An underwater anti-dispersion grout and its preparation method

Abstract

This invention belongs to the technical field of cement-based grouting materials, specifically relating to an underwater anti-dispersion grouting material and its preparation method. The underwater anti-dispersion grouting material comprises the following raw materials in parts by weight: 350-400 parts cement, 40-80 parts active admixture, 400-600 parts fine aggregate, 3-6 parts polycarboxylate superplasticizer, 5-8 parts anti-dispersion agent, and 0.1-0.3 parts expansion agent; the anti-dispersion agent is a mixture of modified polyacrylamide and polyacrylic acid aqueous solution in a mass ratio of 15:1-8; the polyacrylic acid aqueous solution has a solid content of 40-50%; the modified polyacrylamide is copolymerized from acrylamide, unsaturated ether monomers, and acrylic acid in a mass ratio of 10:1-2:0.4-0.7. The grouting material uses modified polyacrylamide, obtained by copolymerizing acrylamide, unsaturated ethers, and acrylic acid, as the main component of the anti-dispersion agent, supplemented by polyacrylic acid to synergistically improve the hydration rate, achieving efficient underwater grouting and strong freeze-thaw resistance.

Description

Technical Field

[0001] This invention belongs to the field of cement-based grouting technology, specifically relating to an underwater anti-dispersion grouting material and its preparation method. Background Technology

[0002] my country has a massive number of water-related engineering projects. Underwater concrete structures undergo long-term service under the influence of factors such as water pressure, temperature gradients, water flow erosion, corrosive environments, and loads. Coupled with poor quality control in some concrete construction projects, defects such as cracks and honeycombing are prone to occur. If these defects are not repaired in time, they will gradually expand and penetrate the structure itself, not only affecting the safe operation of the project, but also potentially causing major risks such as leakage and a decrease in the structural load-bearing capacity.

[0003] Currently, there are many materials available for repairing concrete cracks, such as epoxy grout, quick-sealing materials, polyurethane grout, and elasto-plastic sealants. However, most of these are only suitable for dry or humid environments. Many hydraulic structures lack the conditions to drain water, necessitating concrete crack repair work in aquatic conditions, often requiring underwater operations or even deep-water work. This unique working condition places core demands on repair materials: they must possess excellent underwater anti-dispersion properties to ensure no segregation during mixing and pouring in water, and they must be able to bond tightly to the original concrete substrate and self-fill and densely fill cracks.

[0004] Underwater anti-dispersion cement-based grouting materials have emerged to address this need. The composition of underwater anti-dispersion cement-based grouting materials is similar to that of ordinary cement-based grouting materials. The main difference is the addition of an anti-dispersion agent to the ordinary cement-based grouting material, which increases the viscosity of the mixture, thus preventing aggregate settling and cement slurry loss during underwater pouring. Polyacrylamide is one of the earliest developed and widely used anti-dispersion agents in underwater non-dispersion grouting materials. It has excellent anti-dispersion properties. For example, patent CN105622006B discloses a low-temperature early-strength, high-strength underwater grouting material with the following composition: 30-45 parts ordinary silicate cement, 45-60 parts fine aggregate, 5-10 parts mineral powder, 2-4 parts silica fume, 0.5-1 part composite expansion agent, 0.2-0.5 parts early-strength powder water-reducing agent, 0.1-0.5 parts nano-hydrated calcium silicate, 0.3-0.5 parts composite early-strength agent, and 0.1-0.3 parts anti-dispersion compound. The anti-dispersing compound is a mixture of 6 million molecular weight polyacrylamide and hydroxypropyl guar gum in a mass ratio of 1:3-5. Patent CN114890738B discloses a special underwater lightweight grouting material for filling the suction cylinder of offshore wind turbines and its preparation method, comprising the following raw materials by weight: 550-650 parts ordinary silicate cement; 170-350 parts active filler; 80-150 parts lightweight aggregate; 1.0-3.0 parts water-reducing agent; 0.1-0.5 parts rheology modifier; 0.2-1.0 parts retarder; 10-18 parts underwater anti-dispersing agent; the lightweight aggregate has a particle size of 0.5-3.0 mm and a bulk density ≤200 kg / m³. 3 The underwater anti-dispersant is a polypropylene-based underwater anti-dispersant; the rheology modifier is a precipitant, and the underwater anti-dispersant is a polypropylene-based underwater anti-dispersant, the main component of which is high molecular weight polyacrylamide with a molecular weight of 10-12 million.

[0005] Both of the above technologies rely on high molecular weight polyacrylamide (PAM) for thickening to achieve underwater anti-dispersion effects. However, its molecular chains will carry a large number of air bubbles during the mixing process and form a viscous and stable system that is difficult to break. This leaves many irregularly shaped and unevenly distributed weak pores in the hardened body. Although the addition of active admixtures such as silica fume and mineral powder can optimize the porosity and enhance the density to a certain extent, it is still difficult to eliminate these inferior defects. As a result, the grout body will suffer structural damage or spalling during freeze-thaw cycles because the pores cannot effectively buffer the ice expansion stress, and the grouting repair will fail.

[0006] Therefore, it is necessary to physically or chemically modify polyacrylamide to fundamentally inhibit the generation and stabilization of harmful bubbles while retaining its excellent anti-dispersion ability, thereby improving the freeze-thaw resistance of the grout. Summary of the Invention

[0007] To address the aforementioned technical problems, this invention provides an underwater anti-dispersion grout and its preparation method. The grout uses modified polyacrylamide, obtained by copolymerizing acrylamide, unsaturated ethers, and acrylic acid, as the main anti-dispersion agent. Polyacrylic acid is added to synergistically improve the hydration rate, achieving efficient grouting and strong freeze-thaw resistance. Hydrogen bonds easily form between the amide groups on the polyacrylamide molecules, forming a dense network that encapsulates the bubbles. The side groups of the ether chains disrupt the tight entanglement between polyacrylamide molecules, making the molecular arrangement on the bubble surface loose and weakening the binding force on the bubbles. When bubbles carrying this loose network approach each other, they are more likely to fuse in these weak areas. If the fused large bubbles exceed the binding capacity of the polymer network, they will burst or escape due to excessive buoyancy. After merging, bursting, and escaping, the bubbles that remain in the grout are of moderate size and have a tough structure. These bubbles can exist stably and persistently in the hardened grout, becoming the key pore structure to resist freeze-thaw damage.

[0008] To achieve the above objectives, the following technical solution is adopted:

[0009] An underwater anti-dispersion grouting material comprises the following raw materials in parts by weight: 350-400 parts cement, 40-80 parts active admixture, 400-600 parts fine aggregate, 3-6 parts polycarboxylate superplasticizer, 5-8 parts anti-dispersion agent, and 0.1-0.3 parts expansion agent; wherein the anti-dispersion agent is compounded from modified polyacrylamide and polyacrylic acid aqueous solution in a mass ratio of 15:1-8; the solid content of the polyacrylic acid aqueous solution is 40-50%; and the modified polyacrylamide is copolymerized from acrylamide, unsaturated ether monomers, and acrylic acid in a mass ratio of 10:1-2:0.4-0.7.

[0010] Preferably, the anti-dispersant is a mixture of modified polyacrylamide and polyacrylic acid aqueous solution in a mass ratio of 15:2-6, more preferably 15:4-6, and most preferably 15:5-6.

[0011] The unsaturated ether monomers are selected from one or more of vinyl 2-(2-ethoxyethoxy)ethyl ether, 2-ethoxyethyl vinyl ether, 2-methoxyethyl vinyl ether, vinyl 2-(2-ethoxyethoxy)ethyl ether, triethylene glycol methyl ether methacrylate, and di(ethylene glycol) ethyl ether methacrylate.

[0012] The modified polyacrylamide is prepared by a method comprising the following steps:

[0013] In an inert atmosphere, acrylic acid is added to water to adjust the pH, then acrylamide, unsaturated ether monomers, and an initiator are added, mixed, and polymerized at a higher temperature to obtain modified polyacrylamide.

[0014] The pH adjustment involves neutralizing the pH to 7-8 with an alkali. The alkali is selected from one or a combination of two of sodium hydroxide and sodium bicarbonate. The initiator is a mixture of potassium persulfate and sodium bisulfite in a mass ratio of 0.8-1:0.8-1. The amount of initiator used is 0.6-0.8 wt% of the sum of the masses of acrylamide, unsaturated ether monomers, and acrylic acid. The heating polymerization involves reacting at 30-50°C for 2-5 hours. The amount of water used is 3-5 times the sum of the masses of acrylamide, unsaturated ether monomers, and acrylic acid. After the heating polymerization, the process includes adding a chain transfer agent, crushing, dehydration, drying, and pulverizing. The chain transfer agent is selected from one or a combination of two or more of isopropanol, mercaptoethanol, methanol, and ethanol. The amount of chain transfer agent used is 0.3-0.5 wt% of the sum of the masses of acrylamide, unsaturated ether monomers, and acrylic acid. The crushing process involves breaking the colloid into particles with a particle size of 1-5 cm. The dehydration is performed by extrusion dehydration until the colloidal moisture content drops to 40-50%. The drying is performed at 60-90℃ until constant weight. The pulverization is performed by grinding to 80-120 mesh.

[0015] Modified polyacrylamide, prepared by solution polymerization using acrylamide, unsaturated ether monomers, and acrylic acid, retains the original adsorption and bridging capabilities of the polyacrylamide backbone, ensuring excellent anti-dispersion properties. Simultaneously, it introduces structural weaknesses—ether chain side groups—to the polyacrylamide molecule. These ether chain side groups actively guide the coalescence or collapse of unstable, fine bubbles, eliminating improperly sized and structurally weak bubbles. The retained bubbles exhibit high strength and stability, improving the durability of the hardened slurry under long-term freeze-thaw cycles. However, the ether chain side groups can complex with the polyacrylamide backbone, affecting the Ca in the slurry. 2+ Al 3+ The addition of hydrated active ions reduces the migration rate of ions to cement particles, thus excessively retarding setting. By adding an appropriate amount of polyacrylic acid, its high-density carboxylate groups preferentially compete with ether chains for binding to Ca2+. 2+ Al 3+ This process reduces the amount of active ions bound by ether chains, while short-chain polyacrylic acid molecules can act as hydration nucleus templates, inducing the rapid precipitation of CSH gel and ettringite on the particle surface, thus accelerating hydration. The mass ratio of modified polyacrylamide to polyacrylic acid is crucial for balancing anti-dispersion, freeze-thaw durability, and strength development speed: the amount of modified polyacrylamide must ensure the adsorption and bridging capacity of the main chain to maintain underwater anti-dispersion and bubble optimization; the amount of polyacrylic acid must effectively compete for active ions and induce hydration without causing a sudden increase in slurry viscosity due to excessive carboxyl groups. Ultimately, the two work synergistically to achieve no reduction in anti-dispersion, a more stable bubble system, no excessive retardation, and improved freeze-thaw durability.

[0016] The polyacrylic acid aqueous solution contains polyacrylic acid with a weight-average molecular weight of 2000-3000.

[0017] The cement is ordinary Portland cement with a strength grade ≥42.5.

[0018] The active admixture is selected from one or more of fly ash, silica fume, and slag powder.

[0019] The fly ash is selected from one or a combination of two of the following: Grade I fly ash and Grade II fly ash.

[0020] The silica ash contains 85-92% silica, has an average particle size of 0.1-0.2 μm, and a specific surface area of ​​20,000-25,000 m². 2 / kg.

[0021] The slag powder is selected from one or a combination of two of the following: S105 grade slag powder and S95 grade slag powder.

[0022] The fine aggregate is continuously graded quartz sand with a particle size range of 0.15-0.5 mm.

[0023] The water reduction rate of the polycarboxylate superplasticizer is 30-45%.

[0024] The expanding agent is selected from one or more combinations of sulfoaluminate expanding agents, lime expanding agents, and magnesium oxide expanding agents.

[0025] The underwater anti-dispersion grout also includes water, and the mass ratio of the combined mass of cement and active admixture to water is 2-4:1.

[0026] The present invention also provides a method for preparing the above-mentioned underwater anti-dispersion grout, comprising the following steps:

[0027] The cement, active admixture, fine aggregate, polycarboxylate superplasticizer, anti-dispersion agent, and expansion agent are mixed evenly, and then water is added and mixed evenly to obtain the above-mentioned underwater anti-dispersion grouting material.

[0028] Compared with the prior art, the beneficial effects of the present invention are:

[0029] The grouting material of this invention uses modified polyacrylamide, which is copolymerized from acrylamide, unsaturated ether monomers, and acrylic acid, as the main anti-dispersant component. It is supplemented with polyacrylic acid to synergistically improve the hydration rate, thereby achieving efficient grouting and strong freeze-thaw resistance of the underwater grouting material. Hydrogen bonds are easily formed between the amide groups on the polyacrylamide molecules, which are wrapped into a dense network to encapsulate the bubbles. The side groups of the ether chain disrupt the tight entanglement structure between polyacrylamide molecules, making the molecular arrangement on the bubble surface loose and weakening the binding force on the bubbles. When bubbles carrying this loose network approach each other, they are more likely to fuse in these weak areas. If the fused large bubbles exceed the binding capacity of the polymer network, they will burst or float to the surface due to excessive buoyancy and escape. After merging, bursting, and escaping, the bubbles that are left in the grout are of moderate size and have a tough structure. These bubbles can exist stably and persistently in the hardened grout, becoming the key pore structure to resist freeze-thaw damage. Detailed Implementation

[0030] The present invention will be further described below with reference to specific embodiments, but is not limited to the contents of the specification. Unless otherwise specified, all "parts" mentioned in the embodiments of the present invention are parts by weight. All reagents used are commercially available in the art.

[0031] Polyacrylic acid aqueous solution P890198, viscous liquid, solid content 50% (solvent water), polyacrylic acid weight average molecular weight 2000, from Maclean.

[0032] Polyacrylic acid aqueous solution P815681, viscous liquid, solid content 50% (solvent water), polyacrylic acid weight average molecular weight 3000, from Maclean.

[0033] P180 powdered polycarboxylate superplasticizer, with a water reduction rate of 41%, is from Aolaite.

[0034] CSA-Ⅰ expanding agent, sourced from Tangshan Arctic Bear Building Materials Co., Ltd.

[0035] Example 1

[0036] 1) Under a nitrogen atmosphere, add 0.4 parts by mass of acrylic acid to 49.6 parts by mass of water, add sodium hydroxide to adjust the pH to 7, add 10 parts by mass of acrylamide, 2 parts by mass of triethylene glycol methyl ether methacrylate, and 0.087 parts by mass of initiator composed of potassium persulfate and sodium bisulfite in a mass ratio of 1:1, mix well, heat to 50℃ and polymerize for 2 hours. After the reaction is complete, add 0.050 parts by mass of chain transfer agent mercaptoethanol, crush the colloid into colloidal particles with a particle size of 1-5 cm, squeeze and dehydrate until the water content of the colloid drops to 50%, dry at 80℃ to constant weight, and pulverize to 120 mesh to obtain modified polyacrylamide.

[0037] 2) Mix 350 parts by weight of P.O52.5 cement, 80 parts by weight of grade 1 fly ash, 600 parts by weight of continuously graded quartz sand with a particle size range of 0.15-0.5mm, 6 parts by weight of polycarboxylate superplasticizer P180, 8 parts by weight of anti-dispersant compounded by modified polyacrylamide and polyacrylic acid aqueous solution P815681 (solid content 50%) in a mass ratio of 15:6, and 0.3 parts by weight of CSA-Ⅰ expansion agent evenly, then add 107.5 parts by weight of water and mix evenly to obtain underwater anti-dispersibility grouting material.

[0038] Example 2

[0039] The rest is the same as in Example 1, except that in step 1), 2-methoxyethyl vinyl ether is used instead of triethylene glycol methyl ether methacrylate in equal mass.

[0040] Example 3

[0041] The rest is the same as in Example 1, except that in step 1), the amount of triethylene glycol methyl ether methacrylate is 1 part by mass, the amount of initiator is adjusted accordingly to 0.08 parts by mass, the amount of water is 45.6 parts by mass, and the amount of chain transfer agent mercaptoethanol is 0.046 parts by mass.

[0042] Example 4

[0043] The rest is the same as in Example 1, except that in step 1), the amount of acrylic acid is 0.7 parts by mass, the amount of initiator is adjusted accordingly to 0.089 parts by mass, the amount of water is 50.8 parts by mass, and the amount of chain transfer agent mercaptoethanol is 0.050 parts by mass.

[0044] Example 5

[0045] The rest is the same as in Example 1, except that in step 2), the amount of anti-dispersant compounded by the modified polyacrylamide and the polyacrylic acid aqueous solution P815681 (solid content 50%) in a mass ratio of 15:6 is 5 parts by mass.

[0046] Example 6

[0047] The rest is the same as in Example 1, except that in step 2), the mass ratio of modified polyacrylamide to polyacrylic acid aqueous solution P815681 (solid content 50%) is 15:2.

[0048] Example 7

[0049] The rest is the same as in Example 1, except that in step 2), the mass ratio of modified polyacrylamide to polyacrylic acid aqueous solution P815681 (solid content 50%) is 15:1.

[0050] Example 8

[0051] The rest is the same as in Example 1, except that in step 2), the mass ratio of modified polyacrylamide to polyacrylic acid aqueous solution P815681 (solid content 50%) is 15:8.

[0052] Example 9

[0053] The rest is the same as in Example 1, except that in step 2), polyacrylic acid P815681 (50% solid content) is replaced with an equal mass of polyacrylic acid aqueous solution P890198 (50% solid content).

[0054] Example 10

[0055] 1) Under a nitrogen atmosphere, add 0.4 parts by mass of acrylic acid to 49.6 parts by mass of water, add sodium hydroxide to adjust the pH to 7, add 10 parts by mass of acrylamide, 2 parts by mass of triethylene glycol methyl ether methacrylate, and 0.087 parts by mass of an initiator composed of potassium persulfate and sodium bisulfite in a mass ratio of 1:1. Mix well, heat to 50℃ and polymerize for 2 hours. After the reaction is complete, add 0.050 parts by mass of chain transfer agent isopropanol, crush the colloid into colloidal particles with a particle size of 1-5 cm, squeeze and dehydrate until the water content of the colloid drops to 50%, dry at 80℃ to constant weight, and pulverize to 120 mesh to obtain modified polyacrylamide.

[0056] 2) Mix 400 parts by weight of P.O52.5 cement, 40 parts by weight of grade 1 fly ash, 400 parts by weight of continuously graded quartz sand with a particle size range of 0.15-0.5mm, 3 parts by weight of polycarboxylate superplasticizer P180, 5 parts by weight of anti-dispersion agent compounded by modified polyacrylamide and polyacrylic acid aqueous solution P815681 (solid content 50%) in a mass ratio of 15:6, and 0.3 parts by weight of CSA-Ⅰ expansion agent evenly, then add 110 parts by weight of water and mix evenly to obtain underwater anti-dispersion grouting material.

[0057] Comparative Example 1

[0058] The rest is the same as in Example 1, except that in step 1), the amount of acrylic acid is 0.8 parts by mass, the amount of initiator is adjusted accordingly to 0.09 parts by mass, the amount of water is 51.2 parts by mass, and the amount of chain transfer agent mercaptoethanol is 0.050 parts by mass.

[0059] Comparative Example 2

[0060] The rest is the same as in Example 1, except that in step 1), the amount of triethylene glycol methyl ether methacrylate is 3 parts by mass, the amount of initiator is adjusted accordingly to 0.094 parts by mass, the amount of water is 53.6 parts by mass, and the amount of chain transfer agent mercaptoethanol is 0.054 parts by mass.

[0061] Comparative Example 3

[0062] The rest is the same as in Example 1, except that in step 2), all 8 parts by weight of the anti-dispersant are modified polyacrylamide.

[0063] The grouting materials prepared in the above embodiments and comparative examples were subjected to the following performance tests:

[0064] Compressive strength (28 days): Tested according to the standards DL / T5117-2000 Underwater Non-dispersible Concrete Test Procedure and GB / T 50448-2015 Technical Specification for Application of Cement-based Grouting Materials.

[0065] Freeze-thaw cycle durability: The test was conducted according to standard GB / T 50082-2009, "Test Methods for Long-Term Performance and Durability of Ordinary Concrete," using the rapid freezing method. Each freeze-thaw cycle should be completed within 4 hours, with the thawing time accounting for 1 / 4 of the total freeze-thaw cycle time. During freezing and thawing, the minimum and maximum temperatures at the center of the specimen should be controlled within (-18±2)℃ and (5±2)℃, respectively. At any given time, the center temperature of the specimen should not exceed 7℃ or fall below -20℃. The time required for each specimen to drop from 3℃ to -16℃ should be half the freezing time; the time required for each specimen to rise from -16℃ to 3℃ should be half the thawing time, and the temperature difference between the inside and outside of the specimen should not exceed 28℃. The transition time between freezing and thawing was 10 minutes. After 1000 cycles, the compressive strength was retested, and the compressive strength loss rate was calculated.

[0066] Anti-dispersion: Tested according to standard DL / T5117-2000 Test Procedure for Underwater Non-dispersible Concrete, and the content of suspended solids was determined.

[0067] Setting time: Tested according to standard DL / T5117-2000 Test Procedure for Underwater Non-Dispersible Concrete.

[0068] Table 1 Performance Test Results

[0069] .

[0070] As can be seen from Table 1, the anti-dispersant prepared by the present invention has excellent anti-dispersibility properties. By adjusting the raw materials and ingredients of the modified polyacrylamide and polyacrylic acid, excellent anti-dispersibility, more stable bubble system, no excessive retardation, and improved freeze-thaw durability are achieved.

[0071] The above detailed description is a specific description of one of the feasible embodiments of the present invention. This embodiment is not intended to limit the patent scope of the present invention. All equivalent implementations or modifications that do not depart from the present invention should be included within the scope of the technical solution of the present invention.

Claims

1. An underwater anti-dispersion grout, characterized by, The underwater anti-dispersion grouting material comprises the following raw materials by mass: 350-400 parts of cement, 40-80 parts of active admixture, 400-600 parts of fine aggregate, 3-6 parts of polycarboxylic acid water reducing agent, 5-8 parts of anti-dispersant, and 0.1-0.3 parts of expanding agent; the anti-dispersant is compounded by modified polyacrylamide and polyacrylic acid aqueous solution at a mass ratio of 15:1-8; the polyacrylic acid aqueous solution has a solid content of 40-50 %; the modified polyacrylamide is copolymerized by acrylamide, unsaturated ether monomer and acrylic acid at a mass ratio of 10:1-2:0.4-0.

7.

2. The underwater anti-dispersion grout according to claim 1, characterized in that, The anti-dispersant is compounded by modified polyacrylamide and polyacrylic acid aqueous solution at a mass ratio of 15:2-6.

3. The underwater anti-dispersion grout according to claim 1, characterized in that, The unsaturated ether monomer is selected from one or more than two combinations of ethylene 2-(2-ethoxyethoxy) ethyl ether, 2-ethoxyethyl vinyl ether, 2-methoxyethyl vinyl ether, triethylene glycol methyl ether methacrylate, and di(ethylene glycol) ether methacrylate.

4. The underwater anti-dispersion grout of claim 1, wherein, The modified polyacrylamide is prepared by a method comprising the following steps: Under an inert atmosphere, acrylate is added to water, the pH is adjusted, acrylamide, unsaturated ether monomer and initiator are mixed, polymerization is carried out by heating to obtain modified polyacrylamide.

5. The underwater anti-dispersion grout according to claim 4, characterized in that, The pH is adjusted by neutralization with a base to a pH of 7-8; the base is selected from one or a combination of sodium hydroxide and sodium bicarbonate.

6. The underwater anti-dispersion grout according to claim 4, characterized in that, The initiator is a mixture of potassium persulfate and sodium bisulfite at a mass ratio of 0.8-1:0.8-1; the amount of the initiator is 0.6-0.8 wt% of the total mass of acrylamide, unsaturated ether monomer and acrylic acid.

7. The underwater anti-dispersion grout of claim 1, wherein, The weight average molecular weight of polyacrylic acid in the polyacrylic acid aqueous solution is 2000-3000.

8. The underwater anti-dispersion grout of claim 1, wherein, The cement is ordinary Portland cement with a strength grade of ≥42.5; the active admixture is selected from one or more than two combinations of fly ash, silica fume and slag powder; the fine aggregate is continuous gradation quartz sand with a particle size range of 0.15-0.5 mm; the water reducing rate of the polycarboxylic acid water reducing agent is 30-45 %; and the expanding agent is selected from one or more than two combinations of sulphoaluminate-based expanding agent, lime-based expanding agent and magnesium oxide-based expanding agent.

9. The underwater anti-dispersion grout of claim 1, wherein, The mass ratio of the total mass of cement and active admixture to the mass of water is 2-4:

1.

10. A preparation method of the underwater anti-dispersion grouting material according to any one of claims 1-9, comprising the following steps: The cement, active admixture, fine aggregate, polycarboxylic acid water reducing agent, anti-dispersant and expanding agent are mixed uniformly, and then water is added and mixed uniformly to obtain the underwater anti-dispersion grouting material.