3.4. Effects of Carbonation

Try these first

1. 1.

   What is carbonation?

   Hint

   Think about the gas we exhale.

2. 2.

   What is a potential consequence of reduced alkalinity in concrete?

   Hint

   Consider what protects the steel.

3. 3.

   What reaction occurs during carbonation?

   • CO₂ + Ca(OH)₂ → CaCO₃ + H₂O
   • CO₂ + CaCO₃ → Ca(OH)₂ + H₂O
   • Ca(OH)₂ + H₂O → CaCO₃ + O₂

   Hint

   Think about how CO₂ interacts with concrete.

4. 4.

   True or False: Carbonation increases the pH of concrete.

   • True
   • False

   Hint

   Recall how carbonation affects alkalinity.

5. 5.

   If a concrete structure has experienced carbonation leading to a pH decline to below 9, what steps might be taken to restore its durability?

   Hint

   Consider layers of protection and maintenance strategies.

6. 6.

   Analyze how the interaction between carbonation and moisture affects concrete longevity in coastal areas.

   Hint

   Think about environmental factors affecting structural health.