Bar cover is equal to how many times the size of the aggregate?

In the context of concrete construction, bar cover, also known as concrete cover, refers to the minimum distance between the outer surface of the concrete and the surface of the embedded reinforcing bars (rebars). This concrete cover provides protection to the rebar from environmental factors, corrosion, and mechanical damage.

The specification that bar cover should be 1.33 times the size of the aggregate is a guideline often used to ensure that the concrete can adequately encase the rebar and maintain structural integrity. This ratio helps to ensure that there is sufficient concrete surrounding the rebar so that it is properly anchored and protected from adverse conditions that could weaken its strength over time.

For example, if the size of the aggregate is 20 mm, the minimum cover should be 26.6 mm (20 mm x 1.33), providing a tangible benefit in terms of durability and performance of the concrete structure. This value arises from industry standards and codes that consider various factors, such as exposure conditions, to establish adequate cover requirements for different construction scenarios.

Choosing this ratio enhances the overall performance and longevity of concrete structures, thereby demonstrating a fundamental principle in construction and civil engineering practices regarding the relationship between rebar and concrete.