Page 9 - Foxfire Integral Crystalline Waterproofing

Concrete Degradation Mechanisms: Carbonation
Carbon dioxide from the air reacts with calcium hydroxide to form calcium carbonates. In the presence of moisture, carbonic acid is formed which reduces the alkalinity of concrete, causing the pH value of the concrete to fall into the acidic range, destroying the protective layer and eventually exposing reinforcing steel to corrosion. The rate of carbonation depends upon relative humidity, permeability of the concrete, depth of cover and time.