Offshore wind power UHPC component hole is with super high strength grouting material and its preparation method

Abstract

The present application relates to the technical field of cement-based building materials, and particularly relates to an offshore wind power UHPC component hole super-high-strength grouting material and a preparation method and application thereof, wherein modified basalt micro powder is added as a filler, modified metakaolin and superfine fly ash are added to regulate and control the mineral composition of the modified mineral admixture, and cement is used to achieve good early and late strength and good working performance, and the construction performance of the grouting material is ensured through the addition of an additive, so that the purpose of high elastic modulus and high early strength can be achieved without additional adjustment of the source of aggregate.

Description

Technical Field

[0001] This invention relates to the field of cement-based building materials technology, and in particular to an ultra-high strength grout for the ducts of offshore wind power UHPC components and its preparation method. Background Technology

[0002] With the rapid development of offshore wind power technology, the application and development of deep-sea and large-megawatt units have received increasing attention. Ultra-high performance concrete (UHPC) floating foundations have become the most promising engineering material for offshore floating wind power foundations due to their advantages such as controllable cost and corrosion resistance.

[0003] Existing UHPC floating foundations are typically prefabricated and prestressed on land, with grouting of the ducts using ultra-high strength grouting materials. Current grouting technology typically uses conventional raw materials such as ordinary silicate cement and limestone powder, which cannot meet the ultra-high strength performance requirements, thus affecting the safety of offshore wind turbine floating structures. Summary of the Invention

[0004] To address the problems existing in the prior art, this invention provides an ultra-high strength grouting material for the ducts of offshore wind power UHPC components. By adding modified basalt micro powder as filler, and adding modified metakaolin and ultrafine fly ash to regulate the mineral composition of the modified mineral admixture, and combining it with cement, good early and late strength and good workability are achieved. The admixture ensures the construction performance of the grouting material, and the purpose of high elastic modulus and high early strength can be achieved without additional adjustment of the aggregate source.

[0005] Specifically, the ultra-high strength grouting material for the ducts of offshore wind power UHPC components of this invention is composed of the following raw materials in parts by weight: 40-60 parts cement, 35-45 parts modified basalt powder, 8-10 parts ultrafine fly ash, 5-8 parts modified metakaolin, 1.8-2.8 parts expansion agent, 0.04-0.06 parts defoamer, 0.3-0.6 parts water-reducing agent, 0.05-0.15 parts viscosity reducer, 0.05-0.2 parts shrinkage reducer, and 0.005-0.03 parts thixotropic agent.

[0006] The modified basalt micro powder is obtained by primary modification of basalt micro powder with silane coupling agent, secondary modification with nano-silica and polyether-modified polysiloxane, drying, and air classification.

[0007] The modified metakaolin is obtained by grinding, calcining, modifying with triethanolamine-silane coupling agent, modifying with polycarboxylate superplasticizer-nano calcium carbonate, and air classifying kaolin.

[0008] This invention utilizes ultrafine modified basalt powder to improve the final mechanical properties by leveraging its high strength as a micro-aggregate. Furthermore, surface modification with a coupling agent reduces the water absorption of the basalt aggregate while increasing the bonding between the cement paste and the micro-aggregate, thus thinning the interfacial transition zone and further enhancing the mechanical properties of the hardened paste. Thirdly, coating the basalt powder with nano-silica to form a rigid shell improves the impact resistance of the paste. Finally, the polyether-modified polysiloxane-modified basalt powder exhibits better flow properties compared to unmodified powder, resulting in better workability and lower water addition. Additionally, the invention employs modified metakaolin, utilizing a triethanolamine-silane coupling agent composite activation and a polycarboxylic acid-nano-calcium carbonate dispersion system to enhance the activity index and significantly improve the pozzolanic reaction efficiency.

[0009] Preferably, the cement is composed of 45-80% white silicate cement and 20-55% silicate cement and at least one type of low-heat silicate cement.

[0010] Preferably, the white silicate cement has a strength grade of ≥42.5, and more preferably, the white silicate cement contains not less than 65% C3S minerals.

[0011] Preferably, the silicate cement is P•Ⅰ52.5 or P•Ⅱ52.5 grade.

[0012] Preferably, the low-heat silicate cement is P•LH42.5 grade; more preferably, the low-heat silicate cement contains not less than 50% C2S mineral and not more than 5% C3A mineral.

[0013] Preferably, the modified basalt micro powder preparation process is as follows: 100 parts of basalt micro powder and 100-150 parts of ethanol aqueous solution are ultrasonically mixed and dispersed, the pH value is adjusted to 4-6, 0.5-1.5 parts of silane coupling agent are added dropwise while maintaining the temperature and stirring, 3-5 parts of nano-silica sol are added and stirring continues, 0.1-0.3 parts of polyether-modified polysiloxane are added and stirring continues, followed by centrifugation, drying, and air separation to obtain 10-45 μm micro powder. More preferably, the solid content of the nano-silica sol is 20-30%.

[0014] Preferably, the ultrafine fly ash has a particle size ≤10μm.

[0015] Preferably, the modified metakaolin preparation process is as follows: 100 parts of kaolin are ground to a particle size ≤60μm, calcined at 870-900℃, cooled, sprayed with 0.8-1.2 parts of triethanolamine-silane coupling agent, and then sprayed with 6-10 parts of a polycarboxylate superplasticizer-nano calcium carbonate mixture. The mixture is then air-classified to obtain 10-40μm micro-powder. More preferably, the mass ratio of triethanolamine to silane coupling agent is 1:(1-2), and the mass ratio of polycarboxylate superplasticizer to nano calcium carbonate is 1:(0.5-0.8).

[0016] Preferably, the silane coupling agent is at least one of KH550 and KH560.

[0017] Preferably, the polyether-modified polysiloxane is BYK-348.

[0018] Preferably, the expanding agent is a mixture of a plastic expanding agent and a UEA mineral expanding agent, with a mass ratio of 1-2:100.

[0019] Preferably, the water-reducing agent is at least one of a polyether-type polycarboxylate water-reducing agent or a polyester-type polycarboxylate water-reducing agent, with a water reduction rate ≥35%.

[0020] Preferably, the viscosity reducer is a commercially available product; more preferably, the viscosity reducer is a polycarboxylic acid-based viscosity reducer.

[0021] Preferably, the shrinkage-reducing agent is a commercially available product; more preferably, the shrinkage-reducing agent is a polyether-based shrinkage-reducing agent.

[0022] Preferably, the thixotropic agent is at least one of zeolite, zeolite, and guar gum.

[0023] This invention also relates to a method for preparing ultra-high strength grout for the ducts of offshore wind turbine UHPC components, specifically including the following steps: 1) Weigh each ingredient according to its weight. 2) Mix all the ingredients evenly to obtain the final product.

[0024] The present invention also relates to the application of the above-mentioned ultra-high strength grouting material for the ducts of offshore wind power UHPC components in offshore wind power construction. Preferably, the grouting material is mixed with water at a mass ratio of 1:0.22-0.25, allowed to stand to remove air bubbles, and then transported to a grouting machine for pumping construction.

[0025] This invention draws upon the design concepts of UHPC and alkali-activated cement hydration. Through an innovative strategy of constructing a "dual-modification system + microstructure control," it utilizes an ultra-low water-to-material ratio and a micro-density packing design to achieve multi-dimensional performance breakthroughs in the grouting material for offshore wind power UHPC components. This invention has the following technical advantages:

[0026] 1. Ultra-high strength: This invention uses cement-bonded ultrafine admixtures, which have a large specific surface area and high activity, exhibiting rapid early strength development and high later strength. By selecting ultrafine modified basalt powder and modified metakaolin, and drawing on UHPC formulation experience, ultra-low water consumption is used to reduce micro-defects within the paste, significantly improving the final strength performance.

[0027] 2. Excellent performance: This invention utilizes the physical water-reducing effect of "ball bearing lubrication" from the spherical particles in ultrafine fly ash, the chemical water-reducing effect of polycarboxylate-based high-performance water-reducing agents, and the interface modification and hydrophobic effect of ultrafine modified basalt powder. This achieves high fluidity and maintains high fluidity even at low water-cement ratios.

[0028] 3. Good volume stability: This invention uses an expanding agent to further compensate for the volume shrinkage caused by the hydration of the cementitious material.

[0029] 4. High durability: This invention uses less water, reduces internal defects, and minimizes the diffusion of harmful components such as chloride ions. Detailed Implementation

[0030] To characterize the technical effect of this invention, a grouting material was prepared and its performance was tested. The cement consisted of 70% P·W52.5 white silicate cement and 30% P•Ⅱ52.5 silicate cement. The ultrafine fly ash particle size was ≤10μm. The silane coupling agent was KH550, the polyether-modified polysiloxane was BYK-348, the expanding agent was a mixture of plastic expanding agent and UEA mineral expanding agent at a mass ratio of 2:100, the defoamer was an organosilicon defoamer, and the water-reducing agent... Polyether-type polycarboxylate superplasticizer, viscosity reducer and shrinkage reducer are selected from commercially available products, and thixotropic agent is Wenlun colloid. The preparation process of modified basalt micro powder is as follows: 100 parts of basalt micro powder and 150 parts of ethanol aqueous solution are ultrasonically mixed and dispersed, the pH value is adjusted to 5, 1.2 parts of silane coupling agent are added dropwise and stirred at 60℃, 4 parts of nano silica sol are added and stirring is continued, 0.2 parts of polyether-modified polysiloxane are added and stirring is continued, centrifuged, dried and air-separated to obtain 10-45μm micro powder. More preferably, the nano-silica sol has a solid content of 28%, and the modified metakaolin is prepared by grinding 100 parts of kaolin to a particle size ≤60μm, calcining at 890℃, cooling, spraying 1.2 parts of triethanolamine-silane coupling agent, then spraying 9 parts of polycarboxylate superplasticizer-nano-calcium carbonate mixture, and air classifying 10-40μm micro powder to obtain the product. The mass ratio of triethanolamine to silane coupling agent is 1:1, and the mass ratio of polycarboxylate superplasticizer to nano-calcium carbonate is 1:0.6.

[0031] During the testing process, the flowability, free bleeding rate, pressure bleeding rate, free expansion rate, compressive strength, and flexural strength were tested in accordance with JT / T 946-2022, and the electrical flux was tested in accordance with JTS 153-2015.

[0032] Example 1 The grouting material is composed of the following raw materials in parts by weight: 55 parts cement, 40 parts modified basalt powder, 10 parts ultrafine fly ash, 5 parts modified metakaolin, 2.2 parts expansion agent, 0.05 parts defoamer, 0.5 parts water-reducing agent, 0.07 parts viscosity reducer, 0.1 parts shrinkage reducer, and 0.015 parts thixotropic agent.

[0033] The grouting material was tested and found to have an initial flowability of 15.6 s, a 60-minute flowability of 19.4 s, a 3-hour free bleeding rate of 0, a 0.22 MPa pressure bleeding rate of 0.6%, a 24-hour free expansion rate of 0.6%, a 7-day compressive strength of 90.5 MPa, a 7-day flexural strength of 10.8 MPa, a 28-day compressive strength of 109.8 MPa, a 28-day flexural strength of 14.3 MPa, and a 56-day electrical flux of 550 C.

[0034] Example 2 The grouting material is composed of the following raw materials in parts by weight: 52 parts cement, 45 parts modified basalt powder, 9 parts ultrafine fly ash, 8 parts modified metakaolin, 2.3 parts expansion agent, 0.06 parts defoamer, 0.5 parts water-reducing agent, 0.1 parts viscosity reducer, 0.09 parts shrinkage reducer, and 0.02 parts thixotropic agent.

[0035] The grouting material was tested and found to have an initial flowability of 15.0 s, a flowability of 17.6 s at 60 min, a free bleeding rate of 0 at 3 h, a bleeding rate of 0.4% under 0.22 MPa pressure, a free expansion rate of 0.7% at 24 h, a compressive strength of 93.6 MPa at 7 days, a flexural strength of 11.1 MPa at 7 days, a compressive strength of 116.3 MPa at 28 days, a flexural strength of 15.0 MPa at 28 days, and an electrical flux of 520 C at 56 days.

[0036] Comparative Example 1 The grouting material is composed of the following raw materials in parts by weight: 52 parts cement, 45 parts basalt powder, 9 parts ultrafine fly ash, 8 parts metakaolin, 2.3 parts expansion agent, 0.06 parts defoamer, 0.5 parts water-reducing agent, 0.1 parts viscosity reducer, 0.09 parts shrinkage reducer, and 0.02 parts thixotropic agent.

[0037] The grouting material was tested and found to have an initial flowability of 18.2s, no flowability after 60min, a free bleeding rate of 0 after 3h, a bleeding rate of 1.1% under 0.22MPa pressure, a free expansion rate of 0.3% after 24h, a compressive strength of 68.3MPa after 7d, a flexural strength of 7.2MPa after 7d, a compressive strength of 81.7MPa after 28d, a flexural strength of 8.5MPa after 28d, and an electrical flux of 885C after 56d.

[0038] Comparative Example 2 The grouting material is composed of the following raw materials in parts by weight: 52 parts cement, 45 parts basalt powder, 9 parts ultrafine fly ash, 8 parts modified metakaolin, 2.3 parts expansion agent, 0.06 parts defoamer, 0.5 parts water-reducing agent, 0.1 parts viscosity reducer, 0.09 parts shrinkage reducer, and 0.02 parts thixotropic agent.

[0039] The grouting material was tested and found to have an initial flowability of 17.8 s, a flowability of 21.3 s at 60 min, a free bleeding rate of 0 at 3 h, a bleeding rate of 0.9% under 0.22 MPa pressure, a free expansion rate of 0.4% at 24 h, a compressive strength of 72.5 MPa at 7 days, a flexural strength of 7.4 MPa at 7 days, a compressive strength of 90.2 MPa at 28 days, a flexural strength of 9.3 MPa at 28 days, and an electrical flux of 810 C at 56 days.

[0040] Comparative Example 3 The grouting material is composed of the following raw materials in parts by weight: 52 parts cement, 45 parts modified basalt powder, 9 parts ultrafine fly ash, 8 parts metakaolin, 2.3 parts expansion agent, 0.06 parts defoamer, 0.5 parts water-reducing agent, 0.1 parts viscosity reducer, 0.09 parts shrinkage reducer, and 0.02 parts thixotropic agent.

[0041] The grouting material was tested and found to have an initial flowability of 16.6 s, a 60-minute flowability of 19.7 s, a 3-hour free bleeding rate of 0, a 0.22 MPa pressure bleeding rate of 0.6%, a 24-hour free expansion rate of 0.6%, a 7-day compressive strength of 83.4 MPa, a 7-day flexural strength of 8.8 MPa, a 28-day compressive strength of 99.2 MPa, a 28-day flexural strength of 10.1 MPa, and a 56-day electrical flux of 660 C.

[0042] Comparative Example 4 The grouting material is composed of the following raw materials in parts by weight: 52 parts cement, 54 parts ultrafine fly ash, 8 parts modified metakaolin, 2.3 parts expansion agent, 0.06 parts defoamer, 0.5 parts water-reducing agent, 0.1 parts viscosity reducer, 0.09 parts shrinkage reducer, and 0.02 parts thixotropic agent.

[0043] The grouting material was tested and found to have an initial flowability of 15.6 s, a 60-minute flowability of 18.1 s, a 3-hour free bleeding rate of 0, a 0.22 MPa pressure bleeding rate of 0.7%, a 24-hour free expansion rate of 0.4%, a 7-day compressive strength of 85.1 MPa, a 7-day flexural strength of 8.5 MPa, a 28-day compressive strength of 92.5 MPa, a 28-day flexural strength of 9.6 MPa, and a 56-day electrical flux of 730 C.

[0044] Comparative Example 5 The grouting material is composed of the following raw materials in parts by weight: 52 parts cement, 54 parts S95 grade mineral powder, 8 parts ultrafine fly ash, 2.3 parts expansion agent, 0.06 parts defoamer, 0.5 parts water-reducing agent, 0.1 parts viscosity reducer, 0.09 parts shrinkage reducer, and 0.02 parts thixotropic agent.

[0045] The grouting material was tested and found to have an initial flowability of 18.1 s, no flowability after 60 min, a free bleeding rate of 0.1% after 3 h, a bleeding rate of 1.1% under 0.22 MPa pressure, a free expansion rate of 0.3% after 24 h, a compressive strength of 72.6 MPa after 7 days, a flexural strength of 7.5 MPa after 7 days, a compressive strength of 87.7 MPa after 28 days, a flexural strength of 8.6 MPa after 28 days, and an electrical flux of 910 C after 56 days.

[0046] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A high-strength grout for use in the ducts of offshore wind turbine UHPC components, characterized in that, It is composed of the following raw materials in parts by weight: cement 40-60 parts, modified basalt powder 35-45 parts, ultrafine fly ash 8-10 parts, modified metakaolin 5-8 parts, expanding agent 1.8-2.8 parts, defoamer 0.04-0.06 parts, water-reducing agent 0.3-0.6 parts, viscosity reducer 0.05-0.15 parts, shrinkage reducer 0.05-0.2 parts, thixotropic agent 0.005-0.03 parts. The modified basalt micro powder preparation process is as follows: 100 parts of basalt micro powder and 100-150 parts of ethanol aqueous solution are ultrasonically mixed and dispersed, the pH value is adjusted to 4-6, 0.5-1.5 parts of silane coupling agent are added dropwise while maintaining the temperature and stirring, 3-5 parts of nano-silica sol are added and stirring continues, 0.1-0.3 parts of polyether-modified polysiloxane are added and stirring continues, followed by centrifugation, drying, and air separation to obtain 10-45μm micro powder, thus obtaining the product. The modified metakaolin preparation process is as follows: 100 parts of kaolin are ground to a particle size ≤60μm, calcined at 870-900℃, cooled, sprayed with 0.8-1.2 parts of triethanolamine-silane coupling agent, then sprayed with 6-10 parts of polycarboxylate superplasticizer-nano calcium carbonate mixture, and air-classified to obtain 10-40μm micro powder.

2. The ultra-high strength grout for the ducts of offshore wind power UHPC components according to claim 1, characterized in that, The cement is composed of 45-80% white silicate cement and 20-55% silicate cement or at least one type of low-heat silicate cement.

3. The ultra-high strength grout for the ducts of offshore wind power UHPC components according to claim 2, characterized in that, The white silicate cement has a strength grade ≥42.5, the silicate cement is P•Ⅰ52.5 or P•Ⅱ52.5 grade, and the low-heat silicate cement is P•LH42.5 grade.

4. The ultra-high strength grout for the ducts of offshore wind power UHPC components according to claim 1, characterized in that, The ultrafine fly ash has a particle size ≤10μm.

5. The ultra-high strength grout for the ducts of offshore wind power UHPC components according to claim 1, characterized in that, The expanding agent is a mixture of plastic expanding agent and UEA mineral expanding agent in a mass ratio of 1-2:

100. The water reducing agent is at least one of polyether-type polycarboxylate water reducing agent or polyester-type polycarboxylate water reducing agent, with a water reduction rate ≥35%.

6. The ultra-high strength grout for the ducts of offshore wind power UHPC components according to claim 1, characterized in that, The viscosity reducer is a polycarboxylic acid viscosity reducer, and the shrinkage reducer is a polyether shrinkage reducer.

7. The method for preparing ultra-high strength grout for the ducts of offshore wind turbine UHPC components according to any one of claims 1-6, characterized in that, Includes the following steps: 1) Weigh each ingredient according to its weight. 2) Mix all the ingredients evenly to obtain the final product.

8. The application of the ultra-high strength grouting material for offshore wind power UHPC component ducts according to any one of claims 1-6 in offshore wind power construction, characterized in that, Mix the grouting material with water at a mass ratio of 1:0.22-0.25, allow it to stand to expel air bubbles, and then transport it to the grouting machine for pumping construction.