Preparation And Properties Of Polymer Cement-Based Composite Anti-Corrosion Coating

In recent years,prefabricated building have been vigorously promoted by the country,and the market demand for prefabricated components of prefabricated building has gradually increased.However,the exposed steel bars of prefabricated components are prone to corrosion during the process of pouring,production,storage,transportation,and construction installation.This not only affects the appearance and sales of the components,but also leads to a decrease in the bonding strength of the interface between prefabricated components and post pouring concrete and grouting materials,and a decrease in the quality and durability of the building.Therefore,increasing the development of anti-corrosion materials for steel bars is of great significance in solving the problem of corrosion of exposed steel bars in prefabricated components.Although there are many mature solutions to the problem of steel corrosion,there are corresponding limitations.Based on this,a polymer cement-based composite anti-corrosion coating has been developed,and the basic performance,anti-corrosion performance,microscopic performance,as well as the bonding performance between coated steel bars,concrete,and grouting materials have been tested and analyzed.The specific work content is as follows.（1）Through single variable test,the influence of polymer lotion,pigments and fillers,dispersants,film forming additives,and defoamers on the basic performance of polymer cement based composite anti-corrosion coatings was explored in turn.The viscosity,adhesion,pencil hardness,bending resistance,and impact resistance of coatings prepared with different amounts of raw materials were tested.The results show that the basic performance of the coating is the best when the content of polymer lotion is 45wt%,the content of pigment and filler（ferric oxide red）is 6wt%,the content of dispersant is0.30wt%,and the content of defoamer is 0.20wt%.This formula is recorded as L1.（2）On the basis of formula L1,further investigate the effect of different raw material dosages on the corrosion resistance of coatings.Conduct adhesion loss rate tests,electrochemical tests,salt spray corrosion resistance tests,and liquid medium resistance tests on coatings prepared with different raw material dosages.The results show that the best corrosion resistance formula（L2）of the coating is consistent with the best basic performance formula（L1）of the coating.The corrosion resistance of the coating reaches the best when the content of lotion,pigment and filler,dispersant and defoamer is 45wt%,6wt%,0.30wt%and 0.20wt%respectively.The coating prepared with the best formula has no corrosion in the water,alkali and salt resistance tests,and shows good corrosion resistance.（3）Using uncoated steel bars,epoxy coated steel bars,and polymer cement-based composite anti-corrosion coated steel bars,semi grouted sleeve steel bar connection specimens N₀,N₁,and N₂were prepared in sequence,and subjected to uniaxial tensile tests.The results indicate that the size relationship between the bonding strength of each specimen is N₂>N₀>N₁.Therefore,the developed composite anti-corrosion coating can improve the bonding strength between steel bars and grouting materials to a certain extent.（4）The anticorrosive coatings with different polymer lotion contents and the blank anticorrosive coatings without pigments,fillers,dispersants and defoamers were prepared.The results indicate that the addition of an appropriate amount of epoxy resin can fill the pores between the cement hydration products and tightly bond the cement hydration products with the unhydrated cement particles.The addition of an appropriate amount of functional additives can also make the coating system more stable and the microstructure of the coating more dense.But at the same time,the epoxy resin will also slow down the process of cement hydration.The coating with more lotion will also reduce the production of ettringite,calcium silicate hydrate and other hydration products.