structural design 03 - COVER TO THE REINFORCEMENT

 Concrete cover f=to the reinforcement should be maintained very well during the construction stage in order to avoid the corrosion of the reinforcement bars. So we usually use several cover values such as 25mm, 40mm, 50mm, etc. In order to decide the value for the cover we have to first look at the environment condition. Because the reinforcement c corrosion capacity depends on that. If we have a concrete structure under sea water, it is more vulnerable for corrosion. Inside a covered building which is protected from a roof slab it is less vulnerable for corrosion. So we have to decide the cover according to the conditions.

  

Reinforcement corrosion is an Electo-Chemical reaction. The below reactions are expected to happen there.

In BS 8110 table 3.3 these conditions are defined with related proposed covers. There are 5 main conditions mentioned in it. There may be cases where extra precautions needed beyond those given in the table 3.3

(1).MILD (2).MODERATE (3).SEVERE (4).VERY SEVERE (5).EXTREME are those five.

After the deciding the exposure condition, we can find the related cover from table 3.4 of BS 8110.