What is the common risk of using de-icing salts on concrete with embedded reinforcement?

• A. They improve corrosion resistance.
• B. They can accelerate corrosion of steel reinforcement.
• C. They prevent cracking.
• D. They have no effect on reinforcement.

Answer: (B)

Chloride-containing de-icing salts introduce chloride ions that penetrate concrete and reach the embedded steel, where they disrupt the protective passive film on the steel and increase the conductivity of the pore solution. This combination accelerates the electrochemical corrosion process of reinforcement when moisture and oxygen are present. So the common risk is that de-icing salts accelerate corrosion of steel reinforcement, which can lead to cracking and spalling as the steel expands during rusting. These salts don’t improve corrosion resistance or prevent cracking, and they do affect reinforcement by promoting corrosion, especially where cracks or high exposure to chlorides occur.