Question

The minimum cover in any pretensioned - prestressed concrete member located in an aggressive environment is ........

• A. 20 mm
• B. 25 mm
• C. 30 mm
• D. 40 mm

Hint:

In prestressed concrete, adequate cover is essential for corrosion protection, especially under aggressive environmental exposure. Always refer to IS 1343 for correct cover specifications for both pre- and post-tensioned members.

Answer 1

The Correct Option is C

As per IS 1343:1980 – Code of Practice for Prestressed Concrete, the nominal cover to the prestressing steel is prescribed to ensure durability, especially in aggressive environmental conditions. The aggressive environment refers to conditions where the concrete may be subjected to severe chemical attack, moisture, or other deteriorating factors.
In the case of pretensioned prestressed concrete members, the minimum cover is increased to prevent corrosion and ensure the longevity of the structural member.
For members located in an aggressive environment, the minimum cover should not be less than: \[ \text{Minimum cover} = 30 \text{ mm} \] This is mandated to protect the steel reinforcement from environmental effects and preserve structural integrity over time. The other values (20 mm, 25 mm, and 40 mm) do not meet the specific requirement for aggressive exposure conditions in pretensioned members. 
Therefore, the correct answer is \( \boxed{30 \text{ mm}} \).