A type of concrete for wind turbine towers in frigid regions and its preparation method

Abstract

This invention discloses a type of concrete for wind turbine towers in frigid regions and its preparation method, relating to the field of concrete technology. This invention discloses a type of concrete for wind turbine towers in frigid regions, comprising the following components by weight: 424-428 parts cement, 106-110 parts mineral powder, 32-36 parts silica fume, 652-656 parts fine aggregate, 1065-1069 parts coarse aggregate, 9-9.2 parts water-reducing agent, 0.11-0.13 parts air-entraining agent, 62-66 parts ultrafine fly ash, 149-153 parts water, and 1-2 parts composite polyacrylonitrile fiber; the composite polyacrylonitrile fiber is obtained by mixing triallylamine, dodecyl acrylate, polyacrylonitrile, and magnesium aluminum silicate; the air-entraining agent is a maleic rosin-based twin air-entraining agent; the mineral powder is P8000 type ultrafine mineral powder produced by Jinan Luxin New Building Materials Co., Ltd.; the silica fume has a content >90% and a specific surface area >15m³. 2 / g silica fume; the concrete prepared by this invention for wind turbine towers in frigid regions has good compressive strength and frost resistance.

Description

Technical Field

[0001] This invention relates to the field of concrete technology, specifically to a type of concrete for wind turbine towers in frigid regions and its preparation method. Background Technology

[0002] C80 pumped concrete is safe and reliable, characterized by high fluidity, moderate cohesion, and good water retention. Compared to ordinary concrete, it exhibits higher strength, higher density, higher elastic modulus, and higher durability. The tensioning of steel strands in wind turbine concrete towers requires high rigidity and minimal deformation in the tower sections. C80 concrete allows for the application of greater prestress and earlier prestressing, fully meeting these requirements. Furthermore, it possesses good electrical conductivity and frost resistance, resulting in favorable technical and economic indicators. Therefore, it is widely used in the manufacture of concrete wind turbine towers in frigid regions.

[0003] However, concrete wind turbine towers prepared with C80 pumped concrete in frigid regions have the same inherent disadvantages as concrete. In frigid conditions, the degree of cement hydration in the concrete decreases, leading to an increase in porosity and microcracks in the hardened concrete, resulting in poor frost resistance and reduced compressive strength.

[0004] Therefore, there is an urgent need to develop a type of concrete for wind turbine towers in frigid regions to solve the above problems. Summary of the Invention

[0005] To address the problems existing in the prior art, this invention provides a concrete for wind turbine towers in frigid regions, comprising the following components by weight: 424-428 parts cement, 106-110 parts mineral powder, 32-36 parts silica fume, 652-656 parts fine aggregate, 1065-1069 parts coarse aggregate, 9-9.2 parts water-reducing agent, 0.11-0.13 parts air-entraining agent, 62-66 parts ultrafine fly ash, 149-153 parts water, and 1-2 parts composite polyacrylonitrile fiber; the composite polyacrylonitrile fiber is obtained by mixing triallylamine, dodecyl acrylate, polyacrylonitrile, and magnesium aluminum silicate; the air-entraining agent is a maleic rosin-based twin air-entraining agent.

[0006] Preferably or optionally, the cement is P.O52.5 low-alkali ordinary Portland cement.

[0007] Preferably or optionally, the mineral powder is P8000 type ultrafine mineral powder produced by Jinan Luxin New Building Materials Co., Ltd.

[0008] Preferably or optionally, the silica fume has a content >90% and a specific surface area >15m³. 2 / g of silica fume.

[0009] Preferably or optionally, the fine aggregate is natural river sand with a fineness modulus of 2.6 to 2.9, a mud content of ≤1.5%, and a mud lump content of no more than 0.2%.

[0010] Preferably or optionally, the coarse aggregate is selected from hard, continuously graded crushed stone of 5-20mm produced by an impact crusher, with a crushing index of no more than 5%, a needle-like and flaky content of no more than 7%, a mud content of no more than 0.5%, a mud lump content of no more than 0.2%, and an apparent density ≥1450kg / m³. 3 .

[0011] Preferably or optionally, the ultrafine fly ash is M800 type ultrafine fly ash produced by Dongshi Mineral Products Processing Plant in Lingshou County, Hebei Province, wherein the silica content of the ultrafine fly ash is 52.4%.

[0012] Preferably or optionally, the water-reducing agent is sodium lignosulfonate water-reducing agent.

[0013] A preferred or optional method for preparing concrete for wind turbine towers in frigid regions includes the following preparation steps:

[0014] S1. Ingredients: The following components shall be used for batching: 424-428 parts cement, 106-110 parts mineral powder, 32-36 parts silica fume, 652-656 parts fine aggregate, 1065-1069 parts coarse aggregate, 9-9.2 parts water-reducing agent, 0.11-0.13 parts air-entraining agent, 62-66 parts ultrafine fly ash, 149-153 parts water, and 1-2 parts composite polyacrylonitrile fiber;

[0015] S2. Preliminary Mixture: Stir the cement and composite polyacrylonitrile fiber from step S1 at 120-180 rpm for 10-20 seconds to obtain the preliminary mixture.

[0016] S3. Secondary mixing: Place the fine aggregate and coarse aggregate from step S1 into a mixing container and mix at 120-180 rpm for 10-20 seconds. Then add the initial mixture obtained in step S2 and continue mixing for 10-20 seconds to obtain the secondary mixture.

[0017] S4. Mixing: Mix 45% of the water prepared in step S1 and 0.32 to 0.34 times the mass of the sodium hydroxide prepared in step S1 at 120 to 180 rpm for 20 to 30 minutes to obtain a mixed solution;

[0018] S5. Three-stage mixing: Add mineral powder, silica fume, and the remaining water to the secondary mixture obtained in step S3, and stir at 120-180 rpm for 35-45 seconds to obtain the tertiary mixture;

[0019] S6. Four-stage mixing: Add water-reducing agent and ultrafine fly ash to the three-stage mixture obtained in step S5, and stir at 120-180 rpm for 3-5 minutes. Then add the mixed solution obtained in step S4, and stir at 120-180 rpm for 3-5 minutes. Heat to 96-98℃, continue stirring for 80-100 minutes, and let it cool naturally to room temperature. Then add the air-entraining agent from step S1, and continue stirring for 3-5 minutes to obtain concrete for wind turbine towers in cold regions.

[0020] Preferably or optionally, the preparation method of the composite polyacrylonitrile fiber is as follows: First, triallylamine, dodecyl acrylate, and dimethyl sulfoxide are mixed at a mass ratio of 1:5.2-5.4:9-11 and stirred at 200-400 rpm for 10-14 min. Then, ammonium persulfate at 0.6-0.8 times the mass of triallylamine is added, the temperature is raised to 75-95°C, and stirring is continued for 30-60 min. Next, polyacrylonitrile at 10-14 times the mass of triallylamine is added, and stirring is continued for 30-60 min. Finally, triallyl... Magnesium aluminum silicate with a mass of 0.1 to 0.3 times that of the amine was stirred at 1000 to 3000 rpm for 25 to 35 minutes, and then placed in a spinning box at 140 to 160°C. The fibers were spun using a screw extruder at a spinning speed of 800 to 1000 m / min. The fibers were then cooled and cured by side blowing air for 25 to 35 minutes at 10 to 20°C, a humidity of 60 to 80%, and an air velocity of 0.9 to 1.3 m / s to prepare composite polyacrylonitrile fibers with a length of 3 to 10 mm and a tex of 8 to 12.

[0021] Compared with the prior art, the beneficial effects achieved by the present invention are:

[0022] The concrete for wind turbine towers in frigid regions of the present invention comprises the following components by weight: 424-428 parts cement, 106-110 parts mineral powder, 32-36 parts silica fume, 652-656 parts fine aggregate, 1065-1069 parts coarse aggregate, 9-9.2 parts water-reducing agent, 0.11-0.13 parts air-entraining agent, 62-66 parts ultrafine fly ash, 149-153 parts water, and 1-2 parts composite polyacrylonitrile fiber; the composite polyacrylonitrile fiber is obtained by mixing triallylamine, dodecyl acrylate, polyacrylonitrile, and magnesium aluminum silicate; the air-entraining agent is a maleic rosin-based twin air-entraining agent; the mineral powder is P8000 type ultrafine mineral powder produced by Jinan Luxin New Building Materials Co., Ltd.; the silica fume has a content >90% and a specific surface area >15m³. 2 / g of silica fume.

[0023] First, triallylamine, dodecyl acrylate, and polyacrylonitrile are polymerized to form a hyperbranched modified polyacrylonitrile, which enhances the tensile properties of the composite polyacrylonitrile fiber. Magnesium aluminum silicate is rapidly incorporated into the cavity of the modified polyacrylonitrile, uniformly dispersing the magnesium aluminum silicate within the polyacrylonitrile, further enhancing the tensile properties of the composite polyacrylonitrile fiber. The composite polyacrylonitrile fiber is rapidly dispersed in the concrete through the magnesium aluminum silicate, enhancing the concrete's frost resistance and compressive strength. The incorporation of ultrafine mineral powder, ultrafine fly ash, and silica fume can improve the compressive strength of concrete used in wind turbine towers in frigid regions. Specifically, the incorporation of ultrafine mineral powder optimizes and supplements the cumulative permeation of particles in the 3–32 μm range of the cementitious material system, resulting in good compressive strength for the cement-based cementitious material system. Furthermore, the addition of ultrafine mineral powder reduces the mass loss rate of concrete used in wind turbine towers in frigid regions and improves the concrete's frost resistance.

[0024] Secondly, the addition of maleic rosin-based twin air-entraining agent to concrete can introduce uniform and fine air bubbles, improve the pore structure of concrete, and thus enhance its frost resistance without significantly affecting its strength. However, severe cold climates can reduce the air content and deteriorate the pore structure of concrete, thereby reducing its frost resistance. Some composite polyacrylonitrile fibers hydrolyze in an alkaline mixed solution to form an acrylate-acrylate-acrylamide ternary copolymer. The synergistic effect of the acrylate-acrylate-acrylamide ternary copolymer, the nano-silica in ultrafine fly ash, and the maleic rosin-based twin air-entraining agent makes the bubble liquid film generated by the air-entraining agent more stable after adsorbing the nano-silica, thus avoiding the deterioration of the pore structure of concrete caused by severe cold climates, and thus ensuring the frost resistance of concrete used in wind turbine towers in cold regions. Detailed Implementation

[0025] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0026] To more clearly illustrate the method provided by the present invention, the following embodiments are provided in detail. The testing methods for various indicators of the concrete prepared for wind turbine towers in frigid regions in the following embodiments are as follows:

[0027] Compressive strength: The compressive strength of concrete specimens for wind turbine towers in frigid regions, taken from the same mass examples and comparative examples, was tested according to GB / T50081 after curing at 99% relative humidity for 7 days and 28 days.

[0028] Freeze-thaw resistance: The freeze-thaw resistance grade of concrete for wind turbine towers in frigid regions of the same mass as the example and comparative examples was tested according to GB / T50082.

[0029] Example 1

[0030] A method for preparing concrete for wind turbine towers in frigid regions includes the following preparation steps:

[0031] S1. Ingredients: The following components are used for batching: 424 parts by weight of cement, 106 parts by weight of mineral powder, 32 parts by weight of silica fume, 652 parts by weight of fine aggregate, 1065 parts by weight of coarse aggregate, 9 parts by weight of water-reducing agent, 0.11 parts by weight of air-entraining agent, 62 parts by weight of ultrafine fly ash, 149 parts by weight of water, and 1 part by weight of composite polyacrylonitrile fiber.

[0032] S2. Preliminary Mixture: The cement and composite polyacrylonitrile fiber from step S1 are stirred at 120 rpm for 10 seconds to obtain the preliminary mixture.

[0033] S3. Secondary mixing: Place the fine aggregate and coarse aggregate from step S1 into a mixing container and mix at 120 rpm for 10 seconds. Then add the initial mixture obtained in step S2 and continue mixing for 10 seconds to obtain the secondary mixture.

[0034] S4. Mixing: Mix 45% of the water from step S1 and 0.32 times the mass of sodium hydroxide from step S1 at 120 rpm for 20 min to obtain a mixed solution;

[0035] S5. Three-stage mixing: Add mineral powder, silica fume, and the remaining water to the secondary mixture obtained in step S3, and stir at 120 rpm for 35 seconds to obtain the tertiary mixture;

[0036] S6. Four-stage mixing: Add water-reducing agent and ultrafine fly ash to the three-stage mixture obtained in step S5, stir at 120 rpm for 3 min, then add the mixed solution obtained in step S4, stir at 120 rpm for 3 min, heat to 96℃, continue stirring for 80 min, and after naturally cooling to room temperature, add the air-entraining agent from step S1, and continue stirring for 3 min to obtain concrete for wind turbine towers in frigid regions.

[0037] The cement used is P.O52.5 low-alkali ordinary Portland cement; the mineral powder used is P8000 type ultrafine mineral powder produced by Jinan Luxin New Building Materials Co., Ltd.; the silica fume has a content >90% and a specific surface area >15m³. 2 / g silica fume; the fine aggregate is natural river sand with a fineness modulus of 2.6-2.9, a mud content ≤1.5%, and a mud lump content of no more than 0.2%; the coarse aggregate is hard-textured, 5-20mm continuously graded crushed stone produced by an impact crusher, with a crushing index of no more than 5%, a needle-like and flaky content of no more than 7%, a mud content of no more than 0.5%, a mud lump content of no more than 0.2%, and an apparent density ≥1450kg / m³. 3 The water-reducing agent is sodium lignosulfonate water-reducing agent; the air-entraining agent is maleic rosin-based twin air-entraining agent; the ultrafine fly ash is M800 type ultrafine fly ash produced by Dongshi Mineral Products Processing Plant in Lingshou County, Hebei Province, wherein the silica content of the ultrafine fly ash is 52.4%.

[0038] The preparation method of the composite polyacrylonitrile fiber is as follows: First, triallylamine, dodecyl acrylate, and dimethyl sulfoxide are mixed at a mass ratio of 1:5.2:9 and stirred at 200 rpm for 10 min. Then, ammonium persulfate with a mass of 0.6 times that of triallylamine is added, the temperature is raised to 75°C, and stirring is continued for 30 min. Then, polyacrylonitrile with a mass of 10 times that of triallylamine is added, and stirring is continued for 30 min. Then, magnesium aluminum silicate with a mass of 0.1 times that of triallylamine is added, and stirring is carried out at 1000 rpm for 25 min. Then, the mixture is placed in a spinning box at 140°C and spun using a screw extruder at a spinning speed of 800 m / min. The mixture is then cooled and cured by side blowing air for 25 min at 10°C, 60% humidity, and 0.9 m / s wind speed to obtain composite polyacrylonitrile fiber with a length of 3 mm and 8 tex.

[0039] Example 2

[0040] A method for preparing concrete for wind turbine towers in frigid regions includes the following preparation steps:

[0041] S1. Ingredients: The following components are used for batching: 426 parts by weight of cement, 108 parts by weight of mineral powder, 34 parts by weight of silica fume, 654 parts by weight of fine aggregate, 1067 parts by weight of coarse aggregate, 9.09 parts by weight of water-reducing agent, 0.12 parts by weight of air-entraining agent, 64 parts by weight of ultrafine fly ash, 151 parts by weight of water, and 1.5 parts by weight of composite polyacrylonitrile fiber.

[0042] S2. Preliminary Mixture: The cement and composite polyacrylonitrile fiber from step S1 are stirred at 150 rpm for 15 seconds to obtain the preliminary mixture.

[0043] S3. Secondary mixing: Place the fine aggregate and coarse aggregate from step S1 into a mixing container and mix at 150 rpm for 15 seconds. Then add the initial mixture obtained in step S2 and continue mixing for 15 seconds to obtain the secondary mixture.

[0044] S4. Mixing: Mix 45% of the water from step S1 and 0.33 times the mass of sodium hydroxide from step S1 at 150 rpm for 25 min to obtain a mixed solution;

[0045] S5. Three-stage mixing: Add mineral powder, silica fume, and the remaining water to the secondary mixture obtained in step S3, and stir at 150 rpm for 40 seconds to obtain the three-stage mixture;

[0046] S6. Four-stage mixing: Add water-reducing agent and ultrafine fly ash to the three-stage mixture obtained in step S5, stir at 150 rpm for 4 min, then add the mixed solution obtained in step S4, stir at 150 rpm for 4 min, heat to 97℃, continue stirring for 90 min, and after naturally cooling to room temperature, add the air-entraining agent from step S1, and continue stirring for 4 min to obtain concrete for wind turbine towers in frigid regions.

[0047] The cement used is P.O52.5 low-alkali ordinary Portland cement; the mineral powder used is P8000 type ultrafine mineral powder produced by Jinan Luxin New Building Materials Co., Ltd.; the silica fume has a content >90% and a specific surface area >15m³. 2 / g silica fume; the fine aggregate is natural river sand with a fineness modulus of 2.6-2.9, a mud content ≤1.5%, and a mud lump content of no more than 0.2%; the coarse aggregate is hard-textured, 5-20mm continuously graded crushed stone produced by an impact crusher, with a crushing index of no more than 5%, a needle-like and flaky content of no more than 7%, a mud content of no more than 0.5%, a mud lump content of no more than 0.2%, and an apparent density ≥1450kg / m³. 3 The water-reducing agent is sodium lignosulfonate water-reducing agent; the air-entraining agent is maleic rosin-based twin air-entraining agent; the ultrafine fly ash is M800 type ultrafine fly ash produced by Dongshi Mineral Products Processing Plant in Lingshou County, Hebei Province, wherein the silica content of the ultrafine fly ash is 52.4%.

[0048] The preparation method of the composite polyacrylonitrile fiber is as follows: First, triallylamine, dodecyl acrylate, and dimethyl sulfoxide are mixed at a mass ratio of 1:5.3:10 and stirred at 300 rpm for 12 min. Then, ammonium persulfate with a mass of 0.7 times that of triallylamine is added, the temperature is raised to 85°C, and stirring is continued for 45 min. Then, polyacrylonitrile with a mass of 12 times that of triallylamine is added, and stirring is continued for 45 min. Then, magnesium aluminum silicate with a mass of 0.2 times that of triallylamine is added, and stirring is carried out at 2000 rpm for 30 min. Then, the mixture is placed in a spinning box at 150°C and spun using a screw extruder at a spinning speed of 900 m / min. The mixture is then cooled and cured by side blowing air for 30 min at 15°C, 70% humidity, and 1.1 m / s wind speed to obtain composite polyacrylonitrile fiber with a length of 6 mm and 10 tex.

[0049] Example 3

[0050] A method for preparing concrete for wind turbine towers in frigid regions includes the following preparation steps:

[0051] S1. Ingredients: The following components are used for batching: 428 parts by weight of cement, 110 parts by weight of mineral powder, 36 parts by weight of silica fume, 656 parts by weight of fine aggregate, 1069 parts by weight of coarse aggregate, 9.2 parts by weight of water-reducing agent, 0.13 parts by weight of air-entraining agent, 66 parts by weight of ultrafine fly ash, 153 parts by weight of water, and 2 parts by weight of composite polyacrylonitrile fiber.

[0052] S2. Preliminary Mixture: The cement and composite polyacrylonitrile fiber from step S1 are stirred at 180 rpm for 20 seconds to obtain the preliminary mixture.

[0053] S3. Secondary mixing: Place the fine and coarse aggregates from step S1 into a mixing container and mix at 180 rpm for 20 seconds. Then add the initial mixture obtained in step S2 and continue mixing for 20 seconds to obtain the secondary mixture.

[0054] S4. Mixing: Mix 45% water (by mass of 45% water) and 0.34 times the mass of sodium hydroxide (by mass of 45% water) in step S1 at 180 rpm for 30 min to obtain a mixed solution;

[0055] S5. Three-stage mixing: Add mineral powder, silica fume, and the remaining water to the secondary mixture obtained in step S3, and stir at 180 rpm for 45 seconds to obtain the tertiary mixture;

[0056] S6. Four-stage mixing: Add water-reducing agent and ultrafine fly ash to the three-stage mixture obtained in step S5, stir at 180 rpm for 5 min, then add the mixed solution obtained in step S4, stir at 180 rpm for 5 min, heat to 98℃, continue stirring for 100 min, and after naturally cooling to room temperature, add the air-entraining agent from step S1, and continue stirring for 5 min to obtain concrete for wind turbine towers in frigid regions.

[0057] The cement used is P.O52.5 low-alkali ordinary Portland cement; the mineral powder used is P8000 type ultrafine mineral powder produced by Jinan Luxin New Building Materials Co., Ltd.; the silica fume has a content >90% and a specific surface area >15m³. 2 / g silica fume; the fine aggregate is natural river sand with a fineness modulus of 2.6-2.9, a mud content ≤1.5%, and a mud lump content of no more than 0.2%; the coarse aggregate is hard-textured, 5-20mm continuously graded crushed stone produced by an impact crusher, with a crushing index of no more than 5%, a needle-like and flaky content of no more than 7%, a mud content of no more than 0.5%, a mud lump content of no more than 0.2%, and an apparent density ≥1450kg / m³. 3The water-reducing agent is sodium lignosulfonate water-reducing agent; the air-entraining agent is maleic rosin-based twin air-entraining agent; the ultrafine fly ash is M800 type ultrafine fly ash produced by Dongshi Mineral Products Processing Plant in Lingshou County, Hebei Province, wherein the silica content of the ultrafine fly ash is 52.4%.

[0058] The preparation method of the composite polyacrylonitrile fiber is as follows: First, triallylamine, dodecyl acrylate, and dimethyl sulfoxide are mixed at a mass ratio of 1:5.4:11 and stirred at 400 rpm for 14 min. Then, ammonium persulfate with a mass of 0.8 times that of triallylamine is added, the temperature is raised to 95°C, and stirring is continued for 60 min. Then, polyacrylonitrile with a mass of 14 times that of triallylamine is added, and stirring is continued for 60 min. Then, magnesium aluminum silicate with a mass of 0.3 times that of triallylamine is added, and stirring is carried out at 3000 rpm for 35 min. Then, the mixture is placed in a spinning box at 160°C and spun using a screw extruder at a spinning speed of 1000 m / min. The mixture is then cooled and cured by side blowing air for 35 min at 20°C, 80% humidity, and 1.3 m / s wind speed to obtain composite polyacrylonitrile fiber with a length of 10 mm and 12 tex.

[0059] Comparative Example 1

[0060] A method for preparing concrete for wind turbine towers in frigid regions includes the following preparation steps:

[0061] S1. Ingredients: The following components are used for batching: 426 parts by weight of cement, 108 parts by weight of mineral powder, 34 parts by weight of silica fume, 654 parts by weight of fine aggregate, 1067 parts by weight of coarse aggregate, 9.09 parts by weight of water-reducing agent, 0.12 parts by weight of air-entraining agent, 64 parts by weight of ultrafine fly ash, 151 parts by weight of water, and 1.5 parts by weight of composite polyacrylonitrile fiber.

[0062] S2. Preliminary Mixture: The cement and composite polyacrylonitrile fiber from step S1 are stirred at 150 rpm for 15 seconds to obtain the preliminary mixture.

[0063] S3. Secondary mixing: Place the fine aggregate and coarse aggregate from step S1 into a mixing container and mix at 150 rpm for 15 seconds. Then add the initial mixture obtained in step S2 and continue mixing for 15 seconds to obtain the secondary mixture.

[0064] S4. Mixing: Mix 45% of the water from step S1 and 0.33 times the mass of sodium hydroxide from step S1 at 150 rpm for 25 min to obtain a mixed solution;

[0065] S5. Three-stage mixing: Add mineral powder, silica fume, and the remaining water to the secondary mixture obtained in step S3, and stir at 150 rpm for 40 seconds to obtain the three-stage mixture;

[0066] S6. Four-stage mixing: Add water-reducing agent and ultrafine fly ash to the three-stage mixture obtained in step S5, stir at 150 rpm for 4 min, then add the mixed solution obtained in step S4, stir at 150 rpm for 4 min, heat to 97℃, continue stirring for 90 min, and after naturally cooling to room temperature, add the air-entraining agent from step S1, and continue stirring for 4 min to obtain concrete for wind turbine towers in frigid regions.

[0067] The cement used is P.O52.5 low-alkali ordinary Portland cement; the mineral powder used is S95 slag powder; the silica fume used has a content >90% and a specific surface area >15m³. 2 / g silica fume; the fine aggregate is natural river sand with a fineness modulus of 2.6-2.9, a mud content ≤1.5%, and a mud lump content of no more than 0.2%; the coarse aggregate is hard-textured, 5-20mm continuously graded crushed stone produced by an impact crusher, with a crushing index of no more than 5%, a needle-like and flaky content of no more than 7%, a mud content of no more than 0.5%, a mud lump content of no more than 0.2%, and an apparent density ≥1450kg / m³. 3 The water-reducing agent is sodium lignosulfonate water-reducing agent; the air-entraining agent is maleic rosin-based twin air-entraining agent; the ultrafine fly ash is M800 type ultrafine fly ash produced by Dongshi Mineral Products Processing Plant in Lingshou County, Hebei Province, wherein the silica content of the ultrafine fly ash is 52.4%.

[0068] The preparation method of the composite polyacrylonitrile fiber is as follows: First, triallylamine, dodecyl acrylate, and dimethyl sulfoxide are mixed at a mass ratio of 1:5.3:10 and stirred at 300 rpm for 12 min. Then, ammonium persulfate with a mass of 0.7 times that of triallylamine is added, the temperature is raised to 85°C, and stirring is continued for 45 min. Then, polyacrylonitrile with a mass of 12 times that of triallylamine is added, and stirring is continued for 45 min. Then, magnesium aluminum silicate with a mass of 0.2 times that of triallylamine is added, and stirring is carried out at 2000 rpm for 30 min. Then, the mixture is placed in a spinning box at 150°C and spun using a screw extruder at a spinning speed of 900 m / min. The mixture is then cooled and cured by side blowing air for 30 min at 15°C, 70% humidity, and 1.1 m / s wind speed to obtain composite polyacrylonitrile fiber with a length of 6 mm and 10 tex.

[0069] Comparative Example 2

[0070] Comparative Example 3: P8000 type ultrafine mineral powder produced by Jinan Luxin New Building Materials Co., Ltd.

[0071] A method for preparing concrete for wind turbine towers in frigid regions includes the following preparation steps:

[0072] S1. Ingredients: The following components are used for batching: 426 parts by weight of cement, 108 parts by weight of mineral powder, 34 parts by weight of silica fume, 654 parts by weight of fine aggregate, 1067 parts by weight of coarse aggregate, 9.09 parts by weight of water-reducing agent, 0.12 parts by weight of air-entraining agent, 151 parts by weight of water, and 1.5 parts by weight of polyacrylonitrile fiber.

[0073] S2. Initial Mixture: The cement and polyacrylonitrile fiber from step S1 are stirred at 150 rpm for 15 seconds to obtain the initial mixture;

[0074] S3. Secondary mixing: Place the fine aggregate and coarse aggregate from step S1 into a mixing container and mix at 150 rpm for 15 seconds. Then add the initial mixture obtained in step S2 and continue mixing for 15 seconds to obtain the secondary mixture.

[0075] S4. Mixing: Mix 45% of the water from step S1 and 0.33 times the mass of sodium hydroxide from step S1 at 150 rpm for 25 min to obtain a mixed solution;

[0076] S5. Three-stage mixing: Add mineral powder, silica fume, and the remaining water to the secondary mixture obtained in step S3, and stir at 150 rpm for 40 seconds to obtain the three-stage mixture;

[0077] S6. Four-stage mixing: Add water-reducing agent to the three-stage mixture obtained in step S5, stir at 150 rpm for 4 min, then add the mixed solution obtained in step S4, stir at 150 rpm for 4 min, heat to 97℃, continue stirring for 90 min, and after naturally cooling to room temperature, add the air-entraining agent from step S1, and continue stirring for 4 min to obtain concrete for wind turbine towers in frigid regions.

[0078] The cement used is P.O52.5 low-alkali ordinary Portland cement; the mineral powder used is P8000 type ultrafine mineral powder produced by Jinan Luxin New Building Materials Co., Ltd.; the silica fume has a content >90% and a specific surface area >15m³. 2 / g silica fume; the fine aggregate is natural river sand with a fineness modulus of 2.6-2.9, a mud content ≤1.5%, and a mud lump content of no more than 0.2%; the coarse aggregate is hard-textured, 5-20mm continuously graded crushed stone produced by an impact crusher, with a crushing index of no more than 5%, a needle-like and flaky content of no more than 7%, a mud content of no more than 0.5%, a mud lump content of no more than 0.2%, and an apparent density ≥1450kg / m³. 3 The water-reducing agent is sodium lignosulfonate; the air-entraining agent is maleic rosin-based gemini air-entraining agent.

[0079] The polyacrylonitrile fiber is a composite polyacrylonitrile fiber with a length of 6 mm and a tex of 10.

[0080] Comparative Example 4

[0081] A method for preparing concrete for wind turbine towers in frigid regions includes the following preparation steps:

[0082] S1. Ingredients: The following components are used for batching: 426 parts by weight of cement, 108 parts by weight of mineral powder, 34 parts by weight of silica fume, 654 parts by weight of fine aggregate, 1067 parts by weight of coarse aggregate, 9.09 parts by weight of water-reducing agent, 0.12 parts by weight of air-entraining agent, 64 parts by weight of ultrafine fly ash, 151 parts by weight of water, and 1.5 parts by weight of composite polyacrylonitrile fiber.

[0083] S2. Preliminary Mixture: The cement and composite polyacrylonitrile fiber from step S1 are stirred at 150 rpm for 15 seconds to obtain the preliminary mixture.

[0084] S3. Secondary mixing: Place the fine aggregate and coarse aggregate from step S1 into a mixing container and mix at 150 rpm for 15 seconds. Then add the initial mixture obtained in step S2 and continue mixing for 15 seconds to obtain the secondary mixture.

[0085] S4. Three-stage mixing: Add mineral powder, silica fume and water to the two-stage mixture obtained in step S3, and stir at 150 rpm for 40 seconds to obtain the three-stage mixture;

[0086] S5. Four-stage mixing: Add water-reducing agent and ultrafine fly ash to the three-stage mixture obtained in step S5, stir at 150 rpm for 4 minutes, and after naturally cooling to room temperature, add the air-entraining agent from step S1, and continue stirring for 4 minutes to obtain concrete for wind turbine towers in frigid regions.

[0087] The cement used is P.O52.5 low-alkali ordinary Portland cement; the mineral powder used is P8000 type ultrafine mineral powder produced by Jinan Luxin New Building Materials Co., Ltd.; the silica fume has a content >90% and a specific surface area >15m³. 2 / g silica fume; the fine aggregate is natural river sand with a fineness modulus of 2.6-2.9, a mud content ≤1.5%, and a mud lump content of no more than 0.2%; the coarse aggregate is hard-textured, 5-20mm continuously graded crushed stone produced by an impact crusher, with a crushing index of no more than 5%, a needle-like and flaky content of no more than 7%, a mud content of no more than 0.5%, a mud lump content of no more than 0.2%, and an apparent density ≥1450kg / m³. 3 The water-reducing agent is sodium lignosulfonate water-reducing agent; the air-entraining agent is maleic rosin-based twin air-entraining agent; the ultrafine fly ash is M800 type ultrafine fly ash produced by Dongshi Mineral Products Processing Plant in Lingshou County, Hebei Province, wherein the silica content of the ultrafine fly ash is 52.4%.

[0088] The preparation method of the composite polyacrylonitrile fiber is as follows: First, triallylamine, dodecyl acrylate, and dimethyl sulfoxide are mixed at a mass ratio of 1:5.3:10 and stirred at 300 rpm for 12 min. Then, ammonium persulfate with a mass of 0.7 times that of triallylamine is added, the temperature is raised to 85°C, and stirring is continued for 45 min. Then, polyacrylonitrile with a mass of 12 times that of triallylamine is added, and stirring is continued for 45 min. Then, magnesium aluminum silicate with a mass of 0.2 times that of triallylamine is added, and stirring is carried out at 2000 rpm for 30 min. Then, the mixture is placed in a spinning box at 150°C and spun using a screw extruder at a spinning speed of 900 m / min. The mixture is then cooled and cured by side blowing air for 30 min at 15°C, 70% humidity, and 1.1 m / s wind speed to obtain composite polyacrylonitrile fiber with a length of 6 mm and 10 tex.

[0089] Comparative Example 5

[0090] A method for preparing concrete for wind turbine towers in frigid regions includes the following preparation steps:

[0091] S1. Ingredients: The following components are used for batching: 426 parts by weight of cement, 108 parts by weight of mineral powder, 34 parts by weight of silica fume, 654 parts by weight of fine aggregate, 1067 parts by weight of coarse aggregate, 9.09 parts by weight of water-reducing agent, 0.12 parts by weight of air-entraining agent, 64 parts by weight of ultrafine fly ash, 151 parts by weight of water, and 1.5 parts by weight of composite polyacrylonitrile fiber.

[0092] S2. Preliminary Mixture: The cement and composite polyacrylonitrile fiber from step S1 are stirred at 150 rpm for 15 seconds to obtain the preliminary mixture.

[0093] S3. Secondary mixing: Place the fine aggregate and coarse aggregate from step S1 into a mixing container and mix at 150 rpm for 15 seconds. Then add the initial mixture obtained in step S2 and continue mixing for 15 seconds to obtain the secondary mixture.

[0094] S4. Mixing: Mix 45% of the water from step S1 and 0.33 times the mass of sodium hydroxide from step S1 at 150 rpm for 25 min to obtain a mixed solution;

[0095] S5. Three-stage mixing: Add mineral powder, silica fume, and the remaining water to the secondary mixture obtained in step S3, and stir at 150 rpm for 40 seconds to obtain the three-stage mixture;

[0096] S6. Four-stage mixing: Add water-reducing agent and ultrafine fly ash to the three-stage mixture obtained in step S5, stir at 150 rpm for 4 min, then add the mixed solution obtained in step S4, stir at 150 rpm for 4 min, heat to 97℃, continue stirring for 90 min, and after naturally cooling to room temperature, add the air-entraining agent from step S1, and continue stirring for 4 min to obtain concrete for wind turbine towers in frigid regions.

[0097] The cement used is P.O52.5 low-alkali ordinary Portland cement; the mineral powder used is P8000 type ultrafine mineral powder produced by Jinan Luxin New Building Materials Co., Ltd.; the silica fume has a content >90% and a specific surface area >15m³. 2 / g silica fume; the fine aggregate is natural river sand with a fineness modulus of 2.6-2.9, a mud content ≤1.5%, and a mud lump content of no more than 0.2%; the coarse aggregate is hard-textured, 5-20mm continuously graded crushed stone produced by an impact crusher, with a crushing index of no more than 5%, a needle-like and flaky content of no more than 7%, a mud content of no more than 0.5%, a mud lump content of no more than 0.2%, and an apparent density ≥1450kg / m³. 3 The water-reducing agent is sodium lignosulfonate; the air-entraining agent is rosin; the ultrafine fly ash is M800 type ultrafine fly ash produced by Dongshi Mineral Products Processing Plant in Lingshou County, Hebei Province, wherein the silica content of the ultrafine fly ash is 52.4%.

[0098] The preparation method of the composite polyacrylonitrile fiber is as follows: First, triallylamine, dodecyl acrylate, and dimethyl sulfoxide are mixed at a mass ratio of 1:5.3:10 and stirred at 300 rpm for 12 min. Then, ammonium persulfate with a mass of 0.7 times that of triallylamine is added, the temperature is raised to 85°C, and stirring is continued for 45 min. Then, polyacrylonitrile with a mass of 12 times that of triallylamine is added, and stirring is continued for 45 min. Then, magnesium aluminum silicate with a mass of 0.2 times that of triallylamine is added, and stirring is carried out at 2000 rpm for 30 min. Then, the mixture is placed in a spinning box at 150°C and spun using a screw extruder at a spinning speed of 900 m / min. The mixture is then cooled and cured by side blowing air for 30 min at 15°C, 70% humidity, and 1.1 m / s wind speed to obtain composite polyacrylonitrile fiber with a length of 6 mm and 10 tex.

[0099] Example of effect

[0100] Table 1 below presents the analysis results of the compressive strength and frost resistance of the concrete for wind turbine towers in frigid regions prepared using Examples 1 to 3 and Comparative Examples 1 to 5 of the present invention.

[0101] Table 1

[0102]

[0103] Table 1 shows that the concrete prepared in Examples 1, 2, and 3 for wind turbine towers in frigid regions exhibits good compressive strength and frost resistance. A comparison of the experimental data from Examples 1, 2, and 3 and Comparative Example 1 reveals that concrete prepared using ultrafine mineral powder for wind turbine towers in frigid regions exhibits good compressive strength and frost resistance. Similarly, the experimental data from Examples 1, 2, and 3 and Comparative Example 2 show that concrete prepared using ultrafine fly ash for wind turbine towers in frigid regions exhibits good compressive strength and frost resistance. Finally, the experimental data from Examples 1, 2, and 3 and Comparative Example 3 also show… Concrete for wind turbine towers in frigid regions was prepared using composite polyacrylonitrile fibers, resulting in concrete with good compressive strength and frost resistance. Experimental data from Examples 1, 2, 3, and Comparative Example 4 showed that concrete for wind turbine towers in frigid regions prepared using an alkaline mixed solution with hot stirring during four mixing stages also exhibited good compressive strength and frost resistance. Furthermore, experimental data from Examples 1, 2, 3, and Comparative Example 5 showed that concrete for wind turbine towers in frigid regions prepared using a maleic rosin-based twin air-entraining agent exhibited good frost resistance.

[0104] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No markings in the claims should be construed as limiting the scope of the claims.

Claims

1. A type of concrete for wind turbine towers in frigid regions, characterized in that, The composition by weight is as follows: 424-428 parts cement, 106-110 parts mineral powder, 32-36 parts silica fume, 652-656 parts fine aggregate, 1065-1069 parts coarse aggregate, 9-9.2 parts water-reducing agent, 0.11-0.13 parts air-entraining agent, 62-66 parts ultrafine fly ash, 149-153 parts water, and 1-2 parts composite polyacrylonitrile fiber; the composite polyacrylonitrile fiber is obtained by mixing triallylamine, dodecyl acrylate, polyacrylonitrile, and magnesium aluminum silicate; the air-entraining agent is a maleic rosin-based gemini air-entraining agent. The preparation method of the composite polyacrylonitrile fiber is as follows: First, triallylamine, dodecyl acrylate, and dimethyl sulfoxide are mixed at a mass ratio of 1:5.2~5.4:9~11 and stirred at 200~400 rpm for 10~14 min. Then, ammonium persulfate at 0.6~0.8 times the mass of triallylamine is added, the temperature is raised to 75~95℃, and stirring is continued for 30~60 min. Then, polyacrylonitrile at 10~14 times the mass of triallylamine is added, and stirring is continued for 30~60 min. Finally, ammonium persulfate at 0.6~0.8 times the mass of triallylamine is added. 0.1 to 0.3 times the amount of magnesium aluminum silicate was stirred at 1000 to 3000 rpm for 25 to 35 minutes, and then placed in a spinning box at 140 to 160°C. The fibers were spun using a screw extruder at a spinning speed of 800 to 1000 m / min. The fibers were then cooled and cured by side blowing air at 10 to 20°C, humidity of 60 to 80%, and wind speed of 0.9 to 1.3 m / s for 25 to 35 minutes to prepare composite polyacrylonitrile fibers with a length of 3 to 10 mm and a tex of 8 to 12.

2. The concrete for wind turbine towers in frigid regions according to claim 1, characterized in that, The cement used is P.O52.5 low-alkali ordinary Portland cement.

3. The concrete for wind turbine towers in frigid regions according to claim 1, characterized in that, The mineral powder used is P8000 type ultrafine mineral powder produced by Jinan Luxin New Building Materials Co., Ltd.

4. The concrete for wind turbine towers in frigid regions according to claim 1, characterized in that, The silica fume used has a content >90% and a specific surface area >15m². 2 / g of silica fume.

5. The concrete for wind turbine towers in frigid regions according to claim 1, characterized in that, The fine aggregate is natural river sand with a fineness modulus of 2.6 to 2.9, a mud content of ≤1.5%, and a mud lump content of no more than 0.2%.

6. The concrete for wind turbine towers in frigid regions according to claim 1, characterized in that, The coarse aggregate is selected from hard, continuously graded crushed stone of 5-20mm produced by an impact crusher, with a crushing index of no more than 5%, a needle-like and flaky content of no more than 7%, a mud content of no more than 0.5%, a mud lump content of no more than 0.2%, and an apparent density ≥1450kg / m³. 3 .

7. The concrete for wind turbine towers in frigid regions according to claim 1, characterized in that, The ultrafine fly ash used is M800 type ultrafine fly ash produced by Dongshi Mineral Products Processing Plant in Lingshou County, Hebei Province, wherein the silica content of the ultrafine fly ash is 52.4%.

8. The concrete for wind turbine towers in frigid regions according to claim 1, characterized in that, The water-reducing agent used is sodium lignosulfonate.

9. A method for preparing concrete for wind turbine towers in frigid regions as described in any one of claims 1 to 8, characterized in that, The preparation steps include the following: S1. Ingredients: The following components shall be used for batching: 424~428 parts cement, 106~110 parts mineral powder, 32~36 parts silica fume, 652~656 parts fine aggregate, 1065~1069 parts coarse aggregate, 9~9.2 parts water-reducing agent, 0.11~0.13 parts air-entraining agent, 62~66 parts ultrafine fly ash, 149~153 parts water, and 1~2 parts composite polyacrylonitrile fiber; S2. Preliminary Mixture: Stir the cement and composite polyacrylonitrile fiber from step S1 at 120-180 rpm for 10-20 seconds to obtain the preliminary mixture. S3. Secondary mixing: Place the fine and coarse aggregates from step S1 into a mixing container and mix at 120-180 rpm for 10-20 seconds. Then add the initial mixture obtained in step S2 and continue mixing for 10-20 seconds to obtain the secondary mixture. S4. Mixing: Mix 45% of the water prepared in step S1 and 0.32 to 0.34 times the mass of sodium hydroxide prepared in step S1 at 120 to 180 rpm for 20 to 30 minutes to obtain a mixed solution; S5. Three-stage mixing: Add mineral powder, silica fume, and the remaining water to the secondary mixture obtained in step S3, and stir at 120~180 rpm for 35~45 seconds to obtain the three-stage mixture; S6. Four-stage mixing: Add water-reducing agent and ultrafine fly ash to the three-stage mixture obtained in step S5, and stir at 120~180 rpm for 3~5 min. Then add the mixed solution obtained in step S4, and stir at 120~180 rpm for 3~5 min. Heat to 96~98℃, continue stirring for 80~100 min, and let it cool naturally to room temperature. Then add the air-entraining agent from step S1, and continue stirring for 3~5 min to obtain concrete for wind turbine towers in cold regions.

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