Chloride induced corrosion initiation in RC structures: A thermodynamic view point

International Conference on Sustainable Civil Engineering

June 20-21, 2016 Cape Town, South Africa

K Balaji Rao, Ramendra Pandey and M B Anoop

CSIR-Structural Engineering Research Center, India

Posters & Accepted Abstracts: J Civil Environ Eng

Abstract :

Reinforced concrete structures are susceptible to chloride induced corrosion when exposed to marine environments or to deicing salts. In situations where the chloride ion concentration at the reinforcement surface crosses the critical level, pitting corrosion is induced. Such corrosion processes are causing a great loss to structures worldwide. The present study proposes a thermodynamic approach towards understanding of chloride induced corrosion initiation in RC structures. The system state is defined by the chloride ion concentration at the surface of reinforcement, and, at any given time, system is considered to be in a state of thermodynamic non-equilibrium and yet locally stable with respect to the bifurcation that is assumed to take place when depassivation occurs (when Model 2, presented herein, is considered). However, when Model 1 is considered, the system would be in the state of thermodynamic equilibrium till the depassivation occurs. Thus, the initial conditions obtained from the Models 1 and 2 are different when the corrosion propagation is modeled using the non-equilibrium thermodynamics (exhibiting chaos). It is further shown that, even when the Model 1 is used, the corrosion initiation time can exhibit large variation depending on the system parameters and is verified by simulations using the Fick�s second law of diffusion.

Biography :

Email: balaji@serc.res.in