Study On The Protetive Properties Of Offshore Concrete Coating Based On Bionic Mineralization

In recent years,with the launch of the Maritime Silk Road initiative and the rapid development of coastal economy,many infrastructures such as marine platforms,seaport terminals and large-span bridges have gradually emerged in the sea.Many factors in the marine environment(e.g.corrosion ions,biodegradation,tidal waves,temperature changes,etc.)can affect the durability of marine concrete structures.Surface treatment is the most common anti-corrosion measures of marine concrete.Organic-inorganic hybrid coatings combine the advantages of organic coating with inorganic coating,and are easy to compound with functional components.Inspired by biomineralization in nature,induced biomimetic mineralization reaction can regulate the crystal shape and morphology of inorganic crystals,as the advantages of constructing and regulating surface microstructure technology are obvious..Based on this,the purpose of this paper is to improve the durability of marine concrete,using biomimetic mineralization products and low-surface energy silane,nano-silver composite with bactericidal function,the preparation of organic-inorganic hybrid marine concrete coating with excellent waterproofing performance,resistance to chlorine ion erosion and anti-biodegradation performance,the specific contents of this paper are as follows:(1)The influence of polymer induced calcium carbonate crystallization on the composition and morphology of the product is explored.After XRD,SEM,FT-IR and other experimental characterization,combined with relevant literature data to analyze the mineralization product crystal and structure,the results show that the mineralized product induced by polydopamine is a metamorphological rule,high purity and crystallinity of the square stone,suitable for the design and construction of specific morphology and microstructure,or as an inorganic protective layer on the concrete surface.Using First-Principles to calculate the process of dopamine-induced calcium carbonate crystallization,three possible models were established to calculate the adsorption of dopamine molecules to calcium ions.The results show that dopamine adsorption of calcium ions in the solution may be achieved by phthalates group chelation of calcium ions,and the interaction is strong and suitable as a template for surface and interface inducing mineralization.(2)The effects of mineralizer concentration and number of immersion cycles on dopamine-induced calcium carbonate mineralized grain size,surface morphology,reduced porosity effect and mineralized layer thickness were explored.The results show that the concentration of mineralizer directly affects the size of mineralized grain,and the higher the concentration of mineralizer,the larger the grain size.The number of impregnation cycles mainly affects the thickness and porosity of the mineralized layer,and when the impregnation cycle reaches a certain number of times,the mineralization layer already has a certain thickness and the porosity reduction efficiency is the highest at this time.The conclusion provides a theoretical basis for the subsequent regulation of mineralized layer morphology.(3)According to the mineralization law,the shape of the mineralization layer is regulated on the surface of the test block,and by overlaying the concentration of different mineralization agents and the number of impregnation cycles,a square stone with gradient size is prepared on the surface of the test block to form a slightly rough structure with micro-nano-hybridization,and to reduce the porosity rate of the test block surface.On this basis,the hydrolysis of silane is used to form a hydrophobic silane network with low surface energy,and a waterproof surface with ultra-hydrophobic properties is formed.And through the surface water absorption rate and other related experimental tests and analysis of its waterproof,wear-resistant and anti-ion penetration performance,the results show that the coating not only excellent protection performance,but also significantly improved stability than similar coatings.(4)On the basis of gradient mineralization layer,the reduction of dopamine is used to reduce silver ions to nano-silver particles in situ on the surface of the mineralized layer.The micro-nano-level calcite formed by mineralization is combined to form a micro-nano-hybridized microcosm structure.The composite coating prepared was tested with surface water absorption,resistivity test and biological attachment,and the results showed that the composite coating was waterproof and resistant to ion penetration.The slow release of Ag~+can effectively kill bacteria attached to the concrete surface and surrounding,and the self-cleaning performance of micro-nano-hybridized microcosm structure makes it difficult for subsequent organisms to adhere to the concrete surface,effectively improving the anti-fouling properties and durability of marine concrete.In this paper,the bionic mineralization technology is applied to the durability protective coating of marine concrete,the microstructure is constructed on the concrete surface by inducing biomimetic mineralization technology,and the atomic scale fine regulation of the concrete itself microstructure is carried out,which not only effectively enhances the hydrophobic waterproofing performance of silicone coating,but also greatly improves the bottleneck problems that restrict the use of such coating,such as poor stability and water pressure resistance.Functional nanomaterials are introduced through in situ reduction reactions to further optimize the structure and functionality of composite coatings,so that the protective surface has good waterproof,ion-resistant and bio-fouling corrosion resistance.This study is expected to improve and break through bottlenecks in the application of hydrophobic concrete coating,and provide new ideas for improving the durability of concrete structures in the surface/interface.