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Concrete cover

Concrete cover is the region between the exposed concrete surface and the nearest surface of the reinforcing bar, in reinforced concrete members.


Purpose of Provision of Concrete Cover

  • to protect the reinforcement bars from environmental effects to prevent corrosion
  • to protect the reinforcement bars from fire
  • to give reinforcing bars sufficient embedment to enable them to be stressed without slipping


The amount of cover depth that needs to be provided is usually based on the exposure conditions that the structure is likely to be subjected. The Indian Concrete Code mandates the following:

Nominal Cover Requirements based on Exposure Conditions in Indian Concrete Code IS:456-2000
Exposure Condition Nominal Cover
Mild 20
Moderate 30
Severe 45
Very Severe 50
Extreme 75

Other national codes also specify minimum cover requirements based on their respective local exposure conditions.

Other National Concrete Cover Requirements
Country Concrete Code Range of Concrete Cover
UK BS:8110 25-50
USA ACI:318 40-50
Australia AS:3600 15-30


Large cover depths (50-75 mm) are required to protect reinforcement against corrosion in aggressive environments, but thick cover leads to increased crack widths in flexural reinforced concrete members. Large crack-widths (greater than 0.3 mm) permit ingress of moisture and chemical attack to the concrete, resulting in possible corrosion of reinforcement and deterioration of concrete. Therefore, thick covers defeat the very purpose for which it is provided. There is a need for judicious balance of cover depth and crack width requirements.

Methods of maintaining cover

See also

This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Concrete_cover". A list of authors is available in Wikipedia.
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