10 Causes of Corrosion of Reinforcement in Concrete
The corrosion of reinforcement embedment in concrete is extremely complicated and influenced by the following 10 factors:
1. Non-homogeneities in the metal surface increase the probability of corrosion of steel.
2. Variation in stress in the reinforcement promotes corrosion.
3. Presence of moisture at the concrete-steel interface and pH influence the corrosion. Corrosion is more rapid in acidic solutions and all corrosive factors become ineffective in the absence of moisture.
4. The amount of available oxygen at the concrete-steel interface, considerably influence the rate of corrosion.
5. Presence of salts increases the corrosion rate. But at high concentration, it diminishes the solubility of oxygen, thereby lowering the corrosion rate.
6. The CO2 absorbed into the concrete promotes the corrosion rate of steel.
7. Permeability of concrete is the most important factor affecting the corrosion of reinforcement.
8. Corrosion of steel greatly depends upon the thickness of concrete cover over the steel.
9. Corrosion is also influenced by the relative humidity.
10. The corrosion of steel also depends upon the nature of admixtures used in concrete.