Artificial island spiral jet pile cement-based catalyst, preparation method and application

Abstract

This invention discloses a cement-based catalyst for jet grouting piles on artificial islands, its preparation method, and its application, belonging to the field of foundation reinforcement materials for artificial islands in marine geotechnical engineering. Addressing the problems of seawater salt ion-induced hydration inhibition, poor rheological adaptability of high-pressure jet grouting, insufficient durability under tidal freeze-thaw cycles, and low solid waste utilization, this catalyst is formulated from aluminate-modified aluminoferrite cement clinker, activated perlite carrier, calcium fluorotitanate hydration catalytic phase, quaternized konjac glucomannan jet grouting catalytic phase, carboxymethyl starch ether-xanthan gum tidal flow stabilizer, nickel slag-perlite composite activator, composite dispersant, and purified seawater from the artificial island. It is prepared by microwave support, wet ball milling, and vacuum curing, with a dosage of 15%~19%. The solidified body exhibits a 7-day strength ≥3.6 MPa, a 28-day strength ≥5.8 MPa, a 50-cycle freeze-thaw cycle retention rate ≥98%, and a solid waste utilization rate of 48%. It is suitable for jet grouting of soft soils from 5 to 40 meters deep and can be directly mixed with purified seawater.

Description

Technical Field

[0001] This invention relates to the field of artificial island jet grouting foundation reinforcement technology, specifically to a cement-based catalyst for artificial island jet grouting, its preparation method, and its application. Background Technology

[0002] Jet grouting piles are a common technique for soft soil foundation reinforcement in marine geotechnical engineering. During construction, seawater is typically used to mix the cementitious substrate, and the pile depth covers a soft soil layer of 5m to 40m. Seawater contains a large amount of salt ions (Cl-). - SO4 2- Mg 2+ (e.g., cement slurry) easily adsorbs and coats the surface of cement particles, hindering the cement hydration reaction process, resulting in a reduced hydration rate and insufficient generation of hydration products, leading to low early strength of the jet grouting pile solidified body. Under deep high-pressure jet grouting construction conditions, cement slurry is prone to flocculation, bleeding, pipe blockage, segregation, and other phenomena in the high-pressure shear field, resulting in extremely poor uniformity of construction at all depths. At the same time, since the artificial island is located in an open sea area, the jet grouting pile solidified body is subjected to the coupled effects of tidal wet-dry alternation and freeze-thaw cycles for a long time, leading to the deterioration of the pore structure of the solidified body and accelerated strength decay, which seriously affects the construction quality and long-term service life of the jet grouting pile project on the artificial island.

[0003] Currently, the cementitious materials used in jet grouting pile projects on artificial islands are mainly composite systems of ordinary Portland cement, aluminoferrite cement, and mineral admixtures. However, existing technologies have the following technical problems: traditional Portland cement and conventional mineral admixture systems lack effective means to counteract the inhibitory effect of salt ions in seawater. The adsorption and encapsulation of salt ions on cement particles significantly delays the hydration process, resulting in slow early strength development of the solidified body, and the 7-day strength is insufficient to meet the rapid load-bearing requirements of jet grouting pile projects; high-pressure jet grouting construction has special requirements for the rheological properties of the slurry. Existing cement-based materials lack rheological control mechanisms under high-pressure shear fields, making the slurry prone to flocculation and segregation, resulting in significant loss of fluidity over time. The risk of pipe blockage is high, and it is difficult to maintain a uniform reinforcement effect across the entire depth range of 5m to 40m. The alternating freezing and thawing effects of tides cause irreversible damage to the pore structure of the jet grouting pile solidified body. Conventional air-entraining agents or hydrophobic modification methods can only improve the freeze resistance or impermeability in a single way, and cannot simultaneously meet the dual requirements of resisting freeze-thaw cycles and resisting seawater corrosion. Existing technologies have a low resource utilization rate for marine industrial solid wastes such as blast furnace nickel slag (usually less than 30%), and the dependence on freshwater resources for construction is high, which seriously restricts the convenience and economy of constructing artificial islands in the open sea.

[0004] The closest prior art to this application includes: Chinese invention patent CN108178580A (publication date June 19, 2018, curing agent for mixing piles and jet grouting piles), which discloses a curing agent composed of 35-40% silicate cement, 50-55% granulated blast furnace slag, 8-20% quicklime, 5-10% desulfurized gypsum, 1-3% sodium salt activator and 0.4-0.8% artificial fiber, used for the reinforcement of soft foundations. This technology utilizes an activator to stimulate the activity of slag in the hydration reaction and incorporates artificial fibers to improve crack resistance. However, its cementitious system is mainly based on silicate cement, which fails to address the inhibitory effect of seawater salt ions on cement hydration. Its activator only targets the activation of slag activity and does not possess hydration catalytic function. Its artificial fibers only provide physical reinforcement and do not involve high-pressure jet grouting rheological control of the slurry. Furthermore, this technology uses freshwater mixing, making it unsuitable for construction conditions in remote artificial islands where freshwater is scarce. Chinese invention patent CN119462034B (authorization announcement date August 1, 2025, a seawater-resistant aluminate cement concrete and its preparation method) discloses a seawater-resistant concrete using aluminate cement, composite steel slag micro-powder admixture, and a fluorinated quaternary ammonium salt siloxane modifier. This improves the concrete's density by physically filling pores with ultrafine steel slag micro-powder and chemically bonding with the fluorinated quaternary ammonium salt siloxane modifier, thereby enhancing its resistance to chloride ion penetration. However, this technology is still applied to concrete engineering (including coarse / fine aggregates such as crushed stone and quartz sand), and the functional mechanism of its modifier is "surface hydrophobic barrier" and "physical filling", which does not have the function of catalyzing cement hydration. This technology does not involve the rheological adaptability design under high-pressure jet grouting construction conditions. The synthesis route of its fluorinated quaternary ammonium salt siloxane modifier is complex and costly. It also does not involve the control of the uniformity of jet grouting pile construction at all depths. Chinese invention patent CN119874303B (authorization announcement date November 14, 2025, an early-strength corrosion-resistant ferroaluminate cement-based concrete and its preparation method) discloses an early-strength corrosion-resistant concrete made by compounding ferroaluminate cement with temperature-sensitive water-reducing / slump-retaining polycarboxylate water-reducing agent and internal curing nano-plant fiber emulsion. The adsorption rate of the water-reducing agent is controlled by the hydrophilic-hydrophobic transformation of temperature-sensitive functional groups, which solves the problem of fluidity loss caused by early concentrated heat release in ferroaluminate cement concrete. However, the temperature-sensitive control mechanism of this technology only targets the adsorption behavior of water-reducing agents, and its technical solution is based on "delayed adsorption" rather than "catalytic hydration," failing to counteract the inhibitory effect of seawater salt ions on cement hydration. This technology also targets concrete engineering, and its rheological control mechanism is not designed for the rheological behavior of cement slurry under high-pressure shear field during high-pressure jet grouting. In addition, this technology does not involve durability design under tidal freeze-thaw coupling conditions, nor does it involve the resource utilization of marine solid waste such as blast furnace nickel slag.

[0005] In summary, none of the aforementioned existing technologies offer an effective catalytic solution to the core problem of salt ion inhibition of cement hydration during jet grouting construction on artificial islands under seawater mixing conditions. Furthermore, none disclose a technical solution using calcium fluorotitanate as the hydration catalyst phase, quaternized konjac glucomannan as the jet grouting rheology regulating phase, or a carboxymethyl starch ether-xanthan gum crosslinking system as the tidal stable phase. The existing technologies for jet grouting construction on artificial islands still face challenges related to seawater mixing adaptability, high-pressure jet grouting rheology compatibility, tidal freeze-thaw durability, and deep construction uniformity. There is an urgent need to provide a jet grouting cement-based catalyst integrating hydration catalysis, rheology regulation, and durability enhancement, along with its preparation method. Summary of the Invention

[0006] To address the technical problems of seawater salt ions inhibiting cement hydration, poor rheological adaptability of high-pressure jet grout, insufficient durability under tidal freeze-thaw cycles, and low utilization rate of solid waste resources in the construction of jet grouting piles on artificial islands, this invention provides a cement-based catalyst for jet grouting piles on artificial islands, its preparation method, and its application, so as to improve the construction adaptability and long-term service durability of jet grouting pile cement substrates under marine high-salt, high-pressure jet grouting, and tidal freeze-thaw coupled conditions.

[0007] To achieve the above objectives, the present invention provides a cement-based catalyst for artificial island jet grouting piles, which is made from the following raw materials in parts by weight:

[0008] 40-50 parts of aluminate-modified ferroaluminate cement clinker, 15-19 parts of activated perlite carrier, 11-13 parts of calcium fluorotitanate hydration catalyst, 9-11 parts of quaternized konjac glucomannan spin-jet catalyst, 8-10 parts of carboxymethyl starch ether-xanthan gum tidal stabilizer, 10-12 parts of nickel slag-perlite composite activator, 1.6-2.6 parts of polyglycerol fatty acid ester-alkyl glycoside composite dispersant, and 31-37 parts of artificial island seawater purification agent.

[0009] The aluminate-modified ferroaluminate cement clinker contains 6%~9% aluminate minerals, ≤0.7% free calcium oxide, and a specific surface area ≥530m² / kg; the activated perlite carrier has a porosity of 52%~62% and a pore size of 80~110nm; the catalyst is a special additive for jet grouting pile cement substrate, and its dosage is 15%~19% of the total mass of the cement substrate.

[0010] The calcium fluorotitanate hydration catalyst phase is prepared by reacting calcium fluoride and tricalcium titanate in anhydrous ethanol at a molar ratio of 1:1, refluxing at 75-85°C for 5-7 hours, and then drying and grinding to a particle size ≤6μm. Calcium fluorotitanate accelerates the formation of hydration products by providing fluoride and calcium ions to participate in the formation and growth of crystal nuclei during cement hydration, thereby counteracting the inhibitory effect of seawater salt ions on cement hydration.

[0011] The quaternized konjac glucomannan spin-jet catalytic phase was prepared by dissolving konjac glucomannan (molecular weight 800,000, determined by viscosity method) in isopropanol, adding 3-chloro-2-hydroxypropyltrimethylammonium chloride (mass ratio of 0.4~0.6:1 to konjac glucomannan), reacting at 45~55℃ for 3~5 h, followed by ethanol precipitation, washing, and drying. Then, 6% by mass of nano-zirconia with a particle size of 25~35 nm was added, and the mixture was ground until the particle size was ≤6 μm. The degree of quaternization substitution of the prepared quaternized konjac glucomannan spin-jet catalytic phase was determined by elemental analysis, and the degree of substitution was 0.25~0.40. Quaternized konjac glucomannan regulates the rheological behavior of cement paste under high-pressure shear field through the charge interaction between its cationic quaternary ammonium groups and the surface of cement particles.

[0012] The carboxymethyl starch ether-xanthan gum tidal stabilizer is prepared by mixing carboxymethyl starch ether and xanthan gum at a weight ratio of 5:3, adding 0.3%~0.8% citric acid as a crosslinking agent, and reacting at 40~50℃ for 2~4 hours. After drying and pulverizing to a particle size ≤9μm, the carboxymethyl starch ether-xanthan gum crosslinks to form a three-dimensional network structure, constructing a physical barrier within the solidified body and blocking the erosion channels of seawater salt ions.

[0013] The nickel slag-perlite composite activator is prepared by mixing blast furnace nickel slag and perlite powder at a weight ratio of 8:2, activating at 550~650℃ for 1.5~3h, and grinding to a specific surface area ≥580m² / kg.

[0014] The polyglycerol fatty acid ester-alkyl glycoside composite dispersant is a compound of polyglycerol monooleate and dodecyl glycoside in a weight ratio of 6:4, with an HLB value of 14-15.

[0015] The artificial island purifies seawater with a salinity of 0.6% to 2.6%.

[0016] The present invention also provides a method for preparing the above-mentioned cement-based catalyst for jet grouting piles on artificial islands, comprising the following steps:

[0017] S1: Weigh each raw material according to the weight parts;

[0018] S2: The activated perlite support, the calcium fluorotitanate hydrated catalytic phase, and the quaternized konjac glucomannan spin-sprayed catalytic phase were placed in a microwave support device and treated for 1.8 h at a microwave power of 350 W and a temperature of 48~53℃ to obtain the catalytic substrate.

[0019] S3: Add carboxymethyl starch ether-xanthan gum tidal stabilizer and nickel slag-perlite composite activator to the catalyst substrate, use zirconia balls as the ball milling medium, ball-to-material ratio (2~3):1, use purified seawater from the artificial island as the dispersion medium, wet ball mill for 14 min at a speed of 840~940 r / min to obtain catalyst powder;

[0020] S4: Add polyglycerol fatty acid ester-alkyl glycoside composite dispersant to the purified seawater of the artificial island, and stir for 8 minutes at a speed of 330~350 r / min to obtain an aqueous solution of the additive.

[0021] S5: Add the aqueous solution of the additive to the catalytic powder dropwise over a period of 13-15 minutes, and stir for 22 minutes at a temperature of 28-31℃ and a rotation speed of 530-590 r / min to obtain the catalytic slurry.

[0022] S6: The catalytic slurry is vacuum-cured for 15 minutes under a vacuum of -0.088 to -0.098 MPa, cooled to room temperature, and then pulverized to a particle size of ≤11 μm to obtain the cement-based catalyst for the artificial island jet grouting pile.

[0023] The preferred composition of the catalyst, by weight, is as follows: 45 parts of aluminate-modified iron aluminate cement clinker, 17 parts of activated perlite carrier, 12 parts of calcium fluorotitanate hydration catalyst phase, 10 parts of quaternized konjac glucomannan spin-spray catalyst phase, 9 parts of carboxymethyl starch ether-xanthan gum tidal stabilizer, 11 parts of nickel slag-perlite composite activator, 2.1 parts of polyglycerol fatty acid ester-alkyl glycoside composite dispersant, and 34 parts of artificial island seawater purification agent.

[0024] In the preparation method, the preferred parameters for S2 are: microwave temperature 50℃; the preferred parameters for S3 are: rotation speed 890 r / min; and the preferred parameters for S6 are: vacuum degree -0.093 MPa.

[0025] Further preferred embodiments of the catalyst, by weight, include: 40 parts of aluminate-modified iron aluminate cement clinker, 15 parts of activated perlite support, 11 parts of calcium fluorotitanate hydration catalyst phase, 9 parts of quaternized konjac glucomannan spin-spray catalyst phase, 8 parts of carboxymethyl starch ether-xanthan gum tidal stabilizer, 10 parts of nickel slag-perlite composite activator, 1.6 parts of polyglycerol fatty acid ester-alkyl glycoside composite dispersant, and 31 parts of artificial island seawater purification agent.

[0026] Another further preferred embodiment of the catalyst, by weight, includes: 50 parts of aluminate-modified iron aluminate cement clinker, 19 parts of activated perlite support, 13 parts of calcium fluorotitanate hydration catalyst phase, 11 parts of quaternized konjac glucomannan spin-spray catalyst phase, 10 parts of carboxymethyl starch ether-xanthan gum tidal stabilizer, 12 parts of nickel slag-perlite composite activator, 2.6 parts of polyglycerol fatty acid ester-alkyl glycoside composite dispersant, and 37 parts of artificial island purified seawater.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] 1. By using aluminate-modified ferroaluminate cement clinker and compounding it with a calcium fluorotitanate hydration catalyst, the inhibitory effect of seawater salt ions on cement hydration can be weakened. The unconfined compressive strength of the cured body of this invention is ≥3.6MPa at 7 days and ≥5.8MPa at 28 days.

[0029] 2. Using quaternized konjac glucomannan as the rotary spraying catalyst can improve the shear rheological properties of cement slurry. The rotary spraying flowability of this invention is ≥300mm, and the uniformity of rotary spraying at a full depth of 5~40m is rated as "excellent".

[0030] 3. The carboxymethyl starch ether-xanthan gum crosslinking system is used as a tidal flow stabilizer to block seawater salt ion erosion. After 50 tidal freeze-thaw cycles, the strength retention rate of this invention is ≥98%, and the impermeability grade is ≥P17.

[0031] 4. An activator is prepared by combining blast furnace nickel slag and perlite to achieve the resource utilization of solid waste. The solid waste utilization rate of this invention reaches 43%~51%, and it can be directly mixed with seawater purified by artificial islands.

[0032] 5. A preparation process combining microwave support, wet ball milling, and vacuum curing was adopted to achieve synergistic activation and nano-coating of multi-component catalytic phases. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the preparation process of the cement-based catalyst for artificial island jet grouting piles provided in an embodiment of the present invention. Detailed Implementation

[0034] The present invention will be further described below with reference to embodiments, but the implementation of the present invention is not limited thereto.

[0035] The specifications of the raw materials used in the following examples and comparative examples are as follows:

[0036] Aluminate-modified ferroaluminate cement clinker: prepared by mixing and grinding ferroaluminate cement clinker with aluminate minerals in a certain proportion, with an aluminate mineral content of 7%, a free calcium oxide content of 0.5%, and a specific surface area of ​​535 m². 2 / kg;

[0037] Activated perlite carrier: It is made from natural perlite through crushing, sieving, and preheating and activation at 350~450℃ for 1~2 hours, with a porosity of 58% and a pore size of 95nm.

[0038] Calcium fluoride: analytical grade, particle size ≤2μm;

[0039] Tricalcium titanate: purity ≥98%, particle size ≤3μm;

[0040] Konjac glucomannan: molecular weight 800,000 (determined by viscosity method), purity ≥95%;

[0041] Nano-zirconia: particle size 25~35nm, purity ≥99.5%;

[0042] Carboxymethyl starch ether: degree of substitution 0.6~0.8, purity ≥98%;

[0043] Xanthan gum: Food grade, purity ≥99%;

[0044] Blast furnace nickel slag: specific surface area 450m² 2 / kg, NiO content 0.8%~1.5%;

[0045] Perlite powder: particle size ≤20μm;

[0046] Polyglycerol monooleate: HLB value 11~12, purity ≥95%;

[0047] Dodecyl glycoside: HLB value 14~16, purity ≥98%;

[0048] Citric acid: purity ≥ 99.5%;

[0049] Artificial islands purify seawater: salinity 1.6%.

[0050] The degree of substitution of the quaternized konjac glucomannan spin-spray catalytic phase used in each embodiment was determined by elemental analysis. The degree of substitution was as follows: 0.32 for Example 1, 0.38 for Example 2, 0.35 for Example 3, 0.33 for Example 4, and 0.30 for Example 5.

[0051] The carboxymethyl starch ether-xanthan gum tidal stabilizer used in each embodiment had its cross-linking structure confirmed by Fourier transform infrared spectroscopy (FTIR), and its cross-linking structure was found at 1730 cm⁻¹. -1 ±5cm -1 The characteristic absorption peak of the ester bond (-COO-) appears at 2920 cm⁻¹. -1 ±5cm -1 An absorption peak for the stretching vibration of saturated CH bonds appears at 1640 cm⁻¹. -1 ±5cm -1 An antisymmetric stretching vibration absorption peak of the C=O bond in the carboxylate appeared. Compared with the uncrosslinked carboxymethyl starch ether / xanthan gum physical mixture, the appearance of the above ester bond characteristic absorption peak indicates that carboxymethyl starch ether and xanthan gum underwent an esterification crosslinking reaction under the action of citric acid crosslinking agent.

[0052] The prepared catalyst should be sealed and stored in a cool, dry place, avoiding moisture, and has a shelf life of 6 months.

[0053] The calcium fluorotitanate hydration catalyst phase, quaternized konjac glucomannan spin-jet catalyst phase, carboxymethyl starch ether-xanthan gum tidal stabilizer, nickel slag-perlite composite activator, and polyglycerol fatty acid ester-alkyl glycoside composite dispersant used in the following examples are prepared by the methods described in the content section of this invention; unless otherwise specified, the parameters of each raw material meet the ranges defined in the content of this invention.

[0054] All performance tests were conducted using independently prepared specimens:

[0055] The degree of quaternization substitution was determined by elemental analysis: the degree of quaternization substitution was calculated by determining the nitrogen content in quaternized konjac glucomannan. DS The calculation formula is: DS =162× N % / (14-151.5× N %);in, N % represents the mass percentage of nitrogen as determined by elemental analysis; 162 represents the molar mass (g / mol) of the dehydrated glucose unit of konjac glucomannan; 14 represents the molar mass (g / mol) of nitrogen; and 151.5 represents the quaternary ammonium group (C6H). 15 The molar mass (g / mol) of NOCl.

[0056] The cross-linked structure was confirmed using Fourier transform infrared spectroscopy (FTIR): KBr pellet method was used, with a scanning range of 4000–400 cm⁻¹. -1 4cm resolution -1 The scan was performed 32 times. The characteristic absorption peak of the ester bond (-COO-) is located at 1730 cm⁻¹. -1 ±5cm -1 At this point, the absorption peak of the saturated CH bond stretching vibration is located at 2920 cm⁻¹. -1 ±5cm -1 At this location, the absorption peak of the antisymmetric stretching vibration of the C=O bond in the carboxylate is located at 1640 cm⁻¹. -1 ±5cm -1 Place.

[0057] Jet grout flowability: The flowability of cement mortar was determined in accordance with GB / T 2419-2005 "Determination of Flowability of Cement Mortar";

[0058] 7-day unconfined compressive strength and 28-day unconfined compressive strength: Referring to GB / T 50123-2019 "Standard for Geotechnical Testing Methods", the catalyst and cementitious substrate were mixed in a certain proportion (the catalyst dosage was 17% of the total mass of the cementitious substrate), and then mixed evenly with the soft soil sample of the artificial island to make Φ50mm×100mm cylindrical specimens. After standard curing to the specified age, the test was carried out.

[0059] Tidal freeze-thaw strength retention rate: Referring to the rapid freezing method in GB / T 50082-2024 "Standard for Test Methods of Long-term Performance and Durability of Concrete", the coupled working conditions of tidal wet and dry alternation and freeze-thaw cycle (salinity 30‰~35‰, temperature -20℃~20℃, 12h wet and dry alternation) were simulated, and the strength retention rate was tested after 50 cycles.

[0060] Water permeability grade: Water permeability test shall be conducted in accordance with GB / T 50082-2024;

[0061] Uniformity of full-depth jet grouting: By simulating jet grouting construction at depths of 5m, 15m, 25m, and 35m, core samples of the solidified body at each depth were taken for strength testing, and the coefficient of variation of strength was calculated. A coefficient of variation ≤10% is "excellent", 10%~20% is "good", >20% is "medium", and water seepage and pipe blockage are "poor".

[0062] Solid waste utilization rate: calculated as the percentage of blast furnace nickel slag to the total mass of the catalyst.

[0063] Example 1

[0064] A cement-based catalyst for jet grouting piles on artificial islands comprises, by weight, the following raw materials: 40 parts of aluminate-modified ferroaluminate cement clinker, 15 parts of activated perlite carrier, 11 parts of calcium fluorotitanate hydration catalyst phase, 9 parts of quaternized konjac glucomannan jet grouting catalyst phase (degree of substitution 0.32), 8 parts of carboxymethyl starch ether-xanthan gum tidal stabilizer, 10 parts of nickel slag-perlite composite activator, 1.6 parts of polyglycerol fatty acid ester-alkyl glycoside composite dispersant, and 31 parts of seawater purified by artificial islands.

[0065] The preparation method of the calcium fluorotitanate hydration catalyst phase is as follows: calcium fluoride and tricalcium titanate are placed in a reactor at a molar ratio of 1:1, anhydrous ethanol is added as a dispersion medium, the mixture is refluxed at 80°C for 6 hours, filtered, dried, and ground until the particle size is ≤6μm to obtain the calcium fluorotitanate hydration catalyst phase.

[0066] The preparation method of the quaternized konjac glucomannan spin-jet catalytic phase is as follows: Konjac glucomannan (molecular weight 800,000, determined by viscosity method) is dissolved in isopropanol, and 3-chloro-2-hydroxypropyltrimethylammonium chloride (mass ratio to konjac glucomannan is 0.5:1) is added. The mixture is reacted at 50℃ for 4 hours. After ethanol precipitation, washing, and drying, 6% by mass of nano-zirconia with a particle size of 25-35 nm is added, and the mixture is ground until the particle size is ≤6 μm to obtain the quaternized konjac glucomannan spin-jet catalytic phase. The degree of quaternization substitution is determined to be 0.32 by elemental analysis.

[0067] The preparation method of the carboxymethyl starch ether-xanthan gum tide stabilizer is as follows: carboxymethyl starch ether and xanthan gum are mixed at a weight ratio of 5:3, citric acid accounting for 0.5% of the total solid mass is added as a crosslinking agent, the crosslinking reaction is carried out at 45℃ for 3 hours, and then dried and pulverized to a particle size ≤9μm to obtain the carboxymethyl starch ether-xanthan gum tide stabilizer.

[0068] The preparation method of the nickel slag-perlite composite activator is as follows: blast furnace nickel slag and perlite powder are mixed at a weight ratio of 8:2, placed in a muffle furnace and activated at 600℃ for 2 hours, taken out and cooled naturally, and ground to a specific surface area ≥580m² / kg to obtain the nickel slag-perlite composite activator.

[0069] The preparation method of the polyglycerol fatty acid ester-alkyl glycoside composite dispersant is as follows: polyglycerol monooleate and dodecyl glycoside are compounded at a weight ratio of 6:4, and the HLB value is controlled at 14~15 to obtain the polyglycerol fatty acid ester-alkyl glycoside composite dispersant.

[0070] The catalyst in this embodiment is prepared according to the following steps:

[0071] S1: Weigh each raw material according to the weight parts;

[0072] S2: The activated perlite support, the calcium fluorotitanate hydrated catalytic phase, and the quaternized konjac glucomannan spin-sprayed catalytic phase were placed in a microwave support device and treated for 1.8 h at a microwave power of 350 W and a temperature of 48 °C to obtain the catalytic substrate.

[0073] S3: Add carboxymethyl starch ether-xanthan gum tidal stabilizer and nickel slag-perlite composite activator to the catalyst substrate, use zirconia balls as the ball milling medium, ball-to-material ratio of 2.5:1, use purified seawater from the artificial island as the dispersion medium, and wet ball mill for 14 min at a speed of 840 r / min to obtain catalyst powder.

[0074] S4: Add the polyglycerol fatty acid ester-alkyl glycoside composite dispersant to the purified seawater of the artificial island, and stir for 8 minutes at a speed of 330 r / min to obtain an aqueous solution of the additive.

[0075] S5: The aqueous solution of the auxiliary agent is added dropwise to the catalytic powder over a period of 13 minutes. The mixture is stirred for 22 minutes at a temperature of 28°C and a rotation speed of 530 r / min to obtain a catalytic slurry.

[0076] S6: The catalyst slurry is vacuum-cured for 15 minutes under a vacuum of -0.088MPa, cooled to room temperature, and then pulverized to a particle size of ≤11μm to obtain the cement-based catalyst for the artificial island jet grouting pile.

[0077] The catalyst prepared in this embodiment was mixed with cementitious substrate in a certain proportion (catalyst dosage was 17% of the total mass of cementitious substrate) and used for jet grouting reinforcement of 25m deep soft soil on an artificial island with a moisture content of 86%, a salt content of 1.6%, and an organic matter content of 9%. Tests showed that the jet grouting flowability was 300mm, the 7-day unconfined compressive strength was 3.6MPa, the 28-day unconfined compressive strength was 5.4MPa, the strength retention rate after 50 freeze-thaw cycles was 97%, the impermeability grade was P17, the uniformity of the jet grouting at all depths was "excellent," and the solid waste utilization rate was 43%.

[0078] Example 2

[0079] A cement-based catalyst for jet grouting piles on artificial islands, comprising the following raw materials by weight: 50 parts of aluminate-modified ferroaluminate cement clinker, 19 parts of activated perlite carrier, 13 parts of calcium fluorotitanate hydration catalyst phase, 11 parts of quaternized konjac glucomannan jet grouting catalyst phase (degree of substitution 0.38), 10 parts of carboxymethyl starch ether-xanthan gum tidal stabilizer, 12 parts of nickel slag-perlite composite activator, 2.6 parts of polyglycerol fatty acid ester-alkyl glycoside composite dispersant, and 37 parts of seawater purified by artificial islands.

[0080] The preparation methods for the calcium fluorotitanate hydration catalyst phase, the quaternized konjac glucomannan spin-jet catalyst phase, the carboxymethyl starch ether-xanthan gum tidal flow stabilizer, the nickel slag-perlite composite activator, and the polyglycerol fatty acid ester-alkyl glycoside composite dispersant are all the same as in Example 1. The quaternized konjac glucomannan spin-jet catalyst phase used in this example has a quaternization degree of 0.38 as determined by elemental analysis.

[0081] In the preparation method:

[0082] S2: Microwave temperature 53℃; S3: Zirconia balls as milling media, ball-to-material ratio 2.5:1, rotation speed 940r / min; S4: Rotation speed 350r / min, stirring for 8min; S5: Dropping time 15min, temperature 31℃, rotation speed 590r / min, stirring for 22min; S6: Vacuum degree -0.098MPa.

[0083] The remaining steps are the same as in Example 1.

[0084] The catalyst prepared in this embodiment was used for the soft soil jet grouting reinforcement construction of the artificial island in the same manner as in Example 1, with the catalyst dosage being 17% of the total mass of the cement substrate. Tests showed that the jet grouting flowability was 315 mm, the 7-day unconfined compressive strength was 3.9 MPa, the 28-day unconfined compressive strength was 5.9 MPa, the strength retention rate after 50 tidal freeze-thaw cycles was 98.5%, the impermeability grade was P19, the uniformity of the full-depth jet grouting was "excellent," and the solid waste utilization rate was 51%.

[0085] Example 3

[0086] A cement-based catalyst for jet grouting piles on artificial islands comprises, by weight, the following raw materials: 45 parts of aluminate-modified ferroaluminate cement clinker, 17 parts of activated perlite carrier, 12 parts of calcium fluorotitanate hydrate catalytic phase, 10 parts of quaternized konjac glucomannan jet grouting catalytic phase (degree of substitution 0.35), 9 parts of carboxymethyl starch ether-xanthan gum tidal stabilizer, 11 parts of nickel slag-perlite composite activator, 2.1 parts of polyglycerol fatty acid ester-alkyl glycoside composite dispersant, and 34 parts of seawater purified by artificial islands.

[0087] The preparation methods for the calcium fluorotitanate hydration catalyst phase, the quaternized konjac glucomannan spin-jet catalyst phase, the carboxymethyl starch ether-xanthan gum tidal flow stabilizer, the nickel slag-perlite composite activator, and the polyglycerol fatty acid ester-alkyl glycoside composite dispersant are all the same as in Example 1. The quaternized konjac glucomannan spin-jet catalyst phase used in this example has a quaternization degree of 0.35 as determined by elemental analysis.

[0088] In the preparation method:

[0089] S2: Microwave temperature 50℃; S3: Zirconia balls as milling media, ball-to-material ratio 2.5:1, rotation speed 890r / min; S4: Rotation speed 340r / min, stirring for 8min; S5: Dropping time 14min, temperature 30℃, rotation speed 560r / min, stirring for 22min; S6: Vacuum degree -0.093MPa.

[0090] The remaining steps are the same as in Example 1.

[0091] The catalyst prepared in this embodiment was used for the soft soil jet grouting reinforcement construction of the artificial island in the same manner as in Example 1, with the catalyst dosage being 17% of the total mass of the cement substrate. Tests showed that the jet grouting flowability was 308 mm, the 7-day unconfined compressive strength was 3.8 MPa, the 28-day unconfined compressive strength was 5.8 MPa, the strength retention rate after 50 tidal freeze-thaw cycles was 98%, the impermeability grade was P19, the uniformity of the full-depth jet grouting was "excellent," and the solid waste utilization rate was 48%.

[0092] Example 4

[0093] The difference between this embodiment and Example 3 is that the amount of quaternized konjac glucomannan spin-jet catalyst phase is 8 parts (degree of substitution 0.33), aluminate modified iron aluminate cement clinker is 42 parts, activated perlite carrier is 16 parts, calcium fluorotitanate hydration catalyst phase is 12 parts, carboxymethyl starch ether-xanthan gum tidal stabilizer is 9 parts, nickel slag-perlite composite activator is 11 parts, polyglycerol fatty acid ester-alkyl glycoside composite dispersant is 2.0 parts, and artificial island purified seawater is 33 parts. Other conditions remain the same.

[0094] The catalyst prepared in this embodiment was used for the soft soil jet grouting reinforcement construction of the artificial island in the same manner as in Example 1, with the catalyst dosage being 17% of the total mass of the cement substrate. Tests showed that the jet grouting flowability was 305 mm, the 7-day unconfined compressive strength was 3.7 MPa, the 28-day unconfined compressive strength was 5.6 MPa, the strength retention rate after 50 tidal freeze-thaw cycles was 97.5%, the impermeability grade was P18, the uniformity of the full-depth jet grouting was "excellent," and the solid waste utilization rate was 46%.

[0095] Example 5

[0096] The difference between this embodiment and Example 3 is that: the amount of quaternized konjac glucomannan spin-jet catalyst phase is 10 parts (degree of substitution 0.30), aluminate-modified iron aluminate cement clinker is 48 parts, activated perlite carrier is 18 parts, calcium fluorotitanate hydration catalyst phase is 12 parts, carboxymethyl starch ether-xanthan gum tidal stabilizer is 9 parts, nickel slag-perlite composite activator is 11 parts, polyglycerol fatty acid ester-alkyl glycoside composite dispersant is 2.3 parts, and artificial island purified seawater is 36 parts, while other conditions remain the same.

[0097] The catalyst prepared in this embodiment was used for the soft soil jet grouting reinforcement construction of the artificial island in the same manner as in Example 1, with the catalyst dosage being 17% of the total mass of the cement substrate. Tests showed that the jet grouting flowability was 310 mm, the 7-day unconfined compressive strength was 3.7 MPa, the 28-day unconfined compressive strength was 5.7 MPa, the strength retention rate after 50 tidal freeze-thaw cycles was 97.8%, the impermeability grade was P18, the uniformity of the full-depth jet grouting was "excellent," and the solid waste utilization rate was 47%.

[0098] Comparative Example 1

[0099] The difference from Example 3 is that no calcium fluorotitanate hydration catalyst phase is added, and the missing mass is made up by an equal amount of activated perlite carrier to ensure that the total weight remains unchanged. The other raw materials and preparation methods are the same as in Example 3.

[0100] The material prepared in this comparative example was used for the soft soil jet grouting reinforcement construction of the artificial island in the same manner as in Example 1, with the catalyst dosage being 17% of the total mass of the cement substrate. Tests showed that the jet grouting flowability was 262 mm, the 7-day unconfined compressive strength was 1.0 MPa, the 28-day unconfined compressive strength was 2.2 MPa, the strength retention rate after 50 tidal freeze-thaw cycles was 66.3%, the impermeability grade was P9, the uniformity of the full-depth jet grouting was "medium," and the solid waste utilization rate was 35%.

[0101] Comparative Example 2

[0102] The difference from Example 3 is that no quaternized konjac glucomannan spin-jet catalyst phase is added, and the missing mass is made up by an equal amount of activated perlite carrier to ensure that the total weight remains unchanged. All other raw materials and preparation methods are the same as in Example 3.

[0103] The material prepared in this comparative example was used for the soft soil jet grouting reinforcement construction of the artificial island in the same manner as in Example 1, with the catalyst dosage being 17% of the total mass of the cement substrate. Tests showed that the jet grouting flowability was 258 mm, the 7-day unconfined compressive strength was 1.2 MPa, the 28-day unconfined compressive strength was 2.5 MPa, the strength retention rate after 50 cycles of tidal freeze-thaw cycles was 68.6%, the impermeability grade was P8, the uniformity of the full-depth jet grouting was "poor" (bleeding and pipe blockage occurred), and the solid waste utilization rate was 37%.

[0104] Comparative Example 3

[0105] The difference from Example 3 is that no carboxymethyl starch ether-xanthan gum tide stabilizer is added. The missing mass is made up by an equal amount of activated perlite carrier to ensure that the total weight remains unchanged. All other raw materials and preparation methods are the same as in Example 3.

[0106] The material prepared in this comparative example was used for the soft soil jet grouting reinforcement construction of the artificial island in the same manner as in Example 1, with the catalyst dosage being 17% of the total mass of the cement substrate. Tests showed that the jet grouting flowability was 265 mm, the 7-day unconfined compressive strength was 1.9 MPa, the 28-day unconfined compressive strength was 3.3 MPa, the strength retention rate after 50 tidal freeze-thaw cycles was 63.2%, the impermeability grade was P11, the uniformity of the full-depth jet grouting was "good," and the solid waste utilization rate was 40%.

[0107] Comparative Example 4

[0108] The difference from Example 3 is that no nickel slag-perlite composite activator is added. The missing mass is made up by an equal amount of activated perlite carrier to ensure that the total weight remains unchanged. All other raw materials and preparation methods are the same as in Example 3.

[0109] The material prepared in this comparative example was used for the soft soil jet grouting reinforcement construction of the artificial island in the same manner as in Example 1, with the catalyst dosage being 17% of the total mass of the cementitious substrate. Tests showed that the jet grouting flowability was 270 mm, the 7-day unconfined compressive strength was 2.1 MPa, the 28-day unconfined compressive strength was 3.6 MPa, the strength retention rate after 50 tidal freeze-thaw cycles was 73.5%, the impermeability grade was P12, the uniformity of the full-depth jet grouting was "good," and the solid waste utilization rate was 24%.

[0110] Comparative Example 5

[0111] The difference from Example 3 is that ordinary aluminoferrite cement (aluminate mineral content 3%, free calcium oxide content 1.2%, specific surface area 420m² / kg) is used to replace the aluminate-modified aluminoferrite cement clinker in an equal amount, while the other raw materials and preparation methods are the same as in Example 3.

[0112] The material prepared in this comparative example was used for the soft soil jet grouting reinforcement construction of the artificial island in the same manner as in Example 1, with the catalyst dosage being 17% of the total mass of the cement substrate. Tests showed that the jet grouting flowability was 267 mm, the 7-day unconfined compressive strength was 1.4 MPa, the 28-day unconfined compressive strength was 2.8 MPa, the strength retention rate after 50 freeze-thaw cycles was 70.7%, the impermeability grade was P10, the uniformity of the full-depth jet grouting was "medium," and the solid waste utilization rate was 42%.

[0113] Comparative Example 6

[0114] Commercially available conventional marine soft soil jet grouting curing agent was used. The raw materials, by weight, were: 35 parts silicate cement, 50 parts granulated blast furnace slag, 8 parts quicklime, 5 parts desulfurized gypsum, 1.5 parts sodium salt activator, and 0.5 parts synthetic fiber, prepared using fresh water. The material prepared in this comparative example was used for the soft soil jet grouting pile reinforcement construction on an artificial island in the same manner as in Example 1.

[0115] Tests showed that the jet grouting flowability was 242 mm, the 7-day unconfined compressive strength was 0.8 MPa, the 28-day unconfined compressive strength was 1.7 MPa, the strength retention rate after 50 cycles of tidal freeze-thaw cycles was 59.5%, the impermeability grade was P6, the uniformity of the full-depth jet grouting was "poor", and the solid waste utilization rate was 12%.

[0116] Performance tests were conducted on Examples 1-5 and Comparative Examples 1-6, and the test results are shown in Table 1 below:

[0117] Table 1 Performance test results of Examples 1-5 and Comparative Examples 1-6

[0118] Spinning flow rate (mm) 300 315 308 305 310 262 258 265 270 267 242 7-day strength (MPa) 3.6 3.9 3.8 3.7 3.7 1 1.2 1.9 2.1 1.4 0.8 28-day strength (MPa) 5.4 5.9 5.8 5.6 5.7 2.2 2.5 3.3 3.6 2.8 1.7 Tidal freeze-thaw retention rate (%) 97 98.5 98 97.5 97.8 66.3 68.6 63.2 73.5 70.7 59.5 impermeability grade P17 P19 P19 P18 P18 P9 P8 P11 P12 P10 P6 Uniformity across the entire depth excellent excellent excellent excellent excellent middle Difference good good middle Difference Solid waste utilization rate (%) 43 51 48 46 47 35 37 40 24 42 12

[0119] Results analysis.

[0120] The test data above show that the cement-based catalyst for jet grouting piles on artificial islands prepared in Examples 1-5 of this invention has a jet grouting flow rate ≥300mm and no bleeding or pipe blockage; the 7-day unconfined compressive strength is ≥3.6MPa and the 28-day unconfined compressive strength is ≥5.4MPa, both of which meet the early and long-term strength requirements for jet grouting pile reinforcement projects on artificial islands; after 50 tidal freeze-thaw cycles, the strength retention rate is ≥97.0%, the impermeability grade is ≥P17, the uniformity of jet grouting at all depths is "excellent", and the solid waste utilization rate is ≥43%.

[0121] In Comparative Example 1, without the addition of calcium fluorotitanate hydration catalyst, the inhibitory effect of seawater salt ions on cement hydration could not be effectively offset, and the 7-day strength decreased to 1.0 MPa (a decrease of 73.7%), verifying the core hydration activation effect of the calcium fluorotitanate hydration catalyst.

[0122] Comparative Example 2, without the addition of quaternized konjac glucomannan spin-jet catalyst, showed rheological imbalance in the spin-jet slurry, with the fluidity decreasing to 258 mm. The uniformity of the full-depth spin-jet was "poor," and water seepage and pipe blockage occurred, proving that the rheological regulation effect of the spin-jet catalyst is irreplaceable.

[0123] Comparative Example 3, without the addition of carboxymethyl starch ether-xanthan gum tidal stabilizer, showed a sharp drop in strength retention rate to 63.2% (a decrease of 35.5 percentage points) after tidal freeze-thaw cycles, verifying the adaptability of the tidal stabilizer system to the marine environment of the artificial island and its key role in the synergistic protection against freeze-thaw and salt corrosion.

[0124] In Comparative Example 4, without the addition of nickel slag-perlite composite activator, the solid waste utilization rate dropped to 24%, and the catalytic activity decreased significantly, highlighting the dual value of nickel slag solid waste in both activation and environmental protection.

[0125] In Comparative Example 5, ordinary aluminoferrite cement was used to replace aluminate-modified aluminoferrite cement clinker, resulting in a decrease in salt resistance and a significant deterioration in all performance indicators.

[0126] Comparative Example 6 uses a commercially available conventional spin-spray curing agent, which has no catalytic function, extremely poor salt resistance, and its performance is comprehensively degraded compared to the embodiments of the present invention.

[0127] The above results demonstrate a significant synergistic effect among the core components of this invention. When Comparative Examples 1-3 lacked the calcium fluorotitanate hydration catalyst, the quaternized konjac glucomannan spin-jet catalyst, and the carboxymethyl starch ether-xanthan gum tidal stabilizer, respectively, the 7-day strength of the cured body decreased by 73.7%, 68.4%, and 50.0%, respectively; the tidal freeze-thaw retention rate decreased by 31.7, 29.4, and 34.8 percentage points, respectively; and the impermeability grade decreased by 10, 11, and 8 grades, respectively. These results indicate that the overall performance when all three core functional components are present is far superior to the sum of the performance when any single component is missing. This proves that this invention is not a simple superposition of existing components, but rather an organic combination of functionally mutually supportive technical features, achieving unexpected technical effects.

[0128] In summary, the catalyst prepared by this invention has performance characteristics that match the construction adaptability and long-term durability requirements of jet grouting piles on artificial islands. The synergistic effect of the calcium fluorotitanate hydration catalyst phase, the quaternized konjac glucomannan jet grouting catalyst phase, and the carboxymethyl starch ether-xanthan gum tidal stabilizer achieves integrated functions of "hydration catalysis - rheological regulation - tidal stabilization". The preparation process is controllable, and it can be directly mixed with purified seawater from artificial islands without the need for freshwater resources. It can be applied on a large scale to the reinforcement construction of 5-40m soft soil jet grouting piles on artificial islands.

Claims

1. A cement-based catalyst for artificial island jet grouting piles, characterized in that, The cement clinker is composed of the following components by weight: 40-50 parts of aluminate-modified ferroaluminate cement clinker, 15-19 parts of activated perlite carrier, 11-13 parts of calcium fluorotitanate hydration catalyst, 9-11 parts of quaternized konjac glucomannan spin-spray catalyst, 8-10 parts of carboxymethyl starch ether-xanthan gum tidal stabilizer, 10-12 parts of nickel slag-perlite composite activator, 1.6-2.6 parts of polyglycerol fatty acid ester-alkyl glycoside composite dispersant, and 31-37 parts of artificial island seawater purification agent; the aluminate mineral content in the aluminate-modified ferroaluminate cement clinker is 6%-9%, the free calcium oxide content is ≤0.7%, and the specific surface area is ≥530 m². 2 / kg; the porosity of the activated perlite carrier is 52%~62% and the pore size is 80~110nm; the catalyst is used as an additive for the cement substrate of the jet grouting pile, and the dosage is 15%~19% of the total mass of the cement substrate.

2. The cement-based catalyst for artificial island jet grouting piles according to claim 1, characterized in that, The components by weight are as follows: 45 parts of aluminate-modified iron aluminate cement clinker, 17 parts of activated perlite carrier, 12 parts of calcium fluorotitanate hydration catalyst, 10 parts of quaternized konjac glucomannan spin-spray catalyst, 9 parts of carboxymethyl starch ether-xanthan gum tidal stabilizer, 11 parts of nickel slag-perlite composite activator, 2.1 parts of polyglycerol fatty acid ester-alkyl glycoside composite dispersant, and 34 parts of artificial island seawater purification agent.

3. The cement-based catalyst for artificial island jet grouting piles according to claim 1, characterized in that: The calcium fluorotitanate hydration catalyst phase is prepared by reflux reaction of calcium fluoride and tricalcium titanate at a molar ratio of 1:1, with a particle size ≤6μm; the quaternized konjac glucomannan spin-spray catalyst phase contains 6% by mass of nano-zirconia, with a nano-zirconia particle size of 25~35nm, and the spin-spray catalyst phase particle size ≤6μm.

4. The cement-based catalyst for artificial island jet grouting piles according to claim 1, characterized in that: The carboxymethyl starch ether-xanthan gum tidal stabilizer is prepared by crosslinking carboxymethyl starch ether and xanthan gum at a weight ratio of 5:3, with a particle size ≤9μm; the nickel slag-perlite composite activator is prepared by activating blast furnace nickel slag and perlite powder at a weight ratio of 8:2, with a specific surface area ≥580m². 2 / kg.

5. The cement-based catalyst for artificial island jet grouting piles according to claim 1, characterized in that: The polyglycerol fatty acid ester-alkyl glycoside composite dispersant is a mixture of polyglycerol monooleate and dodecyl glycoside in a weight ratio of 6:4, with an HLB value of 14-15; the seawater purified by the artificial island has a salinity of 0.6%-2.6%.

6. A method for preparing a cement-based catalyst for jet grouting piles on artificial islands, characterized in that, The preparation of the cement-based catalyst for artificial island rotary jet grouting piles according to any one of claims 1 to 5 comprises the following steps: S1: Weighing each raw material according to weight parts; S2: Placing the activated perlite carrier, the calcium fluorotitanate hydrated catalyst phase, and the quaternized konjac glucomannan rotary jet grouting catalyst phase in a microwave support device and treating them for 1.8 h at a microwave power of 350 W and a temperature of 48-53 °C to obtain a catalyst substrate; S3: Adding carboxymethyl starch ether-xanthan gum tidal stabilizer and nickel slag-perlite composite activator to the catalyst substrate and wet ball milling for 14 min at a speed of 840-940 r / min to obtain a catalyst powder; S4: Polyglycerol fatty acid ester-alkyl glycoside composite dispersant is added to the seawater purified by the artificial island and stirred for 8 minutes at a speed of 330~350 r / min to obtain an aqueous solution of the additive; S5: The aqueous solution of the additive is added dropwise to the catalyst powder for 13~15 minutes and stirred for 22 minutes at a temperature of 28~31℃ and a speed of 530~590 r / min to obtain a catalyst slurry; S6: The catalyst slurry is vacuum matured for 15 minutes under a vacuum degree of -0.088~-0.098 MPa, cooled to room temperature, and then pulverized to a particle size ≤11μm to obtain the cement-based catalyst for the jet grouting pile of the artificial island.

7. The preparation method according to claim 6, characterized in that: The microwave treatment temperature in step S2 is 50°C; the wet ball milling speed in step S3 is 890 r / min; and the vacuum degree of the vacuum curing in step S6 is -0.093 MPa.

8. The application of a cement-based catalyst for jet grouting piles on artificial islands, characterized in that: The cement-based catalyst for jet grouting piles on artificial islands according to any one of claims 1 to 5 is used for jet grouting pile reinforcement construction of 5 to 40m soft soil on artificial islands with a water content of 72% to 96%, a salt content of 0.6% to 2.6%, and an organic matter content of 5% to 13%.

Images