Study On Durability Of Coated Protective Concrete Under Salt Solution Erosion

In the northern coastal areas of China,a large number of construction projects,marine engineering and hydraulic concrete structures are corroded by acid,alkali,salt and other corrosive media,which lead to premature "aging disease" and other problems.As an effective measure to prevent and mitigate concrete corrosion,coating protection technology has been widely used.Therefore,this paper takes coated protective concrete as the research object,and analyses the durability of coated protective concrete under different erosion environments.In this paper,the effects of long-term immersion and wet-dry cyclic erosion on the durability of coated protective concrete in 5%chloride solution and 15%sulphate solution were studied,and compared with uncoated protective concrete in the same corrosive environment,the anti-corrosion effect of the protective coating was analyzed.The main contents as follows:By studying the actual corrosion environment of concrete structure,the corrosion environment of 5%chloride solution and 15%sulfate solution was selected to simulate the coastal cold area erosion under natural conditions,and two erosion conditions,long-term immersion and dry-wet cycle,were designed.Considering the influence of different factors on the durability of concrete,the type of coating,erosion time,water cement ratio and concrete strength are taken as experimental variables to complete the production of concrete specimens.Among them,coating types can be divided into coating typel,coating type 2,coating type 3,coating type 4 and coating type 5 according to the brushing mode;erosion time can be divided into 10 days,20 days,30 days,40 days,50 days and 60 days according to the length of time;water cement ratio can be divided into 0.4,0.5,0.6 and 0.7 according to the design value;concrete strength design can be grouped into C20,C30,C40 and C50.After the specimen was made and maintained,the experiments of long-term imnersion and wet-dry cyclic erosion were carried out according to the design groups.By collecting and consulting the literature,it is determined that the durability of concrete specimens under the action of 5%chloride solution is measured by mass loss rate,splitting tensile strength and chloride ion content.Under the action of 15%sulfate solution erosion,the durability of concrete specimens is measured by mass loss rate,compressive strength,flexural strength and sulfate ion content.After the erosion experiment is completed and the specimen is processed,the initial data are collected and sorted out.The initial values of mass loss rate,splitting tensile strength and chloride ion content of coated and uncoated protective concrete specimens under the conditions of 5%chloride solution long-term immersion and dry-wet cyclic erosion were collected,and the coated protective concrete specimens and uncoated protective coagulation under the conditions of 15%sulfate solution long-term immersion and dry-wet cyclic erosion were also collected.Initial values of mass loss rate,compressive strength,flexural strength and sulfate ion content of soil specimens.With the increase of erosion time,the corresponding experimental index values of eroded specimens in each grouping were measured and collected and recorded.The appearance changes of corroded specimens were observed and recorded during the experiment.After recovering the durability index values of the grouped concrete specimens,the experimental data are sorted out and analyzed,and finally the relevant conclusions about the durability of concrete under the action of salt solution erosion are drawn.