Corrosion Control

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How it Works

Protectosil^® CIT penetrates concrete and provides an organofunctional molecule to inhibit the electrochemical corrosion process between the rebar and the chloride ions, oxygen and moisture present in the concrete.

The corrosion process in steel-reinforced concrete is spontaneous and similar to the process in a galvanic cell or battery. Water is only one aspect of corrosion. Water molecules bind electrostatically to concrete, forming the conductive medium for the chloride-ion induced corrosion process that dissolves the rebar. The electrochemical reactions can be described as:

Fe -> Fe₂+ + 2 e^-

Fe₂+ + 2 Cl^- -> FeCl₂

FeCl₂ + H₂O + OH^- -> Fe(OH)₂ + H⁺ + 2 Cl^-

2 Fe(OH)₂ + ½ O₂ -> Fe₂O₃ + 2 H₂O

½ O₂ + H₂O + 2 e^- -> 2 OH^-

In the corrosion process the formation of ferrous oxide (rust) takes up more volume than the original steel and causes stress on the concrete. These stresses manifest themselves as cracks, spalls and delaminations in the concrete structure. But the main consequence of con-crete corrosion is the loss of steel cross-section and the resulting loss of structural capacity. The three main factors affecting the corrosion rate are the concentration of chloride ions, moisture and oxygen. Other factors, such as temperature, also contribute to the speed of the corrosion process.

The proprietary organofunc-tional chemistry of Protectosil^® CIT greatly reduces corrosion currents. This is done chemically by interrupting the electrolytic current and causing a decrease in the corrosion process.