Study On Properties Of CFRP/SFCB Reinforced Anode Reinforced Concrete Structure System

In recent decades,large-scale construction of reinforced concrete structures in coastal areas of China has taken place,and there has been a phenomenon of lack of river sand.Sea sand resources are very abundant in the coastal areas,but the harmful substances such as chlorine salts will reduce the durability of the structure.If the sea sand can be used reasonably,the problem of lack of river sand resources can be solved.The mixed reinforced concrete beam is an ideal form of reinforcement.The corrosion-resistant FRP bar is arranged in the corner area where the section is susceptible to corrosion,and the ductile steel is better placed inside the section,so that the advantages of the two can be combined to solve the problem.The structural durability problem caused by the corrosion of steel bars overcomes the shortcomings of poor ductility of pure FRP bar structures,but if it is in a high chloride environment,the internal steel bars are still in a dangerous state of being susceptible to rust.Impressed current cathodic protection(ICCP)technology is an effective method to inhibit steel corrosion.The carbon fiber material in the carbon fiber FRP bar has excellent electrical conductivity and electrochemical characteristics,and is an auxiliary anode material with superior performance,which can stably control the polarization potential of the steel bar in the corrosion-free zone,thereby effectively controlling Corrosion of steel bars.Based on the above knowledge,this paper proposes a new type of cathodic protection system ICCP-CB(Impressed current cathodic protection-CFRP bars)and ICCP-SFCB(Impressed current cathodic protection-Steel-fiber composite bar),Based on the mixed reinforcement technology,the bars with uniform coverage of the carbon fiber material are selected as the auxiliary anode,and the appropriate protection current density is applied to realize the cathodic protection of the new coastal concrete structure.In this paper,the key issues of the system,the electrochemical and mechanical properties of the anode reinforcement,the bonding properties of the anode reinforcement-sea sand seawater concrete interface,and the application in the actual structure are studied.The main contents include:(1)Electrochemical and mechanical properties of CFRP and composite bars(SFCB)in chloride environment.The anodic polarization acceleration test of CFRP bars and SFCB in the marine environment was carried out.The electrochemical behaviors of CFRP bars and SFCB as auxiliary anodes were investigated.The performance degradation mechanism of CFRP bars and SFCB under anodic polarization was revealed.CFRP bars and SFCB were proposed.The strength is predicted by the model and its service life is assessed.The test results show that CFRP bars and SFCB anodes have excellent electrical conductivity and low electrical resistance.Compared with SFCB,CFRP bars can pass a large electric flux,and does not have significant mechanical properties degradation,and has strong anti-polarization capability.The CFRP bar anode meets the service life requirements of the new cathodic protection system under certain conditions.(2)Study on the bonding properties of a new cathodic protection system using CFRP bars as anodes.The sea sand seawater concrete bond-slip component was designed.The current protection cathodic protection test was carried out with different protection current density and protection time.Study on the change of bonding properties,acidification and corrosion state of CFRP bars in sea sand and seawater concrete members in the research system,and to explore the degree of short-term bond performance degradation of CFRP bars.The test results show that the steel bars move negatively into the corrosion-free zone during the protection of the new cathodic protection system.Compared with the unprotected steel bars,the corrosion rate of the steel bars after cathodic protection is significantly reduced.The short-term anodic bonding performance of CFRP bars as the anode's new cathodic protection system is reliable.Although the chemical reaction on the surface of the CFRP bars after the application of the new cathodic protection system destroys the chemical bonding force,the ultimate bond strength of the ribbed CFRP bars after cathodic protection mainly comes from friction and mechanical occlusion.(3)Study on the flexural behavior of mixed reinforced concrete beams under a new cathodic protection system.CFRP bars and SFCB were used as anode ICCP technology in the mixed reinforcementtechnology.Study the actual situation of the new cathodic protection system in the structure,accelerate the simulation of the deterioration degree of the test piece in the marine environment by pre-corrosion method,and study the protection effect of the new impressed current cathodic protection system.The test results show that the ICCP technology with CFRP bars as the anode effectively prevents further corrosion of the steel bars in the beam under simulated ocean tides,and the bearing capacity is not further reduced.The protection effect of CFRP bars is better.The protection effect of CFRP bars as anode is better,while SFCB ribs appear self-damage during protection.