A concrete composite admixture for precast concrete wind power tower section

Abstract

This invention discloses a concrete composite admixture for precast concrete wind turbine tower components, comprising the following components by weight: 40-60 parts anhydrous calcium sulfoaluminate, 5-15 parts nano-calcium carbonate, 15-30 parts silica fume, 10-20 parts microspheres, 0.2-0.8 parts rheology modifier, 3-5 parts superplasticizer, and 1-5 parts sodium nitrite. The concrete composite admixture of this invention, when used in precast concrete wind turbine tower components, results in concrete with good workability, no bleeding or segregation, self-compacting properties, no need for vibration molding, ultra-long workable time, early strength and high strength, aesthetically pleasing appearance, low binder usage, low creep, minimal expansion, excellent crack resistance, and good durability.

Description

Technical Field

[0001] This invention relates to a functional additive for building concrete, specifically a concrete composite admixture for precast concrete wind turbine tower components, belonging to the field of building materials technology. Background Technology

[0002] With the continuous development of wind power technology, wind turbine capacity is constantly increasing, placing higher demands on the height of wind turbine towers. Common wind power tower structures mainly include steel towers, cast-in-place concrete towers, and precast concrete towers. Compared with steel towers, concrete towers have inherent durability, maintaining their performance even under extreme conditions, and have low maintenance costs. Precast concrete towers can solve problems such as the high construction difficulty of cast-in-place concrete towers and the difficulty in ensuring concrete quality due to harsh construction environments. Precast concrete towers have advantages such as flexible design, production, and construction, low maintenance requirements, and stable quality, making them very suitable for wind farms with high wind shear, which is conducive to increasing power generation. They have become a research focus and development direction in the wind power industry and have been vigorously promoted and applied. However, precast concrete wind turbine towers require high concrete strength, generally above C70, and need to have good load-bearing capacity, long-term performance, and durability. Currently, precast concrete wind turbine tower components mainly use low-slump concrete, achieving a compaction process through horizontal casting with the addition of a high-frequency vibration table. Because concrete molding requires high-frequency vibration, production is noisy, energy-intensive, and results in poor segment appearance quality and numerous air bubbles. With the rapid development of prefabricated buildings and intensified competition among enterprises, precast concrete is now required to not only have high strength and durability, but also high early strength, good workability, and an extended workable time to further accelerate construction progress, shorten the construction period, and improve economic benefits. Therefore, improving the early strength and workability of concrete is an effective technical approach to improve the production efficiency and reduce the production cost of precast concrete wind turbine tower components. Self-compacting concrete possesses excellent properties such as good fluidity and gap passage, and good resistance to bleeding and segregation. It can be cast without vibration, eliminating the problems of high noise and energy consumption caused by vibration, and resulting in segments with fewer air bubbles and a smooth, aesthetically pleasing appearance. Therefore, developing concrete with excellent workability, extended workable time, early strength, and durability for precast concrete wind turbine tower components is of great significance. Summary of the Invention

[0003] To address the shortcomings of existing technologies that primarily use low-slump concrete for precast concrete wind turbine tower components, such as poor workability and the need for high-frequency vibration molding, the present invention aims to provide a concrete composite admixture for precast concrete wind turbine tower components. Concrete with this composite admixture exhibits good workability, no bleeding or segregation, self-compacting properties, no need for vibration molding, extended workability, early strength and high strength, aesthetically pleasing appearance, low adhesive usage, minimal creep, slight expansion, excellent crack resistance, and good durability.

[0004] To achieve the above-mentioned technical objectives, the present invention adopts the following technical solution:

[0005] A concrete composite admixture for precast concrete wind turbine tower components comprises the following components by weight:

[0006]

[0007] The rheology modifier is a mixture of L-rhamnose and L-mannose;

[0008] The superplasticizer is of the following type:

[0009] The anhydrous calcium sulfoaluminate in the concrete composite admixture for precast concrete wind turbine tower components of this invention generates ettringite through a hydration reaction with cement. The large-scale early formation of ettringite in the concrete not only improves early strength but also achieves micro-expansion, enhancing crack resistance. Nano-calcium carbonate modifies concrete materials through chemical, nucleation, and filling effects. The chemical effect involves a reaction with tricalcium aluminate during hydration to produce hydrated calcium carboaluminate in high or low carbonate forms, promoting cement hydration and increasing hardened strength. The nucleation effect of nano-calcium carbonate promotes the hydration and growth of tricalcium silicate in the interfacial transition zone, improving the early strength of the concrete material. Because nano-calcium carbonate particles are much smaller than cement particles and have good dispersibility in the paste, the small voids between cement particles are filled, resulting in a more rational particle size distribution of the cementitious material, leading to increased microstructural density and improved impermeability and frost resistance. Nano-calcium carbonate can effectively modify… Improving the microstructure of cement materials and enhancing the mechanical properties of concrete, especially in controlling cement hydration performance and improving durability, helps overcome the inherent technical shortcomings of concrete materials. Utilizing the water-reducing function of superplasticizers reduces the water content of concrete, thereby increasing its density, reducing porosity, and improving strength. Simultaneously, the slow-release effect of superplasticizers allows for the gradual release of water-reducing properties, extending the workability of concrete while ensuring its self-flowing and compacting performance. Microspheres, being globally shaped particles almost entirely free of porous materials with extremely fine particle sizes, provide excellent filling and 'ball bearing lubrication' effects, resulting in significant physical water reduction. The formulated concrete exhibits good fluidity and low viscosity. Due to the continuous and uniform particle size distribution of microspheres, the concrete gradation is optimized at the microscopic level, leading to denser, stronger concrete with improved impermeability and corrosion resistance.

[0010] The comprehensive effects of the concrete composite admixture for precast concrete wind turbine tower components of this invention are reflected in its ability to improve the workability of concrete, good workability, no bleeding or segregation, self-compacting without vibration molding, ultra-long workable time, beautiful appearance, early strength and high strength, low binder dosage, small creep, micro-expansion, excellent crack resistance, good durability, and economical cost, enabling efficient production of precast concrete wind turbine tower components. Through the slow-release water-reducing effect of the superplasticizer and the 'ball lubrication' effect of the microspheres, it improves the fluidity of the concrete, enabling self-compacting without vibration molding, and providing an ultra-long workable time. The reduction in water consumption and optimization of gradation make the concrete denser and stronger, improving its impermeability and corrosion resistance. The expansion method that promotes the formation of ettringite is used to formulate shrinkage-compensating concrete to achieve the purpose of concrete self-crack resistance. The chemical action, nucleation action, and filling action of nano-calcium carbonate improve the early strength and durability of the concrete.

[0011] As a preferred embodiment, the nano-calcium carbonate is hydrophilic nano-calcium carbonate with a particle size of 0.01–0.1 μm, and more preferably, it is hydrophilic nano-calcium carbonate with a particle size of 0.01–0.05 μm. The main functions of nano-calcium carbonate are its chemical action, nucleation effect, and filling effect. Among these, the effects on the cement hydration process are primarily chemical action and nucleation effect. The chemical action involves reacting with tricalcium aluminate during hydration to produce hydrated calcium carboaluminate in high-carbonate or low-carbonate form, promoting cement hydration and increasing the hardened strength. The nucleation effect of nano-calcium carbonate promotes the hydration and growth of tricalcium silicate in the interfacial transition zone, improving the early strength of concrete materials. Because the particle size of nano-calcium carbonate is much smaller than that of cement particles and it has good dispersibility in the paste, the small gaps between cement particles are filled, resulting in a more rational particle size distribution of the cementitious material, leading to increased microstructure density, effectively improving the microstructure of cement materials, and enhancing the mechanical properties of concrete materials.

[0012] As a preferred embodiment, the silica fume is semi-dense silica fume with a particle size of 0.1–0.5 μm. More preferably, the semi-dense silica fume has a particle size of 0.2–0.4 μm and an amorphous silica content greater than 90%. The main function of silica fume is to act as a seed crystal in the early stages to promote the formation of ettringite; ultrafine silica fume particles can fill the pores between cement particles; and it also forms a gel with hydration products. The use of silica fume significantly reduces the pore size in the hydrated paste, improves the pore size distribution, increases strength, reduces permeability, and enhances durability.

[0013] As a preferred embodiment, the microsphere particle size is 0.1–1 μm. More preferably, the microsphere particle size is 0.2–0.5 μm. The main function of the microspheres is that, as global particles containing almost no porous material, their extremely fine particle size provides excellent filling and 'ball bearing lubrication' effects for concrete, resulting in significant physical water reduction. The prepared concrete has good fluidity and low viscosity. Due to the continuous and uniform particle size distribution of the microspheres, the concrete gradation is greatly optimized at the microscopic level, making the concrete denser, stronger, and improving its impermeability and corrosion resistance.

[0014] As a preferred embodiment, the rheology modifier is composed of L-rhamnose and L-mannose in a mass percentage ratio of 20%–40%: 60%–80%. The composite rheology modifier of L-rhamnose and L-mannose can enhance the plasticity and water retention of concrete, reduce the tendency for bleeding and segregation, and give the concrete excellent workability.

[0015] The superplasticizer of this invention is of the following type: Purchased from Sika AG, Switzerland, it features high plasticity retention and slow-release properties, achieving a slow-release water-reducing effect. While ensuring the self-compacting and workability of concrete, it also helps to extend the workability of concrete.

[0016] Compared with the prior art, the technical solution of the present invention brings the following beneficial effects:

[0017] 1) A composite admixture for precast concrete wind turbine tower components according to the present invention comprises anhydrous calcium sulfoaluminate, nano-calcium carbonate, silica fume, microspheres, rheology modifier, superplasticizer, and sodium nitrite. This composite admixture, through the slow-release water-reducing effect of the superplasticizer and the 'ball lubrication' effect of the microspheres, improves the fluidity of the concrete, enabling it to self-compact and form without vibration, extending its workable time. The reduction in water consumption and optimization of gradation result in denser concrete with higher strength, improving its impermeability and corrosion resistance. The rheology modifier enhances the plasticity and water retention of the concrete, reduces the tendency for bleeding and segregation, and gives the concrete excellent workability.

[0018] 2) This invention provides a composite concrete admixture for precast concrete wind turbine tower components. It utilizes the hydration reaction of anhydrous calcium sulfoaluminate with cement to generate a large amount of ettringite, providing early strength and micro-expansion properties to the concrete, thus improving its crack resistance. Through the chemical, nucleation, and filling effects of nano-calcium carbonate, it promotes cement hydration, while simultaneously making the particle size distribution more rational and increasing the density of the microstructure, thereby improving the early strength and durability of the concrete. Sodium nitrite, as an early strength agent, enhances the early strength of the concrete and also acts as a rust inhibitor and antifreeze agent, preventing steel reinforcement corrosion and preventing freezing damage to the concrete during winter construction, thus improving the concrete's durability. Detailed Implementation

[0019] The following specific embodiments are intended to further illustrate the content of the present invention, but the scope of protection of the present invention is not limited to the following specific embodiments.

[0020] The following embodiments further illustrate the content of the present invention by using concrete composite admixtures for precast concrete wind turbine tower components to prepare precast concrete wind turbine tower segments that can be demolded and hoisted in one day.

[0021] The concrete composite admixture of the present invention has no special requirements in its preparation process; simple stirring is sufficient.

[0022] In the following specific embodiments, unless otherwise specified, all raw materials are commercially available materials purchased directly.

[0023] Example 1

[0024] Concrete composite admixtures for precast concrete wind turbine tower components:

[0025] 40 parts anhydrous calcium sulfoaluminate, 10 parts nano-calcium carbonate (0.02 μm particle size), 25 parts silica fume (0.3 μm particle size), 20 parts microspheres, 0.5 parts rheology modifier (L-rhamnose:L-mannose = 2:8), and high-performance polycarboxylate superplasticizer. 3 parts, sodium nitrite 1.5 parts.

[0026] Preparation of C80 precast concrete wind turbine tower segment concrete:

[0027] P·O52.5 ordinary Portland cement 405kg / m 3 Grade I fly ash 95kg / m³ 3 100kg / m² of concrete composite admixture for precast concrete wind turbine tower components 3 Medium sand 760kg / m 3 4.75~9.5mm crushed stone 303kg / m 3 9.5-16mm crushed stone 707kg / m 3 138 kg / m³ of water 3 .

[0028] Example 2

[0029] Concrete composite admixtures for precast concrete wind turbine tower components:

[0030] 50 parts anhydrous calcium sulfoaluminate, 10 parts nano-calcium carbonate (0.02 μm particle size), 20 parts silica fume (0.3 μm particle size), 15 parts microspheres, 0.5 parts rheology modifier (L-rhamnose:L-mannose = 2:8), and high-performance polycarboxylate superplasticizer. 3 parts, sodium nitrite 1.5 parts.

[0031] Preparation of C80 precast concrete wind turbine tower segment concrete:

[0032] P·O52.5 ordinary Portland cement 405kg / m 3 Grade I fly ash 95kg / m³ 3 100kg / m² of concrete composite admixture for precast concrete wind turbine tower components 3 Medium sand 760kg / m 3 4.75~9.5mm crushed stone 303kg / m 3 9.5-16mm crushed stone 707kg / m 3 138 kg / m³ of water 3 .

[0033] Example 3

[0034] Concrete composite admixtures for precast concrete wind turbine tower components:

[0035] 50 parts anhydrous calcium sulfoaluminate, 15 parts nano-calcium carbonate (0.02 μm particle size), 20 parts silica fume (0.3 μm particle size), 10 parts microspheres, 0.5 parts rheology modifier (L-rhamnose:L-mannose = 3:7), and high-performance polycarboxylate superplasticizer. 3 parts, sodium nitrite 1.5 parts.

[0036] Preparation of C80 precast concrete wind turbine tower segment concrete:

[0037] P·O52.5 ordinary Portland cement 405kg / m 3 Grade I fly ash 95kg / m³ 3 100kg / m² of concrete composite admixture for precast concrete wind turbine tower components 3 Medium sand 760kg / m 3 4.75~9.5mm crushed stone 303kg / m 3 9.5-16mm crushed stone 707kg / m 3 138 kg / m³ of water 3 .

[0038] Example 4

[0039] Concrete composite admixtures for precast concrete wind turbine tower components:

[0040] 60 parts anhydrous calcium sulfoaluminate, 7 parts nano-calcium carbonate (0.02 μm particle size), 15 parts silica fume (0.3 μm particle size), 10 parts microspheres, 0.8 parts rheology modifier (L-rhamnose:L-mannose = 4:6), and high-performance polycarboxylate superplasticizer. 4 parts, sodium nitrite 3.2 parts.

[0041] Preparation of C80 precast concrete wind turbine tower segment concrete:

[0042] P·O52.5 ordinary Portland cement 405kg / m 3 Grade I fly ash 95kg / m³ 3 100kg / m² of concrete composite admixture for precast concrete wind turbine tower components 3 Medium sand 760kg / m 3 4.75~9.5mm crushed stone 303kg / m 3 9.5-16mm crushed stone 707kg / m 3 138 kg / m³ of water 3 .

[0043] Comparative Example 1

[0044] The difference between this comparative example and Example 1 is that the C80 concrete does not contain the concrete composite admixture used for precast concrete wind turbine tower components; the amount of composite admixture is replaced by an equal amount of P·O52.5 ordinary Portland cement. Specifically:

[0045] Preparation of C80 precast concrete wind turbine tower segment concrete:

[0046] P·O52.5 ordinary Portland cement 505kg / m 3 Grade I fly ash 95kg / m³ 3 High-performance polycarboxylate superplasticizer 530P 2.4kg / m² 3 Medium sand 760kg / m 3 4.75~9.5mm crushed stone 303kg / m 3 9.5-16mm crushed stone 707kg / m 3 138 kg / m³ of water 3 .

[0047] Comparative Example 2

[0048] The difference between this comparative example and Example 1 is that the nano-calcium carbonate in the concrete composite admixture used for precast concrete wind turbine tower components is replaced with 800-mesh calcium carbonate. Specifically:

[0049] Concrete composite admixtures for precast concrete wind turbine tower components:

[0050] 40 parts anhydrous calcium sulfoaluminate, 10 parts 800-mesh calcium carbonate, 25 parts silica fume (0.3 μm particle size), 20 parts microspheres, 0.5 parts rheology modifier (L-rhamnose:L-mannose = 2:8), and high-performance polycarboxylate superplasticizer. 3 parts, sodium nitrite 1.5 parts.

[0051] Preparation of C80 precast concrete wind turbine tower segment concrete:

[0052] P·O52.5 ordinary Portland cement 405kg / m 3 Grade I fly ash 95kg / m³ 3 100kg / m² of concrete composite admixture for precast concrete wind turbine tower components 3 Medium sand 760kg / m 3 4.75~9.5mm crushed stone 303kg / m 3 9.5-16mm crushed stone 707kg / m 3 138 kg / m³ of water 3 .

[0053] Comparative Example 3

[0054] The difference between this comparative example and Example 1 is that the concrete composite admixture used for precast concrete wind turbine tower components does not contain microspheres. Specifically:

[0055] Preparation of concrete composite admixtures for precast concrete wind turbine tower components:

[0056] 40 parts anhydrous calcium sulfoaluminate, 10 parts nano calcium carbonate, 25 parts silica fume (0.3 μm particle size), 0.5 parts rheology modifier (L-rhamnose:L-mannose = 2:8), and high-performance polycarboxylate superplasticizer. 3 parts, sodium nitrite 1.5 parts.

[0057] Preparation of C80 precast concrete wind turbine tower segment concrete:

[0058] P·O52.5 ordinary Portland cement 405kg / m 3 Grade I fly ash 95kg / m³ 3 100kg / m² of concrete composite admixture for precast concrete wind turbine tower components 3 Medium sand 760kg / m 3 4.75~9.5mm crushed stone 303kg / m 3 9.5-16mm crushed stone 707kg / m 3 138 kg / m³ of water 3 .

[0059] Comparative Example 4

[0060] The difference between this comparative example and Example 1 is that the rheology modifier in the concrete composite admixture used for precast concrete wind turbine tower components is L-rhamnose. Specifically:

[0061] Preparation of concrete composite admixtures for precast concrete wind turbine tower components:

[0062] 40 parts anhydrous calcium sulfoaluminate, 10 parts nano calcium carbonate (0.02 μm particle size), 25 parts silica fume (0.3 μm particle size), 20 parts microspheres, 0.5 parts rheology modifier (L-rhamnose), and high-performance polycarboxylate superplasticizer. 3 parts, sodium nitrite 1.5 parts.

[0063] Preparation of C80 precast concrete wind turbine tower segment concrete:

[0064] P·O52.5 ordinary Portland cement 405kg / m 3 Grade I fly ash 95kg / m³ 3 100kg / m² of concrete composite admixture for precast concrete wind turbine tower components 3 Medium sand 760kg / m 34.75~9.5mm crushed stone 303kg / m 3 9.5-16mm crushed stone 707kg / m 3 138 kg / m³ of water 3 .

[0065] Comparative Example 5

[0066] The difference between this comparative example and Example 1 is that the rheology modifier in the concrete composite admixture used for precast concrete wind turbine tower components is L-mannose. Specifically:

[0067] Preparation of concrete composite admixtures for precast concrete wind turbine tower components:

[0068] 40 parts anhydrous calcium sulfoaluminate, 10 parts nano calcium carbonate (0.02 μm particle size), 25 parts silica fume (0.3 μm particle size), 20 parts microspheres, 0.5 parts rheology modifier (L-mannose), and high-performance polycarboxylate superplasticizer. 3 parts, sodium nitrite 1.5 parts.

[0069] Preparation of C80 precast concrete wind turbine tower segment concrete:

[0070] P·O52.5 ordinary Portland cement 405kg / m 3 Grade I fly ash 95kg / m³ 3 100kg / m² of concrete composite admixture for precast concrete wind turbine tower components 3 Medium sand 760kg / m 3 4.75~9.5mm crushed stone 303kg / m 3 9.5-16mm crushed stone 707kg / m 3 138 kg / m³ of water 3 .

[0071] Comparative Example 6

[0072] The difference between this comparative example and Example 1 is that the concrete composite admixture used for precast concrete wind turbine tower components does not contain sodium nitrite. Specifically:

[0073] Preparation of concrete composite admixtures for precast concrete wind turbine tower components:

[0074] 40 parts anhydrous calcium sulfoaluminate, 10 parts nano-calcium carbonate (0.02 μm particle size), 25 parts silica fume (0.3 μm particle size), 20 parts microspheres, 0.5 parts rheology modifier (L-rhamnose:L-mannose = 2:8), and high-performance polycarboxylate superplasticizer. 3 copies.

[0075] Preparation of C80 precast concrete wind turbine tower segment concrete:

[0076] P·O52.5 ordinary Portland cement 405kg / m 3 Grade I fly ash 95kg / m³ 3 100kg / m² of concrete composite admixture for precast concrete wind turbine tower components 3 Medium sand 760kg / m 3 4.75~9.5mm crushed stone 303kg / m 3 9.5-16mm crushed stone 707kg / m 3 138 kg / m³ of water 3 .

[0077] Comparative Example 7

[0078] The difference between this comparative example and Example 1 is that the superplasticizer in the concrete composite admixture used for precast concrete wind turbine tower components is PC8020 (a non-high-plasticity polycarboxylate high-performance water-reducing agent). Specifically:

[0079] Preparation of concrete composite admixtures for precast concrete wind turbine tower components:

[0080] 40 parts anhydrous calcium sulfoaluminate, 10 parts nano calcium carbonate (particle size 0.02μm), 25 parts silica fume (particle size 0.3μm), 20 parts microspheres, 0.5 parts rheology modifier (L-rhamnose:L-mannose = 2:8), 3 parts polycarboxylate superplasticizer PC8020 (Jiangsu Zhaojia Building Materials Technology Co., Ltd.), and 1.5 parts sodium nitrite.

[0081] Preparation of C80 precast concrete wind turbine tower segment concrete:

[0082] P·O52.5 ordinary Portland cement 405kg / m 3 Grade I fly ash 95kg / m³ 3 100kg / m² of concrete composite admixture for precast concrete wind turbine tower components 3 Medium sand 760kg / m 3 4.75~9.5mm crushed stone 303kg / m 3 9.5-16mm crushed stone 707kg / m 3 138 kg / m³ of water 3 .

[0083] Table 1 shows the test results of various performance parameters of C80 precast concrete wind turbine tower segments that can be demolded and hoisted in one day. The slump spread, T50, and J-ring spread were tested according to the standard JGJ / T283-2012 "Technical Specification for Application of Self-Compacting Concrete". The compressive strength was tested according to the standard GB / T 50081-2019 "Standard for Test Methods of Physical and Mechanical Properties of Concrete". The restricted expansion rate was tested according to GB50119-2013 "Technical Specification for Application of Concrete Admixtures". The creep test was tested according to the standard GB / T 50082-2009 "Standard for Test Methods of Long-Term Performance and Durability of Ordinary Concrete".

[0084] Table 1. Performance test results of concrete examples and comparative examples of C80 precast concrete wind turbine tower segments.

[0085]

[0086]

[0087] The results show that the precast concrete wind turbine tower segments in Examples 1, 2, 3, and 4 have excellent workability, exhibiting superior slump spread, T50, and J-ring spread performance, which represent filling and gap passage. They can be self-flowed and compacted, and also have high early strength, with a 1-day compressive strength greater than 56 MPa, reaching more than 70% of the design strength, meeting the requirements for demolding and hoisting. This is mainly due to the early formation of a large amount of ettringite, which improves early strength. Because of the high early strength of the concrete, the creep strain is small in the later stage, and the limited expansion rate from 14 days in water to 28 days in air is good, resulting in good crack resistance and better durability.

[0088] Comparative Example 1 shows that, due to the absence of concrete composite admixtures for precast concrete wind turbine tower components, the workability is poor, the early strength is low, and the later creep strain is large. Due to the absence of expansion components, the limited expansion rate from 14 days in water to 28 days in air is low.

[0089] Comparative Example 2 shows that, since it is not nano-calcium carbonate, its early 1-day and late 28-day compressive strengths are relatively low. Therefore, nano-calcium carbonate is very beneficial for early and late strength.

[0090] Comparative Example 3 shows that, due to the absence of microspheres, the concrete viscosity is high, its fluidity is poor, and its gap passage is poor. The 'ball lubrication' effect of microspheres has a significant impact on fluidity.

[0091] Comparative Examples 4 and 5 show that when a single rheology modifier is used, the workability of the concrete is poor, which is not conducive to construction and also affects the strength. However, when the two are properly mixed, they exhibit excellent performance.

[0092] Comparative Example 6 shows that the early 1-day compressive strength is lower due to the absence of sodium nitrite.

[0093] Comparative Example 7 shows that, because it is not a high-plasticity polycarboxylate superplasticizer, the concrete loses a lot of water over time and cannot meet the requirements for long-term operation and construction. Therefore, the appropriate type of superplasticizer has a great impact on the workability of concrete.

Claims

1. A concrete composite admixture for precast concrete wind turbine tower components, characterized in that, Includes the following components by weight: The rheology modifier is a mixture of L-rhamnose and L-mannose; The superplasticizer is of the following type: -530P.

2. The concrete composite admixture according to claim 1, characterized in that: The nano-calcium carbonate is a hydrophilic nano-calcium carbonate with a particle size of 0.01 to 0.1 μm.

3. The concrete composite admixture according to claim 2, characterized in that: The nano-calcium carbonate is a hydrophilic nano-calcium carbonate with a particle size of 0.01 to 0.05 μm.

4. The concrete composite admixture according to claim 1, characterized in that: The microbeads have a particle size of 0.1–1 μm.

5. The concrete composite admixture according to claim 4, characterized in that: The microspheres have a particle size of 0.2–0.5 μm.

6. The concrete composite admixture according to claim 1, characterized in that: The silica fume is semi-densified silica fume with a particle size of 0.1 to 0.5 μm.

7. The concrete composite admixture according to claim 6, characterized in that: The silica fume is semi-densified silica fume with a particle size of 0.2 to 0.4 μm.

8. The concrete composite admixture according to claim 1, characterized in that: The rheology modifier is composed of L-rhamnose and L-mannose in a mass percentage ratio of 20%–40% and 60%–80%.

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