Title : KINETICS OF CORROSION PROPAGATION IN REINFORCED CONCRETE CONTAMINATED WITH CHLORIDES
Authors : Véronique Bouteiller, Valérie L'Hostis, Elisabeth Marie-Victoire, Julien Schneider Frédéric Boinski and Christian Cremona
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Price : 250
Abstract : Rebar corrosion of reinforced concrete is the main cause of deterioration of structures such as bridges, piers, monuments, etc. Considering the amount of structures built using reinforced concrete all along the 20th century, monitoring and control of reinforcement bear a significant practical importance in durability assessment. The aim of this paper is (i) to study the corrosion kinetics of reinforced concrete structures in the propagation phase in order to ascertain the corrosion process versus time and (ii) to propose a prediction for reinforced concrete structure durability based on steel thickness loss. In the aim of improving corrosion comprehension and prediction, within the French national project APPLET, reinforced concrete slabs, polluted by chlorides (mix or wetting/drying cycles) were exposed to outdoor environmental conditions as well as to controlled temperature and relative humidity conditions during a three years period. Corrosion of reinforcement was monitored four times per year by the means of three measurements (half-cell potential, electrochemical impedance spectroscopy and linear polarization resistance) and then, corrosion current density was calculated. Destructive analyses of the steel/concrete interface were also conducted in order to determine the steel loss by gravimetry and the nature of the oxide species by Raman microspectroscopy. Results show that in order to accurately predict the durability of reinforced concretes, measurements need to be performed regularly because the corrosion rate is an instantaneous value that fluctuates with time. Concerning the kinetics of the corrosion propagation phase for chlorinated concretes, the data analysis evidenced that steel thickness loss versus time follows a power law rather than a linear law. Moreover, the occurrence of cracks was related to the steel loss versus time. Finally, the steel loss obtained on samples exposed to outdoor conditions was relatively close to the one observed on samples exposed to controlled conditions.