TMP Concrete Anode

          Normally, rust or corrosion of reinforcing steel in concrete is restricted by high alkaline environment (pH > 12). The passive film on the steel surface is the key for corrosion control in concrete. However, the passive film of reinforcing steel will become unstable or be destroyed in the presence of chloride or carbon dioxide. Concrete is permeable and allows the ingress of chloride and carbon dioxide. The carbon dioxide will react with alkali and form carbonate. Carbonation will reduce the pH value of concrete to about 8. If the carbon dioxide penetrates deeply into concrete and reaches the reinforcing steel, the passive film is destroyed and steel begins to corrode.

          The corrosion of reinforcing steel due to ingress of chloride is more common than that of carbon dioxide. The cracking and spalling of reinforced concrete can be frequently founded in seawater, blackish water, seacoast, salty ground water and etc. The rust is larger than steel. Thus, the internal pressure or expansion within the concrete is the cause of cracking and spalling.

Specific volume of the corrosion product of iron
(Photo Credit: Monteiro and Mehta)

Cracking and Spalling of concrete cover due to corrosion of reinforcing steels.


         Thai Marine Protection Co., Ltd. (TMP) develops zinc anode which is encased in special mortar containing lithium hydroxide. This special mortar will prevent zinc anode from passivation and improve current output of the zinc anode. Moreover, the special mortar does not contain any acid or chemicals such as chloride or bromide which can damage the reinforcing steel in concrete. Therefore, the zinc anode of TMP can be used to control or prevent the rust of reinforcing steel in both new and old concrete structures.

Installation and testing.