Grouting deficiencies of post-tensioned tendons (PTT) have been associated with accelerated corrosion of the strands. A corrosion mitigation method by which a fluid is introduced via the interstitial spaces between the wires of a tendon’s strand has been recently used with promising results. Mechanistic experiments and multiphysics modeling simulation were used to examine the relative importance of alternative corrosion mitigating mechanisms, including oxygen transport limitation, cathodic and anodic inhibition, and ohmic resistance increase. Experimental results yielded a favorable prognosis that impregnating PTT would be successful in mitigating ongoing corrosion of steel strands. Both experiment and modeling pointed to a decrease of surface kinetics - lowered exchange current density for both anodic and cathodic reactions - as the likely main mitigation mechanism. Increasing grout resistivity and concentration polarization of the cathodic reaction did not seem to be dominant factors in mitigating corrosion.

Subject
Electrochemical impedance spectroscopy, Impregnation, Modeling, Corrosion rate, Tendons, Grout, Anodic reactions, Electrical resistivity, Steel, Oxygen, Corrosion resistance, Risk reduction, Exchange current density
Keywords:
post tensioned tendons, impregnation, mitigation, corrosion, EIS
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2019
Association for Materials Protection and Performance (AMPP)
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