Study On Electrochemical Injection Of Inhibitor And Slat-extraction In Reinforced Concrete

Corrosion of the reinforcement is considered to be one of the main reasons thatlead to structural failure of concrete in advance. There are many ways to solve thisproblem, which include adopting anticorrosive coatings, electrochemical treatment(such as electrochemical realkalization, electrochemical salt extraction), andcorrosion inhibitors and so on. Among these methods, electrochemical saltextraction and corrosion inhibitors are thought to be effective on inhibiting thecorrosion of rebars, but both of them have shortcomings of their own. Therefore,more and more researchers focus their attention on electrochemical injection ofinhibitor (EII) technology which is the combination of electrochemical saltextraction and corrosion inhibitors. This technology can not only transfer corrosioninhibitors to steel surface, but also remove chloride ion partly out of the concreteinterior, which give the rebars double protections. Three kinds of problems areinvestigated in this paper (i) the selection of corrosion inhibitors,(ii) the effect ofelectrochemical injection of inhibitors on reinforced concrete with differentmixtures and (iii) the mechanism of electrochemical injection of inhibitors.First, electrochemical methods are adopted to study the single or coupledproperties of several alcohol amine inhibitors in the simulated concrete poresolution, which include self-corrosion potential, linear polarization resistance (LRP),electrochemical impedance spectroscopy (EIS), etc. Based on the EIS of rebar, thepaper establishes equivalent circuit of rebar corrosion process in simulated concretepore solution and further comparing the fitted values to the measured ones indicatesthat the equivalent circuit used is suitable.According to the test results in simulated concrete pore solution, two kinds ofcorrosion inhibitors are selected for EII tests. Self-corrosion potential, LRP and EISare discussed to analyze the effect of W/C and mineral admixtures on theanti-corrosion properties and salt extraction contents in the EII tests by theself-designed electrochemical test device. Meanwhile, this paper also establishes theequivalent circuit, characterizing corrosion process in reinforced concrete, and theresults indicate that the degree of fitting with the measured values is of greataccordance.Then the mechanism of alcohol amine inhibitors is preliminarily discussed and proposed the corrosion inhibitors type suitable for EII method. The subject alsomonitors the electrochemical parameters variation of steel after anti-corrosiontreated, which was combined to contrast the effect of corrosion inhibitors on thecorrosion of reinforcement in concrete with natural infiltration and electro-migration. The result shows that electrochemical injection of corrosion inhibitorstechnology is superior to natural infiltration and subsequently established the modelof LRP in the anti-corrosion process.