An ultra-early strength grouting material in a low-temperature environment, a preparation method and application thereof

Abstract

The application relates to an ultra-early-strength grouting material in a low-temperature environment and a preparation method and application thereof, and the raw material formula of the ultra-early-strength grouting material comprises the following components in parts by weight: fast-hardening sulphoaluminate cement 180-300 parts, ordinary Portland cement 600-800 parts, polypropylene fiber 1-3 parts, glue powder 10-20 parts, microbeads 120-200 parts, quartz sand 800-1200 parts, retarder 3-12 parts, water reducing agent 8-20 parts, expanding agent 25-50 parts, early-strength agent 1-5 parts, anti-freezing agent 5-10 parts and composite additive 5-15 parts, wherein the composite additive comprises water-retaining agent, fluidizing agent and defoaming agent. The application combines the low water-binder ratio in use of the optimized grouting material formula, so that the grouting material can reach more than 30MPa in 5h compressive strength performance and more than 63MPa in 3d compressive strength performance under low-temperature environment (-5 DEG C) maintenance, meanwhile, the grouting material has excellent tensile performance, bonding performance and excellent fluidity, meets the performance requirements of a wind power tower drum, and greatly improves construction efficiency.

Description

Technical Field

[0001] This invention relates to the field of building materials, specifically to an ultra-early strength grouting material for low-temperature environments, its preparation method, and its application. Background Technology

[0002] The rise of low-carbon and clean energy has led to the rapid development of infrastructure such as wind power generation across the country. Grouting materials, as indispensable connecting materials in wind turbine towers and foundation engineering, have crucial performance characteristics.

[0003] Concrete wind turbine towers are C-shaped spliced ​​structures, often located at high altitudes or in open ocean environments, and are affected by low temperatures. During splicing and transportation, the grouting material used in the towers needs to be able to withstand certain low-temperature environments and have good construction performance. Furthermore, wind turbine towers are subjected to significant loads during service, making the bonding performance of materials such as those used in the tower joints particularly critical.

[0004] In existing grouting technologies, cement-based grouts mainly use ordinary Portland cement as the primary gelling material, with admixtures or additives added. Their early strength development is slow, resulting in lower overall strength. For example, CN114956731A provides an early-strength, non-shrinkage grout and its preparation method, while CN114804766A provides an ultra-early-strength grout suitable for harsh environments, its preparation method, and its application. However, neither of these provides specific details regarding the development of early strength. CN112939503A discloses an ultra-early-strength, ultra-high-strength inorganic grout based on ordinary Portland cement and its preparation method. Although its 2-hour compressive strength can reach approximately 20 MPa, it does not further explain the critical strength at 5-6 hours. Furthermore, the water-cement ratio in this invention is too high, leading to a decline in long-term flexural and compressive strength. Moreover, its strength is tested under normal temperature conditions and cannot meet the requirements for use in low-temperature environments. Some grouts used in low-temperature environments also fail to meet requirements such as early strength. Furthermore, there is very little research and application of existing technologies regarding the tensile and bonding performance indicators of grouting materials.

[0005] In summary, existing grouting technologies are insufficient to meet the application requirements of wind turbine towers. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide a grouting material that can be used in low-temperature environments and has high early strength, which is particularly suitable for wind turbine towers.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0008] An ultra-early strength grouting material for low-temperature environments, wherein the raw material formula of the ultra-early strength grouting material comprises the following components by weight: 180-300 parts of rapid-hardening sulfoaluminate cement, 600-800 parts of ordinary silicate cement, 1-3 parts of polypropylene fiber, 10-20 parts of adhesive powder, 120-180 parts of microspheres, 800-1200 parts of quartz sand, 3-12 parts of retarder, 8-20 parts of water-reducing agent, 25-50 parts of expansion agent, 1-5 parts of early strength agent, 5-10 parts of antifreeze agent, and 5-15 parts of composite additives.

[0009] Preferably, the raw material formula of the ultra-early strength grouting material includes the following components: 200-270 parts of rapid-hardening sulfoaluminate cement, 630-700 parts of ordinary silicate cement, 1.5-2.5 parts of polypropylene fiber, 10-20 parts of adhesive powder, 150-200 parts of microspheres, 900-1200 parts of quartz sand, 5-10 parts of retarder, 10-15 parts of water-reducing agent, 30-40 parts of expansion agent, 2-3 parts of early strength agent, 5-10 parts of antifreeze agent, and 5-10 parts of composite additives.

[0010] According to some embodiments of the present invention, when the ultra-early strength grout is used, the amount of water is 8 to 10% of the ultra-early strength grout.

[0011] Furthermore, when using the ultra-early strength grout, the water-cement ratio is 0.18–0.22. Preferably, the water-cement ratio is 0.18–0.20.

[0012] According to some embodiments of the present invention, when the ultra-early strength grout is used, the binder-aggregate ratio is 0.8 to 1.3:1. Preferably, the binder-aggregate ratio is 1.0 to 1.1:1.

[0013] According to some embodiments of the present invention, the rapid-hardening sulfoaluminate cement is selected from grade 52.5 rapid-hardening sulfoaluminate cement, and its 3-day compressive strength is not less than 55 MPa; the ordinary silicate cement is selected from grade 52.5 ordinary silicate cement.

[0014] According to some embodiments of the present invention, the amount of the rapid-hardening sulfoaluminate cement accounts for 18-30% of the total amount of gel material.

[0015] In this invention, the gel material includes rapid-hardening sulfoaluminate cement, ordinary silicate cement, adhesive powder, and microspheres.

[0016] Furthermore, the adhesive powder is a construction adhesive powder.

[0017] Furthermore, the polypropylene fiber has a diameter of 0.1–0.5 mm and a length of 5–15 mm.

[0018] Furthermore, the quartz sand is a combination of 10-20 mesh quartz sand, 20-40 mesh quartz sand, 40-80 mesh and 80-100 mesh quartz sand in a mass ratio of 3.5-4.5:2-3:2-3:1, specifically in a mass ratio of 4:2.5:2.5:1.

[0019] According to some embodiments of the present invention, the retarder is a combination of tartaric acid and a sulfoaluminate cement-specific retarder in a mass ratio of 1:0.7 to 0.8, and the retarder dosage is 2% to 3% of the amount of rapid-hardening sulfoaluminate cement. Preferably, the mass ratio of tartaric acid to the sulfoaluminate cement-specific retarder is 1:0.75. The retarder dosage is 2.8% of the amount of rapid-hardening sulfoaluminate cement.

[0020] In some specific and preferred embodiments, the expanding agent is one or more of the following: ettringite-lime composite expanding agent and plastic expanding agent.

[0021] In some specific and preferred embodiments, the early strength agent is a carbonate and the antifreeze agent is a nitrate.

[0022] In some specific and preferred embodiments, the composite additive is a combination of a water-retaining agent, a fluidizing agent, and a defoamer. Further, the mass ratio of the water-retaining agent, fluidizing agent, and defoamer is 5–7:7–9:1. Preferably, the mass ratio of the water-retaining agent, fluidizing agent, and defoamer is 6–6.5:8.5–9:1, specifically 6.4:8.6:1.

[0023] The second technical solution adopted by the present invention is a method for preparing ultra-early strength grouting material under low temperature environment as described above, which includes mixing all the raw materials of the ultra-early strength grouting material to obtain the ultra-early strength grouting material.

[0024] The third technical solution adopted in this invention is the application of the ultra-early strength grouting material under low temperature environment described above on wind turbine towers.

[0025] The ultra-early strength grout can be used in environments ranging from -10℃ to -5℃.

[0026] Due to the application of the above technical solution, the present invention has the following advantages compared with the prior art:

[0027] This invention optimizes the grout formulation and uses a low water-cement ratio, enabling the grout to achieve a compressive strength of over 30 MPa after 5 hours and over 63 MPa after 3 days of curing in a low-temperature environment (-5℃). It also exhibits excellent tensile strength, bonding properties, and flowability, meeting the performance requirements of wind turbine towers and greatly improving construction efficiency. Detailed Implementation

[0028] As described in the background section, existing grouting technologies are insufficient to meet the application requirements of wind turbine towers. This is mainly because concrete wind turbine towers are often located in high-altitude or ocean environments, where they are affected by low temperatures. During splicing and transportation, the grouting material must be able to adapt to certain low-temperature environments, have good construction performance, and exhibit rapid development of compressive strength within 5-6 hours, reaching 30 MPa, in order to carry out operations such as rebar connection, horizontal and vertical splicing. Furthermore, the 3-day compressive strength must reach above 63 MPa to tension the vertical prestressing tendons. In addition, wind turbine towers are subjected to significant loads during service, making the bonding performance of materials such as tower splices particularly critical.

[0029] This application optimizes the grout formulation and, when used in conjunction with other methods, employs a low water-cement ratio to reduce the impact of capillary pores on strength and other properties after the grout has hardened. To address engineering construction and low-temperature environments, firstly, the combined effects of early-strength cement, early-strength agents, and antifreeze agents stimulate the early strength of the grout, ensuring rapid turnover during construction. Secondly, the use of water-reducing agents and composite additives effectively reduces the consistency changes of the grout after the addition of adhesive powder and polypropylene fibers, achieving an initial flowability of over 320 mm. Simultaneously, the synergistic effect of tartaric acid and the retarder for sulfoaluminate cement accurately adjusts the hydration heat release time of the grout, controlling the flowability to be no less than 280 mm at 30 minutes, and achieving hardening and strength in approximately 2-3 hours, resulting in a 5-hour strength of 30 MPa. Thirdly, the incorporation of adhesive powder and polypropylene fibers into the grout system of this application effectively improves the bonding strength of the grout and significantly enhances its tensile strength. By optimizing the grout formulation and using a low water-cement ratio, the grout of this invention can achieve a compressive strength of over 30 MPa after 5 hours and over 63 MPa after 3 days in a low-temperature environment (-5℃). It also has excellent tensile strength, bonding performance and excellent flowability, meeting the performance requirements of wind turbine towers and greatly improving construction efficiency.

[0030] The technical solutions of the present invention will be described in detail below with reference to specific embodiments, so that those skilled in the art can better understand and implement the technical solutions of the present invention, but the present invention is not limited to the scope of the examples described.

[0031] Example 1

[0032] The ultra-early strength grouting material for low-temperature environments provided in this embodiment has the raw material formula shown in Table 1.

[0033] The polypropylene fiber has a diameter of 0.3 mm, a length of 10 mm, and a smooth, round surface.

[0034] The adhesive powder was purchased commercially as building adhesive powder.

[0035] The microbeads are commercially available microbeads.

[0036] The quartz sand is a combination of 10-20 mesh quartz sand, 20-40 mesh quartz sand, 40-80 mesh quartz sand and 80-100 mesh quartz sand in a mass ratio of 4:2.5:2.5:1.

[0037] The expanding agent is a composite expanding agent of calcite and lime.

[0038] The water-reducing agent is a powdered polycarboxylate high-performance water-reducing agent.

[0039] Retarder for sulfoaluminate cement, brand: Zhongde Zerun, Zhengzhou Zhongde Zerun Building Materials Co., Ltd. (http: / / www.zdzr66.com / doc_23460651.html).

[0040] The composite additive is a mixture of water-retaining agent, fluidizing agent and defoamer. The water-retaining agent is 300-500 mPas carboxymethyl cellulose, the fluidizing agent is BASF 4930F high-efficiency water-reducing agent, and the defoamer is Mingling P803 defoamer.

[0041] The preparation of the ultra-early strength grout in this example involves mixing all the raw materials of the ultra-early strength grout.

[0042] In this example, when using the ultra-early strength grout, 200 parts of water are added to the mixing pot, and the ultra-early strength grout is added and stirred to obtain a mixture. After the mixture is poured into the test mold, it is cured at -5℃ for 7 days, and then transferred to the standard curing box for continued curing.

[0043] Example 2

[0044] The raw material formula of the ultra-early strength grouting material for low-temperature environments provided in this embodiment is shown in Table 1.

[0045] In this example, the amount of water used for the ultra-early strength grouting material is 205 parts, and the other usages are the same as in Example 1.

[0046] Example 3

[0047] The ultra-early strength grouting material for low-temperature environments provided in this embodiment has the raw material formula shown in Table 1. When using it, the amount of water is 205 parts, and the other uses are the same as in Embodiment 1.

[0048] Example 4

[0049] The raw material formula of the ultra-early strength grouting material for low-temperature environments provided in this embodiment is shown in Table 1.

[0050] In this example, the amount of water used for the ultra-early strength grouting material is 210 parts, and the other usages are the same as in Example 1.

[0051] Example 5

[0052] The ultra-early strength grouting material for low-temperature environments provided in this embodiment has the raw material formula shown in Table 1. When using it, the amount of water is 210 parts, and the other components are the same as in Embodiment 1.

[0053] The raw material formulas of the grouting materials provided in Comparative Examples 1 to 6 are shown in Table 2. When using them, the amount of water is 205 parts, and the other uses are the same as in Example 1.

[0054] The grouting materials provided in Examples 1-5 and Comparative Examples 1-6 were tested for fluidity and compressive strength according to GB / T 50448-2015 standard, tensile strength according to T / CBMF 37-2018 (T / CCPA 7-2018) standard, and tensile bond strength according to JGJ / T 70-2009 standard. The results are shown in Table 3.

[0055] Table 1 shows the raw material formulations (parts by weight) of the ultra-early strength grouting materials in Examples 1-5.

[0056]

[0057]

[0058] Table 2 shows the raw material formulas (parts by weight) of the grouting materials for Comparative Examples 1–6.

[0059]

[0060] Table 3 shows the performance test results of the grouting materials in Examples 1-5 and Comparative Examples 1-6.

[0061]

[0062] Note: The compressive strengths at 5h, 1d, and 3d in Table 3 are the compressive strengths of the mixture after curing at -5℃ in the mold for the corresponding time.

[0063] As shown in Table 3, the ultra-early strength grouting material of the representative embodiment of the present invention exhibits high fluidity in low-temperature environments, and the fluidity remains relatively stable, meeting the time requirements for jointing and grouting operations in wind power projects. Simultaneously, the grouting material of the representative embodiment of the present invention demonstrates high compressive strength at the initial time (-5℃, 5h), meeting the requirements for early turnover and hoisting during construction. Compared to ordinary early strength grouting materials, the grouting material of the representative embodiment of the present invention exhibits significantly higher tensile strength and excellent bond strength, significantly improving the performance of concrete towers in bearing wind turbine loads during operation. Furthermore, the grouting material of the representative embodiment of the present invention uses a low water-cement ratio, effectively reducing the number of capillary pores generated during hydration and water evaporation, avoiding later strength degradation, and possessing high engineering application value.

[0064] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

[0065] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

Claims

1. A type of ultra-early strength grouting material for low-temperature environments, characterized in that, The raw material formula of the ultra-early strength grouting material by weight The grout comprises the following components: 180-300 parts of rapid-hardening sulfoaluminate cement, 600-800 parts of ordinary silicate cement, 1-3 parts of polypropylene fiber, 10-20 parts of adhesive powder, 120-200 parts of microspheres, 800-1200 parts of quartz sand, 3-12 parts of retarder, 8-20 parts of water-reducing agent, 25-50 parts of expanding agent, 1-5 parts of early-strength agent, 5-10 parts of antifreeze agent, and 5-15 parts of composite additives. When using the ultra-early-strength grout, the water-cement ratio is 0.18-0.

22. The early-strength agent is a carbonate, and the antifreeze agent is a nitrate. The retarder is a combination of tartaric acid and a sulfoaluminate cement-specific retarder in a mass ratio of 1:0.7-0.

8. The composite additives are a combination of water-retaining agent, fluidizing agent, and defoamer in a mass ratio of 5-7:7-9:

1.

2. The ultra-early strength grouting material under low-temperature conditions according to claim 1, characterized in that, The binder-aggregate ratio of the ultra-early strength grout is 0.8 to 1.3:

1.

3. The ultra-early strength grouting material under low-temperature conditions according to claim 1, characterized in that, When using the ultra-early strength grout, the amount of water used should be 8-10% of the total amount of the ultra-early strength grout.

4. The ultra-early strength grouting material under low-temperature conditions according to claim 1, characterized in that, The rapid-hardening sulfoaluminate cement is selected from grade 52.5 rapid-hardening sulfoaluminate cement, and its 3-day compressive strength is not less than 55 MPa; and / or, the amount of rapid-hardening sulfoaluminate cement accounts for 18-30% of the total amount of gel material; and / or, the ordinary silicate cement is selected from grade 52.5 ordinary silicate cement.

5. The ultra-early strength grouting material under low-temperature conditions according to claim 1, characterized in that: The adhesive powder is a construction adhesive powder; and / or, the polypropylene fiber has a diameter of 0.1-0.5 mm and a length of 5-15 mm.

6. The ultra-early strength grouting material under low-temperature conditions according to claim 1, characterized in that, The retarder dosage is 2% to 3% of the amount of rapid-hardening sulfoaluminate cement.

7. The ultra-early strength grouting material under low-temperature conditions according to claim 1, characterized in that, The expanding agent is one or more of the following: ettringite-lime composite expanding agent and plastic expanding agent.

8. The ultra-early strength grouting material under low-temperature conditions according to claim 1, characterized in that, The quartz sand is a combination of 10-20 mesh quartz sand, 20-40 mesh quartz sand, 40-80 mesh quartz sand and 80-100 mesh quartz sand in a mass ratio of 3.5-4.5:2-3:2-3:

1.

9. A method for preparing an ultra-early strength grouting material under low-temperature conditions according to any one of claims 1 to 8, characterized in that, The preparation method includes mixing all the raw materials of the ultra-early strength grout to obtain the ultra-early strength grout.

10. The application of the ultra-early strength grouting material under low temperature environment according to any one of claims 1 to 8 on wind turbine towers.

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