The primary cause of reinforcement corrosion in concrete is
- AHigh water-cement ratio
- BExposure to carbon dioxideCorrect
- CLow water-cement ratio
- DHigh curing temperature
Solution
Concept
Carbonation and corrosion
Step-by-step solution
1. CO₂ reacts with Ca(OH)₂ and lowers pH. 2. The steel passive film breaks and corrosion starts.
Explanation
Carbonation (and chlorides) are the primary causes of reinforcement corrosion.
Why the other options are wrong
A low w/c ratio improves protection.
Shortcut
CO₂ → carbonation → corrosion.
Correct answer: B) Exposure to carbon dioxide