engleski

Development of method for the inhibitor efficiency assessment in the concrete reinforcement based on EIS

Reinforced concrete is widely used as a building material and plays a significant role in economic development. Despite its advantages, corrosion of the steel rebar remains its most common durability problem which leads to the premature degradation of reinforced concrete structures. Application of corrosion inhibitors, both, admixed and topically applied, is recognized as a mean of fighting reinforcement corrosion. There is a natural reluctance to their use in concrete because they cannot be changed if found to be ineffective, replenished if found to be consumed, or removed if found to have deleterious effects. Because of that, it is necessary to evaluate the inhibitors effectiveness and understand the mechanism of inhibitors action to ensure the proper use. The applicability of electrochemical impedance spectroscopy (EIS) for rating inhibitor efficiency, in a cell consisting of a steel plate covered by a concrete layer containing chlorides and inhibitor, constructed in accordance with EN ISO 16773, has been tested for the first time. The specific construction of the measuring cell enabled acquisition of impedance spectra, from which the following information has been gained: quantification of chloride action, the quantitative inhibitor efficiency, clarification of inhibition mechanism, time dependence of inhibitory activity, separation of effects the inhibitor exerts on concrete itself and on steel/concrete phase boundary and visual inspection of metal surface after the measurement. The obtained results are consistent with the presumed physical model while demonstrating the efficiency of the inhibitors and the differences between them and confirming the applicability of the developed method. The speed of testing and the possibility of quantification of inhibitory efficacy are the main advantages of the tested method and has a large potential to enter in use alongside the widespread ASTM G109 method.

corrosion ; reinforcement ; concrete ; EIS ; migrating inhibitor ; chlorides ; efficiency

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