Study On Corrosion Resistance Of Chemical Reactive Enamel Coated Steel Bars In Tension

Wi th the development of China's marine power strategy,the construction of marine engineering has continued developing rapidly.However,due to the harsh marine environment,marine engineering structure is more prone to accelerated corrosion under load,resulting in the decline of its bearing capacity and durability.As a new type of inorganic anti-corrosion coating,the chemically reactive enamel(CRE)coating studied in this paper can provide effective protection and isolation of external corrosion medium by coating the surface of steel/steel structure.In this paper,the corrosion resistance,corrosion mechanism and mechanical properties of CRE coated steel under the action of tensile strain and corrosion environment were studied.The main experiments and conclusions are as follows:(1)Corrosion resistance and corrosion mechanism of C.RE coated rebar and bare steel under different tensile strain levels and corrosion environment were studied by immersion corrosion test and corrosion weight loss observation.The results show that the corrosion weight loss rate of CRE coated steel is much lower than that of bare steel under the same tensile strain condition.General corrosion occurs on the surface of bare steel,and surface pitting occurs along the cracks of CRE coated rebar under tensile strain.(2)The microstructure properties of CRE coatings before and after corrosion under different tensile strain states were studied by SEM and EDS.The results show that the crack width and crack density of coating increase with the increase of strain level and corrosion time.The EDS results show that the corrosion products of the coated steel bars will be filled into the coating cracks,which can improve the corrosion resistance of the coated steel bars in the later stage of corrosion.(3)The corrosion resistance of bare steel and CRE coated rebar within 120 days of corrosion at different tensile strain levels was quantitatively analyzed by the electrochemical test.The results of open circuit potential(OCP),electrochemical impedance spectroscopy(EIS)and dynamic polarization curve analysis show that the tensile strain can increase the corrosion degree of CRE coated steel,but its corrosion resistance is still better than that of bare steel.The charge transfer resistance of the coated steel bar is more than 4 times higher than that of bare steel after corrosion of 120d under 1000 microstrain conditions.(4)The mechanical property degradation of bare steel and CRE coated reinforcement under the combined action of stress and corrosion environment was studied by a quasi-static tensile test.The results show that the yield strength of CRE coated rebar does not decrease after corrosion for 120 days and is higher than that of bare steel.