On The Mechanism Of Amino Alcohol Based Migrating Corrosion Inhibitors For Marine Reinforced Concrete

The performance and mechanism of amino alcohol based migrating corrosion inhibitors(MCI) for marine reinforced concrete were mainly studied in this paper. Experiments such as concrete durability tests, chemical and electrochemical analysis were used to investigate the effects and mechanism of MCI on concrete durability, the transporting mechanism of MCI in concrete under natural and electric field conditions, and inhibition mechanism on rebar in simulated concrete pore solution. The structure-function relationship between the inhibition performance and structure factors of 5 kinds of alcamines containing amino and hydroxyl groups were studied by electrochemical experiments and quantum chemical calculation. The following conclusions can be obtained.The concrete durability parameters such as carbonation resistance, water and chloride resistance are promoted as the concrete pore structures are improved by amino alcohol based MCI. The phosphate and metasilicate components react with calcium salts in the concrete pores whose reaction product can refine and block some pores. The harmful concrete pores are transformed into harmless pores. At the same time the silane hydrophobic components play a role of waterproof and sealing function. All of these components jointly promote the durability of concrete.Under natural conditions, positive charged component of amino alcohol based MCI transports by capillary absorption and diffusion, while it transports by electromigration under electric field. It could be inferred from the tests of MCI content and penetration depth that electric field largely accelerates the transmission of MCI. Therefore, a proper electric field can be selected for chloride extraction from concrete and MCI migrating into the concrete which plays a role of dual protection and restoration effect for marine reinforced concrete.In the simulated concrete pore solution, amino alcohol based MCI shows good inhibition effect on rebar. It works by adsorbing on the surface and participating in the formation of passive film which increases the film resistance and charge transfer resistance of corrosion process, reduces passive current density and increases the breakdown potential. The inhibition performance of the selected 5 kinds of alcamines is related to their molecular structure and-OH、-NH2 groups. The effect of –NH2 on the inhibition performance for carbon steel is stronger than that of –OH. The molecular structures also have some effect on the inhibition performance.