NASCLA Accredited Commercial General ContractorConcreteEasy
A general contractor is overseeing the placement of concrete for a large elevated slab. The structural drawings specify the use of #6 reinforcing bars with a minimum clear cover of 1.5 inches. During the inspection, it is observed that some rebar is resting directly on the formwork, resulting in inadequate cover. What is the primary purpose of maintaining the specified clear concrete cover over reinforcing steel?
- ATo facilitate easier placement and consolidation of concrete.
- BTo protect the reinforcing steel from corrosion and fire.
- CTo increase the aesthetic appeal of the finished concrete surface.
- DTo ensure proper bond between the concrete and the reinforcement.
Show answer & explanationAnswer & explanation
Correct answer: B. To protect the reinforcing steel from corrosion and fire.
Adequate concrete cover over reinforcing steel is crucial for protecting the rebar from environmental factors such as moisture and chemicals that lead to corrosion. It also provides thermal insulation, enhancing the steel's resistance to fire.
Why the other options are wrong
- A. While adequate spacing helps placement, cover itself isn't primarily for easier consolidation.
- C. Aesthetic appeal is not the primary purpose of concrete cover for structural elements.
- D. Bond is achieved through the deformation of the rebar and concrete adhesion, not primarily by cover thickness.
Concrete Cover
The minimum distance between the surface of the reinforcing steel and the exterior surface of the concrete.
- Protects rebar from corrosion.
- Provides fire resistance.
- Ensures structural integrity and durability.
Memory trick: Cover the steel, fight the rust and feel the heat.