Influence Mechanism And Evaluation Of Coating On Durability Of Concrete Structures Under Marine Environment

Coating protection is one of the most widely used anti-corrosion measures in the structure of marine concrete.The quantitative evaluation of the durability life span of concrete structures by such anticorrosive measures has important guiding significance for guiding the life design of concrete structures in marine engineering and putting forward economical reasonable anticorrosion schemes for engineering structures with different design life.In this study,the effects of coatings on the chloride ion penetration resistance and seawater corrosion resistance of concrete were systematically analyzed by investigating and testing the physical engineering,accelerated aging test and seawater exposure test.In this paper,the appearance and chloride content distribution of Zhanjiang Port,Ningbo Ninghai Area and Shajiao Power Plant Coal Terminal are studied.The results show that the coated protective concrete structure can not completely prevent chloride ions from penetrating into concrete,but the penetration rate is very slow,and the supply of water and oxygen for electrochemical reaction of steel corrosion is reduced,so it can provide good protection.The chloride ions entering the concrete gradually increase with the increase of coating service time during the design protection period.After serving for nearly 20 years,the coating can still keep its appearance intact and play a certain protective role.Through accelerated aging test and ocean exposure test,the protective mechanism of coating on chloride ion permeation of concrete was discussed,and the evaluation method of coating on concrete protection and the life evaluation model of concrete structure were established.The results show that according to the accelerated aging test,exposure test and engineering investigation,the service life of the coatings depends on the materials used in the coatings;External environmental effects have a significant impact on the protective effect of the coating and with the extension of aging time,the adhesive force of the coating decreases gradually,and the protective effect decreases gradually;coating protection can avoid early exposure to chloride ion and reduce chloride ion in concrete;we establish the life calculation model of coating to extend the concrete structure and based on the 5-year exposure data of Qingdao wave splashing area,the service life of concrete structures with coatings is calculated to be about 20 years.