Reinforced concrete-filled steel tube composite pile for marine engineering

Abstract

The present invention relates to the technical field of steel tube composite piles. Disclosed is a reinforced concrete-filled steel tube composite pile for marine engineering, comprising a composite pile body; the composite pile body comprises a first connection pile, a second connection pile, a third connection pile and a pile tip, and a plurality of welding rings are fixedly connected to the circumferential outer walls of the first connection pile, the second connection pile, the third connection pile and the pile tip; a plurality of inner rebars 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. For anti-corrosion requirements of different regions of steel tube composite piles, the present invention designs corresponding coating structures, which exhibit excellent corrosion resistance; the corrosion characteristics of steel tube composite piles in different use environments are fully considered, and reasonably matching these coating structures with different coating materials and thicknesses achieves comprehensive protection of steel tube composite piles.

Description

Reinforced concrete steel pipe composite pile for marine engineering TECHNICAL FIELD

[0001] The present application relates to the technical field of steel pipe composite pile, in particular to a reinforced concrete steel pipe composite pile for marine engineering. BACKGROUND

[0002] Marine engineering refers to a new, reconstruction, expansion project whose main body is located on the sea side of the coastline for the purpose of developing, utilizing, protecting and restoring marine resources, such as cross-sea bridges, offshore dam projects, artificial islands, marine mineral resource exploration and development and its auxiliary projects, marine energy development and utilization projects, landscape development projects, etc. Many of the above projects built above the sea surface need steel pipe piles as pile foundation support. Steel pipe pile is a common foundation support tool, which is often used in the fields of construction and engineering. It has various functions and can be used as a support for bridge pile foundation and a bearing element for building foundation. Steel pipe pile has the advantages of high strength, corrosion resistance and long service life, and is widely used in various engineering projects.

[0003] The utility model discloses a kind of fiber composite piles for marine environment, the fiber composite pile includes pile body and pile tip, FRP cage is arranged in the composite pile, the FRP cage includes pile body FRP cage and pile tip FRP cage, the pile body FRP cage includes the FRP force bar of diameter 20~25mm and the FRP stirrup of diameter 6~10mm, the pile tip FRP cage includes the FRP force bar of diameter 16mm and the FRP stirrup of diameter 6~10mm, splash zone is pasted with 2 layers of FRP cloth, the FRP cloth is 0~90 ° angle with pile body longitudinal axis. Fiber composite pile in the utility model has the advantages of good ductility, good durability, light weight, etc., and can be applied in bridge, port engineering.

[0004] In the actual application process of the above-mentioned and similar technical solutions, the corrosion degree of different parts of the steel pipe pile in the seawater environment is quite different, among which the corrosion rate in the splash zone is the highest, the corrosion in the marine atmospheric zone is lighter, the dry-wet alternating zone is divided into the tidal zone and the splash zone, the corrosion in the tidal zone is relatively light due to the action of the tide on the seawater, the splash zone often forms a wet surface, is subjected to strong sunlight radiation for a long time, and has sufficient oxygen supply, and the corrosion environment is the most severe, the seawater immersion zone refers to the part of the dry-wet alternating zone included in the soil, and the seabed soil zone is also less affected by seawater and has low temperature, and the corrosion is lighter than that in seawater, so the protection effect of a single protection structure cannot cope with the corrosion resistance protection of the entire steel pipe column, and zinc powder is often used to improve the corrosion resistance of the powder coating layer due to its good cathodic protection performance, and graphene itself has impermeability and can isolate various corrosion media, and its excellent electrical conductivity can provide a channel for electrons to form a conductive path, thereby reducing the amount of zinc powder and anti-rust pigment and achieving high-efficiency corrosion protection, but in the actual use process, how to ensure the dispersion effect becomes a key technical problem, and the use of conventional dispersion technology is obviously insufficient, which not only cannot play the high-efficiency protection role of the two, but also can even reduce the physical and mechanical properties of the coating.

[0005] SUMMARY

[0006] The purpose of the present application is to provide a reinforced concrete steel pipe composite pile for ocean engineering to solve the problems raised in the above background art.

[0007] To achieve the above-mentioned purpose, the present application provides the following technical solution: a reinforced concrete steel pipe composite pile for ocean engineering, comprising a composite pile body, the composite pile body comprising a first connecting pile, a second connecting pile, a third connecting pile and a pile tip, and the circumferential outer wall of the first connecting pile, the second connecting pile, the third connecting pile and the pile tip is fixedly connected with a plurality of welding rings, the inner wall of the composite pile body is fixedly connected with a plurality of inner steel bars, 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 bar 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 ring is coated with a fourth composite coating;

[0008] The installation position of the composite pile body is divided into a marine atmospheric zone, a splash zone, a seawater tidal zone, a seawater immersion zone and a seabed soil zone, and the first connecting pile, the second connecting pile and the third connecting pile correspond to different zones respectively, wherein the first connecting pile is in the marine atmospheric zone, the second connecting pile is in the splash zone and the seawater tidal zone, and the third connecting pile is in the seawater immersion zone and the seabed soil zone, and the first composite coating comprises a marine atmospheric coating, a splash coating, a seawater tidal coating, a seawater immersion coating and a seabed soil coating;

[0009] The first auxiliary material and the second auxiliary material are obtained through the first processing method and the second processing 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 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.

[0010] The first auxiliary material comprises pretreated flaky zinc powder, and the first processing method comprises:

[0011] S1: mixing, preparing a mixed solution by mixing xylene and ethyl acetate at a volume ratio of 1:1, and the total volume of the mixed solution is 200% to 1000% of the volume of the flaky zinc powder;

[0012] S2: stirring, stirring the mixed solution uniformly in a ball mill; first, adding 0.5% to 2% of the epoxy resin in the mass fraction of the epoxy resin used in the formula of the fused epoxy powder coating and 0.5% to 2% of the phenolic curing agent in the mass fraction of the phenolic curing agent used in the formula of the fused epoxy powder coating, and stirring at low speed until the epoxy resin and the phenolic curing agent are completely dissolved;

[0013] S3: ball milling, adding flaky zinc powder, and then ball milling under nitrogen protection, the rotation speed of the ball milling is 200 r / min to 500 r / min, the ball milling time is 8 h to 24 h, the ball milling temperature is 30℃ to 50℃, and after the ball milling is completed, the mixture is freeze-dried to obtain pretreated flaky zinc powder.

[0014] Further, the marine atmospheric coating comprises a first inner coating and a first outer coating, the splash coating comprises a second inner coating and a second outer coating, the seawater immersion coating comprises a third inner coating and a third outer coating, and the seabed soil coating comprises a fourth inner coating and a fourth outer coating.

[0015] Further, the third composite coating comprises a first base coating and a first surface coating, the fourth composite coating comprises a second base coating and a second surface coating, and the second composite coating comprises a third base coating and a third surface coating.

[0016] Further, the second auxiliary material comprises pretreated graphene powder, and the second processing method comprises:

[0017] M1: mixing, using an ethyl acetate solution with a total volume of 200% to 800% of the volume of the graphene, adding 0.1% to 0.5% of the epoxy resin in the mass fraction of the epoxy resin used in the formula of the fused epoxy powder coating and the same mass of epoxy-based silane coupling agent as the added 0.1% to 0.5% of the epoxy resin, and stirring until the epoxy resin is completely dissolved;

[0018] M2: stirring, adding graphene, stirring at low speed for 5 min~30 min, then stirring at 75℃~80℃ under reflux for 2h~5h, the mixture is cooled to room temperature and then freeze-dried to obtain the pretreated graphene powder.

[0019] Further, 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 80μm~150μm, and the first outer coating includes a weather-resistant fused epoxy powder coating layer with a thickness of 80μm~150μm;

[0020] The splash coating and the sea water 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 100μm~200μm, and the second outer coating includes a common fused epoxy powder coating layer with a thickness of 100μm~200μm;

[0021] The sea water fully immersed 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 60μm~120μm, and the third outer coating includes a common fused epoxy powder coating layer with a thickness of 80μm~150μm;

[0022] The sea bottom 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 60μm~120μm, and the fourth outer coating includes a wear-resistant fused epoxy powder coating layer with a thickness of 80μm~120μm.

[0023] Further, the third composite coating includes a first base coating and a first surface coating, the first base coating includes a thermal spraying wear-resistant coating layer with a thickness of 200μm~600μm, and the first surface coating includes a sealing coating layer with a thickness of 50μm~100μm;

[0024] The fourth composite coating includes a second base coating and a second surface coating, the second base coating includes a reinforced thermal spraying zinc with a thickness of 200μm~300μm, and the second surface coating is composed of a sealing coating layer with a thickness of 0μm~50μm, an intermediate coating layer with a thickness of 40μm~100μm, and a top coating layer with a thickness of 60μm~80μm from inside to outside, wherein the top coating layer in the fourth composite coating in the sea water tidal zone and the above area position includes a weather-resistant top coating layer;

[0025] The second composite coating includes a third base coating and a third surface coating, the third base coating includes a zinc-based epoxy powder coating layer with a thickness of 50μm~80μm, and the third surface coating includes a common fused epoxy powder coating layer with a thickness of 80μm~100μm;

[0026] The inner single-layer coating includes a zinc-based epoxy powder coating layer with a thickness of 50μm~100μm.

[0027] Further, the zinc-based epoxy powder coating base formula comprises: epoxy resin, phenolic curing agent, dimethyl imidazole, leveling agent, degassing agent, bulking agent and flaky zinc powder, and the third processing method comprises:

[0028] N1: mixing and crushing, mixing the remaining epoxy resin after pretreatment and the leveling agent, toughening agent, curing agent, degassing agent, bulking agent and flaky zinc powder in the formula for 5 min and crushing for 2 min;

[0029] N2: extrusion, the temperature of the extruder I area is 110 DEG C to 115 DEG C, the temperature of the extruder II area is 80 DEG C to 85 DEG C, the main machine speed is 35 Hz to 40 Hz, and the feeding speed is 18 Hz to 22 Hz, and the N1 mixed material is melted and extruded;

[0030] N3: tabletting, the tabletting machine speed is 140 rpm to 160 rpm, the tabletting thickness is 1 mm to 2 mm, the N2 extruded material is cooled and tabletted;

[0031] N4: powder grinding, the ACM grinder feeding speed is 18 Hz to 20 Hz, and the classifier is adjusted to 12 Hz to 15 Hz, and the zinc-based epoxy powder coating is prepared by screening the N3 tabletted material.

[0032] Further, the fourth processing method comprises: adopting bonding equipment to bond and mix the zinc-based epoxy powder in N4, the pretreated flaky zinc powder and the pretreated graphene powder to prepare the zinc-based epoxy powder coating.

[0033] Compared with the prior art, the zinc-based epoxy powder coating has the beneficial effects that:

[0034] The steel pipe composite pile for ocean engineering is provided with a corresponding coating structure according to the corrosion prevention requirements of different regions of the steel pipe composite pile, and excellent corrosion resistance is exhibited, the coating structures fully consider the corrosion characteristics of the steel pipe composite pile in different use environments, and by reasonably matching different coating materials and thicknesses, comprehensive protection of the steel pipe composite pile is realized, in the atmospheric zone, the coating structure mainly adopts zinc-based epoxy powder coating and weather-resistant fusion-bonded epoxy powder coating, these materials have excellent weather resistance and corrosion resistance, can effectively resist corrosion factors in the atmosphere, in the salt spray test, the coating surface has no obvious change, and the spread range is also controlled in a small range, fully proving the excellent corrosion resistance, in the wave-splashing zone and the seawater tidal zone, the coating structure is more complex, and a multilayer structure of thermal spraying zinc-aluminum alloy coating, closed coating, intermediate paint coating and weather-resistant topcoat coating and the like is adopted. These coating materials not only have excellent corrosion resistance, but also can resist seawater erosion and salt spray corrosion, and ensure long-term stable operation of the steel pipe composite pile in these harsh environments.

[0035] Meanwhile, after optimizing the pretreatment measures of the flaky zinc powder and graphene, the efficient utilization in the melting extrusion method or bonding method is realized through the pre-bonding and effective dispersion of the epoxy resin and the zinc powder flake and graphene particles. This improvement not only significantly improves the quality of the powder, such as fluidity and deposition rate, but also significantly improves the physical and mechanical properties and corrosion resistance of the coating. BRIEF DESCRIPTION OF DRAWINGS

[0036] Fig. 1 is a schematic diagram of the composite pile body structure of the present application;

[0037] Fig. 2 is a schematic diagram of the internal structure of the composite pile body of the present application;

[0038] Fig. 3 is a schematic diagram of the first processing method flow structure of the present application;

[0039] Fig. 4 is a schematic diagram of the third processing method flow structure of the present application.

[0040] 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, inner steel bar. DETAILED DESCRIPTION

[0041] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0042] The corrosion in the marine atmospheric zone is relatively light, which is mainly affected by sea salt particles and the joint action of the terrestrial atmosphere, and local corrosion is easily generated in dead angles and the like. The seawater immersion zone refers to the part included in the soil from the dry-wet alternating zone, which can be divided into shallow sea zone, deep sea zone and soil zone. The corrosion 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 zone is much lower than that in the surface layer of seawater and the atmospheric zone, and the water temperature is close to zero, so the corrosion is relatively light. Therefore, it is necessary to provide targeted protection for composite piles in different regions. The surface coating structure of the reinforced concrete steel pipe composite pile provided by the technical solution can be designed to be simple, efficient and clean and environmentally friendly. Under the premise of meeting the anti-corrosion design requirements, the coating thickness of the same corrosion region is greatly reduced, and the additional sacrificial anode block can be omitted, thereby reducing the consumption of various materials.

[0043] As shown in FIG. 1-4, the present application provides a technical solution: a reinforced concrete steel pipe composite pile for ocean engineering, comprising a composite pile body 1, the composite pile body 1 comprises a first connecting pile 101, a second connecting pile 102, a third connecting pile 103 and a pile tip 104, and the circumferential outer wall of the first connecting pile 101, the second connecting pile 102, the third connecting pile 103 and the pile tip 104 is fixedly connected with a plurality of welding rings 105, the inner wall of the composite pile body 1 is fixedly connected with a plurality of inner steels 2, 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 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 position of the composite pile body 1 is divided into an ocean atmosphere area, a wave splash area, a seawater tidal area, a seawater full immersion area and a seabed soil area, and the first connecting pile 101, the second connecting pile 102 and the third connecting pile 103 correspond to different areas respectively, wherein the first connecting pile 101 is in the ocean atmosphere area, the second connecting pile 102 is in the wave splash area and the seawater tidal area, the third connecting pile 103 is in the seawater full immersion area and the seabed soil area, and the first composite coating comprises an ocean atmosphere coating, a wave splash coating, a seawater tidal coating, a seawater full immersion coating and a seabed soil coating; a first auxiliary material and a second auxiliary material are obtained by a first treatment method and a second treatment 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 by a third treatment 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 by a fourth treatment method; the first auxiliary material comprises pretreated flaky zinc powder, and the first treatment method comprises: S1: mixing, a mixed solution is prepared by mixing dimethylbenzene and ethyl acetate at 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, the mixed solution is stirred uniformly in a ball mill; first, 0.5%-2% of the epoxy resin used in the formula by mass fraction of the epoxy resin, and 0.5%-2% of the phenolic curing agent used in the formula by mass fraction of the phenolic curing agent are added to the fusion-bonded epoxy powder coating, and the epoxy resin and the phenolic curing agent are completely dissolved by low-speed stirring; S3: ball milling, the flaky zinc powder is added and ball milled under nitrogen protection, the ball milling speed 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 the mixture is freeze-dried after ball milling to prepare the pretreated flaky zinc powder.

[0044] The marine atmosphere coating layer comprises a first inner coating layer and a first outer coating layer, the sea spray coating layer and the seawater tidal coating layer comprise a second inner coating layer and a second outer coating layer, the seawater full immersion coating layer comprises a third inner coating layer and a third outer coating layer, and the seabed soil coating layer comprises a fourth inner coating layer and a fourth outer coating layer.

[0045] The third composite coating layer comprises a first base coating layer and a first surface coating layer, the fourth composite coating layer comprises a second base coating layer and a second surface coating layer, and the second composite coating layer comprises a third base coating layer and a third surface coating layer.

[0046] The second auxiliary material comprises pretreated graphene powder, and the second treatment method comprises the following steps: M1: mixing, using an ethyl acetate solution with a total volume of 200% to 800% of the volume of the graphene, adding 0.1% to 0.5% of the epoxy resin in the mass fraction of the used epoxy resin in the fused epoxy powder coating formula, and adding an epoxy-based 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;

[0047] M2: stirring, adding graphene, low-speed stirring for 5 min to 30 min, then stirring and refluxing at 75°C to 80°C for 2 h to 5 h, and then performing freeze-drying after the mixture is cooled to room temperature to obtain the pretreated graphene powder.

[0048] The marine atmosphere coating layer comprises a first inner coating layer and a first outer coating layer, the sea spray coating layer and the seawater tidal coating layer comprise a second inner coating layer and a second outer coating layer, the seawater full immersion coating layer comprises a third inner coating layer and a third outer coating layer, and the seabed soil coating layer comprises a fourth inner coating layer and a fourth outer coating layer.

[0049] The third composite coating includes a first bottom coating and a first surface coating, the first bottom coating includes a thermal spraying wear-resistant coating with a thickness of 200-600 μm, and the first surface coating includes a sealing coating with a thickness of 50-100 μm; the fourth composite coating includes a second bottom coating and a second surface coating, the second bottom coating includes reinforced thermal spraying zinc with a thickness of 200-300 μm, and the second surface coating is composed of a sealing coating with a thickness of 0-50 μm, an intermediate coating with a thickness of 40-100 μm, and a top coating with a thickness of 60-80 μm from inside to outside, wherein the top coating of the fourth composite coating in the seawater tidal zone and the above area positions includes a weather-resistant top coating; 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 with a thickness of 50-80 μm, and the third surface coating includes a common fusion epoxy powder coating with a thickness of 80-100 μm; the inner single-layer coating includes a zinc-based epoxy powder coating with a thickness of 50-100 μm.

[0050] The zinc-based epoxy powder coating base formula includes: an epoxy resin, a phenolic curing agent, dimethyl imidazole, a leveling agent, a degassing agent, a loose agent, and a flaky zinc powder, and the third processing method includes: N1: mixing and crushing, mixing the remaining epoxy resin after pretreatment, and the leveling agent, the toughening agent, the curing agent, the degassing agent, the loose agent, and the flaky zinc powder in the formula for 5 min, and crushing for 2 min; N2: extrusion, the temperature of the extruder I zone is 110-115°C, the temperature of the extruder II zone is 80-85°C, the main machine speed is 35-40 Hz, and the feeding speed is 18-22 Hz, and the material after N1 is melted and extruded; N3: tabletting, the tabletting machine speed is 140-160 rpm, and the tabletting thickness is 1-2 mm, and the extruded material of N2 is cooled and tabletted; N4: powder grinding, the ACM grinder feeding speed is 18-20 Hz, and the classifier adjustment is 12-15 Hz, and the zinc-based epoxy powder coating is prepared after the tabletting of N3 is ground and sieved.

[0051] The fourth processing method includes: using a bonding device to mix the zinc-based epoxy powder in N4 with the pretreated flaky zinc powder and the pretreated graphene powder to prepare the zinc-based epoxy powder coating.

[0052] As a specific embodiment, the formula and main preparation method of the zinc-based epoxy powder coatings of examples 1-3 are shown in Table 1.

[0053] Table 1: Formula table of fusion epoxy powder coating Unit: weight parts

[0054] The preparation method of the zinc-based epoxy powder coatings of examples 1-3 by melting extrusion is as follows:

[0055] Step one: pretreatment, the pretreatment process before the addition of flaky zinc powder in the zinc-based epoxy powder coating of examples 1-3 is as follows: prepare a mixed solution of 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 flaky zinc powder, stir the mixed solution uniformly in a ball mill; first add 0.5%-2% of the epoxy resin used in the formulation of the fused epoxy powder coating, and 0.5%-2% of the phenolic curing agent used in the formulation of the fused epoxy powder coating, stir at low speed until the epoxy resin and phenolic curing agent are completely dissolved; then add flaky zinc powder, protect with nitrogen, and then ball mill, the rotation speed is 200r / min-500r / min, the ball milling time is 8h-24h, the ball milling temperature is 30℃-50℃, after ball milling, freeze-dry the mixture to obtain pretreated flaky zinc powder, which is ready for use, the above-mentioned percentage of phenolic curing agent is based on the percentage of the epoxy resin used in the fused epoxy powder coating formulation, the amount of epoxy resin used is adjusted within the range of 0.5%-2% of the mass of the epoxy resin used in the fused epoxy powder coating formulation according to the amount of flaky zinc powder designed to be used in the zinc-based epoxy powder coating, that is, when the amount of flaky zinc powder used is large, the amount of epoxy resin used is also increased accordingly.

[0056] The pretreatment process of graphene before adding in zinc-based epoxy powder coating of Example 2 is as follows: using ethyl acetate solution with a total volume of 700% of the volume of graphene, adding 0.4% of the mass fraction of epoxy resin used in the formulation of the fused epoxy powder coating and the same mass of epoxy-based silane coupling agent as the added 0.4% of the epoxy resin, stirring until the epoxy resin is completely dissolved; then adding graphene, stirring at low speed for 25 min, and then stirring at 75-80°C for 4 h, the mixture is cooled to room temperature and then freeze-dried to obtain the pretreated graphene powder for standby, the above-mentioned selection amount of epoxy resin is adjusted within the range of 0.5%-2% of its mass fraction according to the amount of graphene designed to be used in 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 epoxy-based silane coupling agent is also adjusted accordingly with the selection amount of epoxy resin; Step two: mixing, mixing the remaining epoxy resin after pretreatment of Example 1, Example 2, Example 3-1, and the leveling agent, toughening agent, curing agent, dimethyl imidazole, and flaky zinc powder obtained by S101 pretreatment, and graphene obtained by S101 pretreatment (such as Example 2) and other raw materials in the formulation for 5 min, and crushing for 2 min; Step three: extrusion, the extruder process design: I area temperature 110-115°C, II area temperature 80-85°C, the existing equipment has automatic constant temperature control design, which ensures that the temperature fluctuation space is within the above design range (the same below); main machine speed: 38 Hz, feeding speed: 20 Hz; after setting the equipment speed Hz value, the fluctuation is generally very small (the same below); melt extrude the mixed material according to the above extrusion process; Step four: tabletting, the tabletting machine process design: speed 140-160 rpm, tablet thickness 1-2 mm, use the tabletting machine to cool and tablet the extruded material; Step five: ACM mill powder grinding, the ACM mill process design: feeding speed: 19 Hz, classifier adjustment: 13 Hz; after grinding and sieving the tablet, the zinc-based epoxy powder coating prepared by extrusion is obtained.

[0057] Example 3-2 zinc-based epoxy powder coating bonding method preparation method as follows:

[0058] Step one: pretreatment, the pretreatment process before the addition of flaky zinc powder in the formulation of example 3 is as follows: prepare a mixed solution of 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, and the mixed solution is stirred uniformly in a ball mill; first add 2% of the epoxy resin in the mass fraction of the epoxy resin used in the formulation of the fused epoxy powder coating, and 2% of the phenolic curing agent in the mass fraction of the phenolic curing agent used in the formulation of the fused epoxy powder coating, and stir at 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, the ball milling temperature is 30-40℃, and after the ball milling is completed, the mixture is freeze-dried to obtain the pretreated flaky zinc powder for standby; Step two: mixing, mix the remaining epoxy resin after pretreatment, and the remaining leveling agent, toughening agent, curing agent, dimethyl imidazole and other raw materials in the formulation for 5 min, and crush for 2 min; Step three: extrusion, the process design of the extruder: the temperature in region I is 110-115℃, and the temperature in region II is 80-85℃; the main machine speed is 40 Hz, and the feeding speed is 22 Hz; melt and extrude the mixed S202 material; Step four: tabletting, the process design of the tabletting machine: the speed is adjusted to 140-160 rpm, and the tablet thickness is 1-2 mm; cool and tablet the extruded material; Step five: powder grinding, the process design of the ACM grinder: the feeding speed is 18 Hz, and the classifier adjustment is 12 Hz; screen and divide the tablet of S204 to obtain the powder coating base material for bonding; Step six: bonding, use the bonding equipment to mix the powder coating base material for bonding prepared by grinding with the pretreated flaky zinc powder prepared to obtain the zinc-based epoxy powder coating of example 3-2.

[0059] Preparation method of comparative example 1-3:

[0060] Comparative example 1: prepared by conventional melt extrusion method, that is, all the materials in the formulation of comparative example 1 are mixed, extruded, tabletted, and ground to obtain.

[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 by using a mixing device, such as high-speed dispersion for 5-10 min and crushing for 2-5 min; then add all the remaining materials after mixing, and prepare the zinc-based epoxy powder coating of comparative example 2 according to the extrusion, tabletting and grinding process.

[0062] Comparative example 3-1: melt extrusion method, first mix and disperse the flaky zinc powder in comparative example 3 with the epoxy resin and leveling agent by using the melt extrusion method, and prepare tablets by using the extrusion and tabletting process, then mix the tablets with other components in comparative example 3 according to the mixing, extrusion, tabletting and grinding process to obtain the zinc-based epoxy powder coating.

[0063] Comparative Example 3-2: Bonding method, first, the base material of the zinc-based epoxy powder coating except for the flaky zinc powder in Comparative Example 3 was prepared by using the process of mixing, extruding, tabletting and powdering. Then, the base material of the zinc-based epoxy powder coating, the flaky zinc powder were added into the existing bonding equipment, and the Comparative Example 3-2 zinc-based epoxy powder coating of the existing bonding technology was prepared according to the existing bonding 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 marine atmosphere zone, splash zone, seawater tidal zone, seawater fully immersed zone and seabed soil zone, the composite pile body 1 is further provided with a welding ring 105 and a pile tip 104, and the composite pile body 1 is poured with reinforced concrete.

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

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

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

[0069] The seawater fully immersed zone and the seabed soil zone: the third inner coating and the third outer coating are zinc-based epoxy powder coating with a thickness of 60-80 μm + ordinary fusion-bonded epoxy powder coating with a thickness of 80-100 μm; the third outer coating of the seabed soil zone can also be replaced by wear-resistant fusion-bonded epoxy powder coating with a thickness of 80-100 μm if necessary;

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

[0071] The welding ring 105: the second bottom coating is reinforced thermal spraying zinc-aluminum alloy coating (such as ZnAl15 alloy) with a thickness of 200-300 μm, the second surface coating is sealing coating with a thickness of 0-30 μm (0 μm: the sealing agent penetrates into the metal coating, and the surface coating thickness can be ignored, the same below) + intermediate coating with a thickness of 60-80 μm + top coating with a thickness of 60-80 μm; the top coating of the welding ring exposed to the atmosphere is preferably weather-resistant top coating (such as fluorocarbon top coating, polysiloxane top coating);

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

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

[0074] Example 5

[0075] A reinforced concrete steel pipe composite pile for marine engineering, wherein the outer surface of the steel pipe is divided into a marine atmosphere zone, a wave-splashing zone, a seawater tidal zone, a seawater fully-immersed zone, and a seabed soil 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.

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

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

[0078] The wave-splashing zone and the seawater tidal zone: the second inner coating and the second outer coating are an aluminum-magnesium alloy coating with a thickness of 200-250 μm + a coating of (a sealing coating with a thickness of 40-50 μm + an intermediate paint coating with a thickness of 120-150 μm + a weather-resistant top paint coating with a thickness of 100-120 μm);

[0079] The seawater fully-immersed zone and the seabed soil zone: the third inner coating and the third outer coating are a zinc-based epoxy powder coating with a thickness of 80-120 μm + a common fusion-bonded epoxy powder coating with a thickness of 100-120 μm; when there is a requirement for wear resistance design, the outer coating of the seabed soil zone can be preferably a wear-resistant fusion-bonded epoxy powder coating with a thickness of 100-120 μm;

[0080] The pile tip 104: the first base coating and the first surface coating are a thermal-sprayed wear-resistant coating with a thickness of 400-600 μm + a sealing coating with a thickness of 80-100 μm;

[0081] Welding ring 105: the second base coat is a reinforced thermal spraying magnesium-aluminum alloy coating (such as AlMg5 alloy, same below) with a thickness of 250-300 μm, and the second surface coat is a coating of a sealing paint coating with a thickness of 30-50 μm + an intermediate paint coating with a thickness of 60-100 μm + a top paint coating with a thickness of 60-80 μm; wherein the top paint coating of the welding ring exposed to the atmosphere in the seawater tidal zone and above can preferably be a weather-resistant top paint coating;

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

[0083] The surface of the inner steel bar 2 is coated with a second composite coating for corrosion protection, which is composed of a third base coat and a third surface coat, the third base coat is a thermal spraying aluminum-magnesium alloy coating with a thickness of 120-150 μm, and the third surface coat is a sealing paint coating with a thickness of 30-50 μm.

[0084] Example 6

[0085] A reinforced concrete steel pipe composite pile for marine engineering, wherein the outer surface of the steel pipe is divided into a marine atmosphere zone, a wave-splashing zone, a seawater tidal zone, a seawater fully-immersed zone and a seabed soil zone, the composite pile body 1 is further 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 corrosion protection, wherein:

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

[0088] The wave-splashing zone and the seawater tidal zone: the second inner coating and the second outer coating are reinforced thermal spraying aluminum coatings with a thickness of 250-300 μm + paint coatings of (sealing paint coatings with a thickness of 0-30 μm + intermediate paint coatings with a thickness of 100-120 μm + weather-resistant top paint coatings with a thickness of 80 μm);

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

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

[0091] Welding ring 105: the second base coating is a reinforced thermal spraying magnesium-aluminum alloy coating with a thickness of 200 μm, and the second top coating is a paint coating layer with a thickness of 0 μm-30 μm sealing paint + a thickness of 40 μm-60 μm intermediate paint + a thickness of 60 μm-80 μm topcoat; wherein the topcoat of the welding ring exposed to the atmosphere in the seawater tidal zone and the above area can be preferably a weather-resistant topcoat;

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

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

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

[0095] Table 2: Test data table of main paint and coating properties of Examples 1-3 and Comparative Examples 1-3

[0096] Note:

[0097] GB / T 21782.5-2010: "Powder Coatings - Part 5: Determination of flow properties of a powder / air mixture";

[0098] ISO 8130-5:2021: "Coating powders - Part 5: Determination of flow properties of a powder / air mixture";

[0099] GB / T 21782.10-2008: "Powder Coatings - Part 10: Determination of deposition efficiency";

[0100] ISO 8130-10:2021: "Coating powders - Part 10: Determination of deposition efficiency";

[0101] GB / T 9286-1998: "Cross-hatch test for pigmented and clear coatings film";

[0102] ISO 2409:2020: Paints and varnishes—Cross-cut test;

[0103] GB / T 5210-2006: Color paints and varnishes pull-off test;

[0104] ISO 4624:2023: Paints and varnishes—Pull-off test for adhesion;

[0105] GB / T 10125-2021: Artificial atmosphere corrosion test salt spray test;

[0106] ISO 9227:2022: Corrosion tests in artificial atmospheres Salt spray tests.

[0107] Table 3: Test results of the main composite coating of Examples 4-6

[0108] The test data in Table 2 show that after optimizing the flaky zinc powder and the pretreatment measures of graphene, the pre-bonding and effective dispersion of the epoxy resin with the zinc powder flake and the graphene particles are improved, the efficient use in the melting extrusion method or bonding method is improved, compared with the prior art, not only the powder quality (such as flowability, sedimentation 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 improved, and outstanding product improvement effect is achieved.

[0109] The test data in Table 3 show that the steel pipe composite pile with the corresponding coating structure designed according to the corrosion prevention requirements of different areas has excellent corrosion resistance, and can fully meet the long-life design requirements of the existing steel pipe composite pile, can reduce other additional corrosion prevention measures (such as external anode protection block, external cathode protection current, external wrapping protection measures) of the prior art, reduce or even eliminate the frequency of later maintenance, and can produce outstanding economic and social benefits.

[0110] Table 4: Comparison table of cost and average annual cost analysis of main coating structure

[0111] Table 4 compares the cost of the present application with the prior art, and analyzes the average annual cost during the protection life. The data shows that the unit cost of the main coating structure of the present application can be reduced by more than 50% based on the prior art.

[0112] While embodiments of the application have been shown and described, it is to be understood that the embodiments described are merely exemplary of the principles and application of the present application. Numerous modifications and adaptions can be effected without departing from the spirit and scope of the present application, which is not limited to the embodiments disclosed except insofar as recited in the claims.

Claims

1. A reinforced concrete steel pipe composite pile for offshore engineering, comprising a composite pile body (1), characterized in that: The composite pile body (1) comprises a first connecting pile (101), a second connecting pile (102), a third connecting pile (103) and a pile tip (104), and 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) are fixedly connected with a plurality of welding rings (105), the inner wall of the composite pile body (1) is fixedly connected with a plurality of inner steel bars (2), 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, and the outer surface of the welding ring (105) is coated with a fourth composite coating. The installation position of the composite pile body (1) is divided into a marine atmosphere zone, a wave-splashing zone, a seawater tidal zone, a seawater full-immersion zone and a seabed soil zone, and the first connecting pile (101), the second connecting pile (102) and the third connecting pile (103) correspond to different zones, wherein the first connecting pile (101) is in the marine atmosphere zone, the second connecting pile (102) is in the wave-splashing zone and the seawater tidal zone, and the third connecting pile (103) is in the seawater full-immersion zone and the seabed soil zone, and the first composite coating comprises a marine atmosphere coating, a wave-splashing coating, a seawater tidal coating, a seawater full-immersion coating and a seabed soil coating. The first auxiliary material and the second auxiliary material are obtained by 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 by 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 by the fourth processing method. The first auxiliary material comprises pretreated flaky zinc powder, and the first processing method comprises: S1: mixing, preparing a mixed solution by mixing xylene and ethyl acetate at a volume ratio of 1:1, and the total volume of the mixed solution is 200% to 1000% of the volume of the flaky zinc powder; S2: stirring, stirring the mixed solution uniformly in a ball mill; first, add 0.5% to 2% of the epoxy resin in the mass fraction of the epoxy resin used in the formula of the fused epoxy powder coating, and 0.5% to 2% of the phenolic curing agent in the mass fraction of the phenolic curing agent used in the formula of the fused epoxy powder coating, and stir at low speed until the epoxy resin and the phenolic curing agent are completely dissolved; S3: ball milling, add flaky zinc powder, and then ball mill under nitrogen protection, the ball milling speed is 200r / min to 500r / min, the ball milling time is 8h to 24h, the ball milling temperature is 30℃ to 50℃, and after the ball milling is completed, the mixture is freeze-dried to obtain pretreated flaky zinc powder. The marine atmosphere coating comprises a first inner coating and a first outer coating, the wave-splashing coating and the seawater tidal coating comprise a second inner coating and a second outer coating, the seawater full-immersion coating comprises a third inner coating and a third outer coating, and the seabed soil coating comprises a fourth inner coating and a fourth outer coating.

2. A reinforced concrete steel pipe composite pile for offshore engineering according to claim 1, characterized in that: ​ 3. A reinforced concrete steel pipe composite pile for offshore engineering according to claim 1, characterized in that: The third composite coating comprises a first base coating and a first surface coating, the fourth composite coating comprises a second base coating and a second surface coating, and the second composite coating comprises a third base coating and a third surface coating.

4. A reinforced concrete steel pipe composite pile for offshore engineering according to claim 1, characterized in that: The second auxiliary material comprises pretreated graphene powder, and the second treatment method comprises: M1: mixing, using ethyl acetate solution with a total volume of 200% to 800% of the volume of graphene, adding 0.1% to 0.5% of the mass of epoxy resin used in the formulation of the fused epoxy powder coating, and adding the same mass of epoxy-based silane coupling agent as the added 0.1% to 0.5% of the epoxy resin, stirring until the epoxy resin is completely dissolved; M2: stirring, adding graphene, low-speed stirring for 5 minutes to 30 minutes, then stirring and refluxing at 75°C to 80°C for 2 hours to 5 hours, and then freezing and drying the mixture to obtain the pretreated graphene powder.

5. A reinforced concrete steel pipe composite pile for offshore engineering according to claim 1, characterized in that: The marine atmospheric coating comprises a first inner coating and a first outer coating, the first inner coating comprises a zinc-based epoxy powder coating with a thickness of 80 μm to 150 μm, and the first outer coating comprises a weather-resistant fused epoxy powder coating with a thickness of 80 μm to 150 μm; The wave-splashing coating and the seawater tidal zone coating comprise a second inner coating and a second outer coating, the second inner coating comprises a zinc-based epoxy powder coating with a thickness of 100 μm to 200 μm, and the second outer coating comprises a common fused epoxy powder coating with a thickness of 100 μm to 200 μm; The seawater fully-immersed coating comprises a third inner coating and a third outer coating, the third inner coating comprises a zinc-based epoxy powder coating with a thickness of 60 μm to 120 μm, and the third outer coating comprises a common fused epoxy powder coating with a thickness of 80 μm to 150 μm; The seabed soil coating comprises a fourth inner coating and a fourth outer coating, the fourth inner coating comprises a zinc-based epoxy powder coating with a thickness of 60 μm to 120 μm, and the fourth outer coating comprises a wear-resistant fused epoxy powder coating with a thickness of 80 μm to 120 μm.

6. A reinforced concrete steel pipe composite pile for offshore engineering according to claim 1, characterized in that: The third composite coating comprises a first base coating and a first surface coating, the first base coating comprises a thermal spraying wear-resistant coating with a thickness of 200 μm to 600 μm, and the first surface coating comprises a sealing coating with a thickness of 50 μm to 100 μm; The fourth composite coating comprises a second base coating and a second surface coating, the second base coating comprises a reinforced thermal spraying zinc with a thickness of 200 μm to 300 μm, and the second surface coating comprises a combination of a sealing coating with a thickness of 0 μm to 50 μm, an intermediate coating with a thickness of 40 μm to 100 μm, and a top coating with a thickness of 60 μm to 80 μm, from inside to outside, wherein the top coating in the fourth composite coating in the seawater tidal zone and the above regions comprises a weather-resistant top coating; The second composite coating comprises a third base coating and a third surface coating, the third base coating comprises a zinc-based epoxy powder coating with a thickness of 50 μm to 80 μm, and the third surface coating comprises a common fused epoxy powder coating with a thickness of 80 μm to 100 μm; The inner single-layer coating comprises a zinc-based epoxy powder coating with a thickness of 50 μm to 100 μm.

7. A reinforced concrete steel pipe composite pile for offshore engineering according to claim 6, characterized in that: The zinc-based epoxy powder coating base formula comprises: epoxy resin, phenolic curing agent, dimethyl imidazole, leveling agent, degassing agent, bulking agent and flaky zinc powder, and the third processing method comprises: N1: mixing and crushing, mixing the remaining epoxy resin after pretreatment and the leveling agent, toughening agent, curing agent, degassing agent, bulking agent and flaky zinc powder in the formula for 5 min and crushing for 2 min; N2: extrusion, the temperature of the extruder I region is 110-115 DEG C, the temperature of the extruder II region is 80-85 DEG C, the main machine speed is 35-40 Hz, and the feeding speed is 18-22 Hz, and the N1 mixed material is melted and extruded; N3: tabletting, the tabletting machine speed is 140-160 rpm, the tabletting thickness is 1-2 mm, the N2 extruded material is cooled and tabletted; N4: powder grinding, the ACM grinder feeding speed is 18-20 Hz, the classifier is adjusted to 12-15 Hz, and the zinc-based epoxy powder coating is prepared by grinding and screening the tablet of N3.

8. A reinforced concrete steel pipe composite pile for offshore engineering according to claim 7, characterized in that: The fourth processing method comprises: using a bonding device to bond and mix the zinc-based epoxy powder in N4, pretreated flaky zinc powder and pretreated graphene powder to prepare a zinc-based epoxy powder coating.

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