Studies On The Preparation And Performance Of Marine Concrete Composite Coatings Based On Two-dimensional Layered Zirconium Phosphate

Coating protection is one of the most common and effective measures in the field of concrete corrosion protection,however,traditional coatings suffer from insufficient performance,environmental pollution,and poor permeability.Therefore,in order to improve the durability of marine concrete,this paper firstly based on the functional modification of the two-dimensional nanomaterialα-zirconium phosphate（α-ZrP）,the antimicrobial nanocomposite ZrP-I.M was prepared by inserting polyethyleneimine（PEI）and silver nitrate betweenα-ZrP layers using the intercalation modification method;the surface modification was used to modify hexadecyltrimethoxysilane（HDTMS）withα-ZrP to prepare the hydrophobic nanomaterial S-ZrP.Subsequently,the layers of ZrP-I.M and S-ZrP were assembled and physically blended in combination with polydopamine（PDA）and polymethyl methacrylate（PMMA）,respectively,to prepare marine concrete anti-corrosion coatings（S-ZrP-I.M/PDA coating and S-ZrP/PMMA coating）by regulating the microstructure and morphology of the coatings,and the structural and protective properties of the coatings were investigated,and analyzed the related theoretical mechanisms.The specific studies are as follows:（1）A superhydrophobic composite coating（S-ZrP-I.M/PDA coating）was prepared by assembling ZrP-I.M and PDA layer by layer on the concrete surface using a layer-by-layer assembly method,modulating the process to construct a micro-and nano-rough structure,and using HDTMS to reduce the surface energy of the structure.We analyze the structure and performance of the coating by conducting surface profile and roughness tests,contact angle tests,capillary water absorption tests,anti-bacterial tests,anti-icing tests,and abrasion resistance tests on the samples.The results show that:the microstructure of the coated mortar surface undulation increases,the roughness Ra increases from 0.785μm to 1.785μm,and the water contact angle（WCA）of the surface reaches 154°±3°;after 30 times of repeated friction,the surface water contact angle can still reach 135°,showing good wear resistance performance;The superhydrophobic property makes the water droplets spherical on the sample surface with small contact area,which can delay the condensation time of water droplets and reduce the freezing area of water droplets;the capillary water absorption rate and capillary water absorption coefficient of mortar are reduced by 86.4%and 86.6%respectively by S-ZrP-I.M/PDA coating,and the impermeability effect is 79.5%higher than that of silane-treated samples.The S-ZrP-I.M/PDA coated samples had only a few individual bacteria on the surface and did not form colonies,showing excellent antibacterial and antibacterial,anti-biofouling and anti-corrosion properties.（2）In order to make the concrete with excellent water resistance,resistance to chloride ion penetration and wear resistance of the coating,while maintaining a certain degree of air permeability,PMMA and S-ZrP are compounded to build rough micro-nano"mesh-brick"structures on the concrete surface with PMMA as the"mesh"and S-ZrP as the"brick",so as to prepare a breathable high-performance marine concrete anti-corrosion coating.Surface profile and roughness test,contact angle test,capillary water absorption test,rapid chloride migration（RCM）test,water vapor permeability test and abrasion resistance test were performed on the coatings.It was found that the incorporation amount of S-ZrP affected the roughness,hydrophobicity and impermeability of the coating,and the overall effect was optimal when the incorporation amount of S-ZrP was about 9%.PMMA coated mortar surface roughness Ra decreased from 0.73μm to 0.36μm with a WCA of 88.2°±3°,while roughness Ra increased to1.79μm with a WCA of 131.2°±3°after incorporation of S-ZrP（9%）;In the capillary water absorption test,the water absorption rate of S-ZrP/PMMA coated mortar specimens in the simulated seawater environment was only 0.27%,showing excellent impermeability;in the RCM test,the chloride ion penetration depth of the coated mortar specimens was only 4.2mm,a reduction of 18.2mm compared to the blank group,and the penetration coefficient was 0.442×10^-12m²/s,a reduction of 83.43%.In addition,the contact angle of S-ZrP/PMMA coating is still 123.8°±3°after 100 friction cycles,which only decreases about 8°,showing excellent wear resistance;The water vapor transmission rate of S-ZrP/PMMA coated mortar is 0.7122g/（h·m²）,which is significantly higher than that of the conventional polymer coating,and its water vapor transmission rate is 12.28times higher than that of the epoxy resin coating.S-ZrP/PMMA as a concrete anti-corrosion coating has excellent impermeability,resistance to chloride ion penetration,abrasion resistance and is"breathable".