Development Of Marine Concrete Anti-chlorine And Antifouling Coating Based On Bionic Concept

In the marine environment,the main reason for the durability damage of reinforced concrete structures is the corrosion of chloride salts.At the same time,the large number of fouling organisms will also cause certain damage to the safety of the structure and affect the appearance.In engineering,measures such as adding mineral admixtures,adjusting the concrete mix ratio,adding steel rust inhibitors,increasing the thickness of the protective layer and applying anti-corrosion coatings are mainly taken to delay the corrosion of chloride salts.Take measures such as manual/mechanical removal,ultrasonic cleaning,UV light,and application of antifouling coatings to reduce fouling organisms’ attachment.Among the above protection measures,the coating layer is easy to construct and maintain,can be applied multiple times,can be used in combination with other measures,and can effectively prolong the service life of the structure.However,the existing coatings are mostly single in function,cannot have good anti-chlorine and anti-fouling effects at the same time,and are mostly not environmentally friendly.In response to the above problems,two biomimetic coatings were developed in this paper: one is TA/PA anti-chlorine coating.This is the first time that PA has been used in the field of concrete anticorrosion.Inspired by the adhesion of mussels,the interfacial compatibility between PA and concrete was enhanced with TA biomimetic material as an interlayer.The second is i-PDMS anti-chlorine and anti-fouling multi-functional coating.Inspired by the predation process of Nepenthes,silicone oil was injected into PDMS to prepare a smooth liquid-injected surface(i-PDMS coating)on concrete surface for the first time.The antifouling ability of the i-PDMS coating was preliminarily explored through the adsorption experiments of milk complex protein and BSA single protein.In addition,rapid chloride ion electromigration test(RCM),accelerated natural diffusion test,digital microscope,scanning electron microscope,water contact angle,X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy were carried out to explore the effect of different reaction conditions on the chlorine resistance of the two coatings and their mechanism.In order to explore the long-term stability of the i-PDMS coating in the marine environment,this paper firstly carried out the chlorine resistance test in the real sea in winter,and preliminarily explored the anti-chlorine effect of the i-PDMS coating in the real sea environment.After that,the long-term real sea anti-chlorination and anti-fouling test in summer was carried out to further explore the long-term anti-chlorination and anti-fouling effects of i-PDMS coating in the real sea environment.The results show that the i-PDMS coating has stable properties and excellent anti-chlorine and anti-fouling effect.According to the test data,based on Fick’s second law,this paper establishes a concrete chloride ion diffusion model considering biological effects.By comparing the predicted value of the model with the measured value,the correctness of the model is verified.Aiming at the influence of coating damage on the durability and life of the structure,this paper defines the critical damage area of the coating that needs to be re-coated,and gives a calculation method for the critical damage area of the coating based on the finite element method.The critical damage area of the coating under different conditions is calculated,which has guiding significance for practical engineering.