Electrochemical Impedance Characteristics Of Reinforced Concrete Structure Reinforcement Corrosion Process

Reinforced concrete structure premature corrosion damage is the main reason of reinforced concrete corrosion failure occurs, the corrosion process will not only cause huge economic losses, but also give the person and property of the people bring significant security risks. Reinforced concrete structure with a certain complexity, with the development of electrochemical corrosion studies, monitoring of the open circuit potential, polarization curves and electrochemical corrosion electrochemical noise and other traditional measurement techniques can not meet the needs of complex corrosion system for monitoring and research. Electrochemical impedance measurement techniques in recent years gradually developed a non-destructive, rapid and convenient method of corrosion and electrochemical measurements, measurements of reinforced concrete structure reinforcement corrosion process of electrochemical impedance spectroscopy, the study of reinforcement corrosion process has important theoretical and practical significance. In this thesis, the electrochemical impedance characteristics Q235 steel corrosion behavior in simulated concrete pore fluid and the different stages of corrosion.We study the electrochemical behavior of corrosion of carbon steel Q235 at different p H values and different concentrations of Cl- simulated concrete pore fluid. Changes simulated concrete pore solution p H and Cl- concentration will significantly affect the corrosion behavior of Q235 steel in the studied p H = 12, p H = 11 and the simulated concrete pore solution p H = 10, each of the p H value there is a lower concentration of Clcorrosion behavior of carbon steel Q235 obvious turning point, at p H = 12 When this transition Cl- concentration of 0.05 mol / L, at p H = 11 and p H = 10 When this transition Cl- concentration 0.01 mol / L; when the p H of concrete pore fluid simulation of a certain time, with the Cl- concentration in solution increases, the degree of deterioration Q235 steel surface passivation film more serious, protective effect on carbon steel substrates also more and more weak, uniform corrosion and localized corrosion susceptibility of carbon steel bright sensibility have gradually increased; when the constant concentration of Clsimulated concrete pore solution, with increasing p H of the solution, Q235 steel surface passivation film can be more stably present, the protective effect of carbon steel substrate has become increasingly strong, uniform corrosion susceptibility susceptibility to localized corrosion of carbon steel and are gradually declining.Q235 studied the corrosion of carbon steel in different stages in simulated concrete pore liquid electrochemical impedance characteristics. Q235 carbon steel in simulated concrete pore fluid corrosion process can be divided into four phases: stabilization phase passivation, corrosion initiation phase, the stabilization phase of corrosion and corrosion deterioration stage. Stable passivation stage, carbon steel electrochemical impedance spectroscopy showed a characteristic time constant, there is a lot of capacitance radius arcs; corrosion initiation phase, carbon steel electrochemical impedance spectroscopy showed two time constants features, there are capacitive arc arc and low capacitance at high frequencies under composition; corrosion stable stage, carbon steel electrochemical impedance spectroscopy exhibit features three time constants, there are capacitive arc at high frequencies and "diffusion tail" composed of low frequencies; the inductive loop appears on the corrosion deterioration stage, carbon steel electrochemical impedance spectroscopy. In simulated concrete pore solution with the extension of immersion time, stable passivation stage, the passivation film resistance increases, the passivation film capacitance decreases, the corrosion rate of carbon steel decreases; corrosion initiation phase, blunt film resistance begins to decrease, the passivation film capacitor begins to increase, the charge transfer resistance decreases, the corrosion rate of carbon steel begins to increase; corrosion stable stage, the passivation film resistors, capacitors and passivation film basic charge transfer resistance maintained at a stable value, the corrosion rate of carbon steel is large and stable; corrosion deterioration stage, the passivation film resistance decreases, the passivation film capacitance increases, the charge transfer resistance is reduced, the corrosion rate of carbon steel increases sharply.