What is the role of protective coatings or membranes during retrofitting aging concrete bridges?

• A. They improve durability by moisture barrier and protection against corrosion.
• B. They increase load capacity.
• C. They have no effect on durability.
• D. They trap moisture and worsen corrosion.

Answer: (A)

Protective coatings and membranes are used during retrofitting aging concrete bridges to create a durable moisture barrier that shields the embedded steel from water, chlorides, and other damaging agents. By limiting moisture ingress and chloride access, these systems slow corrosion initiation and propagation, reducing ongoing deterioration and extending the bridge’s service life. They aren’t meant to increase load capacity; their primary role is protection, not strengthening. They also prevent moisture from being trapped and concentrating corrosion, so a proper barrier helps rather than harms durability.