A reinforced concrete steel pipe composite pile for ocean engineering

Abstract

The present invention discloses a reinforced concrete steel pipe composite pile for ocean engineering, which relates to the technical field of steel pipe composite piles. It includes a composite pile body, and the composite pile body includes a first connecting pile, a second connecting pile, a third connecting pile and a pile tip. A plurality of welding rings are fixedly connected to the circumferential outer walls of the first connecting pile, the second connecting pile, the third connecting pile and the pile tip. A plurality of internal steel bars are fixedly connected to the inner wall of the composite pile body. The outer surface of the composite pile body is coated with a first composite coating, and the inner surface of the composite pile body is coated with an inner single-layer coating. The present invention designs corresponding coating structures for the anti-corrosion requirements of different regions of the steel pipe composite pile, and exhibits excellent corrosion resistance. These coating structures fully consider the corrosion characteristics of the steel pipe composite pile in different usage environments, and achieve comprehensive protection of the steel pipe composite pile by reasonably matching different coating materials and thicknesses.

Description

Technical Field

[0001] The present invention relates to the technical field of steel pipe composite piles, and specifically to a reinforced concrete steel pipe composite pile for ocean engineering. Background Art

[0002] Ocean engineering refers to new construction, reconstruction, and expansion projects aimed at developing, utilizing, protecting, and restoring marine resources, with the project main body located seaward of the coastline, such as cross-sea bridges, offshore dike projects, artificial islands, exploration and development of marine mineral resources and their ancillary projects, marine energy development and utilization projects, landscape development projects, etc. Many of the above projects built above the sea surface require steel pipe piles as pile foundation supports. Steel pipe piles are a common foundation support tool often used in the construction and engineering fields. They have diverse functions and can be used as supports for bridge pile foundations or as load-bearing elements for building foundations. The advantages of steel pipe piles include high strength, corrosion resistance, long service life, etc., so they are widely used in various engineering projects.

[0003] A fiber composite pile for marine environment with the patent publication number CN207714308U, the fiber composite pile includes a pile body and a pile tip. An FRP reinforcement cage is arranged inside the composite pile. The FRP reinforcement cage includes a pile body FRP reinforcement cage and a pile tip FRP reinforcement cage. The pile body FRP reinforcement cage includes FRP stress bars with a diameter of 20 - 25 mm and FRP stirrups with a diameter of 6 - 10 mm. The pile tip FRP reinforcement cage includes FRP stress bars with a diameter of 16 mm and FRP stirrups with a diameter of 6 - 10 mm. Two layers of FRP cloth are pasted in the splash zone, and the FRP cloth forms an angle of 0 - 90° with the longitudinal axis of the pile body. The fiber composite pile in the present utility model has advantages such as good ductility, good durability, and light self-weight, and can be applied to bridges and port projects.

[0004] In the process of actual application of the above and similar technical solutions, for the steel pipe piles in the seawater environment, the corrosion degrees of different parts vary greatly. Among them, the corrosion rate in the splash zone is the highest, the corrosion in the marine atmosphere zone is relatively light, and the wet-dry alternate zone is divided into the tidal zone and the splash zone. Due to the action of tides on seawater in the tidal zone, the corrosion is relatively light. In the splash zone, due to the frequent formation of a wet surface, long-term exposure to strong sunlight radiation, and sufficient oxygen supply, the corrosion environment is the most severe. The seawater fully immersed zone refers to the part including the part in the mud downward from the wet-dry alternate zone, and the seabed mud zone is also less affected by seawater and has a low temperature, so the corrosion is lighter than that in seawater. Therefore, for a single protective structure, its protective effect cannot cope with the corrosion protection of the entire steel pipe column. And zinc powder is mostly used to improve the anti-corrosion performance of the powder coating due to its good cathodic protection performance. Graphene itself has impermeability and can isolate various corrosion media. Its excellent electrical conductivity can provide channels for electrons to form a conduction path, which can reduce the usage amount of zinc powder and anti-rust pigments and achieve an efficient anti-corrosion effect. However, in the actual use process, how to ensure the dispersion effect becomes a key technical problem. Using conventional dispersion technology is obviously insufficient, which not only cannot exert the high-efficiency protection effect of the two, but even reduces the physical and mechanical properties of the coating. Summary of the Invention

[0005] The purpose of the present invention is to provide a reinforced concrete steel pipe composite pile for ocean engineering to solve the problems raised in the above background technology.

[0006] To achieve the above purpose, the present invention provides the following technical solution: A reinforced concrete steel pipe composite pile for ocean engineering, including a composite pile body. The composite pile body includes a first connecting pile, a second connecting pile, a third connecting pile, and a pile tip. A plurality of welding rings are fixedly connected to the circumferential outer walls of the first connecting pile, the second connecting pile, the third connecting pile, and the pile tip. A plurality of inner steel bars are fixedly connected to the inner wall of the composite pile body. The outer surface of the composite pile body is coated with a first composite coating, and the inner surface of the composite pile body is coated with an inner single-layer coating. The outer surface of the inner steel bars is coated with a second composite coating, the outer surface of the pile tip is coated with a third composite coating, and the outer surface of the welding rings is coated with a fourth composite coating;

[0007] The installation positions of the composite pile body are divided into the marine atmosphere zone, the splash zone, the seawater tidal zone, the seawater fully immersed zone, and the seabed mud zone. The first connecting pile, the second connecting pile, and the third connecting pile respectively correspond to different zones. Among them, the first connecting pile is in the marine atmosphere zone, the second connecting pile is in the splash zone and the seawater tidal zone, the third connecting pile is in the seawater fully immersed zone and the seabed mud zone, and the first composite coating includes a marine atmosphere coating, a splash coating, a seawater tidal coating, a seawater fully immersed coating, and a seabed mud coating;

[0008] The first auxiliary material and the second auxiliary material are obtained through the first processing method and the second processing method respectively. The first composite coating, the inner single-layer coating, the second composite coating, the third composite coating and the fourth composite coating are prepared through the third processing method, and the first auxiliary material and the second auxiliary material are combined with the first composite coating, the inner single-layer coating, the second composite coating, the third composite coating and the fourth composite coating through the fourth processing method;

[0009] The first auxiliary material includes pretreated flaky zinc powder, and the first processing method includes:

[0010] S1: Mixing. Prepare a mixed solution by mixing xylene and ethyl acetate according to a volume ratio of 1:1. The total volume of the mixed solution is 200% - 1000% of the volume of the flaky zinc powder;

[0011] S2: Stirring. Stir the mixed solution evenly in a ball mill. First, add 0.5% - 2% of the epoxy resin by mass of the epoxy resin used in the fusion-bonded epoxy powder coating formulation, and 0.5% - 2% of the phenolic curing agent by mass of the phenolic curing agent used in the fusion-bonded epoxy powder coating formulation, and stir at a low speed until the epoxy resin and the phenolic curing agent are completely dissolved;

[0012] S3: Ball milling. Add the flaky zinc powder, and perform ball milling under nitrogen protection. The rotation speed of the ball milling is 200 r / min - 500 r / min, the ball milling time is 8 h - 24 h, and the ball milling temperature is 30°C - 50°C. After the ball milling is completed, freeze-dry the mixture to obtain the pretreated flaky zinc powder.

[0013] Furthermore, the marine atmosphere coating includes a first inner coating and a first outer coating, the splash zone coating and the tidal zone coating include a second inner coating and a second outer coating, the seawater immersion coating includes a third inner coating and a third outer coating, and the seabed mud coating includes a fourth inner coating and a fourth outer coating.

[0014] Furthermore, the third composite coating includes a first bottom coating and a first top coating, the fourth composite coating includes a second bottom coating and a second top coating, and the second composite coating includes a third bottom coating and a third top coating.

[0015] Furthermore, the second auxiliary material includes pretreated graphene powder, and the second processing method includes:

[0016] M1: Mixing. Use an ethyl acetate solution with a total volume of 200% - 800% of the volume of graphene, add 0.1% - 0.5% of the epoxy resin by mass of the epoxy resin used in the fusion-bonded epoxy powder coating formulation, and an epoxy group-containing silane coupling agent with the same mass as the added 0.1% - 0.5% of the epoxy resin, and stir until the epoxy resin is completely dissolved;

[0017] M2: Stir, add graphene, stir at low speed for 5 min to 30 min, then stir and reflux at 75 °C to 80 °C for 2 h to 5 h. After the mixture is cooled to room temperature, perform freeze-drying to obtain the pretreated graphene powder.

[0018] Further, the marine atmosphere coating includes a first inner coating and a first outer coating. The first inner coating includes a zinc-based epoxy powder coating layer with a thickness of 80 μm to 150 μm, and the first outer coating includes a weather-resistant fusion-bonded epoxy powder coating layer with a thickness of 80 μm to 150 μm.

[0019] The splash zone coating and the tidal range coating include a second inner coating and a second outer coating. The second inner coating includes a zinc-based epoxy powder coating layer with a thickness of 100 μm to 200 μm, and the second outer coating includes a common fusion-bonded epoxy powder coating layer with a thickness of 100 μm to 200 μm.

[0020] The seawater immersion coating includes a third inner coating and a third outer coating. The third inner coating includes a zinc-based epoxy powder coating layer with a thickness of 60 μm to 120 μm, and the third outer coating includes a common fusion-bonded epoxy powder coating layer with a thickness of 80 μm to 150 μm.

[0021] The seabed soil coating includes a fourth inner coating and a fourth outer coating. The fourth inner coating includes a zinc-based epoxy powder coating layer with a thickness of 60 μm to 120 μm, and the fourth outer coating includes a wear-resistant fusion-bonded epoxy powder coating layer with a thickness of 80 μm to 120 μm.

[0022] Further, the third composite coating includes a first bottom coating and a first surface coating. The first bottom coating includes a thermal spray wear-resistant coating layer with a thickness of 200 μm to 600 μm, and the first surface coating includes a sealing paint coating layer with a thickness of 50 μm to 100 μm.

[0023] The fourth composite coating includes a second bottom coating and a second surface coating. The second bottom coating includes a strengthened thermal spray zinc with a thickness of 200 μm to 300 μm. The second surface coating is composed of a coating layer combination of a sealing paint coating layer with a thickness of 0 μm to 50 μm, an intermediate paint coating layer with a thickness of 40 μm to 100 μm, and a topcoat coating layer with a thickness of 60 μm to 80 μm from the inside to the outside. Among them, the topcoat coating layer in the fourth composite coating in the tidal range zone and above areas includes a weather-resistant topcoat coating layer.

[0024] The second composite coating includes a third bottom coating and a third surface coating. The third bottom coating includes a zinc-based epoxy powder coating layer with a thickness of 50 μm to 80 μm, and the third surface coating includes a common fusion-bonded epoxy powder coating layer with a thickness of 80 μm to 100 μm.

[0025] The inner single-layer coating includes a zinc-based epoxy powder coating layer with a thickness of 50 μm to 100 μm.

[0026] Furthermore, the basic formulation of the zinc-based epoxy powder coating includes: epoxy resin, phenolic curing agent, dimethylimidazole, leveling agent, degassing agent, loosening agent, and flaky zinc powder. The third treatment method includes:

[0027] N1: Mixing and crushing, mixing the remaining epoxy resin after pretreatment, as well as the leveling agent, toughening agent, curing agent, degassing agent, loosening agent, and flaky zinc powder in the formulation for 5 minutes and crushing for 2 minutes;

[0028] N2: Extrusion, the temperature of the first zone of the extruder is 110°C - 115°C, the temperature of the second zone is 80°C - 85°C, the main machine speed is adjusted to 35Hz - 40Hz, and the feeding speed is adjusted to 18Hz - 22Hz to melt and extrude the materials mixed in N1;

[0029] N3: Tablet pressing, the speed of the tablet press is adjusted to 140rpm - 160rpm, and the tablet thickness is 1mm - 2mm. Cool and press the materials extruded in N2;

[0030] N4: Grinding into powder, the feeding speed of the ACM mill is adjusted to 18Hz - 20Hz, and the classifier is adjusted to 12Hz - 15Hz. After grinding, screening the tablets in N3 to obtain the zinc-based epoxy powder coating.

[0031] Furthermore, the fourth treatment method includes: using a bonding device to bond and mix the zinc-based epoxy powder in N4 with the pretreated flaky zinc powder and the pretreated graphene powder to obtain the zinc-based epoxy powder coating.

[0032] Compared with the prior art, the beneficial effects of the present invention are:

[0033] For the reinforced concrete steel pipe composite pile for ocean engineering, corresponding coating structures are designed according to the anti-corrosion requirements of different areas of the steel pipe composite pile, and excellent corrosion resistance is shown. These coating structures fully consider the corrosion characteristics of the steel pipe composite pile in different use environments. By reasonably matching different coating materials and thicknesses, comprehensive protection of the steel pipe composite pile is achieved. In the atmospheric area, the coating structure mainly uses zinc-based epoxy powder coating and weather-resistant fusion-bonded epoxy powder coating. These materials have excellent weather resistance and anti-corrosion performance and can effectively resist corrosion factors in the atmosphere. In the salt spray test, there is no obvious change on the coating surface, and the spreading range is also controlled within a small range, fully proving its excellent corrosion resistance. In the splash zone and tidal range zone of seawater, the coating structure is more complex, adopting a multi-layer structure such as a thermal sprayed zinc-aluminum alloy coating, a sealing paint coating, an intermediate paint coating, and a weather-resistant topcoat coating. These coating materials not only have excellent anti-corrosion performance but also can resist seawater erosion and salt spray corrosion, ensuring the long-term stable operation of the steel pipe composite pile in these harsh environments.

[0034] Meanwhile, after optimizing the pretreatment measures for flaky zinc powder and graphene, through the pre-bonding and effective dispersion of epoxy resin with zinc powder flakes and graphene particles, efficient utilization during the melt extrusion method or the bonding method was achieved. This improvement not only significantly enhanced the quality of the powder, such as fluidity and deposition rate, but also remarkably improved the physical and mechanical properties and corrosion resistance of the coating. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 Schematic diagram of the composite pile body structure of the present invention;

[0036] Figure 2 Schematic diagram of the internal structure of the composite pile body of the present invention;

[0037] Figure 3 Schematic diagram of the flow structure of the first treatment method of the present invention;

[0038] Figure 4 Schematic diagram of the flow structure of the third treatment method of the present invention.

[0039] In the figure: 1, composite pile body; 101, first connecting pile; 102, second connecting pile; 103, third connecting pile; 104, pile tip; 105, welding ring; 2, internal steel bar. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0040] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0041] The corrosion in the marine atmospheric zone is relatively light, mainly affected by the combined action of sea salt particles and the terrestrial atmosphere, and local corrosion is likely to occur in dead corners and other places. The seawater fully immersed zone refers to the part including the area in the soil downward from the wet-dry alternate zone, which can be divided into the shallow sea area, the deep sea area, and the soil area. The corrosivity of seawater is mainly affected by dissolved oxygen, temperature, salinity, pH value, and biological factors. Therefore, the corrosion rate in the shallow sea is greater than that in the marine atmospheric zone. However, the oxygen content in the deep sea area is often much lower than that in the seawater surface layer and the atmospheric zone, and the water temperature is close to zero degree, so the corrosion is relatively light. Therefore, it is necessary to provide targeted protection for the composite piles in different regions. The reinforced concrete steel pipe composite pile provided by this technical solution can have a simple, efficient, clean, and environmentally friendly design for its surface coating structure. On the premise of meeting the anti-corrosion design requirements for the coating structure in the same corrosion area, the coating thickness of this technical solution can be significantly reduced, and at the same time, the external sacrificial anode block can be omitted, reducing the consumption of various materials.

[0042] Such as Figures 1-4As shown in the figure, the present invention provides a technical solution: a reinforced concrete steel pipe composite pile for ocean engineering, including a composite pile body 1, the composite pile body 1 includes a first connecting pile 101, a second connecting pile 102, a third connecting pile 103 and a pile tip 104, and a plurality of welding rings 105 are fixedly connected to the circumferential outer walls of the first connecting pile 101, the second connecting pile 102, the third connecting pile 103 and the pile tip 104. A plurality of inner steel bars 2 are fixedly connected to the inner wall of the composite pile body 1. The outer surface of the composite pile body 1 is coated with a first composite coating, and the inner surface of the composite pile body 1 is coated with an inner single-layer coating. The outer surface of the inner steel bar 2 is coated with a second composite coating. The outer surface of the pile tip 104 is coated with a third composite coating. The outer surface of the welding ring 105 is coated with a fourth composite coating. The installation positions of the composite pile body 1 are divided into the ocean atmosphere zone, the splash zone, the tidal range zone, the fully submerged zone and the seabed mud zone, and the first connecting pile 101, the second connecting pile 102 and the third connecting pile 103 respectively correspond to different zones. Among them, the first connecting pile 101 is in the ocean atmosphere zone, the second connecting pile 102 is in the splash zone and the tidal range zone, and the third connecting pile 103 is in the fully submerged zone and the seabed mud zone. The first composite coating includes an ocean atmosphere coating, a splash coating, a tidal range coating, a fully submerged coating and a seabed mud coating. Through the first treatment method and the second treatment method, a first auxiliary material and a second auxiliary material are respectively obtained. Through the third treatment method, the first composite coating, the inner single-layer coating, the second composite coating, the third composite coating and the fourth composite coating are prepared, and through the fourth treatment method, the first auxiliary material and the second auxiliary material are combined with the first composite coating, the inner single-layer coating, the second composite coating, the third composite coating and the fourth composite coating. The first auxiliary material includes pretreated flaky zinc powder. The first treatment method includes: S1: Mixing, preparing a mixed solution by mixing xylene and ethyl acetate according to a volume ratio of 1:1, and the total volume of the mixed solution is 200% - 1000% of the volume of the flaky zinc powder. S2: Stirring, stirring the mixed solution evenly in a ball mill. First, add epoxy resin accounting for 0.5% - 2% of the mass parts of the epoxy resin used in the fusion-bonded epoxy powder coating formula, and phenolic curing agent accounting for 0.5% - 2% of the mass parts of the phenolic curing agent used in the fusion-bonded epoxy powder coating formula, and stir at a low speed until the epoxy resin and the phenolic curing agent are completely dissolved. S3: Ball milling, adding flaky zinc powder, carrying out ball milling under nitrogen protection, the rotation speed of the ball milling is 200 r / min - 500 r / min, the ball milling time is 8 h - 24 h, the ball milling temperature is 30 °C - 50 °C, and after the ball milling is completed, the mixture is freeze-dried to obtain pretreated flaky zinc powder.

[0043] The ocean atmosphere coating includes a first inner coating and a first outer coating. The splash coating and the tidal range coating include a second inner coating and a second outer coating. The fully submerged coating includes a third inner coating and a third outer coating. The seabed mud coating includes a fourth inner coating and a fourth outer coating.

[0044] The third composite coating includes a first primer coat and a first topcoat, the fourth composite coating includes a second primer coat and a second topcoat, and the second composite coating includes a third primer coat and a third topcoat.

[0045] The second auxiliary material includes pretreated graphene powder, and the second treatment method includes: M1: Mixing, using an ethyl acetate solution with a total volume 200% - 800% of the volume of graphene, adding 0.1% - 0.5% of the epoxy resin by mass parts used in the fusion-bonded epoxy powder coating formulation, and an epoxy group-containing silane coupling agent with the same mass as the added 0.1% - 0.5% of the epoxy resin, and stirring until the epoxy resin is completely dissolved;

[0046] M2: Stirring, adding graphene, stirring at a low speed for 5 min - 30 min, then stirring and refluxing at 75°C - 80°C for 2 h - 5 h, and freeze-drying after the mixture is cooled to room temperature to obtain pretreated graphene powder.

[0047] The marine atmospheric coating includes a first inner coating and a first outer coating. The first inner coating includes a zinc-based epoxy powder coating layer with a thickness of 80 μm - 150 μm, and the first outer coating includes a weather-resistant fusion-bonded epoxy powder coating layer with a thickness of 80 μm - 150 μm; the splash zone coating and the tidal zone coating include a second inner coating and a second outer coating. The second inner coating includes a zinc-based epoxy powder coating layer with a thickness of 100 μm - 200 μm, and the second outer coating includes a common fusion-bonded epoxy powder coating layer with a thickness of 100 μm - 200 μm; the seawater immersion coating includes a third inner coating and a third outer coating. The third inner coating includes a zinc-based epoxy powder coating layer with a thickness of 60 μm - 120 μm, and the third outer coating includes a common fusion-bonded epoxy powder coating layer with a thickness of 80 μm - 150 μm; the seabed soil coating includes a fourth inner coating and a fourth outer coating. The fourth inner coating includes a zinc-based epoxy powder coating layer with a thickness of 60 μm - 120 μm, and the fourth outer coating includes a wear-resistant fusion-bonded epoxy powder coating layer with a thickness of 80 μm - 120 μm.

[0048] The third composite coating includes a first primer coat and a first top coat. The first primer coat includes a thermal spray wear-resistant coating with a thickness of 200 μm to 600 μm, and the first top coat includes a sealant coating with a thickness of 50 μm to 100 μm. The fourth composite coating includes a second primer coat and a second top coat. The second primer coat includes strengthened thermal spray zinc with a thickness of 200 μm to 300 μm, and the second top coat is composed of a combination of coating layers, from the inside out, including a sealant coating with a thickness of 0 μm to 50 μm, an intermediate paint coating with a thickness of 40 μm to 100 μm, and a top paint coating with a thickness of 60 μm to 80 μm. Among them, the top paint coating in the fourth composite coating in the sea tidal range area and above includes a weather-resistant top paint coating. The second composite coating includes a third primer coat and a third top coat. The third primer coat includes a zinc-based epoxy powder coating with a thickness of 50 μm to 80 μm, and the third top coat includes a common fusion-bonded epoxy powder coating with a thickness of 80 μm to 100 μm. The inner single-layer coating includes a zinc-based epoxy powder coating with a thickness of 50 μm to 100 μm.

[0049] The basic formula of the zinc-based epoxy powder coating includes: epoxy resin, phenolic curing agent, dimethylimidazole, leveling agent, degassing agent, loosening agent, and flaky zinc powder. The third treatment method includes: N1: Mixing and crushing, mixing the remaining epoxy resin after pretreatment, as well as the leveling agent, toughening agent, curing agent, degassing agent, loosening agent, and flaky zinc powder in the formula for 5 minutes and crushing for 2 minutes; N2: Extrusion, the temperature of the first zone of the extruder is 110°C to 115°C, the temperature of the second zone is 80°C to 85°C, the main machine speed is adjusted to 35 Hz to 40 Hz, and the feeding speed is adjusted to 18 Hz to 22 Hz to melt and extrude the material mixed in N1; N3: Tablet pressing, the speed of the tablet press is adjusted to 140 rpm to 160 rpm, and the tablet pressing thickness is 1 mm to 2 mm. Cool and tablet press the material extruded in N2; N4: Grinding into powder, the feeding speed of the ACM mill is adjusted to 18 Hz to 20 Hz, and the classifier is adjusted to 12 Hz to 15 Hz. After grinding, screening, and making powder of the tablet in N3, the zinc-based epoxy powder coating is obtained.

[0050] The fourth treatment method includes: using a bonding device to bond and mix the zinc-based epoxy powder in N4 with the pretreated flaky zinc powder and the pretreated graphene powder to obtain the zinc-based epoxy powder coating.

[0051] As a specific implementation method, the formula and main preparation method of Examples 1-3 of the zinc-based epoxy powder coating are shown in Table 1.

[0052] Table 1: Formulation table of fusion-bonded epoxy powder coating Unit: parts by weight

[0053]

[0054] The preparation method of Examples 1-3 of the zinc-based epoxy powder coating by the melt extrusion method is as follows:

[0055] Step 1: Pretreatment. The pretreatment process before adding the flaky zinc powder in the zinc-based epoxy powder coatings of Examples 1-3 is as follows: Prepare a mixed solution by mixing xylene and ethyl acetate in a volume ratio of 1:1. The total volume of the mixed solution is 200% - 1000% of the volume of the flaky zinc powder. Stir the mixed solution evenly in a ball mill; First, add epoxy resin accounting for 0.5% - 2% of the mass parts of the epoxy resin used in the fusion-bonded epoxy powder coating formula, and phenolic curing agent accounting for 0.5% - 2% of the mass parts of the phenolic curing agent used in the fusion-bonded epoxy powder coating formula, and stir at a low speed until the epoxy resin and phenolic curing agent are completely dissolved; Then add the flaky zinc powder, carry out ball milling under nitrogen protection, the rotation speed of the ball milling is 200 r / min - 500 r / min, the ball milling time is 8 h - 24 h, the ball milling temperature is 30 °C - 50 °C. After the ball milling is completed, freeze-dry the mixture to obtain the pretreated flaky zinc powder for standby. The percentage of the above phenolic curing agent is based on the percentage of the selected epoxy resin in the mass parts of the epoxy resin in its fusion-bonded epoxy powder coating formula. The amount of the selected epoxy resin is adjusted accordingly within the range of 0.5% - 2% of the mass parts of the epoxy resin used according to the designed amount of the flaky zinc powder in the zinc-based epoxy powder coating, that is, when the amount of the flaky zinc powder is large, the amount of the selected epoxy resin also increases accordingly.

[0056] The pre-treatment process before adding graphene in the zinc-based epoxy powder coating of Example 2 is as follows: Use an ethyl acetate solution with a total volume 700% of the volume of graphene, add 0.4% of the epoxy resin by mass in the fusion-bonded epoxy powder coating formula and an epoxy group-containing silane coupling agent with the same mass as the added 0.4% of the epoxy resin, and stir until the epoxy resin is completely dissolved; then add graphene, stir at low speed for 25 min, then stir and reflux at 75 °C - 80 °C for 4 h. After the mixture cools to room temperature, perform freeze-drying to obtain the pre-treated graphene powder for standby. The selected amount of the above epoxy resin is adjusted accordingly within the range of 0.5% - 2% by mass according to the designed amount of graphene in the zinc-based epoxy powder coating, that is, when the amount of graphene used is large, the amount of epoxy resin used is also increased accordingly, and the amount of the epoxy group-containing silane coupling agent is also adjusted accordingly with the selected amount of epoxy resin. Step 2: Mixing, mix the remaining epoxy resin after pre-treatment in Example 1, Example 2, and Example 3-1, as well as the leveling agent, toughening agent, curing agent, dimethylimidazole in the formula, the flaky zinc powder obtained by S101 pre-treatment, and the graphene obtained by S101 pre-treatment (such as in Example 2) and other raw materials for 5 min and crush for 2 min; Step 3: Extrusion, the process design of the extruder: Zone I temperature 110 °C - 115 °C, Zone II temperature 80 °C - 85 °C. Existing equipment all has an automatic constant temperature control design to ensure that the temperature fluctuation range is within the above design range (the same below); Main machine speed regulation: 38 Hz, feeding speed regulation: 20 Hz; After the Hz value of the equipment speed regulation is set, it generally fluctuates very little (the same below); Melt and extrude the mixed material according to the above extrusion process; Step 4: Tabletting, the process design of the tabletting machine: speed regulation 140 rpm - 160 rpm, tablet thickness 1 mm - 2 mm. Use the tabletting machine to cool and tablet the extruded material; Step 5: Grinding, the process design of the ACM mill: feeding speed regulation: 19 Hz, classifier adjustment: 13 Hz; After screening the tableted and ground powder, obtain the zinc-based epoxy powder coating prepared by the extrusion method.

[0057] The bonding method for preparing the zinc-based epoxy powder coating of Example 3-2 is as follows:

[0058] Step 1: Pretreatment. The pretreatment process before adding the flaky zinc powder in the formulation of Example 3 is as follows: Prepare a mixed solution by mixing xylene and ethyl acetate in a volume ratio of 1:1. The total volume of the mixed solution is 400% of the volume of the flaky zinc powder. Stir the mixed solution evenly in a ball mill. First, add 2% of the epoxy resin by mass of the epoxy resin used in the fusion-bonded epoxy powder coating formulation and 2% of the phenolic curing agent by mass of the phenolic curing agent used in the fusion-bonded epoxy powder coating formulation, and stir at a low speed until the epoxy resin and phenolic curing agent are completely dissolved. Then add the flaky zinc powder, and perform ball milling under nitrogen protection. The rotation speed of the ball milling is 400 r / min, the ball milling time is 24 h, and the ball milling temperature is 30 °C - 40 °C. After the ball milling is completed, freeze-dry the mixture to obtain the pretreated flaky zinc powder for standby. Step 2: Mixing. Mix the remaining epoxy resin after pretreatment, as well as the remaining leveling agent, toughening agent, curing agent, 2-methylimidazole and other raw materials in the formulation for 5 min and crush for 2 min. Step 3: Extrusion. Extruder process design: Zone I temperature 110 °C - 115 °C, Zone II temperature 80 °C - 85 °C; Main machine speed regulation: 40 Hz, feeding speed regulation: 22 Hz; Melt and extrude the mixed material of S202. Step 4: Tabletting. Tabletting machine process design: Speed regulation 140 rpm - 160 rpm, tablet thickness 1 mm - 2 mm. Cool and tablet the extruded material. Step 5: Grinding. ACM mill process design: Feeding speed regulation: 18 Hz, classifier regulation: 12 Hz; Grind and screen the tablet of S204 to obtain the powder coating base material used in the bonding method. Step 6: Bonding. Use a bonding device to bond and mix the bonding method powder coating base material obtained by grinding with the prepared pretreated flaky zinc powder to obtain the zinc-based epoxy powder coating of Example 3-2.

[0059] Preparation methods of Comparative Examples 1-3:

[0060] Comparative Example 1: Prepared by the conventional melt extrusion method, that is, all the materials in the formulation of Comparative Example 1 are mixed, and then obtained through extrusion, tabletting, and grinding.

[0061] Comparative Example 2: First, mix the flaky zinc powder and graphene in Comparative Example 2 with the epoxy resin in the formulation of Comparative Example 2 using a mixing device, such as high-speed dispersion for 5 min - 10 min and crushing for 2 min - 5 min; then add all the remaining materials after mixing, and obtain the zinc-based epoxy powder coating of Comparative Example 2 according to the extrusion, tabletting, and grinding processes.

[0062] Comparative Example 3-1: Melt extrusion method. First, disperse the flaky zinc powder in Comparative Example 3 with epoxy resin and leveling agent by the melt extrusion method, and obtain tablets through extrusion and tabletting processes. Then, mix, extrude, tablet, and grind the above tablets with other components in Comparative Example 3 to obtain the zinc-based epoxy powder coating.

[0063] Comparative Example 3-2: Bounding method. First, the other components in Comparative Example 3 except for the flaky zinc powder were prepared into the base material of zinc-based epoxy powder coating by the process of mixing, extrusion, tablet pressing, and grinding using the melt extrusion method. Then, using existing bounding equipment, the base material of the above zinc-based epoxy powder coating and flaky zinc powder were added, and the zinc-based epoxy powder coating of Comparative Example 3-2 of the existing bounding technology was prepared according to the existing bounding process.

[0064] Example 4

[0065] A reinforced concrete steel pipe composite pile for ocean engineering, wherein the outer surface of the steel pipe is divided into an ocean atmosphere area, a splash zone, a tidal range zone, a fully submerged seawater zone, and a seabed mud zone. The composite pile body 1 is also attached with a welding ring 105 and a pile tip 104, and the composite pile body 1 is cast with reinforced concrete.

[0066] The outer surface of the steel pipe is coated with an outer composite coating for anti-corrosion protection, wherein:

[0067] Ocean atmosphere area: The first inner coating and the first outer coating are a zinc-based epoxy powder coating with a thickness of 80 μm - 120 μm + a weather-resistant fusion-bonded epoxy powder coating with a thickness of 80 μm - 100 μm;

[0068] Splash zone and tidal range zone: The second inner coating and the second outer coating are a zinc-based epoxy powder coating with a thickness of 100 μm - 150 μm + a common fusion-bonded epoxy powder coating with a thickness of 100 μm - 150 μm;

[0069] Fully submerged seawater zone and seabed mud zone: The third inner coating and the third outer coating are a zinc-based epoxy powder coating with a thickness of 60 μm - 80 μm + a common fusion-bonded epoxy powder coating with a thickness of 80 μm - 100 μm; when necessary, the third outer coating in the seabed mud zone can also be replaced with a wear-resistant fusion-bonded epoxy powder coating with a thickness of 80 μm - 100 μm;

[0070] Pile tip 104: The first bottom coating and the first surface coating are a thermal sprayed wear-resistant coating with a thickness of 200 μm - 400 μm + a sealing coating with a thickness of 50 μm - 80 μm;

[0071] Welding ring 105: The second bottom coating is a strengthened thermal sprayed zinc-aluminum alloy coating (such as ZnAl 15 alloy) with a thickness of 200 μm - 300 μm, and the second surface coating is a coating with a thickness of 0 μm - 30 μm sealing coating (0 μm: the sealing agent penetrates into the metal coating, and the thickness of its surface coating can be ignored, the same below) + an intermediate coating with a thickness of 60 μm - 80 μm + a topcoat with a thickness of 60 μm - 80 μm; for the welding ring exposed to the atmosphere, its topcoat is preferably a weather-resistant topcoat (such as fluorocarbon topcoat, polysiloxane topcoat);

[0072] The inner surface of the steel pipe of the composite pile body 1 is coated with an inner single-layer coating for anti-corrosion protection, and the inner single-layer coating is a zinc-based epoxy powder coating with a thickness of 50μm to 80μm;

[0073] The surface of the inner steel bar 2 is coated with a second composite coating for anti-corrosion protection, which consists of a third primer coating and a third topcoat. The third primer coating is a zinc-based epoxy powder coating with a thickness of 60μm to 80μm, and the third topcoat is a general fusion-bonded epoxy powder coating with a thickness of 80μm to 100μm.

[0074] Example 5

[0075] A reinforced concrete steel pipe composite pile for offshore engineering, wherein the outer surface of the steel pipe is divided into a marine atmosphere zone, a splash zone, a tidal range zone, a seawater immersion zone, and a seabed mud zone. A welding ring 105 and a pile tip 104 are also attached to the composite pile body 1, and the composite pile body 1 is cast with reinforced concrete.

[0076] The outer surface of the steel pipe is coated with an outer composite coating for anti-corrosion protection, wherein:

[0077] Marine atmosphere zone: The first inner coating and the first outer coating are a thermal sprayed zinc-aluminum alloy coating with a thickness of 120μm to 140μm + (a closed coating with a thickness of 30μm to 50μm + an intermediate paint coating with a thickness of 60μm to 80μm + a weather-resistant topcoat coating with a thickness of 60μm to 80μm) coating;

[0078] Splash zone and tidal range zone: The second inner coating and the second outer coating are an aluminum-magnesium alloy coating with a thickness of 200μm to 250μm + (a closed coating with a thickness of 40μm to 50μm + an intermediate paint coating with a thickness of 120μm to 150μm + a weather-resistant topcoat coating with a thickness of 100μm to 120μm) coating;

[0079] Seawater immersion zone and seabed mud zone: The third inner coating and the third outer coating are a zinc-based epoxy powder coating with a thickness of 80μm to 120μm + a general fusion-bonded epoxy powder coating with a thickness of 100μm to 120μm; when there is a wear-resistant design requirement, the outer coating of the seabed mud zone can preferably be a wear-resistant fusion-bonded epoxy powder coating with a thickness of 100μm to 120μm;

[0080] Pile tip 104: The first primer coating and the first topcoat are a thermal sprayed wear-resistant coating with a thickness of 400μm to 600μm + a closed coating with a thickness of 80μm to 100μm;

[0081] Welding ring 105: The second bottom coating is a reinforced thermally sprayed magnesium-aluminum alloy coating (such as Al Mg5 alloy, the same below) with a thickness of 250 μm to 300 μm, and the second surface coating is a coating consisting of a sealing paint coating with a thickness of 30 μm to 50 μm + an intermediate paint coating with a thickness of 60 μm to 100 μm + a topcoat coating with a thickness of 60 μm to 80 μm; among them, the topcoat coating of the welding ring exposed to the atmosphere in the tidal zone and above can preferably be a weather-resistant topcoat coating;

[0082] The inner surface of the steel pipe of the composite pile body 1 is coated with an inner single-layer coating for anti-corrosion protection, and the inner single-layer coating is a zinc-based epoxy powder coating with a thickness of 80 μm to 100 μm;

[0083] The surface of the inner steel bar 2 is coated with a second composite coating for anti-corrosion protection, which consists of a third bottom coating and a third surface coating. The third bottom coating is a thermally sprayed aluminum-magnesium alloy coating with a thickness of 120 μm to 150 μm, and the third surface coating is a sealing paint coating with a thickness of 30 μm to 50 μm.

[0084] Example 6

[0085] A reinforced concrete steel pipe composite pile for ocean engineering, wherein the outer surface of the steel pipe is divided into a marine atmosphere zone, a splash zone, a tidal zone, a fully immersed seawater zone, and a seabed mud zone. The composite pile body 1 is also attached with a welding ring 105 and a pile tip 104, and the composite pile body 1 is cast with reinforced concrete.

[0086] The outer surface of the steel pipe is coated with an outer composite coating for anti-corrosion protection, where:

[0087] Marine atmosphere zone: The first inner coating and the first outer coating are a zinc-based epoxy powder coating with a thickness of 80 μm to 100 μm + a weather-resistant fusion-bonded epoxy powder coating with a thickness of 80 μm to 100 μm;

[0088] Splash zone and tidal zone: The second inner coating and the second outer coating are a reinforced thermally sprayed aluminum coating with a thickness of 250 μm to 300 μm + a coating consisting of (a sealing paint coating with a thickness of 0 μm to 30 μm + an intermediate paint coating with a thickness of 100 μm to 120 μm + a topcoat coating with a thickness of 80 μm);

[0089] Fully immersed seawater zone and seabed mud zone: The third inner coating and the third outer coating are a zinc-based epoxy powder coating with a thickness of 60 μm to 80 μm + a common fusion-bonded epoxy powder coating with a thickness of 80 μm to 100 μm; when there is a wear-resistant design requirement, the outer coating of the seabed mud zone can preferably be a wear-resistant fusion-bonded epoxy powder coating with a thickness of 80 μm to 100 μm;

[0090] Pile tip 104: The first bottom coating and the first surface coating are a thermal spraying wear-resistant coating with a thickness of 200 μm to 300 μm + a sealing paint coating with a thickness of 50 μm to 80 μm;

[0091] Welding ring 105: The second bottom coating is a reinforcing thermal spraying magnesium-aluminum alloy coating with a thickness of 200 μm, and the second surface coating is a paint coating consisting of a sealing paint coating with a thickness of 0 μm to 30 μm + an intermediate paint coating with a thickness of 40 μm to 60 μm + a topcoat coating with a thickness of 60 μm to 80 μm; Among them, the topcoat coating of the welding ring in the seawater tidal difference area and above areas exposed to the atmosphere can preferably be a weather-resistant topcoat coating;

[0092] The inner surface of the steel pipe of the composite pile body 1 is coated with an inner single-layer coating for anti-corrosion protection, and the inner single-layer coating is a zinc-based epoxy powder coating with a thickness of 50 μm to 60 μm.

[0093] The surface of the inner steel bar 2 is coated with a second composite coating for anti-corrosion protection, which is composed of a third bottom coating and a third surface coating. The third bottom coating is a zinc-based epoxy powder coating with a thickness of 50 μm to 60 μm, and the third surface coating is a common fusion-bonded epoxy powder coating with a thickness of 80 μm to 100 μm.

[0094] The main properties of the main composite coating are tested under the same conditions, and the test results are shown in Table 2 and Table 3.

[0095] Table 2: Data table of the main paint and coating performance tests of Examples 1-3 and Comparative Examples 1-3

[0096]

[0097] Remarks:

[0098] GB / T 21782.5-2010: "Powder coatings - Part 5: Determination of the flowability of powder / air mixtures";

[0099] ISO 8130-5:2021: "Coating powders - Part 5: Determination of flow properties of a powder / air mixture";

[0100] GB / T 21782.10-2008: "Powder coatings - Part 10: Determination of deposition efficiency";

[0101] ISO 8130-10:2021: "Coating powders - Part 10: Determination of deposition efficiency";

[0102] GB / T 9286-1998: "Cross-cut test for paints and varnishes films"

[0103] ISO 2409:2020: "Paints and varnishes—Cross-cut test"

[0104] GB / T 5210-2006: "Pull-off adhesion test for paints and varnishes"

[0105] ISO 4624:2023: "Paints and varnishes—Pull-off test for adhesion"

[0106] GB / T 10125-2021: "Artificial atmosphere corrosion test—Salt spray test"

[0107] ISO 9227:2022: "Corrosion tests in artificial atmospheres—Salt spray tests"

[0108] Table 3: Test results table of corrosion resistance performance of the main composite coatings in Examples 4-6

[0109]

[0110]

[0111] The test data in Table 2 shows that after optimizing the pretreatment measures of flaky zinc powder and graphene in the present invention, by using the pre-bonding and effective dispersion of epoxy resin with zinc powder flakes and graphene particles, its high-efficiency utilization in the melt extrusion method or bonding method is improved. Compared with the prior art, not only the powder quality (such as fluidity, deposition rate) is greatly improved, but also the physical and mechanical properties (such as adhesion) and corrosion resistance (such as salt spray test) of the coating are significantly enhanced, achieving outstanding product improvement effects.

[0112] The test data in Table 3 shows that the corresponding coating structure designed for the anti-corrosion requirements in different regions of the steel pipe composite pile of the present invention has excellent corrosion resistance, can fully meet the long-life design requirements of existing steel pipe composite piles, can reduce additional anti-corrosion measures of other prior arts (such as external anode protection blocks, external cathodic protection currents, external wrapping protection measures), reduce or even eliminate the later maintenance frequency, and can generate outstanding economic and social benefits.

[0113] Table 4: Analysis and comparison table of the cost and average annual cost of the main coating structures

[0114]

[0115] Table 4 compares the cost of the present invention with that of the prior art and analyzes the average annual cost during its protection life. The data shows that the unit cost of the main coating structure of the present invention can be reduced by more than 50% based on the prior art.

[0116] Although the embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A reinforced concrete steel pipe composite pile for ocean engineering, comprising a composite pile body (1), characterized in that: The composite pile body (1) includes a first connecting pile (101), a second connecting pile (102), a third connecting pile (103) and a pile tip (104), and a plurality of welding rings (105) are fixedly connected to the circumferential outer walls of the first connecting pile (101), the second connecting pile (102), the third connecting pile (103) and the pile tip (104). A plurality of internal steel bars (2) are fixedly connected to the inner wall of the composite pile body (1). The outer surface of the composite pile body (1) is coated with a first composite coating, and the inner surface of the composite pile body (1) is coated with an inner single-layer coating. The outer surface of the internal steel bar (2) is coated with a second composite coating, the outer surface of the pile tip (104) is coated with a third composite coating, and the outer surface of the welding ring (105) is coated with a fourth composite coating; The installation positions of the composite pile body (1) are divided into the marine atmospheric zone, the splash zone, the tidal zone, the fully submerged zone and the seabed mud zone, and the first connecting pile (101), the second connecting pile (102) and the third connecting pile (103) respectively correspond to different zones. Among them, the first connecting pile (101) is in the marine atmospheric zone, the second connecting pile (102) is in the splash zone and the tidal zone, the third connecting pile (103) is in the fully submerged zone and the seabed mud zone, and the first composite coating includes a marine atmospheric coating, a splash coating, a tidal coating, a fully submerged coating and a seabed mud coating; Through the first treatment method and the second treatment method, a first auxiliary material and a second auxiliary material are respectively obtained. Through the third treatment method, a first composite coating, an inner single-layer coating, a second composite coating, a third composite coating and a fourth composite coating are prepared, and through the fourth treatment method, the first auxiliary material and the second auxiliary material are combined with the first composite coating, the inner single-layer coating, the second composite coating, the third composite coating and the fourth composite coating; The first auxiliary material includes pretreated flaky zinc powder, and the first treatment method includes: S1: Mixing, preparing a mixed solution by mixing xylene and ethyl acetate according to a volume ratio of 1:1, and the total volume of the mixed solution is 200% - 1000% of the volume of the flaky zinc powder; S2: Stirring, stirring the mixed solution evenly in a ball mill; first adding epoxy resin accounting for 0.5% - 2% of the mass parts of the epoxy resin used in the fusion-bonded epoxy powder coating formula, and phenolic curing agent accounting for 0.5% - 2% of the mass parts of the phenolic curing agent used in the fusion-bonded epoxy powder coating formula, and stirring at a low speed until the epoxy resin and the phenolic curing agent are completely dissolved; S3: Ball milling, adding flaky zinc powder, and performing ball milling under nitrogen protection. The rotation speed of the ball milling is 200 r / min - 500 r / min, the ball milling time is 8 h - 24 h, the ball milling temperature is 30°C - 50°C, and after the ball milling is completed, the mixture is freeze-dried to obtain pretreated flaky zinc powder; The marine atmospheric coating includes a first inner coating and a first outer coating, the splash coating and the tidal coating include a second inner coating and a second outer coating, the fully submerged coating includes a third inner coating and a third outer coating, and the seabed mud coating includes a fourth inner coating and a fourth outer coating; The marine atmosphere coating includes a first inner coating and a first outer coating. The first inner coating includes a zinc-based epoxy powder coating layer with a thickness of 80 μm to 150 μm, and the first outer coating includes a weather-resistant fusion-bonded epoxy powder coating layer with a thickness of 80 μm to 150 μm; The splash coating and the seawater tidal range coating include a second inner coating and a second outer coating. The second inner coating includes a zinc-based epoxy powder coating layer with a thickness of 100 μm to 200 μm, and the second outer coating includes a common fusion-bonded epoxy powder coating layer with a thickness of 100 μm to 200 μm; The seawater immersion coating includes a third inner coating and a third outer coating. The third inner coating includes a zinc-based epoxy powder coating layer with a thickness of 60 μm to 120 μm, and the third outer coating includes a common fusion-bonded epoxy powder coating layer with a thickness of 80 μm to 150 μm; The seabed soil coating includes a fourth inner coating and a fourth outer coating. The fourth outer coating includes a zinc-based epoxy powder coating layer with a thickness of 60 μm to 120 μm, and the fourth outer coating includes a wear-resistant fusion-bonded epoxy powder coating layer with a thickness of 80 μm to 120 μm.

2. The reinforced concrete steel pipe composite pile for ocean engineering according to claim 1, characterized in that: The third composite coating includes a first primer coating and a first topcoat. The fourth composite coating includes a second primer coating and a second topcoat. The second composite coating includes a third primer coating and a third topcoat.

3. A reinforced concrete steel pipe composite pile for ocean engineering according to claim 1, characterized in that: The second auxiliary material includes pretreated graphene powder. The second treatment method includes: M1: Mixing. Using an ethyl acetate solution with a total volume 200% to 800% of the volume of graphene, adding 0.1% to 0.5% of the epoxy resin by mass in the fusion-bonded epoxy powder coating formulation and an epoxy group-containing silane coupling agent with the same mass as the added 0.1% to 0.5% of the epoxy resin, and stirring until the epoxy resin is completely dissolved; M2: Stirring. Adding graphene, stirring at low speed for 5 min to 30 min, then stirring and refluxing at 75 °C to 80 °C for 2 h to 5 h. After the mixture cools to room temperature, it is freeze-dried to obtain the pretreated graphene powder.

4. A reinforced concrete steel pipe composite pile for ocean engineering according to claim 1, characterized in that: The third composite coating includes a first primer coating and a first topcoat. The first primer coating includes a thermal sprayed wear-resistant coating with a thickness of 200 μm to 600 μm, and the first topcoat includes a sealing paint coating with a thickness of 50 μm to 100 μm; The fourth composite coating includes a second primer coating and a second topcoat. The second primer coating includes a reinforced thermal sprayed zinc with a thickness of 200 μm to 300 μm. The second topcoat is composed of a coating combination including a sealing paint coating with a thickness of 0 μm to 50 μm, an intermediate paint coating with a thickness of 40 μm to 100 μm, and a topcoat with a thickness of 60 μm to 80 μm from the inside to the outside. The topcoat in the fourth composite coating in the seawater tidal range area and above includes a weather-resistant topcoat; The second composite coating includes a third primer coating and a third topcoat. The third primer coating includes a zinc-based epoxy powder coating layer with a thickness of 50 μm to 80 μm, and the third topcoat includes a common fusion-bonded epoxy powder coating layer with a thickness of 80 μm to 100 μm; The inner single-layer coating includes a zinc-based epoxy powder coating layer with a thickness of 50 μm to 100 μm.

5. A reinforced concrete steel pipe composite pile for ocean engineering according to claim 4, characterized in that: The basic formulation of the zinc-based epoxy powder coating includes: epoxy resin, phenolic curing agent, dimethylimidazole, leveling agent, degassing agent, loosening agent, and flaky zinc powder. The third treatment method includes: N1: Mixing and crushing, mixing the remaining epoxy resin after pretreatment, as well as the leveling agent, toughening agent, curing agent, degassing agent, loosening agent, and flaky zinc powder in the formulation for 5 minutes and crushing for 2 minutes; N2: Extrusion, the temperature of the first zone of the extruder is 110°C - 115°C, the temperature of the second zone is 80°C - 85°C, the main machine speed is adjusted to 35Hz - 40Hz, and the feeding speed is adjusted to 18Hz - 22Hz to melt and extrude the materials mixed in N1; N3: Tablet pressing, the speed of the tablet press is adjusted to 140rpm - 160rpm, and the tablet thickness is 1mm - 2mm. Cool and press the extruded materials in N2; N4: Grinding into powder, the feeding speed of the ACM mill is adjusted to 18Hz - 20Hz, and the classifier is adjusted to 12Hz - 15Hz. Grind the tablets in N3 into powder and sieve to obtain the zinc-based epoxy powder coating.

6. The reinforced concrete steel pipe composite pile for ocean engineering according to claim 5, characterized in that: The fourth treatment method includes: using a bonding device to bond and mix the zinc-based epoxy powder in N4 with the pretreated flaky zinc powder and the pretreated graphene powder to obtain the zinc-based epoxy powder coating.

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