Anti-corrosion photovoltaic pile foundation and construction method and application thereof

Abstract

The application provides an anti-corrosion photovoltaic pile and a construction method and application thereof, and relates to the technical field of photovoltaic piles.The anti-corrosion photovoltaic pile comprises a reinforcement cage, an anti-corrosion coating, a solidified shell and an emulsion layer formed on the reinforcement cage.The anti-corrosion coating comprises the following components: cement, hydroxypropyl methyl cellulose ether, nano-aluminum oxide, water reducing agent, nano-zinc oxide, molybdate solution and additives.The solidified shell comprises the following components: water glass and M10 cement neat paste.The emulsion layer comprises the following components: graphene dispersion liquid, silane coupling agent, water-based acrylic emulsion and organic silicone defoamer.The application not only reduces the free chloride ion concentration near the reinforcement, but also inhibits the migration of chloride ions from the external environment to the surface of the reinforcement, increases the bonding performance between the coating and the reinforcement, and plays a physical barrier role through the solidified shell, thereby achieving the anti-corrosion and antibacterial effects in cooperation, and effectively prolonging the service life of the photovoltaic pile in a beach environment.

Description

Technical Field

[0001] This invention relates to the technical field of photovoltaic pile foundations, and in particular to a corrosion-resistant photovoltaic pile foundation, its construction method, and its application. Background Technology

[0002] In the process of global energy structure transformation towards cleaner and lower-carbon energy, photovoltaic power generation, as one of the core application forms of renewable energy, is gradually expanding its development scenarios from traditional rooftops and deserts to tidal flats with broader resource potential. Tidal flats are typical highly corrosive environments, and their erosion of pile foundations exhibits characteristics of "multi-factor synergy and all-round penetration": On the one hand, tidal flat soils are rich in highly corrosive ions such as chloride and sulfate ions, and are in a state of alternating wet and dry conditions for a long time. That is, the lower part of the pile foundation is soaked in seawater during high tide and exposed to a high-humidity, high-salt-fog atmosphere after low tide. This alternating effect accelerates the destruction of the passivation film on the pile foundation surface, triggering a superimposed reaction of electrochemical and chemical corrosion. On the other hand, the soil in tidal flat areas is mostly silty clay or silt, with poor air permeability and high organic matter content, which easily forms a local anaerobic environment, fostering the growth of microorganisms such as sulfate-reducing bacteria. The acidic substances produced during the metabolism of microorganisms further aggravate the biological corrosion of the pile foundation, leading to continuous thinning of the pile foundation cross section and a continuous decline in mechanical properties. In severe cases, it may cause pile foundation fracture, photovoltaic array tilting, or even collapse, resulting in huge economic losses and safety hazards.

[0003] The prior art CN119434247B discloses a construction method for photovoltaic cast-in-place piles, including: setting out the layout area of ​​the photovoltaic pile foundations according to the designed pile foundation locations; determining sampling points within the layout area of ​​the photovoltaic pile foundations according to the terrain in the first direction, collecting the three-dimensional coordinates of each sampling point, and generating the longitudinal profile lines of each string of the photovoltaic pile foundation array; obtaining the pile top elevation of each string, and superimposing the pile top elevation with the longitudinal profile lines of each string of the photovoltaic pile foundation array to obtain the site leveling elevation of each pile foundation; performing site leveling according to the site leveling elevation; and constructing cast-in-place piles; wherein each string is arranged along the first direction; while ensuring that the photovoltaic cast-in-place piles meet the bearing requirements, the construction of the photovoltaic cast-in-place piles can follow the original topographic features of the site and follow the slope, reducing concrete waste and construction costs.

[0004] While the above-mentioned scheme can achieve the construction of photovoltaic cast-in-place piles, when photovoltaic pile foundations are applied in tidal flat environments, the high concentration of chloride ions in the tidal flat soil allows chloride ions to easily penetrate through concrete pores and coating defects to the surface of the reinforcing steel, damaging the passivation film and triggering electrochemical corrosion. In addition, the area below the surface of the tidal flat is an anaerobic environment, where sulfate-reducing bacteria use sulfate as an electron acceptor to metabolize and produce sulfides. These sulfides react with the reinforcing steel to form ferrous sulfide, damaging the protective layer on the surface of the reinforcing steel and forming a "microbial + chemical" synergistic corrosion, which shortens the service life of the photovoltaic pile foundation.

[0005] In view of this, the present invention is hereby proposed. Summary of the Invention

[0006] One of the objectives of this invention is to provide a corrosion-resistant photovoltaic pile foundation with multiple corrosion-resistant properties, which can extend its service life in tidal flat environments.

[0007] The second objective of this invention is to provide a construction method for corrosion-resistant photovoltaic pile foundations, which can achieve multiple corrosion protection effects.

[0008] The third objective of this invention is to provide an application of corrosion-resistant photovoltaic pile foundations with a long service life in tidal flat environments.

[0009] In order to achieve the above-mentioned objectives of the present invention, the following technical solution is adopted:

[0010] In a first aspect, there is a corrosion-resistant photovoltaic pile foundation, the corrosion-resistant photovoltaic pile foundation comprising a reinforcing cage, and an anti-corrosion coating, a cured shell and an emulsion layer formed on the reinforcing cage;

[0011] The anti-corrosion coating comprises the following components:

[0012] Cement, hydroxypropyl methylcellulose ether, nano-alumina, water-reducing agent, nano-zinc oxide, molybdate solution, and additives;

[0013] The cured shell comprises the following components:

[0014] Water glass and M10 cement paste;

[0015] The emulsion layer comprises the following components:

[0016] Graphene dispersions, silane coupling agents, aqueous acrylic emulsions, and organosilicon defoamers.

[0017] Furthermore, the mass ratio of the cement, hydroxypropyl methylcellulose ether, nano-alumina, water, water-reducing agent, nano-zinc oxide, molybdate solution, and additives is 123.6-133.6: 0.150-0.160: 1.25-1.65: 29-35: 1.8-2.2: 1.0-1.2: 0.5-0.7: 0.875-1.275;

[0018] Preferably, the concentration of the molybdate solution is 20wt%-30wt%;

[0019] Preferably, the molybdate solution includes at least one of sodium molybdate solution and ammonium molybdate solution;

[0020] Preferably, the additives include at least one of defoamers and shrinkage reducers.

[0021] Furthermore, the mass ratio of the water glass to the M10 cement paste is (0.5-1.5):(3.5-4.5).

[0022] Preferably, the thickness of the cured shell is 8cm-10cm.

[0023] Furthermore, the emulsion layer includes a first emulsion layer and a second emulsion layer;

[0024] Preferably, the thickness of the first emulsion layer is 0.6 mm to 0.8 mm;

[0025] Preferably, the thickness of the second emulsion layer is 1.2 mm or more.

[0026] Secondly, a construction method for an anti-corrosion photovoltaic pile foundation as described in any of the above claims includes the following steps:

[0027] The steel cage is immersed in an anti-corrosion coating slurry to form an anti-corrosion coating, thus obtaining a pre-treated steel cage.

[0028] The pretreated steel cage is vertically inserted into the borehole, and mixed mud is first injected to form a solidified shell. Then, a mixed emulsion is sprayed on the surface to form an emulsion layer, thus obtaining the anti-corrosion photovoltaic pile foundation.

[0029] Furthermore, the steel cage is assembled from surface-treated main bars and surface-treated stirrups;

[0030] Preferably, the surface treatment includes sandblasting, zinc phosphate solution immersion, and acetone cleaning.

[0031] Furthermore, the preparation method of the anti-corrosion coating slurry includes the following steps:

[0032] First, cement and hydroxypropyl methylcellulose ether are added and dry-mixed. Then, nano-alumina, water, and water-reducing agent are added and mixed and dispersed. Next, nano-zinc oxide, molybdate solution, and additives are added and mixed and dispersed to obtain the anti-corrosion coating slurry.

[0033] Furthermore, after the steel cage is immersed in the anti-corrosion coating slurry, the process also includes a step of curing the steel cage in saturated lime water to obtain a pretreated steel cage.

[0034] Furthermore, the method for preparing the mixed emulsion includes the following steps:

[0035] First, the graphene dispersion is mixed and dispersed with ethanol, then a silane coupling agent, an aqueous acrylic emulsion, and an organosilicon defoamer are added and stirred to obtain the mixed emulsion.

[0036] Thirdly, the application of any of the above-mentioned anti-corrosion photovoltaic pile foundations in tidal flat environments.

[0037] Compared with the prior art, the present invention has at least the following beneficial effects:

[0038] The anti-corrosion photovoltaic pile foundation provided by the present invention includes a steel cage, and an anti-corrosion coating, a curing shell and an emulsion layer formed on the steel cage. It has multiple anti-corrosion properties, which not only reduce the concentration of free chloride ions near the steel bars, but also inhibit the migration of chloride ions from the external environment to the surface of the steel bars. At the same time, it increases the adhesion between the coating and the steel bars, and also plays a physical barrier role through the curing shell. Together, they achieve anti-corrosion and antibacterial effects, which can effectively extend the service life of the photovoltaic pile foundation in the tidal flat environment.

[0039] The construction method for corrosion-resistant photovoltaic pile foundations provided by this invention can achieve multiple corrosion protection effects.

[0040] The corrosion-resistant photovoltaic pile foundation provided by this invention has a long service life in tidal flat environments. Detailed Implementation

[0041] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0042] According to a first aspect of the present invention, a corrosion-resistant photovoltaic pile foundation is provided, the corrosion-resistant photovoltaic pile foundation comprising a reinforcing cage, and an anti-corrosion coating, a cured shell and an emulsion layer formed on the reinforcing cage;

[0043] The anti-corrosion coating comprises the following components:

[0044] Cement, hydroxypropyl methylcellulose ether, nano-alumina, water-reducing agent, nano-zinc oxide, molybdate solution, and additives;

[0045] The cured shell comprises the following components:

[0046] Water glass and M10 cement paste;

[0047] The emulsion layer comprises the following components:

[0048] Graphene dispersions, silane coupling agents, aqueous acrylic emulsions, and organosilicon defoamers.

[0049] The anti-corrosion photovoltaic pile foundation of this invention has multiple anti-corrosion properties. It not only reduces the concentration of free chloride ions near the steel bars, but also inhibits the migration of chloride ions from the external environment to the surface of the steel bars. At the same time, it increases the adhesion between the coating and the steel bars, and also plays a physical barrier role through the solidified shell. Together, they achieve anti-corrosion and antibacterial effects, which can effectively extend the service life of the photovoltaic pile foundation in the tidal flat environment.

[0050] It should be noted that applying an anti-corrosion coating slurry to the surface of the reinforcing cage to form an anti-corrosion coating, followed by curing in saturated lime water, provides sufficient calcium ions to the coating, promoting the cement hydration reaction. The particle filling and nucleation effects of nano-alumina and nano-zinc oxide reduce the number of micropores and interconnected pores in the coating matrix, refining the pore structure. Furthermore, the chemical adsorption and physical binding of chloride ions by nano-alumina particles can reduce the concentration of free chloride ions near the reinforcing steel, lowering the risk of steel corrosion. The polymer film formed by hydroxypropyl methylcellulose ether not only acts as a barrier but also tightly binds nanoparticles, cement, and hydration products, forming a smaller and denser protective layer that inhibits the migration of chloride ions from the external environment to the steel surface and increases the adhesion between the coating and the steel. Simultaneously, molybdate solution and nano-zinc oxide can inhibit sulfate-reducing bacteria from gradually reducing sulfate ions to sulfides, thereby preventing sulfides from reacting with the steel to form iron sulfide. The solidified shell also acts as a physical barrier, synergistically achieving anti-corrosion and antibacterial effects.

[0051] In a preferred embodiment, the mass ratio of cement, hydroxypropyl methylcellulose ether, nano-alumina, water, water-reducing agent, nano-zinc oxide, molybdate solution, and additives can be 123.6-133.6:0.150-0.160:1.25-1.65:29-35:1.8-2.2:1.0-1.2:0.5-0.7:0.875-1.275.

[0052] The additives include, but are not limited to, at least one of defoamers and shrinkage reducers, and can be obtained by mixing defoamers and shrinkage reducers in a mass ratio of 1:3.

[0053] In a preferred embodiment, the concentration of the molybdate solution can be 20wt%-30wt%, with typical but non-limiting concentrations such as 20wt%, 21wt%, 22wt%, 23wt%, 24wt%, 25wt%, 26wt%, 27wt%, 28wt%, 29wt%, and 30wt%.

[0054] In a preferred embodiment, the molybdate solution includes, but is not limited to, at least one of sodium molybdate solution and ammonium molybdate solution.

[0055] In this invention, water glass and M10 cement paste in the mixed mud react synergistically to generate calcium silicate gel, which quickly solidifies and hardens to form a high-strength solidified shell. The lateral constraint of the solidified shell enhances the overturning resistance of the pile foundation. Its three-dimensional network structure can adsorb chloride ions in the soil and physically block corrosive media from penetrating into the pile body, effectively inhibiting the intrusion of corrosive media that leads to the failure of the pile foundation function and extending its service life in the tidal flat environment.

[0056] In a preferred embodiment, the mass ratio of water glass to M10 cement paste can be (0.5-1.5):(3.5-4.5), and is more preferably 1:4.

[0057] In a preferred embodiment, the thickness of the cured shell formed by water glass and M10 cement paste can be 8cm-10cm, for example, 8cm, 9cm, or 10cm, but is not limited thereto.

[0058] In this invention, a mixed emulsion is obtained by mixing graphene dispersion, silane coupling agent, aqueous acrylic emulsion, and organosilicon defoamer. The emulsion layer is then sprayed to form an emulsion layer. The graphene sheets form a three-dimensional conductive network that can self-heal microcracks through electrochemical deposition. After the siloxane groups of the silane coupling agent are hydrolyzed, they react with the hydroxyl groups of the aqueous acrylic emulsion and the hydration products of the cement slurry at the top of the pile to form a chemical bond. At the same time, a hydrophobic layer is formed on the surface to block the penetration of salt spray and rainwater. This also increases the ability of the photovoltaic pile foundation to resist ultraviolet aging and further extends the service life of the photovoltaic pile foundation in the tidal flat environment.

[0059] In a preferred embodiment, the emulsion layer includes, but is not limited to, a first emulsion layer and a second emulsion layer; wherein the thickness of the first emulsion layer can be 0.6 mm to 0.8 mm; and the thickness of the second emulsion layer can be 1.2 mm or more.

[0060] According to a second aspect of the present invention, a construction method for an anti-corrosion photovoltaic pile foundation as described in any one of the above claims is provided, comprising the following steps:

[0061] The steel cage is immersed in an anti-corrosion coating slurry to form an anti-corrosion coating, thus obtaining a pre-treated steel cage.

[0062] The pretreated steel cage is vertically inserted into the borehole. First, mixed mud is injected to form a solidified shell, and then a mixed emulsion is sprayed on the surface to form an emulsion layer, thus obtaining a corrosion-resistant photovoltaic pile foundation.

[0063] The construction method for corrosion-resistant photovoltaic pile foundations of this invention can achieve multiple corrosion protection effects.

[0064] In a preferred embodiment, the reinforcing cage is assembled from surface-treated main bars and surface-treated stirrups; the surface treatment includes, but is not limited to, sandblasting, zinc phosphate solution immersion, and acetone cleaning.

[0065] The main reinforcement bars and stirrups are sandblasted, soaked in a 5% zinc phosphate solution, and cleaned with acetone. They are then assembled according to the design and tied with double strands of galvanized iron wire to form a steel cage.

[0066] In a preferred embodiment, the method for preparing the anti-corrosion coating slurry includes the following steps:

[0067] First, add cement and hydroxypropyl methylcellulose ether and dry mix. Then, add nano-alumina, water, and water-reducing agent and mix and disperse. Finally, add nano-zinc oxide, molybdate solution, and additives and mix and disperse to obtain the anti-corrosion coating slurry.

[0068] Cement and hydroxypropyl methylcellulose ether are added to a mixing pot and dry-mixed for 30-40 seconds. Then, nano-alumina with a particle size of 20 nm, deionized water, and water-reducing agent are added and mixed. The mixture is ultrasonically dispersed for 10-20 minutes. Next, nano-zinc oxide with a particle size of 50 nm, molybdate solution, and other additives are added and ultrasonically dispersed for 15-20 minutes. The mixture is then stirred at 700-900 rpm for 2-3 minutes to obtain the anti-corrosion coating slurry.

[0069] In a preferred embodiment, the reinforcing cage is immersed in an anti-corrosion coating slurry for soaking treatment, then slowly removed to form an anti-corrosion coating on the surface of the reinforcing cage. It is then placed in saturated lime water for curing for 7-8 days to provide sufficient calcium ions for the coating and promote the cement hydration reaction, thus obtaining a pretreated reinforcing cage.

[0070] In this invention, the filling and nucleation effects of nano-alumina particles and nano-zinc oxide particles can reduce the number of micropores and interconnected pores such as capillaries in the coating substrate, refining the pore structure. Furthermore, the chemical adsorption and physical binding of chloride ions by nano-alumina particles can reduce the concentration of free chloride ions near the reinforcing steel, thus reducing the risk of steel corrosion. The polymer film formed by hydroxypropyl methylcellulose ether not only has a barrier effect but also tightly binds nanoparticles, cement, and hydration products, forming a protective layer with smaller and denser pores. This inhibits the migration of chloride ions from the external environment to the surface of the reinforcing steel and also increases the adhesion between the coating and the reinforcing steel. At the same time, molybdate solution and nano-zinc oxide can inhibit sulfate-reducing bacteria from gradually reducing sulfate ions to sulfides, thereby preventing sulfides from reacting with the reinforcing steel to form iron sulfide. The solidified shell also acts as a physical barrier, synergistically achieving anti-corrosion and antibacterial effects.

[0071] In this invention, a dual-liquid high-pressure grouting pump can be used to inject mixed mud under high pressure to form a solidified shell, and then a pure pressure grouting method can be used to fill the gaps, forming a dual physical protection and load-bearing reinforcement structure. This effectively solves the problems of low bearing capacity and easy collapse of soft soil foundations in tidal flats. Water glass and M10 cement paste react synergistically to generate calcium silicate gel, which quickly solidifies and hardens to form a high-strength solidified shell. The lateral constraint of the solidified shell enhances the overturning resistance of the pile foundation. Its three-dimensional network structure can adsorb chloride ions in the soil and physically block corrosive media from penetrating into the pile body, effectively inhibiting the intrusion of corrosive media that leads to the failure of pile foundation function and extending its service life in tidal flat environments.

[0072] In a preferred embodiment, the method for preparing the mixed emulsion includes the following steps:

[0073] First, the graphene dispersion is mixed and dispersed with ethanol. Then, silane coupling agent, aqueous acrylic emulsion, and organosilicon defoamer are added and stirred to obtain a mixed emulsion.

[0074] A graphene dispersion with a concentration of 0.6 mg / mL was mixed with ethanol and ultrasonically dispersed for 30-40 minutes. Then, silane coupling agent KH-570, aqueous acrylic emulsion, and organosilicon defoamer were added and stirred for 1-2 hours to obtain a mixed emulsion.

[0075] In this invention, a high-pressure airless sprayer can be used to spray two layers of mixed emulsion onto the exposed surface of the pile foundation, followed by drying and curing to form an emulsion layer. This method specifically addresses the cracking and corrosion problems caused by alternating wet and dry conditions and ultraviolet radiation at the pile top in areas with fluctuating water levels. The three-dimensional conductive network formed by the graphene sheets can self-heal microcracks through electrochemical deposition. After the siloxane groups of the silane coupling agent are hydrolyzed, they react with the hydroxyl groups of the water-based acrylic emulsion and the hydration products of the cement slurry at the pile top to form a chemical bond. At the same time, a hydrophobic layer is formed on the surface to block the penetration of salt spray and rainwater. This also increases the photovoltaic pile foundation's resistance to ultraviolet aging and further extends the service life of the photovoltaic pile foundation in tidal flat environments.

[0076] In summary, the construction method of the present invention first prepares an anti-corrosion coating on the surface of the reinforcing cage, then injects mixed mud during drilling for curing, and finally sprays a mixed emulsion on the surface of the pile foundation to obtain an anti-corrosion photovoltaic pile foundation, thereby achieving multiple anti-corrosion effects.

[0077] According to a third aspect of the present invention, an application of the corrosion-resistant photovoltaic pile foundation described in any of the preceding claims in a tidal flat environment is provided.

[0078] The corrosion-resistant photovoltaic pile foundation provided by this invention has a long service life in tidal flat environments.

[0079] The present invention will be further illustrated by the following examples. Unless otherwise specified, the materials in the examples are prepared according to existing methods or purchased directly from the market.

[0080] Example 1

[0081] A corrosion-resistant photovoltaic pile foundation is prepared by the following construction method:

[0082] S1: Add 128.6 kg of cement (purchased from AALBORG Ltd., type P·W52.5 white silicate cement, fineness 0.6%) and 0.155 kg of hydroxypropyl methylcellulose ether (NDJ viscosity 200000 mPa·s) to a mixing bowl, dry mix for 35 seconds, then add 1.45 kg of 20 nm nano-alumina (purity 99.99%, purchased from Shanghai Maclean Biochemical Technology Co., Ltd.), 32 kg of deionized water, and 2.0 kg of water-reducing agent, ultrasonically disperse for 15 minutes, then add... Add 1.1 kg of 50 nm nano zinc oxide (99.99% purity, purchased from Hebei Ruihuang Metal Materials Co., Ltd.), 0.6 kg of 25 wt% sodium molybdate solution, and 1.025 kg of other additives (obtained by mixing defoamer and shrinkage reducer in a mass ratio of 1:3; the defoamer is an inorganic siloxane with pH 7.2, and the shrinkage reducer is a silicate shrinkage reducer). Disperse the mixture ultrasonically for 17 min to obtain a mixture. Slowly pour the mixture into a mixing pot and stir at 800 r / min for 2 min to obtain an anti-corrosion coating slurry.

[0083] S2: According to the pile foundation design, process the main reinforcement to the appropriate length, and then use a bending machine to bend the steel bars into the designed rings as stirrups. Sandblast the surface of the main reinforcement and stirrups to remove surface rust and impurities. Immerse the main reinforcement and stirrups in a 5% zinc phosphate solution for 4 minutes, and then thoroughly clean their surface with acetone solution. Then, arrange the processed main reinforcement evenly on a flat operating table according to the design spacing (200mm), and fix it with positioning clamps to ensure that the main reinforcement is parallel and the center of the ring is collinear. Put the stirrups on the outside of the main reinforcement, distribute them according to the design spacing, and tie them with double strands of galvanized iron wire to make a steel cage. Then immerse the steel cage in the anti-corrosion coating slurry of step S1 and let it stand for 25 seconds. Slowly take it out and then place it in saturated lime water for curing for 7 days. The saturated lime water curing environment can provide sufficient calcium ions for the coating, promote the cement hydration reaction, and at the same time avoid the occurrence of calcium corrosion, thus obtaining a pretreated steel cage.

[0084] S3: After the pile position is verified by the surveying and supervision team, the piles are laid out. Before construction, the pile position dimensions are checked and leveling points are set to facilitate control of the pile driving height.

[0085] S4: Use a JK580 crawler hydraulic drilling rig. After alignment, drill to the designed depth of 2.2m and a diameter of 40cm. After clearing the soil at the bottom of the hole, lift the drill. Do not bend the drill rod. Remove loose soil from the hole opening in time. Use a sounding plumb bob or hand lamp to check the hole depth and the thickness of loose soil (allowable deviation ≤10cm).

[0086] S5: Insert the pretreated steel cage from step S2 vertically into the designated borehole. During the insertion process, monitor the verticality in real time using a bidirectional verticality detector, and control the deviation within 0.5%. Then, use a dual-liquid high-pressure grouting pump (model: Lubang Machinery SYZJ-90 / 125) to spray a mixture of water glass and M10 cement paste (water-cement ratio 0.75) into the grout. The mass ratio of water glass to M10 cement paste is 1:4. The grouting pressure is 2.7MPa. After standing for 45 minutes, a 9cm thick solidified shell is formed on the inner wall of the hole.

[0087] S6: Use M10 cement grout (water-cement ratio 0.75), and perform pure pressure grouting using a BW250 grouting pump. Install a plug, pressure gauge, and return grout pipeline at the borehole opening. Install a tee and gate valve at the grouting pump outlet. After grouting to the ground and with consistent concentration, maintain pressure for 5 minutes, or stop when the grout concentration at the cross-flow hole reaches the standard and the pressure reaches 0.075 MPa (final pressure 0.5 MPa). If grouting is still impossible at 0.5 MPa, radial grouting is required. Record pressure and flow rate changes during grouting. After completion, close the gate valve and stop the pump.

[0088] S7: Mix 0.6 kg of graphene dispersion with a concentration of 0.6 mg / mL with 17.5 kg of ethanol, and ultrasonically disperse for 35 min. Add 6 kg of silane coupling agent KH-570, 35 kg of water-based acrylic emulsion, and 0.15 kg of organosilicon defoamer (polyether modified silicone oil), and stir for 1.5 h to obtain a mixed emulsion. Then, use a high-pressure airless sprayer to spray the exposed surface of the pile foundation twice, and dry for 2.5 h. The thickness of the first dry film is controlled at 0.7 mm, and the thickness of the second dry film is controlled at 1.3 mm. After drying, cover with plastic film for 24 h for curing to obtain a corrosion-resistant photovoltaic pile foundation suitable for tidal flat environments.

[0089] Example 2

[0090] A corrosion-resistant photovoltaic pile foundation is prepared by the following construction method:

[0091] S1: Add 123.6 kg of cement (purchased from AALBORG Ltd., type P·W52.5 white silicate cement, fineness 0.6%) and 0.150 kg of hydroxypropyl methylcellulose ether (NDJ viscosity 200000 mPa·s) to a mixing bowl, dry mix for 30 seconds, then add 1.25 kg of 20 nm nano-alumina (purity 99.99%, purchased from Shanghai Maclean Biochemical Technology Co., Ltd.), 29 kg of deionized water, and 1.8 kg of water-reducing agent, ultrasonically disperse for 10 minutes, then add... Add 1.0 kg of 50 nm nano zinc oxide (99.99% purity, purchased from Hebei Ruihuang Metal Materials Co., Ltd.), 0.5 kg of 25 wt% sodium molybdate solution, and 0.875 kg of other additives (obtained by mixing defoamer and shrinkage reducer in a mass ratio of 1:3; the defoamer is an inorganic siloxane with pH 7.2, and the shrinkage reducer is a silicate shrinkage reducer). Disperse the mixture ultrasonically for 15 min to obtain a mixture. Slowly pour the mixture into a mixing pot and stir at 700 r / min for 2 min to obtain an anti-corrosion coating slurry.

[0092] S2: According to the pile foundation design, process the main reinforcement to a suitable length, and then use a bending machine to bend the steel bars into the designed rings as stirrups. Sandblast the surface of the main reinforcement and stirrups to remove surface rust and impurities. Immerse the main reinforcement and stirrups in a 5% zinc phosphate solution for 3 minutes, and then thoroughly clean their surface with acetone solution. Then, arrange the processed main reinforcement evenly on a flat operating table at a design spacing of 150mm, and fix it with positioning clamps to ensure that the main reinforcement is parallel and the center of the ring is collinear. Put the stirrups on the outside of the main reinforcement, distribute them at the design spacing, and tie them with double strands of galvanized iron wire to make a steel cage. Then, immerse the steel cage in the anti-corrosion coating slurry of step S1 and let it stand for 20 seconds. Slowly take it out and then place it in saturated lime water for curing for 7 days. The saturated lime water curing environment can provide sufficient calcium ions for the coating, promote the cement hydration reaction, and at the same time avoid the occurrence of calcium corrosion, thus obtaining a pretreated steel cage.

[0093] S3: After the pile position is verified by the surveying and supervision team, the piles are laid out. Before construction, the pile position dimensions are checked and leveling points are set to facilitate control of the pile driving height.

[0094] S4: Use a JK580 crawler hydraulic drilling rig. After alignment, drill to the designed depth of 1.5m and a diameter of 30cm. After clearing the soil at the bottom of the hole, lift the drill. Do not bend the drill rod. Remove loose soil from the hole opening in time. Use a sounding plumb bob or hand lamp to check the hole depth and the thickness of loose soil (allowable deviation ≤10cm).

[0095] S5: Insert the pretreated steel cage from step S2 vertically into the designated borehole. During the insertion process, monitor the verticality in real time using a bidirectional verticality detector, and control the deviation within 0.5%. Then, use a dual-liquid high-pressure grouting pump (model: Lubang Machinery SYZJ-90 / 125) to spray a mixture of water glass and M10 cement paste (water-cement ratio 0.75) into the grout. The mass ratio of water glass to M10 cement paste is 1:4. The grouting pressure is 2.5MPa. Let it stand for 40 minutes to form an 8cm thick solidified shell on the inner wall of the hole.

[0096] S6: Use M10 cement grout (water-cement ratio 0.75), and construct using a BW250 grouting pump and pure pressure grouting method. Install a plug, pressure gauge, and return grout pipeline at the borehole opening. Install a tee and gate valve at the grouting pump outlet. After grouting to the ground and with consistent concentration, hold the pressure for 5 minutes, or stop when the grout concentration at the cross-flow hole reaches the standard and the pressure reaches 0.05 MPa (final pressure 0.5 MPa). If grouting is still impossible at 0.5 MPa, radial grouting is required. Record pressure and flow rate changes during grouting, and close the gate valve and stop the pump after completion.

[0097] S7: Mix 0.5 kg of graphene dispersion with a concentration of 0.6 mg / mL with 15 kg of ethanol, and ultrasonically disperse for 30 min. Add 5 kg of silane coupling agent KH-570, 30 kg of water-based acrylic emulsion, and 0.1 kg of organosilicon defoamer (polyether modified silicone oil), and stir for 1 h to obtain a mixed emulsion. Then, use a high-pressure airless sprayer to spray two layers of the mixed emulsion onto the exposed surface of the pile foundation, and dry them for 2 h respectively. The thickness of the first dry film is controlled at 0.6 mm, and the thickness of the second dry film is controlled at 1.2 mm. After drying, cover with plastic film for 24 h to obtain a corrosion-resistant photovoltaic pile foundation suitable for tidal flat environments.

[0098] Example 3

[0099] A corrosion-resistant photovoltaic pile foundation is prepared by the following construction method:

[0100] S1: Add 133.6 kg of cement (purchased from AALBORG Ltd., type P·W52.5 white silicate cement, fineness 0.6%) and 0.160 kg of hydroxypropyl methylcellulose ether (NDJ viscosity 200000 mPa·s) to a mixing bowl and dry mix for 40 seconds. Then add 1.65 kg of 20 nm nano-alumina (purity 99.99%, purchased from Shanghai Maclean Biochemical Technology Co., Ltd.), 35 kg of deionized water, and 2.2 kg of water-reducing agent. Ultrasonically disperse for 20 minutes, then add... 1.2 kg of 50 nm nano zinc oxide (99.99% purity, purchased from Hebei Ruihuang Metal Materials Co., Ltd.), 0.7 kg of 25 wt% sodium molybdate solution, and 1.275 kg of other additives (obtained by mixing defoamer and shrinkage reducer in a mass ratio of 1:3; the defoamer is an inorganic siloxane with pH 7.2, and the shrinkage reducer is a silicate shrinkage reducer) were ultrasonically dispersed for 20 min to obtain a mixture. The mixture was then slowly poured into a mixing pot and stirred at 900 r / min for 3 min to obtain an anti-corrosion coating slurry.

[0101] S2: According to the pile foundation design, process the main reinforcement to the appropriate length, and then use a bending machine to bend the steel bars into the designed rings as stirrups. Sandblast the surface of the main reinforcement and stirrups to remove surface rust and impurities. Immerse the main reinforcement and stirrups in a 5% zinc phosphate solution for 5 minutes, and then thoroughly clean their surface with acetone solution. Then, arrange the processed main reinforcement evenly on a flat operating table at a design spacing of 250mm, and fix it with positioning clamps to ensure that the main reinforcement is parallel and the center of the ring is collinear. Put the stirrups on the outside of the main reinforcement, distribute them at the design spacing, and tie them with double strands of galvanized iron wire to make a steel cage. Then, immerse the steel cage in the anti-corrosion coating slurry of step S1 and let it stand for 30 seconds. Slowly take it out and then place it in saturated lime water for curing for 8 days. The saturated lime water curing environment can provide sufficient calcium ions for the coating, promote the cement hydration reaction, and at the same time avoid the occurrence of calcium corrosion, thus obtaining a pretreated steel cage.

[0102] S3: After the pile position is verified by the surveying and supervision team, the piles are laid out. Before construction, the pile position dimensions are checked and leveling points are set to facilitate control of the pile driving height.

[0103] S4: Use a JK580 crawler hydraulic drilling rig. After alignment, drill to the designed depth of 3m and a diameter of 50cm. After clearing the soil at the bottom of the hole, lift the drill. Do not bend the drill rod. Remove loose soil from the hole opening in time. Use a sounding plumb bob or hand lamp to check the hole depth and the thickness of loose soil (allowable deviation ≤10cm).

[0104] S5: Insert the pre-treated steel cage from step S2 vertically into the designated borehole. During the insertion process, monitor the verticality in real time using a bidirectional verticality detector, and control the deviation within 0.5%. Then, use a dual-liquid high-pressure grouting pump (model: Lubang Machinery SYZJ-90 / 125) to spray a mixture of water glass and M10 cement paste (water-cement ratio 0.75) into the grout. The mass ratio of water glass to M10 cement paste is 1:4. The grouting pressure is 3.0MPa. After standing for 50 minutes, a 10cm thick solidified shell is formed on the inner wall of the hole.

[0105] S6: Use M10 cement grout (water-cement ratio 0.75), and construct using a BW250 grouting pump and pure pressure grouting method. Install a plug, pressure gauge, and return grout pipeline at the borehole opening. Install a tee and gate valve at the grouting pump outlet. After grouting to the ground and with consistent concentration, hold the pressure for 5 minutes, or stop when the grout concentration at the cross-flow hole reaches the standard and the pressure reaches 0.1 MPa (final pressure 0.5 MPa). If grouting is still impossible at 0.5 MPa, radial grouting is required. Record pressure and flow rate changes during grouting, and close the gate valve and stop the pump after completion.

[0106] S7: Mix 0.7 kg of graphene dispersion with a concentration of 0.6 mg / mL with 20 kg of ethanol, and ultrasonically disperse for 40 min. Add 7 kg of silane coupling agent KH-570, 40 kg of water-based acrylic emulsion, and 0.2 kg of organosilicon defoamer (polyether modified silicone oil), and stir for 2 h to obtain a mixed emulsion. Then, use a high-pressure airless sprayer to spray the exposed surface of the pile foundation twice, and dry for 3 h. The thickness of the first dry film is controlled at 0.8 mm, and the thickness of the second dry film is controlled at 1.5 mm. After drying, cover with plastic film for 24 h for curing to obtain a corrosion-resistant photovoltaic pile foundation suitable for tidal flat environments.

[0107] Example 4

[0108] This embodiment provides a corrosion-resistant photovoltaic pile foundation suitable for tidal flat environments. The only difference from Embodiment 1 is that in step S1, an ammonium molybdate solution is used to replace the sodium molybdate solution in equal amounts.

[0109] The remaining steps and parameters are the same as in Example 1.

[0110] Example 5

[0111] This embodiment provides a corrosion-resistant photovoltaic pile foundation suitable for tidal flat environments. The only difference from Embodiment 1 is that in step S2, the main reinforcement and stirrups are not subjected to sandblasting, zinc phosphate solution immersion, or acetone cleaning.

[0112] The remaining steps and parameters are the same as in Example 1.

[0113] Example 6

[0114] This embodiment provides a corrosion-resistant photovoltaic pile foundation suitable for tidal flat environments. The only difference from Embodiment 1 is that in step S2, the steel cage is not placed in saturated lime water for curing.

[0115] The remaining steps and parameters are the same as in Example 1.

[0116] Example 7

[0117] This embodiment provides a corrosion-resistant photovoltaic pile foundation suitable for tidal flat environments. The only difference from Embodiment 1 is that in step S5, the mass ratio of water glass to M10 cement paste is 0.5:4.5.

[0118] The remaining steps and parameters are the same as in Example 1.

[0119] Example 8

[0120] This embodiment provides a corrosion-resistant photovoltaic pile foundation suitable for tidal flat environments. The only difference from Embodiment 1 is that in step S5, the mass ratio of water glass to M10 cement paste is 1.5:3.5.

[0121] The remaining steps and parameters are the same as in Example 1.

[0122] Example 9

[0123] This embodiment provides a corrosion-resistant photovoltaic pile foundation suitable for tidal flat environments. The only difference from Embodiment 1 is that in step S7, the mixed emulsion is sprayed onto the exposed surface of the pile foundation only once to form a dry film with a thickness of 2.0 mm.

[0124] The remaining steps and parameters are the same as in Example 1.

[0125] Example 10

[0126] This embodiment provides a corrosion-resistant photovoltaic pile foundation suitable for tidal flat environments. The only difference from Embodiment 1 is that in step S7, the mixed emulsion is sprayed three times on the exposed surface of the pile foundation to form three layers of dry film. The thickness of the first layer of dry film is controlled at 0.5 mm, the thickness of the second layer of dry film is controlled at 0.7 mm, and the thickness of the third layer of dry film is controlled at 1.3 mm.

[0127] The remaining steps and parameters are the same as in Example 1.

[0128] Comparative Example 1

[0129] This comparative example provides a photovoltaic pile foundation, which differs from Example 1 only in that the reinforcing cage is not immersed in the anti-corrosion coating slurry in step S2, the mixed mud is not sprayed in step S5, and the spraying treatment is not performed in step S7.

[0130] The remaining steps and parameters are the same as in Example 1.

[0131] Comparative Example 2

[0132] This comparative example provides a photovoltaic pile foundation, which differs from Example 1 only in that no spraying treatment is performed in step S7;

[0133] The remaining steps and parameters are the same as in Example 1.

[0134] Comparative Example 3

[0135] This comparative example provides a photovoltaic pile foundation, which differs from Example 1 only in that the mixed mud was not sprayed in step S5;

[0136] The remaining steps and parameters are the same as in Example 1.

[0137] Comparative Example 4

[0138] This comparative example provides a photovoltaic pile foundation, which differs from Example 1 only in that hydroxypropyl methylcellulose ether is not added to the anti-corrosion coating slurry in step S1.

[0139] The remaining steps and parameters are the same as in Example 1.

[0140] Comparative Example 5

[0141] This comparative example provides a photovoltaic pile foundation, which differs from Example 1 only in that, in step S1, nano-alumina is not added to the anti-corrosion coating slurry;

[0142] The remaining steps and parameters are the same as in Example 1.

[0143] Comparative Example 6

[0144] This comparative example provides a photovoltaic pile foundation, which differs from Example 1 only in that, in step S1, nano zinc oxide is not added to the anti-corrosion coating slurry;

[0145] The remaining steps and parameters are the same as in Example 1.

[0146] Comparative Example 7

[0147] This comparative example provides a photovoltaic pile foundation, which differs from Example 1 only in that sodium molybdate solution is not added to the anti-corrosion coating slurry in step S1.

[0148] The remaining steps and parameters are the same as in Example 1.

[0149] Comparative Example 8

[0150] This comparative example provides a photovoltaic pile foundation, which differs from Example 1 only in that water glass is not added to the mixed mud in step S5;

[0151] The remaining steps and parameters are the same as in Example 1.

[0152] Comparative Example 9

[0153] This comparative example provides a photovoltaic pile foundation, which differs from Example 1 only in that, in step S7, graphene dispersion was not added to the mixed emulsion;

[0154] The remaining steps and parameters are the same as in Example 1.

[0155] Comparative Example 10

[0156] This comparative example provides a photovoltaic pile foundation, which differs from Example 1 only in that, in step S7, water-based acrylic emulsion is not added to the mixed emulsion;

[0157] The remaining steps and parameters are the same as in Example 1.

[0158] Test case

[0159] The photovoltaic pile foundations of Examples 1-10 and Comparative Examples 1-10 were subjected to performance tests, and the results are shown in Tables 1, 2 and 3, 4, respectively.

[0160] Simulation conditions for the anti-corrosion experiment in tidal flat environment: Prepare artificial seawater with a concentration of 3.5 wt% (artificial seawater preparation concentration: sodium chloride 24.53 g / L, magnesium chloride 5.20 g / L, sodium sulfate 4.09 g / L, calcium chloride 1.16 g / L, potassium chloride 0.695 g / L, sodium bicarbonate 0.201 g / L, potassium bromide 0.101 g / L). The characteristic of the seawater full immersion zone is that the specimen is completely submerged in seawater for a long time. The characteristic of the water level fluctuation zone is that the seawater rises and falls periodically. The artificial seawater is injected into and discharged from the tank using a water pump to realize the dry and wet cycle simulation (6 hours dry, 6 hours wet). The samples were placed in the seawater full immersion zone and the water level fluctuation zone for 10 days, 30 days, 40 days, 80 days, 100 days and 200 days respectively, and then electrochemical tests were performed.

[0161] The electrochemical testing procedure is as follows: Referring to the "Test Methods for Long-Term Performance and Durability of Ordinary Concrete (GBJ82-85)," the corroded steel bars are removed from the concrete. A 1cm high steel bar sample is taken from the bottom of the steel bars embedded in the concrete. The residual concrete on the bottom surface is ground away, ultrasonically treated with alcohol, and then dried. Electrochemical impedance spectroscopy (EIS) testing is then performed: The steel bars are subjected to EIS testing on an electrochemical workstation, using a frequency range of 10... -2 Hz to 10 5 The excitation signal is a sinusoidal voltage with a perturbation amplitude of 10mV (vs. OCP) at Hz. The electrolytic cell adopts a three-electrode system, with a silver / silver chloride electrode as the reference electrode, a platinum sheet electrode as the auxiliary electrode, and a steel bar electrode as the working electrode.

[0162] Table 1. Summary of Test Results for the Fully Immersed Seawater Zone

[0163]

[0164] Table 2 Summary of Test Results for the Fully Immersed Seawater Zone

[0165]

[0166] As shown in Tables 1 and 2, the resistance values ​​of the passivation film on the reinforcing bars in Examples 1-5 of the present invention are all greater than those in Comparative Examples 1-3, and show an increasing trend with time. This indicates that a passivation film still exists on the surface of the reinforcing bars, and also shows that its corrosion resistance is better under full seawater immersion. This may be because nano-alumina and nano-zinc oxide can fill the pores of the coating and physically block chloride ion penetration. Meanwhile, molybdate solution and zinc oxide work together to form a composite passivation film, which inhibits electrochemical corrosion and microbial corrosion by sulfate-reducing bacteria. Water glass and M10 cement slurry form a solidified shell of a certain thickness as the first anti-corrosion barrier, which physically prevents direct contact. The exposed part of the pile foundation is sprayed with mixed emulsion and then cured, which plays a hydrophobic role and blocks seawater erosion, thereby further improving the corrosion resistance of the photovoltaic pile foundation under full seawater immersion.

[0167] Table 3. Summary of Test Results for Water Level Fluctuation Zones

[0168]

[0169] Table 4 Summary of Test Results for Water Level Fluctuation Zones

[0170]

[0171] As shown in Tables 3 and 4, the resistance values ​​of the steel bar passivation film in Examples 1-5 of the present invention are all greater than those in Comparative Examples 1-3, indicating that the corrosion resistance of Examples 1-5 is better under the condition of water level fluctuation. This may be due to the synergistic effect of the composite passivation film, the solidified shell and the mixed emulsion, which makes the photovoltaic pile foundation have better salt spray corrosion resistance when used in the tidal flat environment.

[0172] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. An anticorrosion photovoltaic pile foundation, characterized by, The corrosion-resistant photovoltaic pile foundation includes a steel cage, and an anti-corrosion coating, a cured shell, and an emulsion layer formed on the steel cage; The anti-corrosion coating comprises the following components: Cement, hydroxypropyl methylcellulose ether, nano-alumina, water-reducing agent, nano-zinc oxide, molybdate solution, and additives; The cured shell comprises the following components: Water glass and M10 cement paste; The emulsion layer comprises the following components: Graphene dispersions, silane coupling agents, aqueous acrylic emulsions, and organosilicon defoamers.

2. The corrosion-proof photovoltaic pile foundation according to claim 1, characterized in that, The mass ratio of the cement, hydroxypropyl methylcellulose ether, nano-alumina, water, water-reducing agent, nano-zinc oxide, molybdate solution, and additives is 123.6-133.6: 0.150-0.160: 1.25-1.65: 29-35: 1.8-2.2: 1.0-1.2: 0.5-0.7: 0.875-1.275; The concentration of the molybdate solution is 20wt%-30wt%; The molybdate solution includes at least one of sodium molybdate solution and ammonium molybdate solution; The additives include at least one of defoamers and shrinkage reducers.

3. The corrosion-proof photovoltaic pile foundation according to claim 1, characterized in that, The mass ratio of water glass to M10 cement paste is (0.5-1.5):(3.5-4.5). The thickness of the cured shell is 8cm-10cm.

4. The corrosion-proof photovoltaic pile foundation according to claim 1, characterized in that, The emulsion layer includes a first emulsion layer and a second emulsion layer; The thickness of the first emulsion layer is 0.6mm-0.8mm; The thickness of the second emulsion layer is greater than 1.2 mm.

5. A method of constructing a corrosion-protected photovoltaic pile foundation according to any one of claims 1 to 4, characterized in that Includes the following steps: The steel cage is immersed in an anti-corrosion coating slurry to form an anti-corrosion coating, thus obtaining a pre-treated steel cage. The pretreated steel cage is vertically inserted into the borehole, and mixed mud is first injected to form a solidified shell. Then, a mixed emulsion is sprayed on the surface to form an emulsion layer, thus obtaining the anti-corrosion photovoltaic pile foundation.

6. The construction method according to claim 5, characterized in that, The steel cage is assembled from surface-treated main bars and surface-treated stirrups; The surface treatment includes sandblasting, zinc phosphate solution immersion, and acetone cleaning.

7. The construction method according to claim 5, characterized in that, The preparation method of the anti-corrosion coating slurry includes the following steps: First, cement and hydroxypropyl methylcellulose ether are added and dry-mixed. Then, nano-alumina, water, and water-reducing agent are added and mixed and dispersed. Next, nano-zinc oxide, molybdate solution, and additives are added and mixed and dispersed to obtain the anti-corrosion coating slurry.

8. The construction method according to claim 5, characterized in that, After the steel cage is immersed in the anti-corrosion coating slurry, the process also includes a step of curing the steel cage in saturated lime water to obtain a pretreated steel cage.

9. The construction method according to claim 5, characterized in that, The method for preparing the mixed emulsion includes the following steps: First, the graphene dispersion is mixed and dispersed with ethanol, then a silane coupling agent, an aqueous acrylic emulsion, and an organosilicon defoamer are added and stirred to obtain the mixed emulsion.

10. The application of the anti-corrosion photovoltaic pile foundation according to any one of claims 1-4 in a tidal flat environment.

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