Fabrication And Properties Of Colorful Superhydrophobic Concrete Coating

Concrete is widely used in architecture because of its advantages such as high strength,low cost,good durability and plasticity.However,due to its hydrophilicity and porous structures,concrete materials are wetted by water very easily and usually suffers from damages caused by oxidative corrosion,freezing environment and other phenomenon with water as a medium,thus accelerating the failure rate of concrete.The lack of durability of concrete not only brings huge losses to people’s lives,but also consumes a lot of financial and resources for its repair work,and also produces unnecessary carbon emissions,increasing the earth’s environmental burden.In last 30 years,Superhydrophobic coating with excellent waterrepellent property has great potential to solve this problem.Based on the superhydrophobic principle,this paper described a colorful and stable superhydrophobic coating which can meet the requirements of waterproof and decorative to proposed to solve the above-mentioned problem of the concrete.The main research contents are as follows:(1)We developed a colorful superhydrophobic concrete(CSC)coating and achieved its large-area fabrication by spraying technology.The coexistence of the micro/nano-meter scale structures including sands,cement particles and low surface energy groups from stone protective reagent DC-30 contributed to the remarkable superhydrophobicity with a contact angle of 158 ± 0.5° and a sliding angle of 5 ± 0.8°.(2)The color of the CSC coating could be adjusted as red,yellow,blue,and green by adding different iron oxide dyes,respectively.The color saturation and the wettability of the CSC coating could be further changed by controlling the dye concentration.The effects of iron oxide dye on the macro morphology and superhydrophobic properties of the CSC coating were also studied.Combined with the micro morphology,the reasons for the change of color saturation and wettability of the CSC coating with dye concentration were revealed.(3)Due to the high mechanical strength and self-similarity,the CSC coating possessed good surface robustness and retained superhydropobicity after sandpaper test,sand impact test,and even knife scratch test and tape peel test.The prepared CSC coating also showed excellent chemical durability,water droplets with p H values from 0 to 14 could easily roll off from the coating surface,and steel bar in the concrete with the CSC coating could be protected from electrochemical corrosion.In addition,the CSC coating had good resistance against extreme weather conditions including cold rain,strong wind and overexposure to sunlight,showing excellent anti-icing,anti-irradiation and self-cleaning capabilities.The CSC coating was expected to have promising application prospects in concrete architectures.