A high-strength and high-stability ZR-6 type modified slag marine composite material and a preparation method thereof

Abstract

The application belongs to the technical field of civil engineering materials, and provides a ZR-6 type modified slag high-strength and high-stability marine composite material applied to marine pile foundation protection and a preparation method thereof. The ZR-6 type modified slag marine composite material comprises the following components in parts by weight: S105 slag powder 80-150 parts, calcium hydroxide powder 30-60 parts, ultra-fine silicon powder 10-15 parts, phosphate sulfate composite activator 12-30 parts, high-performance alloy powder (FeCoCrNiAl0.4) 5-10 parts, poly-magnesium-acrylate-silicate 5-10 parts, and anti-dispersion agent 1-5 parts. The application aims to solve the problems of low strength, high energy consumption, large loss and poor corrosion resistance of the existing marine pile foundation composite material protection technology, and the prepared ZR-6 type modified slag marine composite material has the advantages of high strength, solid waste recycling, small loss and high impermeability and crack resistance, has low cost and good curing effect, and can be well applied to offshore pile foundation solidification soil protection engineering. The application has significant economic, environmental and social benefits.

Description

Technical Field

[0001] This invention relates to the fields of civil engineering materials technology and offshore wind power engineering technology, and in particular to a ZR-6 type modified slag high-strength and high-stability marine composite material for marine pile foundation protection and its preparation method. Background Technology

[0002] In recent years, with the continuous development of the metallurgical and thermal power industries, the output of industrial solid wastes such as slag powder, ultrafine silica powder, and fly ash has been increasing, putting enormous pressure on the environment. The main methods for treating industrial solid waste include comprehensive utilization, disposal, storage, and dumping. Comprehensive utilization refers to extracting or converting usable resources and other raw materials from solid waste through recycling, processing, and recycling. Through technological innovation and policy support, the utilization rate of industrial solid waste can be further improved, realizing the transformation from "waste" to "treasure," thereby reducing environmental pressure and promoting sustainable development.

[0003] With the booming development of the offshore wind power market, the piles alter the original water flow conditions after the wind turbine foundations are built, subjecting the foundations to strong scouring. This necessitates protection and reinforcement of the foundations, leading to increasing attention being paid to underwater solidification materials for offshore wind turbine foundations. Traditional cement-based composite materials, while offering good performance, suffer from drawbacks such as low strength, high energy consumption, significant erosion, and poor corrosion resistance due to the marine environment. Furthermore, cement production generates substantial amounts of CO2 and pollutants, placing significant pressure on the environment and hindering environmental protection. From a construction perspective, composite materials should possess good flowability and overall performance that resists erosion, thereby reducing the cost of composite material protection technology and improving its effectiveness. Solid waste-based composite materials are environmentally friendly cementitious materials with great development potential, and are expected to become a new type of building material to replace cement.

[0004] Therefore, in order to address the shortcomings of existing technologies and better meet the performance and environmental protection requirements of composite materials in marine environments, and considering the problems of low strength, high energy consumption, large loss, and poor corrosion resistance of existing marine pile foundation composite material protection technologies, it is necessary to propose a modified slag high-strength, high-stability marine composite material and its preparation method for marine pile foundation protection. This will ensure reduced environmental pollution, reduced material loss, improved material stability and durability, and enhanced protection capabilities for marine pile foundations. Summary of the Invention

[0005] Objective: This invention addresses the problems of low strength, high energy consumption, large loss, and poor corrosion resistance in existing marine pile foundation composite material protection technologies. It proposes a ZR-6 type modified slag high-strength, high-stability marine composite material and its preparation method. The prepared ZR-6 type modified slag marine composite material possesses advantages such as high strength, solid waste reusability, low loss, and high impermeability and crack resistance. It is low-cost and has good solidification effect, making it well-suited for marine pile foundation solidification soil protection projects. Besides solving the aforementioned problems, it also offers significant economic, environmental, and social benefits.

[0006] A ZR-6 type modified slag high-strength, high-stability marine composite material and its preparation method, comprising the following components by weight: 80-150 parts of S105 slag powder, 30-60 parts of calcium hydroxide powder, 10-15 parts of ultrafine silica powder, 12-30 parts of phosphate-sulfate composite activator, and high-performance alloy powder (FeCoCrNiAl). 0.4 5-10 parts of magnesium polyacrylate-silicate, 5-10 parts of anti-dispersant agent, and 1-5 parts of anti-dispersant agent.

[0007] Preferably, the S105 slag powder is a byproduct of blast furnace iron ore smelting and has an activity greater than 105%; the calcium hydroxide powder (Ca(OH)2) is an inorganic compound, a white hexagonal crystalline powder with a density of 2.243 g / cm³. 3 The ultrafine silicon powder is a powder collected during the production of metallic silicon or silicon alloys, and it has a high specific surface area and pozzolanic activity.

[0008] Preferably, the phosphate-sulfate composite activator is an additive that combines the properties of phosphate and sulfate, and is composed of a mixture of sodium dihydrogen phosphate, disodium hydrogen phosphate, sodium phosphate, and calcium sulfate compounds.

[0009] Preferably, the magnesium polyacrylate-silicate is a novel admixture that combines the rapid bonding and strengthening effect of magnesium polyacrylate with the durability-improving properties of silicate. It can promote the formation of calcium silicate hydrate (CSH) gel in the early stage of hydration, improve the early strength of concrete, and the silicate component can fill the pores of concrete, reduce porosity, and improve impermeability and corrosion resistance.

[0010] Preferably, the main component of the anti-dispersant is polyacrylamide, which is a water-soluble high-molecular-weight organic compound with a high specific surface area.

[0011] Preferably, the preparation method includes the following steps:

[0012] (1) Add S105 slag powder, calcium hydroxide powder, ultrafine silica powder and phosphate sulfate composite activator to the mortar mixer according to the predetermined mixing ratio, add water and stir slowly for 3 minutes; (2) Add high performance alloy powder, magnesium polyacrylate-silicate and anti-dispersant, add water and stir slowly for 3 minutes to make the materials as uniform as possible; (3) Inject the mixed composite material into a standard mold that is uniformly coated with Vaseline, inject it in two batches and vibrate for 20 seconds; (4) Wrap the molded sample with disposable plastic wrap to prevent the moisture from evaporating quickly. Demold after 24 hours at room temperature, and cure in a standard curing box at 20±2℃ and humidity greater than 90% for 3 days, 7 days and 28 days to obtain ZR-6 type modified slag high strength and high stability marine composite material.

[0013] This invention provides a ZR-6 type modified slag high-strength, high-stability marine composite material and its preparation method, which has the following advantages compared with the prior art:

[0014] (1) The ZR-6 type modified slag high-strength and high-stability marine composite material prepared by the present invention explores the applicability of solid waste in marine engineering, solves the environmental problems caused by the large-scale use of cement in traditional cement-based materials (e.g., CO2 emissions), not only can it consume a large amount of industrial solid waste and realize the sustainable utilization of multiple solid waste resources, but it is also environmentally friendly and easy to promote, with significant economic, environmental and social benefits.

[0015] (2) In this invention, S105 slag powder, under the activation of an alkaline environment with excellent effects of quicklime, ultrafine silica powder, and phosphate-sulfate composite activators, accelerates the hydration reaction to form dense products such as ettringite and hydrated calcium silicate, resulting in high-performance alloy powder FeCoCrNiAl. 0.4 The addition of magnesium polyacrylate-silicate gives the material excellent filling and healing properties, exhibiting high strength and excellent durability. Its unconfined compressive strength can reach 13~32 MPa, and it is resistant to Cl. - Its corrosion resistance is 10 times that of ordinary composite materials, and its curing effect is excellent. It has led to the development of a protective material suitable for slag-based systems in marine environments.

[0016] (3) The ZR-6 type modified slag high-strength and high-stability marine composite material and its preparation method prepared by the present invention effectively solve the problems of low strength, high energy consumption, large loss and poor corrosion resistance of existing marine pile foundation composite material protection technology. The multi-dimensional woven structure of high-performance alloy powder overlapping in non-dense or cracked areas and the bonding performance of magnesium polyacrylate-silicate stably exert its filling and compacting effect, further enhancing the strength and stability of the material. At the same time, magnesium polyacrylate causes hydrophobic intermediates to be generated on the surface of the material, ensuring its long-term resistance to erosion and corrosion. Attached Figure Description

[0017] Figure 1 This is a flowchart illustrating the steps of a ZR-6 type modified slag high-strength, high-stability marine composite material and its preparation method for use in marine pile foundation protection, as provided in an embodiment of the present invention. Detailed Implementation

[0018] To make the objectives, features, and advantages of this application more apparent and understandable, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments. Obviously, the described embodiments are only some, not all, of the embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0019] The following will further describe a method for preparing a modified epoxy composite material suitable for marine environments in this exemplary embodiment.

[0020] like Figure 1 The process involves adding S105 slag powder, calcium hydroxide powder, ultrafine silica powder, and a phosphate-sulfate composite activator to a mortar mixer according to a predetermined mixing ratio, followed by slow mixing with water for 3 minutes. The S105 slag powder is a byproduct of iron ore smelting in a blast furnace, with an activity greater than 105%, and its main components include silicates, aluminates, calcium phosphates, and iron oxides. The quicklime, namely calcium hydroxide (Ca(OH)2), is a white, hexagonal, powdery, alkaline substance with a density of 2.243 g / cm³. 3 Adding slaked lime can increase alkalinity, which is beneficial to the formation of hydration products such as calcium silicate and SO₂. and AlO 3+ The ionization of plasma accelerates the hydration reaction, promoting structural density and improving overall integrity and impermeability. The ultrafine silica powder, primarily composed of silicon dioxide, exhibits high activity. Silica can undergo a Poisson reaction with calcium hydroxide to form CSH gel, enhancing the material's strength and durability. A phosphate-sulfate composite activator is used as the activator, with the phosphate activator primarily providing phosphorus ions (P... 5+ These ions promote hydration reactions by reacting with calcium ions to form insoluble phosphate rock or other hydration products, thereby accelerating the hydration process. Sulfate activators, on the other hand, provide sulfate ions (SO₄²⁻) to promote hydration reactions. This promotes the hydration reaction, especially with the aluminum phase, to form ettringite, a hydration product beneficial for early strength development. It further accelerates the hydration reaction of the slag powder. The reaction formula is as follows:

[0021]

[0022] As the hydration reaction continues, Al2O SO As ions are continuously consumed and particles are continuously dissolved, the amount of hydration products increases. Needle-shaped ettringite, irregular monosulfide hydrated calcium sulfoaluminate, plate-shaped calcium hydroxide, locally formed CSH gelling particles, and unhydrated particles interweave and overlap to form a dense and hard solid, exhibiting high gelling properties. With prolonged curing time, unhydrated particles continue to hydrate, making the hardened body even denser and further improving mechanical properties. Under the combined action of the alkaline environment created by calcium hydroxide powder, ultrafine silica powder, and the phosphate-sulfate composite activator, the hydration reaction of the mineral powder, the Poisson reaction of the ultrafine silica powder, and the formation of hydration products such as calcium silicate are accelerated. The formation process of hydration products is also a process of continuous particle dissolution. Hydrated products and unhydrated particles interweave and overlap, tightly bound together by molecular or chemical bonds to form a dense and hard solid, exhibiting high mechanical properties.

[0023] like Figure 1 The high-performance alloy powder, magnesium polyacrylate-silicate, and anti-dispersant are added, and water is added and stirred slowly for 3 minutes to ensure the materials are mixed as evenly as possible. The high-performance alloy powder is FeCoCrNiAl. 0.4 It can react with cross-linked polymers to form overlapping multidimensional woven structures, creating high-viscosity three-dimensional polymers, thereby enhancing structural strength. During clay solidification, high-performance alloy powder can thin the double electric layer on the particle surface, enhancing interparticle attraction. The ultrafine eutectic layers in the alloy powder effectively enhance the compressive strength, flexural strength, and crack resistance of the composite material. The magnesium polyacrylate-silicate is a novel admixture combining the rapid bonding and strengthening effect of magnesium polyacrylate with the durability-improving properties of silicate. It promotes CSH gel formation in the early stages of hydration, improving the early strength of concrete. The silicate component fills concrete pores, reducing porosity and improving impermeability and corrosion resistance. Simultaneously, magnesium polyacrylate generates hydrophobic intermediates on the material surface, and the hydration reaction's consumption of adsorbed and free water provides a favorable environment for soil strength growth in marine environments, acting like a "protective armor." This not only reduces water erosion but also improves the structure's impermeability, crack resistance, and erosion resistance. The main component of the anti-dispersant is polyacrylamide, a water-soluble high-molecular-weight organic compound with a high specific surface area. Anti-dispersants are chemical substances that prevent or reduce the dispersion or flocculation of solid particles in a suspension. They work by altering the surface charge of the particles or by providing a bridging effect, allowing the particles to attract each other and combine into larger aggregates, thereby improving the overall integrity, impermeability, crack resistance, and anti-dispersion properties of composite materials.

[0024] The following are specific embodiments of the present invention:

[0025] Example 1

[0026] The slag powder-based composite material used in this embodiment includes the following mass percentages: 80 parts of S105 slag powder, 30 parts of calcium hydroxide powder, 10 parts of ultrafine silica powder, 15 parts of phosphate sulfate composite activator, 10 parts of high-performance alloy powder, 5 parts of magnesium polyacrylate-silicate, and 3 parts of anti-dispersant agent.

[0027] Weigh the S105 slag powder, calcium hydroxide powder, ultrafine silica powder, and phosphate sulfate composite activator according to the above proportions and add them to the mortar mixer. Add water and stir slowly for 3 minutes. Then add high-performance alloy powder, magnesium polyacrylate-silicate, and anti-dispersant agent, add water and stir slowly for 3 minutes to ensure the materials are mixed as evenly as possible. Pour the mixed composite material into a standard mold that has been evenly coated with Vaseline. Pour in twice and vibrate for 20 seconds. Wrap the molded sample with disposable plastic wrap to prevent rapid evaporation of moisture. Demold after 24 hours at room temperature and cure in a standard curing chamber at 20±2℃ and humidity greater than 90% for 3 days, 7 days, and 28 days to obtain ZR-6 type modified slag high-strength and high-stability marine composite material.

[0028] In marine engineering, the basic requirements for composite materials are a compressive strength greater than 400 kPa and a flowability greater than 210 mm. However, chemical substances in seawater, such as salts (mainly sodium chloride), sulfuric acid, and carbonates, can react with the mineral components in composite materials, causing them to dissolve, decompose, or change their structure. For example, chloride ions, sulfate ions, and carbonate ions in seawater can react with calcium to form soluble calcium bicarbonate (Ca(HCO3)2), leading to the dissolution of the composite material. Therefore, considering the impact of chemical erosion in the marine environment is of great significance for protecting marine engineering structures. Therefore, after comprehensive consideration, the unconfined compressive strength test in the "Standard for Geotechnical Testing Methods" (GB / T 50123-2019), the anti-dispersion test in the "Test Procedure for Underwater Non-dispersible Concrete" (DL / T 5117-2021), the flowability test in the "Japanese Ministry of Construction JHSA313-1992 Standard", and the chloride salt immersion test in "Research on the Development of Nano-curing Agent Materials and Study on Soil Solidification Performance" (Zhang Xingchen) were used to evaluate the mechanical properties and durability of the above composite materials.

[0029] All axial stresses of the specimen should be calculated using the following formula:

[0030]

[0031] In the formula, σ—axial stress, kPa; C—calibration coefficient of the force gauge, N / 0.01 mm; R—force gauge reading, 0.01 mm; A a —Area of ​​the sample during shearing, in cm²2 .

[0032] The total loss of the sample should be calculated using the following formula:

[0033]

[0034] In the formula, L is the amount of water lost (%), m0 is the mass of the container (g), m1 is the total mass before immersion (g), and m2 is the total mass after immersion (g).

[0035] The tests were conducted according to relevant standard testing methods, and the results are shown in Table 1 below.

[0036] Table 1. Results of the experiment in Example 1

[0037] 0 - 4.5 336 0.00 7 13.1 - - 0.00 28 15.6 - - 0.01 90 17.2 - - 0.01

[0038] As shown in Table 1, the ZR-6 modified slag high-strength, high-stability marine composite material has the advantages of high strength, low loss and high durability, while meeting the fluidity requirements (greater than 210 mm) for engineering construction. In particular, the polymethyl methacrylate-silicate increases the density of the material in the process of resisting chloride ion erosion. The filling of high-performance alloy powder causes the formation of hydrophobic intermediates on the material surface, ensuring its long-term resistance to corrosion. The diffusion of chloride ions in the material is greatly slowed down. In the same amount of time, the number of chloride ions that invade is greatly reduced, which slows down the occurrence of corrosion. This also reflects that the composite material has good integrity and excellent impermeability.

[0039] Comparative Example 1

[0040] The slag powder-based composite material used in this embodiment comprises the following mass percentages: 80 parts S105 slag powder, 30 parts calcium hydroxide powder, 10 parts ultrafine silica powder, 15 parts phosphate-sulfate composite activator, 10 parts high-performance alloy powder, and 3 parts anti-dispersion agent. Magnesium polyacrylate-silicate material was not added. The effect of this material on the composite material was compared and analyzed using the same method as in Example 1. Tests were conducted according to relevant standard test methods, and the results are shown in Table 2 below.

[0041] Table 2 Comparative Example 1 Experiment Results

[0042] 0 - 6.3 351 0.00 7 12.5 - - 0.08 28 15.2 - - 0.12 90 16.3 - - 0.16

[0043] As shown in Table 2, the composite material can meet the basic requirements in engineering, but compared with Example 1, its strength is reduced, its loss is increased, and the Cl content in the material is higher. -The content is greatly increased because magnesium polyacrylate-silicate, as a new type of industrial building material, has special properties such as high mechanical strength, chemical corrosion resistance, and adsorption performance. Its influence on the performance of mineral powder-based composite materials is multifaceted. In addition to accelerating the hydration process and improving the pore structure, it can solve problems such as poor impact resistance, weak toughness and poor corrosion resistance of materials. It can also enhance the interaction force between particles and adsorb some harmful ions, thereby improving the mechanical properties and durability of composite materials.

[0044] Example 2

[0045] The importance of scour protection for offshore wind power foundations is reflected in the following aspects: (1) Ensuring the stability of wind power facilities: The foundation of offshore wind farms is usually located on the seabed. If the soil or rocks around the foundation are eroded by the scouring action of water flow, it may cause the wind turbine towers to become unstable or even collapse, thereby affecting the operational safety of the entire wind farm. (2) Reducing maintenance costs: If the offshore wind power foundation does not have good scour protection measures, it may lead to frequent maintenance and reinforcement, increasing the operating costs of the wind farm. (3) Extending the lifespan of the wind farm: Through effective scour protection measures, the wind power foundation can be protected from erosion, extending the lifespan of the wind farm and improving the return on investment. (4) Protecting the marine environment: Scour protection measures for wind power foundations can reduce interference with the seabed environment and protect the integrity of the marine ecosystem.

[0046] Therefore, it is necessary to take anti-erosion measures. This invention provides a composite material for marine pile foundation protection, which can effectively protect offshore wind turbine foundations from erosion, ensuring the stable operation of offshore wind farms and the protection of the marine environment. A flue test was used to conduct an anti-erosion test on the samples to evaluate the material's anti-erosion effect. A higher anti-erosion rate is better. To analyze the anti-erosion effect of the composite material, the following formula was used:

[0047]

[0048] In the formula: E is the erosion resistance rate of the composite material; m1 is the original mass of the sample; m2 is the maximum mass of the sample lost due to erosion under a certain water flow.

[0049] The composite material comprises the following components in parts by weight: 120 parts of S105 slag powder, 50 parts of calcium hydroxide powder, 13 parts of ultrafine silica powder, 22 parts of phosphate sulfate composite activator, 8 parts of high-performance alloy powder, 8 parts of magnesium polyacrylate-silicate, and 5 parts of anti-dispersion agent.

[0050] Multiple parallel tests revealed that the material has a 28-day compressive strength of 28.2 MPa and can withstand water flow of 4-10 m / s. It meets the requirements of marine engineering for the erosion resistance of composite materials (greater than 4 m / s), has excellent performance and low cost, and is worth promoting.

[0051] Example 3

[0052] To reflect the impact of high-performance alloy powder and magnesium polyacrylate-silicate on crack initiation and repair, unconfined compressive strength tests were conducted on composite materials containing and without S105 mineral powder, designated as Group A and Group B, respectively. The results showed that the strength of Group A samples was 3.7 times higher than that of Group B, and cracks appeared later. Subsequently, unconfined compressive strength tests were performed again on solidified soil samples with existing cracks after 7 and 28 days. Group B showed an increase in strength, as the CSH gel generated by the hydration reaction of the mineral powder repaired the cracks. The strength increase in Group A was approximately 2.1 times that of Group B. This is because magnesium polyacrylate-silicate promoted the hydration reaction in an alkaline environment, and the synergistic effect of the high-performance alloy powder and magnesium polyacrylate-silicate strengthened the connection at the crack opening. Under suitable alkaline conditions, the enhanced bonding ability of magnesium polyacrylate-silicate and the recovery of sample strength increased the self-healing ability, thus improving the durability of cracked samples. This is crucial for composite materials subjected to long-term water erosion and corrosion in marine environments.

[0053] The foregoing has shown and described the main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely preferred examples and are not intended to limit the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A ZR-6 type modified slag high-strength, high-stability marine composite material, characterized in that, The components include the following parts by weight: 80-150 parts S105 slag powder, 30-60 parts calcium hydroxide powder, 10-15 parts ultrafine silica powder, 12-30 parts phosphate-sulfate composite activator, and high-performance alloy powder FeCoCrNiAl. 0.4 5-10 parts, magnesium polyacrylate-silicate 5-10 parts, anti-dispersant 1-5 parts.

2. The ZR-6 type modified slag high-strength, high-stability marine composite material according to claim 1, characterized in that, The phosphate-sulfate composite activator is composed of a mixture of sodium dihydrogen phosphate, disodium hydrogen phosphate, sodium phosphate, and calcium sulfate compounds.

3. The ZR-6 type modified slag high-strength, high-stability marine composite material according to claim 1, characterized in that, The anti-dispersant is polyacrylamide.

4. The preparation method of a ZR-6 type modified slag high-strength, high-stability marine composite material according to claim 1, characterized in that, The preparation method includes the following steps: (1) Add S105 slag powder, calcium hydroxide powder, ultrafine silica powder and phosphate sulfate composite activator to the mortar mixer according to the predetermined mixing ratio, add water and stir slowly for 3 min; (2) Add high performance alloy powder, magnesium polyacrylate-silicate and anti-dispersant, add water and stir slowly for 3 min to make the materials as uniform as possible; (3) Inject the mixed composite material into a standard mold that is uniformly coated with Vaseline, inject it in two batches and vibrate for 20 s; (4) Wrap the molded sample with disposable plastic wrap to prevent the moisture from evaporating quickly. Under room temperature conditions, demold after 24 hours, and cure in a standard curing box at 20±2℃ and humidity greater than 90% for 3 d, 7 d and 28 d to obtain ZR-6 type modified slag high strength and high stability marine composite material.

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