for rebar cover can vary based on factors like exposure conditions and structural type, as outlined in the relevant building codes. Generally, for No. 9 rebar, which has a diameter of approximately 0.4 inches or 10 mm, a concrete cover of at least 25% ensures that the rebar is adequately embedded within the concrete, providing both durability and structural integrity. This cover also aligns with standard practices that ensure concrete structures remain safe and functional over their intended lifespan. Understanding these requirements is essential for construction professionals to ensure compliance with building codes and to enhance the longevity of their structures.