Concrete for wind power tower drum and preparation method thereof

Abstract

The invention provides concrete for a wind power tower drum and a preparation method thereof, and belongs to the technical field of building materials.The preparation method comprises the following steps that methyl laurate and methyl palmitate are fully mixed, dried kieselguhr is added, vacuum impregnation is conducted, and a composite phase change material is obtained; adding the SiO2-modified ethyl cellulose into absolute ethyl alcohol, performing ultrasonic treatment, adding the composite phase-change material, mixing, stirring, filtering, and performing vacuum drying to obtain a microcapsule composite phase-change material; zinc phosphate, phosphoric acid, water, KH560 and the cobalt modified biochar material are mixed and stirred, the pretreated steel fibers are added for impregnation, ultrasonic treatment and continuous stirring are performed, and surface modified steel fibers are obtained after drying; and uniformly mixing the gravel aggregate, the cement, the surface modified steel fiber, the microcapsule composite phase change material, the mineral admixture, the auxiliary agent and the water to prepare the concrete for the wind power tower drum. The mechanical strength and the corrosion resistance of the concrete can be improved, and the freeze-thaw resistance is also improved.

Description

Technical Field

[0001] The present invention relates to the technical field of building materials, and in particular to concrete for wind power towers and a preparation method thereof. Background Art

[0002] With the increasing global demand for renewable energy, wind power has become a core component of green energy. Its high efficiency, cleanliness, and sustainability make it a crucial tool for addressing climate change and environmental issues. As a key component of wind power systems, wind turbine towers must not only withstand the immense pressure of wind but also face the test of various extreme environments. Wind towers are typically installed in locations with unique climatic conditions, such as coastal areas, high-altitude cold regions, and mountainous areas. The natural environmental factors in these areas pose significant challenges to the long-term operation and structural stability of wind turbine towers, placing high demands on the materials used in the concrete used in wind turbine towers.

[0003] Single concrete is an important structural material for wind turbine towers. Although it has certain strength, its brittle characteristics make it prone to cracks during long-term use, resulting in a decrease in durability. Especially under extreme climatic conditions, the brittleness problem of concrete becomes more and more obvious, especially in cold areas. When the concrete of wind turbine towers undergoes periodic freezing and thawing, the moisture inside them freezes in the pores and expands, and then shrinks after melting, causing cracks in the concrete, which directly affects the structural safety of the wind turbine tower. In addition, wind turbine towers are usually exposed to harsh environmental conditions and are eroded by salt spray, moisture and acidic rain for a long time. The chlorides and acidic substances in salt spray and moisture can penetrate into the concrete and corrode the steel fibers therein. After corrosion, the steel fibers will expand, and then cracks will appear in the concrete. The generation of these cracks not only reduces the compressive strength of the concrete, but also greatly reduces the physical and mechanical properties of the concrete, thereby affecting the structural stability of the wind turbine tower. In addition, wind turbine towers are exposed to wind and vibration environments for a long time. The periodic vibration of wind will generate internal stress inside the wind turbine tower structure, which also requires the concrete used for wind turbine towers to have good mechanical properties.

[0004] Therefore, it is necessary to provide a concrete for wind turbine tower and a preparation method thereof to solve the problems existing in the above-mentioned prior art. Summary of the Invention

[0005] In view of this, the present invention provides concrete for a wind turbine tower and a preparation method thereof, which can improve the mechanical strength and corrosion resistance of the concrete while improving the freeze-thaw resistance.

[0006] To achieve the above object, the present invention provides a method for preparing concrete for wind turbine towers, comprising the following steps: S1. After thoroughly mixing 20-30 parts of methyl laurate and 10-15 parts of methyl palmitate, by mass, 30 parts of dried diatomaceous earth were added, and vacuum impregnation was performed to obtain a composite phase change material; 2-5 parts of SiO2-modified ethyl cellulose were added to anhydrous ethanol, and after ultrasonic treatment, 30-40 parts of the composite phase change material were added, mixed, filtered, and vacuum dried to obtain a microcapsule composite phase change material; S2. After mixing 30 parts of zinc phosphate, 200 parts of phosphoric acid, 800 parts of water, 5-8 parts of KH560, and 0.5-3 parts of cobalt-modified biochar material, the pretreated steel fiber was added for impregnation, ultrasonically treated with continuous stirring, and dried to obtain surface-modified steel fiber; S3. By mass, mix 1000-1200 parts of sand and gravel aggregate, 800-900 parts of cement, 150-200 parts of surface-modified steel fiber, 10-30 parts of microcapsule composite phase change material, 160-200 parts of mineral admixture, 17-25 parts of additives and 150-220 parts of water to prepare concrete for wind turbine tower.

[0007] The present invention adopts encapsulation microencapsulation technology to prepare a microcapsule composite phase change material, and utilizes SiO2-modified ethyl cellulose to encapsulate diatomaceous earth loaded with methyl laurate and methyl palmitate to obtain a composite phase change material, so that the surface pores of the diatomaceous earth are finer, thereby preventing the desorption and seepage of the two phase change materials, methyl laurate and methyl palmitate, in the diatomaceous earth, thereby avoiding the loading efficiency of the diatomaceous earth and the subsequent excessive seepage of methyl laurate and methyl palmitate affecting the subsequent hydration process of concrete for wind power towers, thereby affecting the overall freeze-thaw resistance and mechanical strength; the microcapsule composite phase change material can absorb / release latent heat at the phase change point, delay overcooling or overheating of the matrix, and reduce the heat load and cold load of the entire concrete material; when the temperature decreases, the microcapsule composite phase change material releases latent heat, slows down the overall internal temperature drop rate, delays the generation of an overcooling state of the matrix, alleviates crack expansion caused by extreme temperature changes, effectively improves the overall freeze-thaw resistance, extends the building life, and reduces maintenance costs.

[0008] In addition, the nano-silica in SiO2-modified ethyl cellulose forms a rigid skeleton, which not only provides mechanical support but also disperses certain stresses, further improving the overall durability and mechanical properties. Nano-silica particles increase the density of the matrix and participate in the cement hydration process around the fibers, significantly improving the bonding properties of the overall material.

[0009] The present invention improves the overall compressive strength of concrete materials by incorporating surface-modified steel fibers, while allowing them to act as bridges for surrounding cracks in the concrete matrix, thereby reducing the generation of cracks. In addition, the present invention combines surface phosphorylation with cobalt-modified biochar materials to impart good corrosion resistance to the steel fiber surface and good bonding strength with the matrix. 2+ / Co 3+ The redox couple catalyzes the conversion of phosphates, accelerating the formation of a denser passivation layer on the surface of the steel fiber, further isolating it from corrosive substances and water erosion. In addition, the addition of cobalt-modified biochar material increases the surface roughness of the steel fiber, creating a stronger mechanical bite force between the steel fiber and the cement slurry in the concrete matrix, thereby improving the interfacial bonding strength and further reducing the occurrence of cracks.

[0010] Optionally, the composite phase change material is obtained by fully mixing methyl laurate and methyl palmitate, adding dried diatomaceous earth, and impregnating at 30°C and -0.1 MPa vacuum for 24 hours; the dried diatomaceous earth is obtained by drying diatomaceous earth at 60-70°C for 16-24 hours.

[0011] Diatomaceous earth itself has a rich microporous structure and a large specific surface area. The present invention uses a vacuum impregnation method to allow methyl laurate and methyl palmitate to fully enter and be vacuum-adsorbed in the pore structure of the diatomaceous earth, forming a composite phase change material with a high specific surface area, which can more efficiently store and release heat.

[0012] Optionally, the SiO2-modified ethyl cellulose is prepared by mixing 20 parts by mass of modified ethyl cellulose and 20-50 parts by mass of a 5% nano-silicon dioxide suspension, stirring at 50°C for 3-5 hours, filtering, washing with deionized water for 2-5 times, and vacuum drying at 60-80°C for 8-12 hours; The modified ethyl cellulose is prepared by adding 10 parts by mass of ethyl cellulose to 50 parts by mass of a 30% aqueous solution of amino-terminated hyperbranched polyamide, stirring at 100-140° C. for 6-10 hours, filtering, washing with deionized water for 2-5 times, and vacuum drying at 60-80° C. for 8-12 hours.

[0013] The present invention uses amino-terminated hyperbranched polyamide to modify ethyl cellulose, so as to achieve surface grafting of nano-silicon dioxide to form a rigid skeleton, thereby effectively reducing the influence of the composite phase change material on the overall mechanical strength.

[0014] Optionally, in step S1, the ultrasonic treatment time is 10-15 min, the mixing time is 30 min, and the vacuum drying temperature is 60-80° C. and the time is 8-12 h.

[0015] Optionally, the cobalt-modified biochar material is prepared by adding 10-15 parts by mass of rice straw fine powder and 20-40 parts by mass of cobalt sulfate heptahydrate to 100 parts by mass of deionized water, ultrasonically treating for 30-50 minutes, mixing and stirring for 1-2 hours, drying in a 60°C oven for 12-16 hours, and pyrolyzing in a muffle furnace at 600°C for 3 hours; The rice straw fine powder is obtained by washing the rice straw with water, drying it in an oven at 60° C. for 24 hours, and then processing it into fine powder using a blender.

[0016] The present invention utilizes rice straw to pyrolyze at high temperature to form biochar, realizing the utilization of renewable resources. Cobalt sulfate heptahydrate provides cobalt ions to form cobalt oxides or other compounds during the pyrolysis process, which are evenly distributed on the surface of the biochar.

[0017] Optionally, the pretreated steel fiber is prepared by washing the steel fiber with acetone and deionized water in sequence, pickling with a sulfuric acid solution with a mass concentration of 10% at 60° C. for 3 to 5 minutes, and then washing with deionized water.

[0018] The present invention washes the steel fiber to remove residual grease and surface pollutants, and the pickling provides a suitable basis for the subsequent nucleation of the phosphate coating.

[0019] Optionally, in step S2, the mixing and stirring time is 10 to 15 minutes, the immersion temperature is 40° C. to 65° C. and the time is 20 to 30 minutes, the ultrasonic treatment and continuous stirring time is 30 to 50 minutes, and the drying time is 24 to 36 hours.

[0020] Optionally, in step S3, 10 to 15 parts by mass of recycled tire rubber particles are further added and mixed with sand and gravel aggregate, cement, surface-modified steel fiber, microcapsule composite phase change material, mineral admixture, additives and water to obtain wind turbine tower concrete; The recycled tire rubber particles are produced by crushing waste rubber tires.

[0021] Preferably, the recycled tire rubber particles are black irregular particles with a particle size of about 1.0 mm.

[0022] The present invention adds recycled tire rubber particles during the preparation of concrete for wind turbine towers, thereby realizing the recycling of waste rubber tires; when the concrete is subjected to external forces, the flexibility of the recycled tire rubber particles can reduce the stress directly exerted by the external forces on the concrete matrix, thereby reducing the generation of cracks.

[0023] Optionally, the mineral admixtures are silica fume and fly ash, and the additives are polycarboxylate water reducer and sodium gluconate retarder.

[0024] The present invention also provides concrete for a wind turbine tower, which is prepared using the above-mentioned method for preparing concrete for a wind turbine tower.

[0025] The present invention adopts the above proportions to better bring into play the comprehensive performance of the concrete for wind power towers produced.

[0026] The above technical solution of the present invention includes at least the following beneficial effects: 1. The present invention utilizes microencapsulation technology to prepare a microcapsule composite phase-change material. The composite phase-change material, created by encapsulating diatomaceous earth loaded with methyl laurate and methyl palmitate using SiO2-modified ethyl cellulose, refines the pores on the diatomaceous earth's surface. This prevents desorption and leakage of the phase-change material from the diatomaceous earth, thus reducing the loading efficiency of the diatomaceous earth and the subsequent impact of excessive leakage of methyl laurate and methyl palmitate on the subsequent hydration process of the wind turbine tower concrete, which in turn affects the overall freeze-thaw resistance and mechanical strength. The material absorbs and releases latent heat at the phase transition point, regulating temperature changes, slowing cooling rates, delaying supercooling, and enhancing freeze-thaw resistance.

[0027] 2. In the present invention, nano-silica in SiO2-modified ethyl cellulose is used as a rigid skeleton to provide mechanical support, effectively disperse stress, and thus enhance the durability and mechanical properties of the composite material.

[0028] 3. The present invention improves the compressive strength of concrete and reduces crack formation by incorporating surface-modified steel fibers. At the same time, it combines cobalt-modified biochar materials with phosphorylation treatment to give the steel fibers good corrosion resistance and bonding strength. Cobalt ions promote phosphate conversion, accelerate the formation of a passivation layer on the surface of the steel fibers, enhance corrosion resistance, improve interfacial bonding, and reduce crack formation. DETAILED DESCRIPTION

[0029] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. The described embodiments are only part of the embodiments of the present invention. All other embodiments obtained by ordinary technicians in this field based on the described embodiments of the present invention are within the scope of protection of the present invention.

[0030] Example 1 60 parts of diatomaceous earth were dried at 70°C for 24 hours to obtain dried diatomaceous earth; 30 parts of methyl laurate and 15 parts of methyl palmitate were fully mixed, and then 30 parts of dried diatomaceous earth were added, and the mixture was immersed at 30°C and -0.1MPa vacuum for 24 hours to obtain a composite phase change material; 10 parts of ethyl cellulose were added to 50 parts of a 30% aqueous solution of amino-terminated hyperbranched polyamide, and the mixture was stirred at 130°C for 8 hours, filtered, washed with deionized water 4 times, and vacuum dried at 70°C for 9 hours to obtain a modified ethyl cellulose. Cellulose; 20 parts of modified ethyl cellulose and 50 parts of nano-silica suspension with a mass concentration of 5% were mixed, stirred at 50°C for 4 hours, filtered, washed with deionized water 5 times, and vacuum dried at 70°C for 10 hours to obtain SiO2-modified ethyl cellulose; 5 parts of SiO2-modified ethyl cellulose were added to 100 parts of anhydrous ethanol and ultrasonically treated for 15 minutes, and then 40 parts of composite phase change material were added and mixed for 30 minutes. The mixture was filtered and vacuum dried at 80°C for 12 hours to obtain a microcapsule composite phase change material.

[0031] The rice straw was cleaned with water, dried in an oven at 60°C for 24 hours, and processed into fine powder with a blender to obtain rice straw fine powder; 10 parts of rice straw fine powder and 40 parts of cobalt sulfate heptahydrate were added to 100 parts of deionized water, ultrasonically treated for 50 minutes, mixed and stirred for 2 hours, dried in an oven at 60°C for 16 hours, and pyrolyzed in a muffle furnace at 600°C for 3 hours to obtain cobalt-modified biochar material; the steel fiber was rinsed with acetone and deionized water in turn, and heated at 60°C with a mass concentration of The pretreated steel fiber was pickled with a 10% sulfuric acid solution for 5 minutes and rinsed with deionized water to obtain a pretreated steel fiber; 30 parts of zinc phosphate, 200 parts of phosphoric acid, 800 parts of water, 8 parts of KH560 (CAS: 2530-83-8), and 3 parts of cobalt-modified biochar materials were mixed and stirred for 15 minutes, and then the pretreated steel fiber was added and immersed at 65°C for 25 minutes, ultrasonically treated and continuously stirred for 50 minutes, and then dried at room temperature for 30 hours to obtain a surface-modified steel fiber.

[0032] 1200 parts of sand and gravel aggregate, 15 parts of recycled tire rubber particles, 900 parts of cement, 200 parts of surface-modified steel fiber, 30 parts of microcapsule composite phase change material, 140 parts of silica fume, 60 parts of fly ash, 15 parts of polycarboxylic acid water reducer, 10 parts of sodium gluconate retarder and 220 parts of water are mixed and stirred uniformly to prepare concrete for wind turbine towers; among them, the recycled tire rubber particles are made by crushing waste rubber tires, are black irregular particles, and have a particle size of about 1.0 mm.

[0033] Example 2 60 parts of diatomaceous earth were dried at 65°C for 24 hours to obtain dried diatomaceous earth; 20 parts of methyl laurate and 10 parts of methyl palmitate were fully mixed, and then 30 parts of dried diatomaceous earth were added, and the mixture was immersed at 30°C and -0.1MPa vacuum for 24 hours to obtain a composite phase change material; 10 parts of ethyl cellulose were added to 50 parts of a 30% aqueous solution of amino-terminated hyperbranched polyamide, mixed and stirred at 100°C for 6 hours, filtered, washed twice with deionized water, and vacuum dried at 65°C for 10 hours to obtain a modified ethyl cellulose. SiO2-modified ethyl cellulose was prepared by mixing 20 parts of modified ethyl cellulose and 30 parts of a nano-silica suspension with a mass concentration of 5%, stirring at 50°C for 3.5 hours, filtering, washing with deionized water three times, and vacuum drying at 65°C for 8 hours to obtain SiO2-modified ethyl cellulose; 4 parts of SiO2-modified ethyl cellulose were added to 100 parts of anhydrous ethanol and ultrasonically treated for 15 minutes, and then 40 parts of a composite phase change material were added and stirred for 30 minutes. The mixture was filtered and vacuum dried at 80°C for 12 hours to obtain a microcapsule composite phase change material.

[0034] The rice straw was cleaned with water, dried in an oven at 60°C for 24 hours, and processed into fine powder with a blender to obtain rice straw fine powder; 15 parts of rice straw fine powder and 40 parts of cobalt sulfate heptahydrate were added to 100 parts of deionized water, ultrasonically treated for 50 minutes, mixed and stirred for 2 hours, dried in an oven at 60°C for 16 hours, and pyrolyzed in a muffle furnace at 600°C for 3 hours to obtain cobalt-modified biochar material; the steel fiber was rinsed with acetone and deionized water in sequence, and heated at 60°C with a mass concentration of 1.5-2.0%. The pretreated steel fiber was prepared by pickling with 10% sulfuric acid solution for 5 minutes and rinsing with deionized water. 30 parts of zinc phosphate, 200 parts of phosphoric acid, 800 parts of water, 8 parts of KH560 (CAS: 2530-83-8), and 1.5 parts of cobalt-modified biochar material were mixed and stirred for 15 minutes, and then the pretreated steel fiber was added and immersed at 65°C for 30 minutes. The steel fiber was ultrasonically treated and continuously stirred for 50 minutes, and then dried at room temperature for 36 hours to obtain the surface-modified steel fiber.

[0035] 1200 parts of sand and gravel aggregate, 15 parts of recycled tire rubber particles, 900 parts of cement, 200 parts of surface-modified steel fiber, 20 parts of microcapsule composite phase change material, 120 parts of silica fume, 50 parts of fly ash, 15 parts of polycarboxylic acid water reducer, 7 parts of sodium gluconate retarder and 200 parts of water are mixed and stirred uniformly to prepare concrete for wind turbine towers; among them, the recycled tire rubber particles are made by crushing waste rubber tires, are black irregular particles, and have a particle size of about 1.0 mm.

[0036] Example 3 60 parts of diatomaceous earth were dried at 70°C for 16 hours to obtain dried diatomaceous earth; 28 parts of methyl laurate and 15 parts of methyl palmitate were fully mixed, and then 30 parts of dried diatomaceous earth were added, and the mixture was immersed at 30°C and -0.1MPa vacuum for 24 hours to obtain a composite phase change material; 10 parts of ethyl cellulose were added to 50 parts of a 30% aqueous solution of amino-terminated hyperbranched polyamide, mixed and stirred at 100°C for 6 hours, filtered, washed twice with deionized water, and vacuum dried at 70°C for 8 hours to obtain a modified ethyl cellulose. Cellulose; 20 parts of modified ethyl cellulose and 20 parts of nano-silica suspension with a mass concentration of 5% were mixed, stirred at 50°C for 3 hours, filtered, washed twice with deionized water, and vacuum dried at 60°C for 8 hours to obtain SiO2-modified ethyl cellulose; 2 parts of SiO2-modified ethyl cellulose were added to 100 parts of anhydrous ethanol and ultrasonically treated for 10 minutes, and then 30 parts of composite phase change material were added and mixed for 30 minutes. The mixture was filtered and vacuum dried at 60°C for 12 hours to obtain a microcapsule composite phase change material.

[0037] The rice straw was cleaned with water, dried in an oven at 60°C for 24 hours, and processed into fine powder with a blender to obtain rice straw fine powder; 12 parts of rice straw fine powder and 25 parts of cobalt sulfate heptahydrate were added to 100 parts of deionized water, ultrasonically treated for 30 minutes, mixed and stirred for 1 hour, dried in an oven at 60°C for 12 hours, and pyrolyzed in a muffle furnace at 600°C for 3 hours to obtain cobalt-modified biochar material; the steel fiber was rinsed with acetone and deionized water in sequence, and quenched with a mass concentration of 1% at 60°C. The pretreated steel fiber was prepared by pickling with 10% sulfuric acid solution for 4 minutes and rinsing with deionized water. 30 parts of zinc phosphate, 200 parts of phosphoric acid, 800 parts of water, 5 parts of KH560 (CAS: 2530-83-8), and 0.5 parts of cobalt-modified biochar material were mixed and stirred for 10 minutes, and then the pretreated steel fiber was added and immersed at 45°C for 20 minutes. Ultrasonic treatment was carried out and continuous stirring was continued for 30 minutes, and then dried at room temperature for 24 hours to obtain the surface-modified steel fiber.

[0038] 1000 parts of sand and gravel aggregate, 10 parts of recycled tire rubber particles, 800 parts of cement, 150 parts of surface-modified steel fiber, 12 parts of microcapsule composite phase change material, 100 parts of silica fume, 40 parts of fly ash, 12 parts of polycarboxylic acid water reducer, 5 parts of sodium gluconate retarder and 150 parts of water are mixed and stirred uniformly to prepare concrete for wind turbine towers; among them, the recycled tire rubber particles are made by crushing waste rubber tires, are black irregular particles, and have a particle size of about 1.0 mm.

[0039] Example 4 60 parts of diatomaceous earth were dried at 70°C for 18 hours to obtain dried diatomaceous earth; 25 parts of methyl laurate and 15 parts of methyl palmitate were fully mixed, 30 parts of dried diatomaceous earth were added, and the mixture was immersed at 30°C and -0.1MPa vacuum for 24 hours to obtain a composite phase change material; 10 parts of ethyl cellulose were added to 50 parts of a 30% aqueous solution of amino-terminated hyperbranched polyamide, the mixture was mixed and stirred at 120°C for 8 hours, filtered, washed with deionized water 3 times, and vacuum dried at 65°C for 10 hours to obtain a modified ethyl cellulose. cellulose; 20 parts of modified ethyl cellulose were added to 35 parts of a nano-silica suspension with a mass concentration of 5%, stirred at 50°C for 4.5 hours, filtered, washed with deionized water 4 times, and vacuum dried at 75°C for 11 hours to obtain SiO2-modified ethyl cellulose; 3 parts of SiO2-modified ethyl cellulose were added to 100 parts of anhydrous ethanol and ultrasonically treated for 12 minutes, and then 38 parts of composite phase change material were added and mixed for 30 minutes. The mixture was filtered and vacuum dried at 75°C for 10 hours to obtain a microcapsule composite phase change material.

[0040] The rice straw was cleaned with water, dried in an oven at 60°C for 24 hours, and processed into fine powder with a blender to obtain rice straw fine powder; 14 parts of rice straw fine powder and 40 parts of cobalt sulfate heptahydrate were added to 100 parts of deionized water, ultrasonically treated for 40 minutes, mixed and stirred for 2 hours, dried in an oven at 60°C for 15 hours, and pyrolyzed in a muffle furnace at 600°C for 3 hours to obtain cobalt-modified biochar material; the steel fiber was rinsed with acetone and deionized water in turn, and heated at 60°C with a mass concentration of The pretreated steel fiber was pickled with a 10% sulfuric acid solution for 4 minutes and rinsed with deionized water to obtain a pretreated steel fiber; 30 parts of zinc phosphate, 200 parts of phosphoric acid, 800 parts of water, 7 parts of KH560 (CAS: 2530-83-8), and 3 parts of cobalt-modified biochar materials were mixed and stirred for 12 minutes, and then the pretreated steel fiber was added and immersed at 60°C for 25 minutes, ultrasonically treated and continuously stirred for 45 minutes, and then dried at room temperature for 30 hours to obtain a surface-modified steel fiber.

[0041] 1,100 parts of sand and gravel aggregate, 12 parts of recycled tire rubber particles, 820 parts of cement, 170 parts of surface-modified steel fiber, 15 parts of microcapsule composite phase change material, 110 parts of silica fume, 50 parts of fly ash, 12 parts of polycarboxylic acid water reducer, 6 parts of sodium gluconate retarder, and 170 parts of water were mixed and stirred evenly to prepare concrete for wind turbine towers; among them, the recycled tire rubber particles were made by crushing waste rubber tires, and were black irregular particles with a particle size of about 1.0 mm.

[0042] Example 5 65 parts of diatomaceous earth were dried at 60°C for 24 hours to obtain dried diatomaceous earth; 25 parts of methyl laurate and 10 parts of methyl palmitate were fully mixed, and then 30 parts of dried diatomaceous earth were added, and the mixture was immersed at 30°C and -0.1MPa vacuum for 24 hours to obtain a composite phase change material; 10 parts of ethyl cellulose were added to 50 parts of a 30% aqueous solution of amino-terminated hyperbranched polyamide, mixed and stirred at 140°C for 10 hours, filtered, washed with deionized water 4 times, and vacuum dried at 80°C for 12 hours to obtain a modified ethyl cellulose. cellulose; 20 parts of modified ethyl cellulose and 50 parts of nano-silica suspension with a mass concentration of 5% were mixed, stirred at 50°C for 5 hours, filtered, washed three times with deionized water, and vacuum dried at 80°C for 12 hours to obtain SiO2-modified ethyl cellulose; 5 parts of SiO2-modified ethyl cellulose were added to 100 parts of anhydrous ethanol and ultrasonically treated for 12 minutes, and then 35 parts of composite phase change material were added and stirred for 30 minutes. The mixture was filtered and vacuum dried at 70°C for 12 hours to obtain a microcapsule composite phase change material.

[0043] The rice straw was cleaned with water, dried in an oven at 60°C for 24 hours, and processed into fine powder with a blender to obtain rice straw fine powder; 12 parts of rice straw fine powder and 40 parts of cobalt sulfate heptahydrate were added to 100 parts of deionized water, ultrasonically treated for 40 minutes, mixed and stirred for 1.5 hours, dried in an oven at 60°C for 16 hours, and pyrolyzed in a muffle furnace at 600°C for 3 hours to obtain cobalt-modified biochar material; the steel fiber was rinsed with acetone and deionized water in turn, and heated at 60°C with a mass concentration of The pretreated steel fiber was pickled with a 10% sulfuric acid solution for 5 minutes and rinsed with deionized water to obtain a pretreated steel fiber; 30 parts of zinc phosphate, 200 parts of phosphoric acid, 800 parts of water, 8 parts of KH560 (CAS: 2530-83-8), and 2.5 parts of cobalt-modified biochar material were mixed and stirred for 13 minutes, and then the pretreated steel fiber was added and immersed at 65°C for 25 minutes, ultrasonically treated and continuously stirred for 35 minutes, and then dried at room temperature for 28 hours to obtain a surface-modified steel fiber.

[0044] 1200 parts of sand and gravel aggregate, 10 parts of recycled tire rubber particles, 800 parts of cement, 160 parts of surface-modified steel fiber, 20 parts of microcapsule composite phase change material, 120 parts of silica fume, 60 parts of fly ash, 10 parts of polycarboxylic acid water reducer, 10 parts of sodium gluconate retarder and 220 parts of water are mixed and stirred uniformly to prepare concrete for wind turbine towers; among them, the recycled tire rubber particles are made by crushing waste rubber tires, are black irregular particles, and have a particle size of about 1.0 mm.

[0045] Example 6 60 parts of diatomaceous earth were dried at 60°C for 16 hours to obtain dried diatomaceous earth; 20 parts of methyl laurate and 15 parts of methyl palmitate were fully mixed, and then 30 parts of dried diatomaceous earth were added, and the mixture was immersed at 30°C and -0.1MPa vacuum for 24 hours to obtain a composite phase change material; 10 parts of ethyl cellulose were added to 50 parts of a 30% aqueous solution of amino-terminated hyperbranched polyamide, mixed and stirred at 100°C for 6 hours, filtered, washed twice with deionized water, and vacuum dried at 60°C for 8 hours to obtain a modified ethyl cellulose. cellulose; 20 parts of modified ethyl cellulose and 20 parts of nano-silica suspension with a mass concentration of 5% were mixed, stirred at 50°C for 3 hours, filtered, washed twice with deionized water, and vacuum dried at 60°C for 8 hours to obtain SiO2-modified ethyl cellulose; 2 parts of SiO2-modified ethyl cellulose were added to 100 parts of anhydrous ethanol and ultrasonically treated for 10 minutes, and then 30 parts of composite phase change material were added and mixed for 30 minutes. The mixture was filtered and vacuum dried at 60°C for 8 hours to obtain a microcapsule composite phase change material.

[0046] The rice straw was cleaned with water, dried in an oven at 60°C for 24 hours, and processed into fine powder with a blender to obtain rice straw fine powder; 10 parts of rice straw fine powder and 20 parts of cobalt sulfate heptahydrate were added to 100 parts of deionized water, ultrasonically treated for 30 minutes, mixed and stirred for 1 hour, dried in an oven at 60°C for 12 hours, and pyrolyzed in a muffle furnace at 600°C for 3 hours to obtain cobalt-modified biochar material; the steel fiber was rinsed with acetone and deionized water in sequence, and quenched with a mass concentration of 1% at 60°C. The pretreated steel fiber was prepared by pickling with 10% sulfuric acid solution for 3 minutes and rinsing with deionized water. 30 parts of zinc phosphate, 200 parts of phosphoric acid, 800 parts of water, 5 parts of KH560 (CAS: 2530-83-8), and 0.5 parts of cobalt-modified biochar material were mixed and stirred for 12 minutes, and then the pretreated steel fiber was added and immersed at 40°C for 25 minutes. The steel fiber was ultrasonically treated and continuously stirred for 30 minutes, and then dried at room temperature for 24 hours to obtain the surface-modified steel fiber.

[0047] 1000 parts of sand and gravel aggregate, 900 parts of cement, 150 parts of surface modified steel fiber, 10 parts of microcapsule composite phase change material, 140 parts of silica fume, 40 parts of fly ash, 15 parts of polycarboxylic acid water reducer, 5 parts of sodium gluconate retarder and 160 parts of water were mixed and stirred uniformly to prepare concrete for wind turbine tower.

[0048] The present invention also carried out comparative examples and related tests.

[0049] Comparative Example 1 Compared with Example 1, the only difference is that no microcapsule composite phase change material is added, and other preparation methods and components are completely the same, and finally concrete for wind turbine towers is prepared.

[0050] Comparative Example 2 Compared with Example 1, the only difference is that the composite phase change material is directly added instead of the microcapsule composite phase change material. The other preparation methods and components are completely the same, and finally concrete for wind turbine towers is prepared.

[0051] Comparative Example 3 Compared with Example 1, the only difference is that steel fibers are directly added instead of surface-modified steel fibers. Other preparation methods and components are completely the same, and concrete for wind turbine towers is finally prepared.

[0052] Performance testing The mechanical properties of the concrete for wind turbine towers prepared in Examples 1 to 6 and Comparative Examples 1 to 3 were tested. According to the national standard GB / T50081-2019 Test method for physical and mechanical properties of concrete, the compressive strength and flexural strength tests of the samples prepared in Examples 1 to 6 and Comparative Examples 1 to 3 were performed to evaluate their mechanical properties. The specific mechanical property test results are shown in Table 1.

[0053] Table 1: Mechanical properties test table

[0054] As shown in Table 1, the wind turbine tower concrete produced in Examples 1-6 of the present invention all meet the ultra-high strength (C80 grade) requirements for wind turbine towers, and their mechanical properties are significantly superior to those of Comparative Examples 2 and 3. Compared to Comparative Example 2, Example 1 significantly improves its overall mechanical properties due to the use of a microcapsule composite phase change material instead of a composite phase change material. The lack of surface modification of the steel fibers in Comparative Example 3 also significantly impacts its mechanical properties. The lack of recycled tire rubber particles in Example 6 results in slightly lower mechanical strength than in Examples 1-5.

[0055] The wind turbine tower concrete prepared in Examples 1 to 6 and Comparative Examples 1 to 3 was poured into a mold, vibrated and molded, and moisturized. After demolding for 24 hours, the concrete was moved to a standard curing room and cured for 90 days to prepare a sample. Referring to the frost resistance test method in the national standard GB / T4111-2013 Test method for concrete blocks and bricks, the samples prepared using Examples 1 to 6 and Comparative Examples 1 to 3 were subjected to 5 freeze-thaw cycles, and the damage on the surface of the samples was inspected. The compressive strength after the freeze-thaw cycle was tested to calculate the compressive strength loss rate (%) using formula (I) to evaluate the freeze-thaw resistance of the samples.

[0056] (I) In formula (I), , is the compressive strength of the sample before freeze-thaw cycles, is the compressive strength of the sample after freeze-thaw cycles. The specific freeze-thaw resistance test results of the sample's apparent state and compressive strength loss rate (%) after freeze-thaw cycles are shown in Table 2.

[0057] Table 2: Freeze-thaw resistance test table

[0058] As can be seen from Table 2, the samples made of concrete for wind turbine towers of the present invention performed well after 5 freeze-thaw cycles, and no obvious peeling appeared on the surface. However, problems occurred in Comparative Examples 1 to 3 after the freeze-thaw cycles, and the compressive strength loss rate increased significantly. Among them, since Comparative Example 1 did not add microcapsule composite phase change material, the freeze-thaw resistance was significantly reduced.

[0059] Salt spray corrosion tests were conducted on samples of wind turbine tower concrete prepared using Examples 1-6 and Comparative Examples 1-3 after curing. The corrosion tests were conducted at room temperature. The salt spray protocol was as follows: artificial seawater at a 20-fold concentration was prepared and sprayed onto the concrete surface once every 6 hours, four times a day, for a 90-day test period. The degree of surface damage and deterioration of the test samples was observed, and the mass loss rate (%) of the samples was calculated using Formula (II) to evaluate the corrosion resistance of the samples. The composition of the artificial seawater at a 20-fold concentration used in the tests is shown in Table 3.

[0060] Table 3: Composition of artificial seawater at 20 times the concentration

[0061] (II) In formula (II), K m is the mass loss rate of the sample (%), m 0 is the initial mass of the sample, m 1 is the mass of the sample after the 90-day salt spray corrosion test. The specific corrosion resistance test results of the sample's apparent state and mass loss rate (%) after the 90-day salt spray corrosion test are shown in Table 4.

[0062] Table 4: Corrosion resistance test table

[0063] Table 4 shows that the samples cured with the wind turbine tower concrete prepared according to the present invention still performed well after a 90-day salt spray corrosion test, demonstrating that the wind turbine tower concrete prepared according to the present invention has excellent corrosion resistance. Comparative Examples 2 and 3 exhibited significantly reduced corrosion resistance, with both exhibiting cracks after the salt spray corrosion test. In Comparative Example 3, due to the lack of steel fiber modification, the steel fibers rusted and expanded, resulting in internal cracking and overall material flaking. This significantly increased mass loss and significantly reduced corrosion resistance.

[0064] In summary, the concrete for wind turbine towers prepared by the present invention has made significant progress in mechanical properties, freeze-thaw resistance and corrosion resistance, and can be better applied to wind turbine tower materials to increase the service life of wind turbine towers.

[0065] The above is a preferred embodiment of the present invention. Those skilled in the art may make several improvements and modifications without departing from the principles of the present invention. These improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing concrete for wind turbine tower, characterized in that: The steps include: S1. After thoroughly mixing 20-30 parts of methyl laurate and 10-15 parts of methyl palmitate, by mass, 30 parts of dried diatomaceous earth were added, and vacuum impregnation was performed to obtain a composite phase change material; 2-5 parts of SiO2-modified ethyl cellulose were added to anhydrous ethanol, and after ultrasonic treatment, 30-40 parts of the composite phase change material were added, mixed, filtered, and vacuum dried to obtain a microcapsule composite phase change material; S2. After mixing 30 parts of zinc phosphate, 200 parts of phosphoric acid, 800 parts of water, 5-8 parts of KH560, and 0.5-3 parts of cobalt-modified biochar material, the pretreated steel fiber was added for impregnation, ultrasonically treated with continuous stirring, and dried to obtain surface-modified steel fiber; S3. By mass, mix 1000-1200 parts of sand and gravel aggregate, 800-900 parts of cement, 150-200 parts of surface-modified steel fiber, 10-30 parts of microcapsule composite phase change material, 140-200 parts of mineral admixture, 17-25 parts of additives and 150-220 parts of water to prepare concrete for wind turbine tower.

2. The method for preparing concrete for wind turbine tower according to claim 1, characterized in that: The composite phase change material is obtained by fully mixing methyl laurate and methyl palmitate, adding dried diatomaceous earth, and impregnating at 30° C. and -0.1 MPa vacuum for 24 hours; the dried diatomaceous earth is obtained by drying diatomaceous earth at 60-70° C. for 16-24 hours.

3. The method for preparing concrete for wind turbine tower according to claim 1, characterized in that: The SiO2-modified ethyl cellulose is prepared by mixing 20 parts by mass of modified ethyl cellulose and 20-50 parts by mass of a 5% nano-silicon dioxide suspension, stirring at 50°C for 3-5 hours, filtering, washing with deionized water for 2-5 times, and vacuum drying at 60-80°C for 8-12 hours. The modified ethyl cellulose is prepared by adding 10 parts of ethyl cellulose to 50 parts of an aqueous solution of amino-terminated hyperbranched polyamide with a mass concentration of 30%, mixing and stirring at 100-140° C. for 6-10 hours, filtering, washing with deionized water for 2-5 times, and vacuum drying at 60-80° C. for 8-12 hours.

4. The method for preparing concrete for wind turbine tower according to claim 1, characterized in that: In step S1, the ultrasonic treatment time is 10-15 minutes, the mixing time is 30 minutes, and the vacuum drying temperature is 60-80° C. and the time is 8-12 hours.

5. The method for preparing concrete for wind turbine tower according to claim 1, characterized in that: The cobalt-modified biochar material is prepared by adding 10-15 parts by mass of rice straw powder and 20-40 parts by mass of cobalt sulfate heptahydrate to 100 parts by mass of deionized water, ultrasonically treating for 30-50 minutes, mixing and stirring for 1-2 hours, drying in a 60°C oven for 12-16 hours, and pyrolyzing in a muffle furnace at 600°C for 3 hours. The rice straw fine powder is obtained by washing the rice straw with water, drying it in an oven at 60° C. for 24 hours, and then processing it into fine powder using a blender.

6. The method for preparing concrete for wind turbine tower according to claim 1, characterized in that: The pretreated steel fiber is prepared by sequentially washing the steel fiber with acetone and deionized water, pickling it with a sulfuric acid solution with a mass concentration of 10% at 60° C. for 3 to 5 minutes, and then washing it with deionized water.

7. The method for preparing concrete for wind turbine tower according to claim 1, characterized in that: In step S2, the mixing and stirring time is 10-15 minutes, the immersion temperature is 40° C.-65° C. and the time is 20-30 minutes, the ultrasonic treatment and continuous stirring time is 30-50 minutes, and the drying time is 24-36 hours.

8. The method for preparing concrete for wind turbine tower according to claim 1, characterized in that: In step S3, 10 to 15 parts by mass of recycled tire rubber particles are added, mixed with sand and gravel aggregate, cement, surface-modified steel fiber, microcapsule composite phase change material, mineral admixture, additives and water, and stirred uniformly to prepare concrete for wind turbine towers; The recycled tire rubber particles are produced by crushing waste rubber tires.

9. The method for preparing concrete for wind turbine tower according to claim 1, characterized in that: The mineral admixtures are silica fume and fly ash, and the additives are polycarboxylate water reducer and sodium gluconate retarder.

10. A concrete for a wind power tower, characterized in that: The concrete is prepared by the method for preparing concrete for a wind turbine tower according to any one of claims 1 to 9.

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