An ultra-high-strength offshore wind power jacket grouting material, a preparation method and application thereof

Abstract

The application belongs to the field of building materials and relates to an ultra-high-strength offshore wind power guide pipe frame grouting material and a preparation method and application thereof. The ultra-high-strength offshore wind power guide pipe frame grouting material comprises, in terms of weight parts, cement 700-900 parts, viscosity-reducing reinforcing agent 150-350 parts, modified nano material 10-30 parts, water reducing agent 7-9 parts, defoaming agent 1-2 parts, plastic expansive agent 0.1-0.5 parts, fine aggregate 750-850 parts, stainless steel fiber 120-160 parts and water 160-170 parts. The modified nano material is nano silicon dioxide modified by a silane coupling agent. The viscosity-reducing reinforcing agent is composed of a viscosity reducer and silica fume in a weight ratio of (1-2):1. The grouting material has a 28d compressive strength of greater than or equal to 170 MPa and excellent fatigue resistance. The grouting connection test piece is not damaged after 2 million times of fatigue test, and the residual bearing capacity retention rate is higher than 80%, thereby meeting the requirements of long service life and reliable connection of the wind turbine in a harsh deep-sea environment.

Description

Technical Field

[0001] This invention belongs to the field of building materials technology, and relates to an ultra-high strength offshore wind power jacket grouting material, its preparation method and application. Background Technology

[0002] Grouting material for offshore wind turbine jacket structures is used to create annular connection gaps between the offshore wind turbine jacket structure and the seabed pile foundation. After curing, it forms a critical grouting connection section, reliably transferring the enormous vertical loads, horizontal loads, and overturning moments generated by the upper wind turbine structure to the seabed pile foundation through the jacket structure. It is a core component ensuring the overall structural stability and safety. Because of its critical load-bearing position and harsh environment, enduring complex loads and seawater corrosion over long periods, high requirements are placed on the compressive strength, fatigue resistance, and durability of the grouting material.

[0003] Currently, existing offshore wind turbine jacket grouting materials mainly use ordinary Portland cement (P·O 52.5) ​​as the primary cementitious material, compounded with active mineral admixtures such as silica fume and slag powder, and add polycarboxylate-based high-performance water-reducing agents to adjust fluidity. This type of grouting material performs well in large-scale wind turbine applications in conventional sea areas. However, as my country's offshore wind power development extends to deeper waters, with larger single-unit capacities and taller towers, the supporting structure will bear greater loads and face harsher service environments, placing higher demands on the compressive strength of the grouting material. Summary of the Invention

[0004] To address the above technical problems, this invention provides an ultra-high strength offshore wind turbine jacket grouting material, its preparation method, and its application. The grouting material has a 28-day compressive strength ≥170MPa and excellent fatigue resistance. The grouting connection specimens showed no damage after completing 2 million fatigue tests, and the residual bearing capacity retention rate was higher than 80%. This can meet the requirements of ultra-long service life and reliable connection of wind turbines in the harsh environment of deep sea.

[0005] The technical solution provided by this invention is as follows: In a first aspect, the present invention provides an ultra-high strength offshore wind power jacket grouting material, which is composed of the following components in parts by weight: 700-900 parts cement, 150-350 parts viscosity reducer and reinforcing agent, 10-30 parts modified nanomaterials, 7-9 parts water-reducing agent, 1-2 parts defoamer, 0.1-0.5 parts plastic expansion agent, 750-850 parts fine aggregate, 120-160 parts stainless steel fiber, and 160-170 parts water; in, The modified nanomaterial is nano-silica with a silane coupling agent surface modified; The viscosity reducing and enhancing agent is composed of a viscosity reducing agent and silica fume in a weight ratio of (1~2):1.

[0006] In conjunction with the first aspect of the present invention, in some embodiments, the water-to-material ratio of the ultra-high strength offshore wind turbine jacket grout is 0.07 to 0.097. Specifically, the water-to-material ratio of the present invention is the ratio of water to the total mass of all dry raw materials.

[0007] In conjunction with the first aspect of the present invention, in some embodiments, the modified nanomaterial is prepared by a method comprising the following steps: drying nano-silica, mixing it with an ethanol solution of a silane coupling agent, adjusting the pH value of the mixture to an acidic range suitable for hydrolysis reaction; performing a surface grafting reaction by heating under stirring and ultrasonic assistance; and after the reaction is completed, washing and drying to obtain the modified nanomaterial.

[0008] In conjunction with the first aspect of the present invention, in some embodiments, the viscosity reducer meets the requirements of the "Standard for Acceptance of Construction Quality of Railway Concrete Engineering" (GB / T 10424-2018), with a viscosity ratio ≤45%, 7-day compressive strength ≥90%, and 28-day compressive strength ≥100%; the silica fume meets the requirements of the "Silica Fume for Mortar and Concrete" (GB / T 27690-2011), with a SiO2 content ≥94% and a specific surface area ≥20000 m². 2 / kg.

[0009] In conjunction with the first aspect of the invention, in some embodiments, the cement is P·W 52.5 silicate cement.

[0010] In conjunction with the first aspect of the present invention, in some embodiments, the water-reducing agent is a viscosity-reducing polycarboxylate high-performance water-reducing agent with a water reduction rate ≥35%.

[0011] In conjunction with the first aspect of the present invention, in some embodiments, the defoamer is an organosilicon defoamer.

[0012] In conjunction with the first aspect of the present invention, in some embodiments, the plasticizing agent is a nitroso compound plasticizing agent.

[0013] In conjunction with the first aspect of the present invention, in some embodiments, the fine aggregate is composed of continuously graded fine aggregates of 10-20 mesh, 20-40 mesh and 40-70 mesh, in a weight ratio of (3-4):(1.5-2.5):(2.5-3.5).

[0014] In some embodiments of the present invention, the stainless steel fiber has a diameter of 0.12~0.2mm and a length of 6~12mm.

[0015] Secondly, the present invention also provides a method for preparing ultra-high strength offshore wind turbine jacket grouting material, comprising the following steps: Prepare the following by weight: 700-900 parts cement, 150-350 parts viscosity reducer and reinforcing agent, 10-30 parts modified nanomaterials, 7-9 parts water-reducing agent, 1-2 parts defoamer, 0.1-0.5 parts plastic expansion agent, 750-850 parts fine aggregate, 120-160 parts stainless steel fiber, and 160-170 parts water.

[0016] According to the weight proportions, cement, viscosity reducer, modified nanomaterials, water reducer, defoamer, plastic expansion agent, fine aggregate and stainless steel fiber are thoroughly mixed and stirred evenly to obtain ultra-high strength offshore wind power jacket grouting dry mix. Add the dry-mixed ultra-high strength offshore wind turbine jacket grout to the mixer, then add water and mix for 6 to 8 minutes to obtain the ultra-high strength offshore wind turbine jacket grout.

[0017] Thirdly, the present invention provides the application of the above-mentioned ultra-high strength offshore wind turbine jacket grouting material in the grouting connection of offshore wind turbine structures.

[0018] The ultra-high strength offshore wind turbine jacket grouting material provided by this invention uses P·W 52.5 silicate cement instead of traditional gray silicate cement, which reduces water consumption while ensuring the strength and stability of the grouting material. A viscosity-reducing and reinforcing agent is used to improve the workability of the low water-to-cement ratio grouting material and increase its strength. A silane coupling agent is used to modify nano-silica, changing it from "hydrophilic" to "cement matrix-philic," enhancing interparticle repulsion, improving dispersion stability, and increasing the interfacial bonding force between nano-silica and the cement matrix, significantly increasing the strength of the grouting material. A viscosity-reducing polycarboxylate superplasticizer is used to lower the viscosity of the grouting material and improve its fluidity. An antifoaming agent is used to eliminate harmful large pores and improve the density of the grouting material. Basalt sand and quartz sand are used as fine aggregates, and a three-gradation method is used to form the densest packing skeleton, improving the strength of the grouting material. Stainless steel fibers are used to reinforce and toughen the material, control the development of microcracks, and improve durability.

[0019] Compared with the prior art, the present invention has at least the following beneficial effects: (1) The ultra-high strength offshore wind power jacket grouting material provided by the present invention has excellent mechanical properties: 1d compressive strength ≥80MPa, 3d compressive strength ≥120MPa, 28d compressive strength ≥170MPa, 28d axial tensile strength ≥9MPa. The early compressive strength is high, the later compressive strength is sufficient, and the axial tensile strength is significantly increased compared with conventional wind power grouting materials. It exhibits obvious strain hardening phenomenon and has ultra-high toughness.

[0020] (2) The ultra-high strength offshore wind power jacket grouting material provided by the present invention has excellent fatigue resistance: under the action of 50% failure load amplitude, the grouting connection specimens have no damage after 2 million fatigue tests. After the fatigue test, the residual bearing capacity of the specimens is more than 80%, which can effectively guarantee the service life.

[0021] (3) The ultra-high strength offshore wind power jacket grouting material provided by the present invention has good working performance: the initial flowability of the grouting material is ≥290mm, the flowability of 30min is ≥260mm, the cohesiveness is good, it is not easy to separate into layers, it is easy to pump, and the construction time is long. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 The load-displacement curves are for grouting connection specimens 1, 2, and 3 of the present invention.

[0024] Figure 2 These are actual photos of the bearing capacity test specimens 1, 2, and 3 of the grouting connection according to the present invention. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below in conjunction with the embodiments of this invention. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0026] Existing cementitious material systems, primarily based on ordinary silicate cement, have reached their performance limits when pursuing ultra-high compressive strengths exceeding 150 MPa. Furthermore, according to materials science principles, increasing strength requires reducing the water-to-material ratio to decrease porosity and increase density, but this drastically increases the viscosity of the grout. Current technologies rely on water-reducing agents and traditional viscosity-reducing agents with insufficient synergistic effect under ultra-low water-to-material ratio conditions, limiting their ability to control the viscosity of the grout structure. This makes it impossible to guarantee both ultra-high strength and the fluidity requirements of offshore grouting construction, hindering their ability to withstand the long-term challenges of the complex deep-sea environment.

[0027] To address the above technical problems, this invention provides an ultra-high strength offshore wind turbine jacket grouting material, its preparation method, and its application. The grouting material has a 28-day compressive strength ≥170MPa and excellent fatigue resistance. The grouting connection specimens showed no damage after completing 2 million fatigue tests, and the residual bearing capacity retention rate was higher than 80%. This can meet the requirements of ultra-long service life and reliable connection of wind turbines in the harsh environment of deep sea.

[0028] Ultra-high strength offshore wind turbine jacket grouting material: The ultra-high strength offshore wind power jacket grouting material provided by this invention comprises, by weight, 700-900 parts cement, 150-350 parts viscosity reducer and reinforcing agent, 10-30 parts modified nanomaterials, 7-9 parts water-reducing agent, 1-2 parts defoamer, 0.1-0.5 parts plastic expansion agent, 750-850 parts fine aggregate, 120-160 parts stainless steel fiber, and 160-170 parts water.

[0029] This invention uses P·W 52.5 silicate cement instead of traditional gray silicate cement, which reduces water consumption while ensuring the strength and stability of the grout. In some specific embodiments of this invention, the cement is P·W 52.5 silicate cement.

[0030] This invention employs a viscosity-reducing polycarboxylate high-performance water-reducing agent to lower the viscosity of the grout and improve its fluidity. In some specific embodiments of this invention, the water-reducing agent is a viscosity-reducing polycarboxylate high-performance water-reducing agent with a water reduction rate ≥35%.

[0031] This invention uses a defoamer to eliminate harmful large pores and improve the density of the grouting material. In some specific embodiments of this invention, the defoamer is an organosilicon-based defoamer.

[0032] This invention employs a viscosity-reducing and reinforcing agent to improve the workability and strength of grouts with low water-to-material ratios. In some specific embodiments of this invention, the viscosity-reducing and reinforcing agent is composed of a viscosity reducer and silica fume in a weight ratio of (1~2):1. The viscosity reducer performance should meet the requirements of the "Standard for Acceptance of Construction Quality of Railway Concrete Engineering" (GB / T 10424-2018), with a viscosity ratio ≤45%, 7-day compressive strength ≥90%, and 28-day compressive strength ≥100%. The silica fume performance should meet the requirements of "Silica Fume for Mortar and Concrete" (GB / T27690-2011), with a SiO2 content ≥94% and a specific surface area ≥20000 m². 2 / kg. The modified nanomaterial is nano-silica modified with a silane coupling agent. The manufacturing process is as follows: SiO2 is dried in an oven at 105℃ for 2-3 hours to remove adsorbed moisture from the surface; silane coupling agent is weighed according to the ratio of silane coupling agent to nanomaterials = 1%-5% (mass ratio) and dissolved in anhydrous ethanol to prepare a silane solution with a concentration of 5%-10%; the pH of the solution is then adjusted to 4.5 with dilute hydrochloric acid; the dried nano-silica is added to a high-speed stirrer, the speed is adjusted to 1000 r / min, and the prepared silane solution is slowly added dropwise while stirring; after the addition is completed, the temperature is raised to 80℃, and the stirring reaction is maintained for 2 hours to promote the condensation reaction between silanol groups and hydroxyl groups on the surface of nanomaterials. During the process, ultrasonic dispersion (20 kHz) is performed for 15 minutes to further disperse any local agglomerates that may form during the reaction; after the reaction, the product is washed twice with anhydrous ethanol to remove ungrafted free coupling agent; the washed product is dried in an 80℃ vacuum oven for 6 hours to obtain surface-modified nano-silica.

[0033] This invention utilizes a silane coupling agent to modify nano-silica, transforming it from a "hydrophilic" to a "cement-matrix-friendly" material. The surface of the "hydrophilic" nano-silica exhibits strong hydrogen bonds and electrostatic attraction, making it prone to aggregation. After modification with the silane coupling agent, an organic molecular layer is grafted onto the surface, generating steric hindrance and electrostatic repulsion. This enhances the interparticle repulsion, improves dispersion stability, and strengthens the interfacial bonding between the nano-silica and the cement matrix, significantly increasing the strength of the grout.

[0034] The plastic expander is a nitroso compound plastic expander.

[0035] This invention uses stainless steel fibers to reinforce and toughen the material, while controlling the development of microcracks and improving durability. In some embodiments of this invention, the stainless steel fibers have a diameter of 0.12~0.2mm and a length of 6~12mm.

[0036] In some embodiments of the present invention, the fine aggregate is one or more of quartz sand, basalt sand, corundum sand, and silicon carbide sand, and is arranged in a three-gradation manner to form the densest packing skeleton, which can improve the strength of the grouting material.

[0037] Furthermore, the fine aggregate is basalt sand, composed of 10-20 mesh basalt sand, 20-40 mesh basalt sand, and 40-70 mesh basalt sand in a weight ratio of (3-4):(1.5-2.5):(2.5-3.5). This invention controls the amount of fine aggregate, avoiding excessively high costs for this ultra-high strength offshore wind turbine jacket grouting material.

[0038] In some embodiments of the present invention, the water-to-material ratio in the ultra-high strength offshore wind turbine jacket grout is 0.07–0.097, with a relatively low amount of fresh water. Specifically, the water-to-material ratio in the present invention is the ratio of water to the total mass of all dry raw materials. It is generally believed that the lower the water-to-material ratio, the worse the fluidity of the grout.

[0039] This invention features a low water-to-material ratio but excellent fluidity. Firstly, it uses P·W 52.5 silicate cement instead of traditional gray silicate cement, reducing water consumption. Secondly, it employs a viscosity-reducing polycarboxylate superplasticizer to lower the viscosity of the grout and improve its fluidity. Thirdly, it uses a viscosity-reducing reinforcing agent containing a viscosity reducer, which significantly reduces viscosity and enhances fluidity. The ultra-high strength offshore wind turbine jacket grout provided by this invention exhibits excellent fluidity, with an initial fluidity ≥290mm and a 30-minute fluidity ≥260mm.

[0040] Preparation method The method for preparing ultra-high strength offshore wind turbine jacket grouting material provided by the present invention includes the following steps: Prepare the following by weight: 700-900 parts cement, 150-350 parts viscosity reducer and reinforcing agent, 10-30 parts modified nanomaterials, 7-9 parts water-reducing agent, 1-2 parts defoamer, 0.1-0.5 parts plastic expansion agent, 750-850 parts fine aggregate, 120-160 parts stainless steel fiber, and 160-170 parts water; the cement is P·W 52.5 Silicate cement; the viscosity reducing and strengthening agent is composed of viscosity reducing agent and silica fume in a weight ratio of (1~2):1; the modified nanomaterial is nano-silica modified by silane coupling agent; the water reducing agent is a viscosity reducing polycarboxylate high-strength water reducing agent; the plastic expansion agent is a nitroso compound plastic expansion agent; the fine aggregate is composed of 10~20 mesh fine aggregate, 20~40 mesh fine aggregate and 40~70 mesh fine aggregate in a weight ratio of (3~4):(1.5~2.5):(2.5~3.5); the stainless steel fiber has a diameter of 0.12~0.2mm and a length of 6~12mm.

[0041] The cement, viscosity reducer, modified nanomaterials, water-reducing agent, defoamer, plastic expansion agent, basalt sand and stainless steel fiber are thoroughly mixed and stirred to obtain ultra-high strength offshore wind power jacket grouting dry mix. Add the dry-mixed ultra-high strength offshore wind power jacket grout to the mixer, then add water and mix for 6 to 8 minutes to obtain the ultra-high strength offshore wind power jacket grout.

[0042] This preparation method is simple, time-saving, and suitable for on-site preparation.

[0043] application: The ultra-high strength offshore wind turbine jacket grouting material provided by this invention possesses excellent workability, ultra-high strength, superior durability, and low shrinkage. Furthermore, its preparation method is simple. When used to connect large-capacity wind turbines or wind turbine support structures in deep-sea environments to pile foundations, it enhances the durability of the connection mechanism. Under a 50% failure load amplitude, the grouting connection specimens showed no failure after 2 million fatigue tests. The residual bearing capacity of the specimens after the fatigue tests exceeded 80%, effectively guaranteeing service life. It is particularly suitable for projects in harsh deep-sea environments and projects with stringent service life requirements.

[0044] Example: The equipment used in the embodiments and comparative examples is as follows: Forced mixer, cement mortar mixer, pressure testing machine, concrete electrical flux measuring instrument.

[0045] The technical solution of the present invention is described in detail below through examples. Unless otherwise specified, the raw materials, equipment, or solvents used are all common raw materials, equipment, or solvents available on the market. Unless otherwise specified, the raw materials with the same name used in the following examples and comparative examples are all the same raw materials. It should be noted that, except for the viscosity reducing and reinforcing agent and modified nanomaterials, all raw materials of the ultra-high strength offshore wind power jacket grouting material provided by the present invention are ordinary raw materials purchased from the market, and the raw materials for preparing the viscosity reducing and reinforcing agent and modified nanomaterials can also be purchased from the market.

[0046] The raw materials used in the ultra-high strength offshore wind turbine jacket grouting materials in the following embodiments and comparative examples are as follows: 1. Cement The cement used is P·W 52.5 silicate cement, which conforms to the GB / T 2015-2017 standard. Its 28-day compressive strength is not less than 52.5 MPa, and its whiteness is not less than 87 (Grade 1) or 89 (Extra Grade). 2. Viscosity reducing and strengthening agent Except for the viscosity-reducing and reinforcing agents in Examples 7 and 8, which are composed of a viscosity reducer and silica fume in a weight ratio of 1:1, the viscosity-reducing and reinforcing agents in the other examples and comparative examples 1, 2, and 4 have a weight ratio of viscosity reducer to silica fume of 1.5:1. The viscosity reducer strength should meet the requirements of the "Standard for Acceptance of Construction Quality of Railway Concrete Engineering" (GB / T 10424-2018), with a viscosity ratio ≤45%, 7-day compressive strength ≥90%, and 28-day compressive strength ≥100%. The silica fume strength should meet the requirements of "Silica Fume for Mortar and Concrete" (GB / T27690-2011), with a SiO2 content ≥94% and a specific surface area ≥20000 m². 2 / kg.

[0047] 3. Modified nanomaterials The modified nanomaterial is nano-silica modified with a silane coupling agent: Materials preparation: Take 100.0g of nano-silica and dry it in an oven at 105℃ for 2.5 hours. Weigh out 2.0g of silane coupling agent according to the ratio of silane coupling agent to nano-silica (2%). Dissolve 2.0g of silane coupling agent in anhydrous ethanol to prepare a 6% silane solution. Adjust the pH of the silane coupling agent solution to 4.5 with dilute hydrochloric acid.

[0048] Modification reaction: 100.0 g of dried nano-silica was added to a high-speed stirrer, and the entire prepared silane coupling agent solution was slowly added dropwise while stirring at 1000 r / min. After the addition was complete, the temperature was raised to 80℃, and the reaction was continued with stirring for 2 hours. At the 30-minute mark after the start of the reaction, ultrasonic dispersion at 20 kHz was applied for 15 minutes. After the reaction was completed, the product was washed twice with anhydrous ethanol. The washed product was then dried in a vacuum oven at 80℃ for 6 hours to obtain surface-modified nano-silica.

[0049] Comparative Example 4 is unmodified nano-silica.

[0050] 4. Water-reducing agent The water-reducing agent is a viscosity-reducing polycarboxylate high-performance water-reducing agent with a water reduction rate of ≥35%; Shanghai Yingshan New Materials Co., Ltd., PC-200 type polycarboxylate water-reducing agent; 5. Defoamer The defoamer is an organosilicon defoamer; Shanghai Yingshan New Materials Co., Ltd., DF-04 type defoamer; 6. Plastic expanding agent The plastic expander is a nitroso compound plastic expander, manufactured by China Academy of Building Research, type CABR-PEA2; 7. Fine aggregate Except for Example 7, where the fine aggregate is basalt sand, which is composed of 10-20 mesh basalt sand, 20-40 mesh basalt sand and 40-70 mesh basalt sand, with a weight ratio of 3.5:2.0:2.5, and Example 8, where the weight ratio is 4:2:2.5, the weight ratios in the other examples and comparative examples 1-4 are 3:2:3. 8. Stainless steel fiber Except for Example 6, where the stainless steel fiber diameter is 0.12 mm and the length is 6 mm, the stainless steel fibers in the other examples and comparative examples 1, 3, and 4 have a diameter of 0.2 mm and a length of 12 mm.

[0051] The raw materials for the grouting material for offshore wind turbine jackets in Comparative Example 5 are: Ordinary Portland cement (P·O 52.5) ​​850 parts cement, silica fume 100 parts, fly ash 100 parts, PC-200 type polycarboxylate superplasticizer 8 parts, DF-04 type defoamer 2 parts, plastic expansion agent 0.4 parts, sand 900 parts, water 170 parts.

[0052] The preparation methods used for the ultra-high strength offshore wind turbine jacket grouting material in the following examples and comparative examples are as follows: Examples 1-9: (1) According to the weight proportions in Table 1, cement, viscosity reducer, modified nanomaterial, water reducer, defoamer, plastic expansion agent, basalt sand and stainless steel fiber are thoroughly mixed and stirred evenly to obtain ultra-high strength offshore wind power jacket grouting dry mix. (2) According to the weight proportions in Table 1, add the dry mixture of ultra-high strength offshore wind power jacket grouting material obtained in step (1) to a forced mixer, then add water and stir for 7 minutes to obtain ultra-high strength offshore wind power jacket grouting material.

[0053] Comparative Example 1: The preparation method used in Comparative Example 1 is the same as that in Examples 1-9. The difference is that the modified nanomaterials were omitted in Comparative Example 1, and the weight parts of water-reducing agent and water were slightly reduced (see Table 1 for dosage).

[0054] Comparative Example 2: The preparation method used in Comparative Example 2 is the same as that in Examples 1-9. The difference is that, based on Example 1, the stainless steel fiber was omitted in Comparative Example 2, while the amount of basalt sand was increased and the weight parts of water-reducing agent and water were reduced (see Table 1 for the amount).

[0055] Comparative Example 3: The preparation method used in Comparative Example 3 is the same as that in Examples 1-9. The difference is that the viscosity reducing and strengthening agent is omitted in Comparative Example 3 based on Example 1. At the same time, the weight of the viscosity reducing and strengthening agent is added to the cement, and the weight of the water reducing agent and water is slightly increased (see Table 1 for dosage).

[0056] Comparative Example 4 The preparation method used in Comparative Example 4 is the same as that in Example 1, except that no modified nano-silica is added and the amounts of other components are the same. The difference is that Comparative Example 4 uses unmodified nano-silica based on Example 1.

[0057] Comparative Example 5 The preparation method of the offshore wind power jacket grouting material in Comparative Example 5 is the same as that in Examples 1-9, except that the raw materials of Comparative Example 5 are: 850 parts of ordinary Portland cement (P·O 52.5), 100 parts of silica fume, 100 parts of fly ash, 8 parts of PC-200 polycarboxylate superplasticizer, 2 parts of DF-04 defoamer, 0.4 parts of plastic expansion agent, 900 parts of sand, and 170 parts of water.

[0058] Table 1. Composition and dosage of grouting material for offshore wind turbine jacket structures in the examples and comparative cases (unit: parts by weight)

[0059] The performance of the ultra-high strength offshore wind turbine jacket grouting materials prepared in the examples and comparative examples was tested using the following methods: flowability was tested according to GB / T 50448-2015; compressive and tensile strengths were tested according to GB / T 17671-2021 Cement Mortar Strength Test Method (ISO Method); electrical flux was tested according to the electrical charge method in GB / T 50082-2009 Standard for Test Methods of Long-Term Performance and Durability of Ordinary Concrete. The strength test results are shown in Table 2.

[0060] Table 2. Strength test results of grouting materials for offshore wind turbine jacket structures in the examples and comparative cases.

[0061] As can be seen from the strength test results of the examples and comparative examples in Table 2, all technical indicators of Examples 1-9 meet the strength requirements, exhibiting good fluidity, high mechanical strength, and excellent durability. The cementitious material combination of cement and viscosity-reducing reinforcing agent in the examples has low water demand and suitable viscosity, effectively ensuring the fluidity and strength of the ultra-high strength offshore wind turbine jacket grout. The nano-silica, modified with a silane coupling agent, can effectively disperse the cement matrix and improve the density of the hardened grout, thereby enhancing strength and durability. The use of stainless steel fibers prevents rusting in the marine environment and significantly improves mechanical strength, resulting in reinforcement and toughening effects.

[0062] Comparative Example 1 did not incorporate modified nanomaterials but incorporated stainless steel fibers. The toughness of the grout was significantly enhanced, but the increase in compressive strength was limited, and the density was reduced, resulting in a decrease in resistance to chloride ion penetration, which failed to meet the requirements.

[0063] Comparative Example 2, which did not incorporate stainless steel fibers, showed a significant decrease in the mechanical strength of the grout, especially the axial tensile strength. Compared to 140MPa wind power grout products in the industry, only the compressive strength increased slightly, and it remained brittle, failing to meet the high strength and high toughness requirements of deep-sea large wind turbines for wind power grout.

[0064] In Comparative Example 3, no viscosity reducer or reinforcing agent was added. Despite increasing the amount of water and water-reducing agent, the fluidity of the grout still failed to meet the standard, and the density was reduced, resulting in a decrease in resistance to chloride ion penetration and a decline in durability.

[0065] In Comparative Example 4, the addition of unmodified nano-silica resulted in grout that failed to meet the required fluidity and lost its fluidity within 30 minutes.

[0066] Comparative Example 5 used ordinary silicate cement without adding viscosity reducer, modified nano-silica, or stainless steel fiber. The mechanical strength of the grout, especially the axial tensile strength, decreased significantly, and the compressive strength only reached 140 MPa. Furthermore, the reduced density led to a decrease in resistance to chloride ion penetration, which failed to meet the requirements.

[0067] In some specific embodiments of the present invention, to verify the long-term durability of this material under harsh conditions, the fatigue performance testing and evaluation of the specimens were conducted in accordance with the "Technical Specification for Grouting Connection of Foundation Structures in Offshore Wind Farm Engineering" (NB / T11727-2024) and related standards referenced therein. The test conditions were as follows: the grouting connection specimen was designed at a 1:8 scale, referencing the actual grouting space of one leg of the wind turbine foundation jacket in an offshore wind power project, with a design bearing capacity of 950 kN. The ultra-high strength offshore wind power jacket grout prepared in Example 4 was poured into the actual grouting space. Three grouting connection specimens were prepared in parallel, namely grouting connection specimen 1, specimen 2, and specimen 3.

[0068] See Figure 1 , Figure 2 The model test results show that the average ultimate load of specimens 1, 2 and 3 exceeds 1500kN, far exceeding the design bearing capacity of 950kN, and the average ultimate displacement exceeds 6mm. During the bearing capacity test, the grouting connected specimens went through the elastic deformation stage, the bond slip stage and the crushing failure stage, showing excellent bearing capacity.

[0069] The components were loaded with a sinusoidal waveform of constant amplitude and uniform velocity, with a trough load of 50 kN and peak loads of 40% and 50% of the component's bearing capacity. Under these 40% and 50% load amplitudes (far exceeding the conventional 35% test level), the grouting connection specimens showed no damage after 2 million fatigue tests, and the residual bearing capacity of the specimens remained above 80% after the fatigue tests. This fully demonstrates that the grouting material of this invention can effectively resist complex alternating loads in deep-sea areas, ensuring that the structure has extremely high fatigue safety reserves and reliability over a service life of up to 25 years or even longer.

[0070] In summary, the ultra-high strength offshore wind turbine jacket grouting material provided by this invention has excellent workability, ultra-high compressive strength and other technical characteristics, which meet the technical requirements of offshore wind turbine jacket grouting materials. Moreover, the preparation method is simple and it is suitable for grouting of wind turbine jackets in large-capacity wind turbines or deep-sea environments.

[0071] In the description of this specification, the references to terms such as "one embodiment / mode," "some embodiments / modes," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment / mode or example is included in at least one embodiment / mode or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment / mode or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments / modes or examples. Furthermore, without contradiction, those skilled in the art can combine and integrate the different embodiments / modes or examples described in this specification, as well as the features of different embodiments / modes or examples.

[0072] It should be noted that in this invention, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element. In this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise expressly specified.

[0073] The above description is merely a specific embodiment of the present invention, enabling those skilled in the art to understand or implement the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features of the invention herein.

Claims

1. A high-strength grouting material for offshore wind turbine jacket structures, characterized in that, By weight, it comprises: 700-900 parts cement, 150-350 parts viscosity reducer and reinforcing agent, 10-30 parts modified nanomaterials, 7-9 parts water-reducing agent, 1-2 parts defoamer, 0.1-0.5 parts plastic expansion agent, 750-850 parts fine aggregate, 120-160 parts stainless steel fiber, and 160-170 parts water; in, The modified nanomaterial is nano-silica with a silane coupling agent surface modified; The viscosity reducing and enhancing agent is composed of a viscosity reducing agent and silica fume in a weight ratio of (1~2):

1.

2. The ultra-high strength offshore wind turbine jacket grouting material as described in claim 1, characterized in that: The water-to-material ratio of the ultra-high strength offshore wind turbine jacket grout is 0.07 to 0.

097.

3. The ultra-high strength offshore wind turbine jacket grouting material as described in claim 1, characterized in that: The modified nanomaterial is prepared by a method including the following steps: drying nano-silica, mixing it with an ethanol solution of a silane coupling agent, adjusting the pH value of the mixture to an acidic range suitable for hydrolysis reaction, and heating under stirring and ultrasonic assistance to carry out a surface grafting reaction. After the reaction is complete, the modified nanomaterial is obtained by washing and drying.

4. The ultra-high strength offshore wind turbine jacket grouting material as described in claim 1, characterized in that: The silica fume contains ≥94% SiO2 and has a specific surface area ≥20000 m². 2 / kg.

5. The ultra-high strength offshore wind turbine jacket grouting material as described in claim 1, characterized in that: The cement is P·W52.5 silicate cement; and / or; The water-reducing agent is a viscosity-reducing polycarboxylate high-performance water-reducing agent with a water reduction rate ≥35%; and / or; The defoamer is a silicone-based defoamer; and / or; The plastic expander is a nitroso compound plastic expander.

6. The ultra-high strength offshore wind turbine jacket grouting material as described in claim 1, characterized in that: The fine aggregate consists of 10-20 mesh fine aggregate, 20-40 mesh fine aggregate and 40-70 mesh fine aggregate in a weight ratio of (3-4):(1.5-2.5):(2.5-3.5).

7. The ultra-high strength offshore wind turbine jacket grouting material as described in claim 6, characterized in that: The fine aggregate is one or more of the following: quartz sand, basalt sand, corundum sand, and silicon carbide sand.

8. The ultra-high strength offshore wind turbine jacket grouting material as described in claim 1, characterized in that: The stainless steel fibers have a diameter of 0.12~0.2mm and a length of 6~12mm.

9. A method for preparing an ultra-high strength offshore wind turbine jacket grout, characterized in that, The process includes the following steps: preparing raw materials according to the weight proportions described in claim 1; mixing cement, viscosity reducer, modified nanomaterials, water-reducing agent, defoamer, plastic expansion agent, fine aggregate and stainless steel fiber evenly to obtain ultra-high strength offshore wind power jacket grouting dry mix; Add the obtained dry mixture into the mixer, then add water and mix for 6 to 8 minutes to obtain ultra-high strength offshore wind power jacket grouting material.

10. The application of the ultra-high strength offshore wind turbine jacket grouting material according to any one of claims 1 to 8 in the grouting connection of offshore wind turbine structures.

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