Research Articles | Challenge Journal of Concrete Research Letters

Corrosion of steel bars in saturated Ca(OH)2 and concrete pore solution

Amir Poursaee
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Abstract


Testing steel in solution has the advantage of avoiding the long time necessary for chlorides to penetrate the concrete cover.  It is well known that steel in high alkaline environments is passive and the protective capability of the passive film increases with pH.  The pH of saturated calcium hydroxide solution is lower than concrete pore solution which does induce passivation but not to the degree encountered by steel in good quality concrete.  Nevertheless, saturated calcium hydroxide has been used in many studies of rebar corrosion as a substitute for pore solution.  This paper discusses the electrochemical behavior of low carbon steel bars is chloride free and chloride contaminated pore solution and saturated calcium hydroxide solution.  Results show that the passive film on the steel immersed in pore solution and saturated Ca(OH)2 have similar composition.  However, as a result of lower pH in saturated Ca(OH)2 solution, the passive layer formed in this solution is less protective and does not offer enough passivity to steel to simulate a realistic concrete environment.

Keywords


pore solution; corrosion; Ca(OH)2; raman spectroscopy; cyclic polarization; linear polarization resistance

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