摘要
The corrosion of rebar in reinforced concrete in marine environments causes significant damage to structures built in ocean environments. Studies on the process and mechanism of corrosion of rebar in the presence of multiple ions may help to control damage and predict the service life of reinforced concrete structures in such environments. The effect of interactions between sulfate and chloride ions and calcium hydroxide on the electrochemical behavior ofrebar are also important for evaluation of structure durability. In this work, electrochemical impedance spectroscopy （EIS） plots of rebar in Ca（OH）2 solution and cement grout, including NaC1 and Na2SO4 as aggressive salts, were measured for different immersion times. The results show that corrosion of rebar was controlled by the rate of charge transfer as the rebar was exposed to chloride solution. In the presence of high concentrations of sulfate ions in the electrolyte, generation and dissolution of the passive film proceeded simultaneously and corrosion was mainly controlled by the diffusion rate. When Na2SO4 and NaC1 were added to Ca（OH）2 solution, the instantaneous corrosion rate decreased by a factor of 10 to 20 as a result of the higher pH of the corroding solution.
The corrosion of rebar in reinforced concrete in marine environments causes significant damage to structures built in ocean environments. Studies on the process and mechanism of corrosion of rebar in the presence of multiple ions may help to control damage and predict the service life of reinforced concrete structures in such environments. The effect of interactions between sulfate and chloride ions and calcium hydroxide on the electrochemical behavior of rebar are also important for evaluation of structure durability. In this work, electrochemical impedance spectroscopy(EIS) plots of rebar in Ca(OH)_2 solution and cement grout, including NaCl and Na_2SO_4 as aggressive salts, were measured for different immersion times. The results show that corrosion of rebar was controlled by the rate of charge transfer as the rebar was exposed to chloride solution. In the presence of high concentrations of sulfate ions in the electrolyte, generation and dissolution of the passive film proceeded simultaneously and corrosion was mainly controlled by the diffusion rate. When Na_2SO_4 and NaCl were added to Ca(OH)_2 solution, the instantaneous corrosion rate decreased by a factor of 10 to 20 as a result of the higher p H of the corroding solution.
基金
Supported by the National Natural Science Foundation of China(Nos.51178230,51378269,5142010501)
the National Basic Research Program of China(973 Program)(No.2015CB655100)
the Qingdao Science and Technological Foundation(Nos.13-1-4-176-jch,13-1-4-115-jch)
