Research On The Properties Of Toughened Water-borne Epoxy Coating Reinforcement And Its Application In Concrete Under Harsh Environment

The corrosion of steel bar in concrete structure in harsh environment has become the main reason to threaten the structure safety and reduce the service life.The application of epoxy coating steel bar is an important means to improve the durability of concrete structure in harsh environment.However,the traditional epoxy coating is brittle and easy to crack,which causes damage in the construction and transportation,thus affecting the corrosion resistance,and causing serious pollution.Therefore,it is of great significance to develop high-performance green water-based epoxy resin and epoxy-coated steel reinforcement.The main research contents of this paper:（1）The film forming process of toughening water-based epoxy resin and water-based epoxy curing agent was studied,and the results showed that the film is heated to 80℃after the curing for 6h at 40℃for 4-5 h;（2）Study the influence of filler type,fineness,and single compound mixing ratio on the tensile properties of water-based epoxy coating,basic mechanical properties,electrochemical properties,salt spray resistance,acid and alkali salt resistance,It is found that the packing content has a great influence on the coating fracture elongation rate,Filler fineness affects the tensile strength of the coating greatly,Titanium dioxide in the filling can significantly improve the corrosion resistance of the coating and have little impact on the mechanical properties of the coating,When titanium dioxide:light calcium carbonate:precipitated barium sulfate=9:9:3,At 20%of the amount,Coated steel bar electrode immersed in 3.5%sodium chloride solution with a 90d corrosion current density of 0.145μA/cm~2,No significant change in salt spray for 500h;（3）On this basis,The tensile performance results of water epoxy coated reinforcement show that the deformation of 20%packing when the tensile strain is 23735με,Until the coating cracks during the neck shrinkage stage;The maximum longitudinal strain(E_yy)of a 20%epoxy coating with 20%packing is 8.8,Under the same conditions,the imported coating and domestic coating are only 0.19 and 0.41;In the cold-bending test,At the bending angle of 180,The outer semicirof reinforced steel with 20%packing shows no visible cracking or stripping;（4）The test results of the bonding performance of reinforced steel and concrete show that the relative bonding strength of reinforced steel and concrete mixed with 20%filler can reach 94.5%.The corrosion resistance test of coated steel in light aggregate concrete shows that 20%at 90d has the best performance,corrosion current density is 0.178μA/cm~2and 0.091μA/cm~2respectively is 10.51μA/cm~2and 9.077μA/cm~2,It shows that the preparation of water-based epoxy coating effectively prevents steel corrosion in concrete in harsh environment.