Study On The Performance Of Admixed Corrosion Inhibitor In Marine Reinforced Concrete Structure

The problem of insufficient durability of the reinforced concrete structure in marine environment has become more and more serious,and among the measures to improve the durability of concrete structure such as using special steel,protective coating,catholic protection and corrosion inhibitor,application of corrosion inhibitor have been widely recognized.Although the inorganic corrosion inhibitor,compound amino alcohols corrosion inhibitor and multicomponent compound of a new type corrosion inhibitors have been a lot of research,the comprehensive performance evaluation of the effect of resistance to corrosion relatively few studies.The traditional inorganic corrosion inhibitor is in lack of reliable evidence for selection of environmental protection and high efficiency;The corrosion resistance mechanism and permeable adsorption theories still need further study of corrosion inhibitors for compound amino alcohols;In advocate green environment protection at the same time,the protective effect about a new type of multicomponent corrosion inhibitors whether get the requirements still need further study.So the corrosion resistance and mechanism research of the above corrosion inhibitors have very important significance,not only provides certain support for development about efficient,environmental friendly corrosion inhibitors,but also have great significance for corrosion inhibitor screening and application in practical engineering.The paper selects three typical types of corrosion inhibitors: IOCI inorganic corrosion inhibitor,OCCI organic corrosion inhibitor,MuCI hybrid commercial corrosion inhibitor.First,the capillary water absorption test,RCM chloride penetration test and XRD phase analysis test were carried out to study the effect of concrete compactness to corrosion inhibitor;Then dry-wet circulation,half cell potential was used to study the corrosion resistance performance on the reinforced mortar test block;Weightlessness test and SEM scanning electron microscope test were carried out to analyze the efficiency of corrosion resistance,observe adsorption and film-forming on the surface of the carbon steel.Corrosion inhibitors were discussed to study the film adsorbing process and mechanism on the surface of the carbon steel electrode by electrochemical test.Through the above experimental study,several conclusions were reached as the follow:(1)To a certain extent three kinds of corrosion inhibitors can promote the cement hydration,improve the compactness of concrete and the resistance to chloride ion penetration.The experimental results showed that OCCI is better than IOCI corrosion inhibitor and superior to the MuCI on the resistance to chloride ion permeability.(2)Dry-wet cycle and the half cell potential test results showed that the mixing corrosion inhibitor can effectively reduce the corrosion rate of the steel in the mortar test block,the efficiency of corrosion inhibiting: OCCI is 91.8%,IOCI corrosion inhibitor is 83.6%,MuCI is 80.6%.The application of corrosion inhibitor improves the corrosion potential of the steel bar in the mortar,and it make the steel bar corrosion is hard to occurrence and effectively extend the corrosion time.(3)Scanning Electron Microscopy(SEM)and weightlessness experiment results showed that IOCI corrosion inhibitors can oxidize and form passivation film,OCCI corrosion inhibitor can physical adsorption film and MuCI hybrid corrosion inhibitor through the two ways for work together to form protective film.Membrane can effectively restrain the chloride ion erosion.The completeness and compactness of OCCI film is the best.Corrosion resistance rate increases with the increase of the dosage in concrete simulated liquid.When the adding amount is 0.5%,the corrosion inhibitor was not appear accelerated corrosion phenomenon.(4)Results of electrochemical impedance spectroscopy and polarization curve test showed that the application of corrosion inhibitors increased membrane resistance and charge transfer resistance.Then membrane capacitance and the electric double layer capacitance were reduced,and effectively reduced the electron charge transfer rate and the corrosion electrochemical cathode-anode reaction process.The application of corrosion inhibitors reduced the corrosion current density of carbon steel electrode,and improved the corrosion potential the breakdown potential,and the chloride ions critical density.