Concrete cover, in reinforced concrete, is the least distance between the surface of embedded reinforcement and the outer surface of the concrete (ACI 130). The concrete cover depth can be measured with a cover meter. The purpose of concrete cover is to protect the reinforcement from corrosion, fire, and other potential damage.
The required concrete cover depends on several factors, including the environmental conditions to which the structure will be exposed, the size of the reinforcing steel, the concrete strength, and the type of structure being constructed. Generally, larger diameter reinforcement bars require more concrete cover than smaller ones.
In most cases, local building codes and engineering standards specify the minimum required concrete cover for various types of structures. It is important to adhere to these requirements to ensure the safety and longevity of the structure.