Preparation method and application of a new type of UHPC wind power tower drum

Abstract

This invention provides a novel method for preparing UHPC wind turbine towers and its application. The UHPC, by weight, comprises: 60 parts cement, 14-18 parts silica fume, 17-22 parts quartz sand, 20-25 parts fly ash, 2-3 parts modified polyvinyl alcohol fiber, 0.8-1.5 parts high-efficiency water-reducing agent, 0.5-0.8 parts dispersant, and 20-23 parts water. The method for preparing the modified polyvinyl alcohol fiber is as follows: 121g of tris(hydroxymethyl)aminomethane is added to 600mL of water, stirred to dissolve, and then the pH is adjusted to 8.0 with hydrochloric acid. The final volume is then adjusted to 1000mL with water. L, obtain buffer solution; take 3g catechol and 3g 1,6-hexanediamine, add to buffer solution, mix well to obtain functional solution; take 5g polyvinyl alcohol fiber, add to functional solution, shake for 24h, take out and wash with water, dry at 40±5℃ to obtain deposited fiber; take 10g SiC-SiO2 modified particles, sonicate for 15min and disperse in 1000mL water to obtain SiC-SiO2 particle dispersion; immerse the deposited fiber in SiC-SiO2 particle dispersion, stir at 120r / min for 2h, take out and wash with water, dry at 40±5℃ to obtain. This invention ensures that the prepared UHPC has excellent mechanical properties while improving chloride ion penetration resistance and durability.

Description

Technical Field

[0001] This invention belongs to the field of concrete products technology, specifically relating to a novel UHPC wind turbine tower preparation method and its application. Background Technology

[0002] The wind turbine tower is the main structure of a wind turbine generator and plays a crucial role in wind power generation. Its specific functions are as follows: 1. Supporting the wind turbine: As the main support structure of the wind turbine, the wind turbine tower ensures that all parts of the turbine can be stably suspended high in the air. This includes not only major components such as blades and generators, but also control systems and other auxiliary equipment. 2. Absorbing vibration energy: Under wind power, the generator set will generate vibrations, and the design of the wind turbine tower can absorb these vibrations, reducing the instability impact on the entire structure. 3. Transferring weight: The wind turbine tower is also responsible for transferring the weight of the hundreds of tons of wind turbine generator to the foundation ring, which is crucial for the maintenance and power transmission functions of the wind turbine generator. In short, the existence of the wind turbine tower ensures the safe and stable operation of the generator set. The diameter and height of the wind turbine tower vary depending on the wind turbine model and geographical location. For example, the tower height of onshore wind turbine generators is typically between 80-120 meters, while offshore wind turbine generators are much taller, reaching over 200 meters.

[0003] Existing wind turbine towers can be categorized into truss type, steel pipe type, and reinforced concrete type based on their structural form. Among these, reinforced concrete wind turbine towers combine the advantages of both steel and concrete. The fabrication of such towers requires the use of high-performance concrete to ensure their strength, stability, and durability. For example, Chinese invention patent CN107285714A discloses a high-ductility polyvinyl alcohol fiber concrete and its preparation method. This high-ductility polyvinyl alcohol fiber concrete uses cement, fly ash, quartz sand, admixtures, water, and high-strength, high-modulus polyvinyl alcohol fibers as raw materials. The concrete preparation method includes: material preparation; mixing cement, fly ash, quartz sand, and admixtures until homogeneous; adding water to a mixer and mixing for a certain time; adding high-strength, high-modulus polyvinyl alcohol fibers in batches and mixing until homogeneous; after mixing, molding, vibrating, curing, and demolding to obtain the concrete. The raw materials used in this invention and the high-ductility polyvinyl alcohol fiber concrete prepared by the above method have good flexural strength, impact strength and crack resistance, enabling the structure to have ductile failure properties.

[0004] However, the direct addition of polyvinyl alcohol fibers reduces the fluidity of concrete. This reduced fluidity may lead to poor filling and compaction of concrete during construction, which in turn may indirectly result in more voids during construction. Consequently, the concrete products produced will have a reduced ability to resist chloride ion penetration. Chloride ion penetration can cause steel reinforcement corrosion, which in turn affects the stability and durability of the structure. Summary of the Invention

[0005] To address the problems existing in the background technology, this invention provides a novel method for preparing UHPC wind turbine towers and its application, ensuring that the prepared UHPC has excellent mechanical properties while improving its resistance to chloride ion penetration, i.e., improving its durability.

[0006] To achieve the above objectives, in a first aspect, the present invention provides a method for preparing a novel UHPC wind turbine tower, wherein the UHPC comprises, by weight, the following raw material components: 60 parts cement, 14-18 parts silica fume, 17-22 parts quartz sand, 20-25 parts fly ash, 2-3 parts modified polyvinyl alcohol fiber, 0.8-1.5 parts high-efficiency water-reducing agent, 0.5-0.8 parts dispersant, and 20-23 parts water;

[0007] The modified polyvinyl alcohol fiber is prepared as follows:

[0008] A1. Take 121g of tris(hydroxymethyl)aminomethane, add it to 600mL of water, stir until completely dissolved, then add hydrochloric acid to adjust the pH to 8.0, and make up to 1000mL with water to obtain a buffer solution.

[0009] A2. Weigh 3g of catechol and 3g of 1,6-hexanediamine, add them to the buffer solution obtained in A1, stir and mix well to obtain the functional solution.

[0010] A3. Weigh 5g of polyvinyl alcohol fiber, add it to the functional solution obtained in A2, shake and react for 24h, take it out, wash it with water, and dry it at 40±5℃ to obtain deposited fiber.

[0011] A4. Weigh 10g of SiC-SiO2 modified particles and disperse them in 1000mL of water under ultrasonication for 15min to obtain SiC-SiO2 particle dispersion.

[0012] A5. Immerse the deposited fiber obtained in A3 into the SiC-SiO2 particle dispersion obtained in A4, stir at 120 r / min for 2 h, take it out, wash it with water, and dry it at 40±5℃ to obtain the modified polyvinyl alcohol fiber.

[0013] Furthermore, the preparation method of the SiC-SiO2 modified particles is as follows:

[0014] B1. Weigh 20g of nano-SiC-SiO2 coated particles, add them to 120mL of 2-ethylhexanol, then add 0.8g of p-toluenesulfonic acid, stir magnetically, and heat in a microwave oven for 4 hours to obtain the product.

[0015] B2. The product obtained in B1 is washed by centrifugation with ethanol 3-4 times to remove residual 2-ethylhexanol, and then vacuum dried to constant weight to obtain SiC-SiO2 modified particles.

[0016] Furthermore, the preparation method of the nano-SiC-SiO2 coated particles is as follows:

[0017] B11. Weigh 16g of nano-SiC and disperse it in 160mL of isopropanol. Sonicate the dispersion for 30min to obtain SiC dispersion.

[0018] B12. Transfer the SiC dispersion obtained in B11 to a 1000ml three-necked flask, stir thoroughly, and slowly add ammonia solution and tetraethyl orthosilicate solution by dripping, controlling the dripping rate to 1 drop / s. In a constant temperature water bath with electric stirring, control the reaction temperature to 40℃ and react for 6 hours to obtain the reaction solution.

[0019] B13. The reaction solution obtained in B12 is centrifuged and washed with isopropanol. The resulting precipitate is dried in a 105℃ forced-air drying oven to obtain nano-SiC-SiO2 coated particles.

[0020] Furthermore, in B12, the ammonia solution is prepared by mixing ammonia, water, and isopropanol in a mass ratio of 2:1:1.

[0021] Furthermore, in B12, the tetraethyl orthosilicate solution is prepared by mixing tetraethyl orthosilicate and isopropanol in a 1:1 mass ratio.

[0022] Furthermore, in B12, the molar ratio of ammonia to tetraethyl orthosilicate is 2:1; the molar ratio of nano-SiC to tetraethyl orthosilicate is 5:1.

[0023] Furthermore, the cement used is P.O52.5 grade cement; the high-efficiency water-reducing agent is a polycarboxylate-based water-reducing agent.

[0024] Furthermore, the dispersant includes triisopropanolamine and / or triethanolamine.

[0025] Furthermore, the fabrication method of the novel UHPC wind turbine tower includes the following steps:

[0026] S1. First, mix cement, silica fume and fly ash evenly, then add quartz sand and mix evenly. Then add water, high-efficiency water-reducing agent and dispersant and stir. Finally, add modified polyvinyl alcohol fiber, stir and mix evenly to obtain UHPC.

[0027] S2. The steel reinforcement skeleton is pre-embedded in the mold. The UHPC obtained in S1 is used for casting, molding and curing to obtain tower segments. The segments are connected and assembled to obtain the new UHPC wind turbine tower.

[0028] Secondly, the present invention provides an application of a novel UHPC wind turbine tower, which is prepared by the above-mentioned preparation method and is used as the main structure of a wind power generation tower.

[0029] This application has the following beneficial effects:

[0030] 1. The UHPC raw material for wind turbine towers prepared in this invention includes modified polyvinyl alcohol fibers. In the preparation of modified polyvinyl alcohol fibers, catechol and 1,6-hexanediamine react on the surface of polyvinyl alcohol fibers to form a deposit, thereby changing the surface properties of the fibers. This facilitates the further adhesion of SiC-SiO2 modified particles to the surface of the fibers. The further adhesion of SiC-SiO2 modified particles to the surface of the deposited fibers can, on the one hand, improve the interfacial strength between the fibers and the cement matrix, thereby improving the mechanical properties of the concrete. On the other hand, it can affect the micropore structure of the concrete, increase the density of the concrete, and thus reduce the penetration path of chloride ions.

[0031] 2. In the preparation of SiC-SiO2 modified particles of the present invention, 2-ethylhexanol reacts chemically with the hydroxyl groups on the surface of the outer SiO2 layer of nano-SiC-SiO2 coated particles, effectively changing the surface properties of the outer SiO2 layer, making the surface of the outer SiO2 layer change from hydrophilic to hydrophobic. The hydrophobic nanoparticles can effectively inhibit the transmission of water and corrosive media such as chlorides and sulfates in concrete, reduce the contact between these media and steel bars, thereby reducing the risk of corrosion and extending the service life of the structure.

[0032] 3. In the preparation of the nano-SiC-SiO2 coated particles of the present invention, nano-SiO2 has high pozzolanic activity, which can improve the hydration reaction rate and hydration effect of cement. Its nucleation effect and filling effect make the concrete structure more compact, thereby improving the strength and durability of concrete. SiC is known for its high hardness and good wear resistance. Its incorporation can significantly improve the wear resistance of concrete. Coating SiC with nano-SiO2 can comprehensively improve the strength, durability and wear resistance of concrete, making the overall performance of concrete more excellent. Attached Figure Description

[0033] Figure 1 This is a comparison trend chart of the compressive strength of UHPC obtained in Examples 1-6 and Comparative Examples 1-6 of the present invention;

[0034] Figure 2 This is a comparison trend chart of the tensile strength of UHPC obtained in Examples 1-6 and Comparative Examples 1-6 of the present invention;

[0035] Figure 3 This is a comparison trend chart of the chloride ion diffusion coefficients of UHPCs prepared in Examples 1-6 and Comparative Examples 1-6 of the present invention. Detailed Implementation

[0036] The present application will be further described in detail below with reference to the embodiments.

[0037] Unless otherwise specified, the raw materials used in the embodiments and comparative examples of this application are all commercially available.

[0038] Example 1

[0039] A novel method for manufacturing a UHPC wind turbine tower includes the following steps:

[0040] S1, Prefabricated UHPC;

[0041] By weight, first mix 60 parts of cement, 16 parts of silica fume and 22 parts of fly ash, then add 20 parts of quartz sand and mix well. Next, add 21 parts of water, 1 part of high-efficiency water-reducing agent and 0.6 parts of dispersant, and stir thoroughly. Finally, add 2.5 parts of modified polyvinyl alcohol fiber, stir and mix well to obtain UHPC.

[0042] S2, pouring;

[0043] The steel reinforcement skeleton is pre-embedded in the mold, and the UHPC obtained by S1 is used for casting. It is formed and cured according to national standards to obtain tower segments. The segments are connected and assembled to obtain the new UHPC wind turbine tower.

[0044] The cement used is P.O52.5 grade cement; the high-efficiency water-reducing agent is a polycarboxylate-based water-reducing agent; and the dispersant is triisopropanolamine.

[0045] The preparation method of modified polyvinyl alcohol fiber is as follows:

[0046] A1. Take 121g of tris(hydroxymethyl)aminomethane, add it to 600mL of water, stir until completely dissolved, then add hydrochloric acid to adjust the pH to 8.0, and dilute to 1000mL with water to obtain a buffer solution.

[0047] A2. Weigh 3g of catechol and 3g of 1,6-hexanediamine, add them to the buffer solution obtained in A1, stir and mix well to obtain the functional solution.

[0048] A3. Weigh 5g of polyvinyl alcohol fiber, add it to the functional solution obtained in A2, shake and react for 24h, take it out, wash it with water, and dry it at about 40℃ to obtain deposited fiber.

[0049] A4. Weigh 10g of SiC-SiO2 modified particles and disperse them in 1000mL of water under ultrasonication for 15min to obtain SiC-SiO2 particle dispersion.

[0050] A5. Immerse the deposited fiber obtained in A3 into the SiC-SiO2 particle dispersion obtained in A4, stir at 120 r / min for 2 h, take it out, wash it with water, and dry it at about 40℃ to obtain the modified polyvinyl alcohol fiber.

[0051] The preparation method of SiC-SiO2 modified particles is as follows:

[0052] B1. Weigh 20g of nano-SiC-SiO2 coated particles, add them to 120mL of 2-ethylhexanol, then add 0.8g of p-toluenesulfonic acid, stir magnetically, and heat in a microwave oven for 4 hours to obtain the product.

[0053] B2. The product obtained in B1 is washed three times by centrifugation with ethanol to remove residual 2-ethylhexanol, and then vacuum dried to constant weight to obtain SiC-SiO2 modified particles.

[0054] The preparation method of nano-SiC-SiO2 coated particles is as follows:

[0055] B11. Weigh 16g of nano-SiC and disperse it in 160mL of isopropanol. Sonicate the dispersion for 30min to obtain SiC dispersion.

[0056] B12. Transfer the SiC dispersion obtained in B11 to a 1000ml three-necked flask, stir thoroughly, and slowly add ammonia solution and tetraethyl orthosilicate solution by dripping, controlling the dripping rate to 1 drop / s. In a constant temperature water bath with electric stirring, control the reaction temperature to 40℃ and react for 6 hours to obtain the reaction solution.

[0057] The ammonia solution is prepared by mixing ammonia, water and isopropanol in a mass ratio of 2:1:1; the tetraethyl orthosilicate solution is prepared by mixing tetraethyl orthosilicate and isopropanol in a mass ratio of 1:1; the molar ratio of ammonia to tetraethyl orthosilicate is 2:1; and the molar ratio of nano-SiC to tetraethyl orthosilicate is 5:1.

[0058] B13. The reaction solution obtained in B12 is centrifuged and washed with isopropanol. The resulting precipitate is dried in a 105℃ forced-air drying oven to obtain nano-SiC-SiO2 coated particles.

[0059] The above preparation method yields a novel UHPC wind turbine tower, which is used as the main structure of a wind power generation tower.

[0060] Example 2

[0061] The only difference between this embodiment and Embodiment 1 is: S1, prefabricated UHPC;

[0062] By weight, first mix 60 parts of cement, 14 parts of silica fume and 20 parts of fly ash, then add 17 parts of quartz sand and mix well. Next, add 23 parts of water, 1.5 parts of high-efficiency water-reducing agent and 0.8 parts of dispersant, and stir thoroughly. Finally, add 2 parts of modified polyvinyl alcohol fiber, stir and mix well to obtain UHPC.

[0063] Example 3

[0064] The only difference between this embodiment and Embodiment 1 is: S1, prefabricated UHPC;

[0065] By weight, first mix 60 parts of cement, 18 parts of silica fume and 25 parts of fly ash, then add 17 parts of quartz sand and mix well. Next, add 20 parts of water, 0.8 parts of high-efficiency water-reducing agent and 0.5 parts of dispersant, and stir thoroughly. Finally, add 3 parts of modified polyvinyl alcohol fiber, stir and mix well to obtain UHPC.

[0066] Example 4

[0067] The only difference between this embodiment and Embodiment 1 is: S1, prefabricated UHPC;

[0068] By weight, first mix 60 parts of cement, 17 parts of silica fume and 21 parts of fly ash, then add 18 parts of quartz sand and mix well. Next, add 21 parts of water, 1 part of high-efficiency water-reducing agent and 0.6 parts of dispersant, and stir thoroughly. Finally, add 2.5 parts of modified polyvinyl alcohol fiber, stir and mix well to obtain UHPC.

[0069] Example 5

[0070] The only difference between this embodiment and Embodiment 1 is: S1, prefabricated UHPC;

[0071] By weight, first mix 60 parts of cement, 16 parts of silica fume and 24 parts of fly ash, then add 21 parts of quartz sand and mix well. Next, add 22 parts of water, 1.2 parts of high-efficiency water-reducing agent and 0.7 parts of dispersant, and stir thoroughly. Finally, add 3 parts of modified polyvinyl alcohol fiber, stir and mix well to obtain UHPC.

[0072] Example 6

[0073] The only difference between this embodiment and Embodiment 1 is: S1, prefabricated UHPC;

[0074] By weight, first mix 60 parts of cement, 15 parts of silica fume and 21 parts of fly ash, then add 21 parts of quartz sand and mix well. Next, add 21 parts of water, 0.9 parts of high-efficiency water-reducing agent and 0.6 parts of dispersant, and stir thoroughly. Finally, add 2.2 parts of modified polyvinyl alcohol fiber, stir and mix well to obtain UHPC.

[0075] Comparative Example 1

[0076] The only difference between this comparative example and Example 1 is that the coating process step is removed in the preparation of the modified polyvinyl alcohol fiber, that is, the nano-SiC-SiO2 coated particles are replaced with nano-SiO2.

[0077] Specifically, the preparation method of modified polyvinyl alcohol fiber is as follows:

[0078] A1. Take 121g of tris(hydroxymethyl)aminomethane, add it to 600mL of water, stir until completely dissolved, then add hydrochloric acid to adjust the pH to 8.0, and dilute to 1000mL with water to obtain a buffer solution.

[0079] A2. Weigh 3g of catechol and 3g of 1,6-hexanediamine, add them to the buffer solution obtained in A1, stir and mix well to obtain the functional solution.

[0080] A3. Weigh 5g of polyvinyl alcohol fiber, add it to the functional solution obtained in A2, shake and react for 24h, take it out, wash it with water, and dry it at about 40℃ to obtain deposited fiber.

[0081] A4. Weigh 10g of SiO2 modified particles and disperse them in 1000mL of water under ultrasonication for 15min to obtain a SiO2 particle dispersion.

[0082] A5. Immerse the deposited fiber obtained in A3 into the SiO2 particle dispersion obtained in A4, stir at 120 r / min for 2 h, take it out, wash it with water, and dry it at about 40℃ to obtain the modified polyvinyl alcohol fiber.

[0083] The preparation method of SiO2 modified particles is as follows:

[0084] B1. Weigh 20g of nano-SiO2, add it to 120mL of 2-ethylhexanol, then add 0.8g of p-toluenesulfonic acid, stir magnetically, and heat in a microwave oven for 4 hours to obtain the product.

[0085] B2. The product obtained in B1 is washed three times by centrifugation with ethanol to remove residual 2-ethylhexanol, and then vacuum dried to constant weight to obtain SiO2 modified particles.

[0086] Comparative Example 2

[0087] The only difference between this comparative example and Example 1 is that the modification process step after coating is removed in the preparation of modified polyvinyl alcohol fibers, that is, the modification process step of nano-SiC-SiO2 coated particles is removed.

[0088] Specifically, the preparation method of modified polyvinyl alcohol fiber is as follows:

[0089] A1. Take 121g of tris(hydroxymethyl)aminomethane, add it to 600mL of water, stir until completely dissolved, then add hydrochloric acid to adjust the pH to 8.0, and dilute to 1000mL with water to obtain a buffer solution.

[0090] A2. Weigh 3g of catechol and 3g of 1,6-hexanediamine, add them to the buffer solution obtained in A1, stir and mix well to obtain the functional solution.

[0091] A3. Weigh 5g of polyvinyl alcohol fiber, add it to the functional solution obtained in A2, shake and react for 24h, take it out, wash it with water, and dry it at about 40℃ to obtain deposited fiber.

[0092] A4. Weigh 10g of nano-SiC-SiO2 coated particles and disperse them in 1000mL of water under ultrasonication for 15min to obtain SiC-SiO2 particle dispersion.

[0093] A5. Immerse the deposited fiber obtained in A3 into the SiC-SiO2 particle dispersion obtained in A4, stir at 120 r / min for 2 h, take it out, wash it with water, and dry it at about 40℃ to obtain the modified polyvinyl alcohol fiber.

[0094] The preparation method of nano-SiC-SiO2 coated particles is as follows:

[0095] B11. Weigh 16g of nano-SiC and disperse it in 160mL of isopropanol. Sonicate the dispersion for 30min to obtain SiC dispersion.

[0096] B12. Transfer the SiC dispersion obtained in B11 to a 1000ml three-necked flask, stir thoroughly, and slowly add ammonia solution and tetraethyl orthosilicate solution by dripping, controlling the dripping rate to 1 drop / s. In a constant temperature water bath with electric stirring, control the reaction temperature to 40℃ and react for 6 hours to obtain the reaction solution.

[0097] The ammonia solution is prepared by mixing ammonia, water and isopropanol in a mass ratio of 2:1:1; the tetraethyl orthosilicate solution is prepared by mixing tetraethyl orthosilicate and isopropanol in a mass ratio of 1:1; the molar ratio of ammonia to tetraethyl orthosilicate is 2:1; and the molar ratio of nano-SiC to tetraethyl orthosilicate is 5:1.

[0098] B13. The reaction solution obtained in B12 is centrifuged and washed with isopropanol. The resulting precipitate is dried in a 105℃ forced-air drying oven to obtain nano-SiC-SiO2 coated particles.

[0099] Comparative Example 3

[0100] The only difference between this comparative example and Example 1 is that the coating process step is removed in the preparation of the modified polyvinyl alcohol fiber, and the modification process step after coating is also removed, that is, the SiC-SiO2 modified particles are replaced with nano-SiO2.

[0101] Specifically, the preparation method of modified polyvinyl alcohol fiber is as follows:

[0102] A1. Take 121g of tris(hydroxymethyl)aminomethane, add it to 600mL of water, stir until completely dissolved, then add hydrochloric acid to adjust the pH to 8.0, and dilute to 1000mL with water to obtain a buffer solution.

[0103] A2. Weigh 3g of catechol and 3g of 1,6-hexanediamine, add them to the buffer solution obtained in A1, stir and mix well to obtain the functional solution.

[0104] A3. Weigh 5g of polyvinyl alcohol fiber, add it to the functional solution obtained in A2, shake and react for 24h, take it out, wash it with water, and dry it at about 40℃ to obtain deposited fiber.

[0105] A4. Weigh 10g of nano-SiO2 and disperse it in 1000mL of water under ultrasonication for 15min to obtain a SiO2 particle dispersion.

[0106] A5. Immerse the deposited fiber obtained in A3 into the SiO2 particle dispersion obtained in A4, stir at 120 r / min for 2 h, take it out, wash it with water, and dry it at about 40℃ to obtain the modified polyvinyl alcohol fiber.

[0107] Comparative Example 4

[0108] The only difference between this comparative example and Example 1 is that in the preparation of the modified polyvinyl alcohol fiber, the polyvinyl alcohol fiber is directly mixed with SiC-SiO2 modified particles.

[0109] The preparation method of modified polyvinyl alcohol fiber is as follows: Weigh 10g of SiC-SiO2 modified particles and 5g of polyvinyl alcohol fiber, and directly mix the two physically to obtain modified polyvinyl alcohol fiber.

[0110] Comparative Example 5

[0111] The only difference between this comparative example and Example 1 is that the polyvinyl alcohol fiber is not modified, that is, the modified polyvinyl alcohol fiber is replaced with polyvinyl alcohol fiber.

[0112] Specifically, S1, prefabricated UHPC;

[0113] By weight, first mix 60 parts of cement, 16 parts of silica fume and 22 parts of fly ash, then add 20 parts of quartz sand and mix well. Next, add 21 parts of water, 1 part of high-efficiency water-reducing agent and 0.6 parts of dispersant, and stir thoroughly. Finally, add 2.5 parts of polyvinyl alcohol fiber, stir and mix well to obtain UHPC.

[0114] Comparative Example 6

[0115] The only difference between this comparative example and Example 1 is that the modified polyvinyl alcohol fiber has been removed.

[0116] Specifically, S1, prefabricated UHPC;

[0117] By weight, first mix 60 parts of cement, 16 parts of silica fume and 22 parts of fly ash, then add 20 parts of quartz sand and mix well. Then add 21 parts of water, 1 part of high-efficiency water-reducing agent and 0.6 parts of dispersant, stir thoroughly and mix well to obtain UHPC.

[0118] Test case

[0119] Test items and basis: 1. Compressive strength - GB / T50081-2019;

[0120] 2. Tensile strength - GB / T50081-2019;

[0121] 3. Chloride ion penetration resistance ----- Tested using the rapid chloride ion migration coefficient method in GB / T50082-2009, "Standard for Test Methods of Long-term Performance and Durability of Ordinary Concrete".

[0122] Test subjects: UHPCs prepared in Examples 1-6 and Comparative Examples 1-6.

[0123] Test results: See Table 1 and appendix. Figure 1-3 .

[0124]

[0125] Results Analysis: The analysis of Examples 1-6 and Comparative Examples 4-5, combined with the data in Table 1, and... Figure 1-3 It can be seen that the direct addition of polyvinyl alcohol fibers can improve the compressive and tensile strength of the concrete, but at the same time, it will also lead to an increase in the chloride ion diffusion coefficient of the concrete (a decrease in chloride ion penetration resistance).

[0126] Using a physical mixture of polyvinyl alcohol fiber and SiC-SiO2 modified particles can further improve the compressive and tensile strength of the concrete compared to adding polyvinyl alcohol fiber alone. However, it has almost no effect on the concrete's resistance to chloride ion penetration (the chloride ion diffusion coefficient hardly changes).

[0127] Furthermore, the inventors, using polyvinyl alcohol fiber content as a single variable, conducted multiple sets of comparative experiments and found that, without considering the impact on the mechanical properties of concrete, the resistance of concrete to chloride ion penetration actually showed a trend of first increasing and then decreasing with the increase of polyvinyl alcohol fiber content. However, considering that the improvement in the mechanical properties of concrete is insufficient when the polyvinyl alcohol fiber content is too low, all cases will not be elaborated here.

[0128] Analysis of Examples 1-6 and Comparative Examples 1-6, combined with data from Table 1 and Figure 1-3 It can be seen that the use of modified polyvinyl alcohol fiber can significantly improve the compressive strength, tensile strength and chloride ion penetration resistance of the concrete.

[0129] In the preparation of modified polyvinyl alcohol fibers, the coating of SiC by nano-SiO2, the surface modification of the outer SiO2 layer, the surface modification of polyvinyl alcohol fibers, and particle adhesion can all improve the compressive strength, tensile strength, and chloride ion penetration resistance of the prepared concrete, and there is a synergistic effect among the three.

[0130] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

[0131] Furthermore, various different embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed by the present invention.

Claims

1. A method for manufacturing a UHPC wind turbine tower, characterized in that, The UHPC comprises the following raw material components by weight: 60 parts cement, 14-18 parts silica fume, 17-22 parts quartz sand, 20-25 parts fly ash, 2-3 parts modified polyvinyl alcohol fiber, 0.8-1.5 parts high-efficiency water-reducing agent, 0.5-0.8 parts dispersant, and 20-23 parts water; The modified polyvinyl alcohol fiber is prepared as follows: A1. Take 121g of tris(hydroxymethyl)aminomethane, add it to 600mL of water, stir until completely dissolved, then add hydrochloric acid to adjust the pH to 8.0, and make up to 1000mL with water to obtain a buffer solution. A2. Weigh 3g of catechol and 3g of 1,6-hexanediamine, add them to the buffer solution obtained in A1, stir and mix well to obtain the functional solution. A3. Weigh 5g of polyvinyl alcohol fiber, add it to the functional solution obtained in A2, shake and react for 24h, take it out, wash it with water, and dry it at 40±5℃ to obtain deposited fiber. A4. Weigh 10g of SiC-SiO2 modified particles and disperse them in 1000mL of water under ultrasonication for 15min to obtain SiC-SiO2 particle dispersion. A5. Immerse the deposited fiber obtained in A3 into the SiC-SiO2 particle dispersion obtained in A4, stir at 120 r / min for 2 h, take it out and wash it with water, and dry it at 40±5℃ to obtain the modified polyvinyl alcohol fiber. The preparation method of the SiC-SiO2 modified particles is as follows: B1. Weigh 20g of nano-SiC-SiO2 coated particles, add them to 120mL of 2-ethylhexanol, then add 0.8g of p-toluenesulfonic acid, stir magnetically, and heat in a microwave oven for 4 hours to obtain the product. B2. The product obtained in B1 is washed by centrifugation with ethanol 3-4 times to remove residual 2-ethylhexanol, and then vacuum dried to constant weight to obtain SiC-SiO2 modified particles. The preparation method of the nano-SiC-SiO2 coated particles is as follows: B11. Weigh 16g of nano-SiC and disperse it in 160mL of isopropanol. Sonicate the dispersion for 30min to obtain SiC dispersion. B12. Transfer the SiC dispersion obtained in B11 to a three-necked flask, stir thoroughly, and add ammonia solution and tetraethyl orthosilicate solution dropwise at a rate of 1 drop / s. In a constant temperature water bath with electric stirring, control the reaction temperature at 40℃ and react for 6 hours to obtain the reaction solution. B13. The reaction solution obtained in B12 is centrifuged and washed with isopropanol. The resulting precipitate is dried in a 105℃ forced-air drying oven to obtain nano-SiC-SiO2 coated particles.

2. The method for manufacturing a UHPC wind turbine tower according to claim 1, characterized in that, In B12, the ammonia solution is prepared by mixing ammonia, water, and isopropanol in a mass ratio of 2:1:

1.

3. The method for manufacturing a UHPC wind turbine tower according to claim 1, characterized in that, In B12, the tetraethyl orthosilicate solution is prepared by mixing tetraethyl orthosilicate and isopropanol in a 1:1 mass ratio.

4. The method for manufacturing a UHPC wind turbine tower according to claim 1, characterized in that, In B12, the molar ratio of ammonia to tetraethyl orthosilicate is 2:1; the molar ratio of nano-SiC to tetraethyl orthosilicate is 5:

1.

5. The method for manufacturing a UHPC wind turbine tower according to claim 1, characterized in that, The cement used is P.O52.5 grade cement; the high-efficiency water-reducing agent is a polycarboxylate-based water-reducing agent.

6. The method for manufacturing a UHPC wind turbine tower according to claim 1, characterized in that, The dispersant includes triisopropanolamine and / or triethanolamine.

7. The method for manufacturing a UHPC wind turbine tower according to any one of claims 1-6, characterized in that, Includes the following steps: S1. First, mix cement, silica fume and fly ash evenly, then add quartz sand and mix evenly. Then add water, high-efficiency water-reducing agent and dispersant and stir. Finally, add modified polyvinyl alcohol fiber, stir and mix evenly to obtain UHPC. S2. The steel reinforcement skeleton is pre-embedded in the mold. The UHPC obtained in S1 is used for casting, molding and curing to obtain the tower segments. The segments are connected and assembled to obtain the UHPC wind turbine tower.

8. An application of a UHPC wind turbine tower, characterized in that, The UHPC wind turbine tower is manufactured using the preparation method described in any one of claims 1-7, and the UHPC wind turbine tower is used as the main structure of the wind power generation tower.

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