1. Why does concrete corrode?

Concrete corrosion primarily stems from two factors:

- Chemical corrosion: Acidic substances (such as acid rain and industrial exhaust gases) react with calcium hydroxide in the concrete, causing surface powdering; chloride ion penetration can destroy the passive film on the steel reinforcement surface, leading to rust.

- Physical erosion: Environmental changes like freeze-thaw cycles and wet-dry alternation can create micro-cracks inside the concrete, accelerating the intrusion of harmful substances.

2. How do anti-corrosion coatings protect concrete?

Anti-corrosion coatings function through the following mechanisms:

- Barrier isolation: The coating forms a dense protective film, blocking moisture, oxygen, and corrosive media from contacting the concrete.

- Chemical inertness: Some coatings contain acid- and alkali-resistant components that can neutralize external corrosive substances.