An impact-resistant paste with high impact resistance and a method for preparing the same

Abstract

The application discloses an impact-resistant paste slurry with high impact resistance and a preparation method thereof. The impact-resistant paste slurry comprises the following raw materials in parts by weight: 100-200 parts of sulphoaluminate cement, 30-50 parts of composite light aggregate, 3-8 parts of acrylamide-acrylic acid copolymer, 1-2 parts of polyvinyl butyral, 0.05-0.1 part of hydrophobically modified hydroxypropyl methylcellulose, 0.3-0.8 part of polycarboxylate superplasticizer, 0.1-0.3 part of nano attapulgite, 1-3 parts of composite fiber, 40-60 parts of water and 0.01-0.05 part of retarder. The paste slurry overcomes the defects of poor impact resistance and poor fluidity of cement grouting in the prior art.

Description

Technical Field

[0001] This invention relates to the field of impact slurry preparation technology, and more specifically to an impact slurry with high impact resistance and its preparation method. Background Technology

[0002] With the rapid development of the civil engineering and water conservancy industries, the existence of underground seepage problems affects foundation deformation, bearing capacity, and stability, increasing the difficulty of engineering construction and operation and maintenance costs. Foundation seepage prevention has become a major challenge in water conservancy projects, and forming a grouting curtain is an important means of foundation seepage prevention. Grouting involves injecting prepared grout into poor foundations using grouting equipment under appropriate grouting pressure. This can strengthen the foundation, control the deformation of surrounding rock, and control underground water inrush. During the grouting process, under pressure, the uncured flowing grout can diffuse in rock fissures. After a period of time, the grout solidifies and hardens, making the rock mass a unified whole.

[0003] In grouting projects, the applicability of grouting materials should be considered. Different geological conditions require different grouting materials, and selecting the appropriate material is crucial for effective plugging and seepage prevention in poor foundations. For example, coarse-particle cement-based grouting materials should not be used in sand layers and rock masses with micropores (fractures) to avoid difficulties in injection and waste of resources. Chemical grouting materials are excellent for this situation due to their fine particles, high fluidity, and significant seepage prevention performance. However, in deep overburden layers or other strata with large seepage channels, chemical grouting materials are difficult to retain due to the scouring and carrying effect of water flow, hindering rapid leak repair. In such cases, cement-based grouting materials can demonstrate their advantages. However, due to the different main raw materials and additives used in current cement-based grouting materials, their performance varies considerably. Therefore, in the research and selection of grouting materials, it is necessary to clarify the various performance parameters of the materials to determine their applicability. In addition, grouting materials may be used in different deteriorating environments. Due to the special nature and complexity of grouting projects, it is essential to consider the durability of grouting materials.

[0004] Under conditions of high-flow-rate water inflow, the erosion resistance of grouting materials is of paramount importance, specifically the grout retention rate under different water flow conditions, to ensure effective sealing. However, conventional cement-based grouting materials suffer from poor water erosion resistance, making them highly susceptible to water flow erosion and unable to form an effective curtain, thus unsuitable for complex formations with severe leakage under high-flow-rate water inflow. Therefore, using erosion-resistant pastes to address such problems is essential; however, current pastes exhibit poor impact resistance and fluidity, failing to meet construction requirements. Summary of the Invention

[0005] To achieve the above objectives, the present invention provides an impact-resistant grout with high impact resistance and its preparation method, overcoming the defects of poor impact resistance and poor fluidity of existing cement grouts.

[0006] The first aspect of the present invention provides an impact-resistant paste with high impact resistance, the impact-resistant paste comprising the following raw materials in parts by weight: 100-200 parts of sulfoaluminate cement, 30-50 parts of composite lightweight aggregate, 3-8 parts of acrylamide-acrylic acid copolymer, 1-2 parts of polyvinyl butyral, 0.05-0.1 parts of hydrophobically modified hydroxypropyl methylcellulose, 0.3-0.8 parts of polycarboxylate superplasticizer, 0.1-0.3 parts of nano-attapulgite, 1-3 parts of composite fiber, 40-60 parts of water, and 0.01-0.05 parts of retarder.

[0007] Existing impact slurries typically consist of cement, water, hydroxypropyl methylcellulose (HPMC), and some retarder. However, these slurries have poor water impact resistance, especially in hydraulic engineering, where they are prone to leakage when sealing underground pipelines. This invention creatively modifies HPMC with palmitic acid to achieve hydrophobicity. Under the action of the catalyst DCC / DMAP, alkyl groups are grafted onto hydroxyl groups at 90-100℃, altering the amphiphilicity of HPMC with hydrophobic groups. This transforms HPMC from a simple hydrophilic thickener into a modifier with multiple functions, including thixotropic regulation, hydrophobic impermeability, and interface enhancement. In impact slurries, this modification not only improves the material's workability but also significantly enhances impact resistance through synergistic effects with nano-attapulgite. Furthermore, the linear molecular chains of acrylamide-acrylic acid copolymer and the flexible chains of polyvinyl butyral intertwine to form a polymer network; nano-attapulgite is embedded in the network through hydrogen bonding and physical adsorption, forming a "polymer-nanofiller" composite network. This network provides the thixotropic properties of the paste, making it easily broken by shear forces during mixing and construction, thus improving its fluidity. Upon settling, the network recovers, preventing bleeding and segregation of the paste. Simultaneously, the hydrophobic side chains of the hydrophobically modified hydroxypropyl methylcellulose interact with the hydrophobic butyraldehyde groups of polyvinyl butyral, reducing the hydration swelling of the polymer chains and lowering static viscosity. Meanwhile, its hydrophilic backbone synergistically retains water with the hydrophilic groups of the acrylamide-acrylic acid copolymer, preventing excessive water absorption due to the high specific surface area of ​​the nano-attapulgite, thus achieving a balance between water retention and fluidity. Furthermore, the rod-like structure of the nano-attapulgite is interwoven within the cement hydration products, forming a "nano-reinforcing skeleton," while polyvinyl butyral and acrylamide-acrylic acid copolymer form a flexible transition layer at the interface, reducing stress concentration in the cement matrix. When the material is subjected to impact, the nano-attapulgite can hinder crack propagation, while the polymer film absorbs energy through plastic deformation; both synergistically improve impact toughness.

[0008] Furthermore, the composite lightweight aggregate comprises hollow ceramic microspheres and expanded shale with surface silanization treatment, and the mass ratio of the two is 1:(0.5-2); wherein the hollow ceramic microspheres have a particle size of 50-150μm and a wall thickness of 2-5μm; and the expanded shale with surface silanization treatment has a particle size of 0.5-2mm.

[0009] Compared with existing technologies, the spherical structure of hollow ceramic microspheres can reduce the viscosity of slurry, while the porous structure of expanded shale can absorb excess water.

[0010] Furthermore, the composite fiber comprises ultra-high molecular weight polyethylene fiber treated with silane coupling agent and basalt fiber, and the mass ratio of the two is (1:1) to (3:1); wherein the length of the polyethylene fiber is 3-6 mm and the length of the basalt fiber is 6-12 mm.

[0011] Compared with existing technologies, the silane coupling agent used in this invention is KH-550, and the final polyethylene fiber has a molecular weight of 5 million to 8 million Da. When the paste is subjected to impact load, the ultra-high molecular weight polyethylene fiber can absorb kinetic energy through elastic deformation and consume energy through interfacial friction with the cement matrix, thus delaying crack propagation. Its shorter length (3-6 mm) allows it to disperse well in the paste, uniformly distributed at the microscale, forming a flexible network that inhibits the generation of microcracks. The longer length (6-12 mm) of the basalt fiber allows it to cross potential crack surfaces at the macroscale, forming a bridging effect, bearing tensile stress and limiting crack propagation. Its high elastic modulus can quickly transfer impact stress, avoiding local stress concentration, while the rigid structure can enhance the paste's resistance to deformation. When the mass ratio of the two is (1:1) to (3:1), the short and long fibers form a gradient reinforcement network, resulting in stronger impact energy absorption capacity, suitable for multiple impacts or dynamic loading environments, and superior impact fatigue resistance of the paste.

[0012] Furthermore, the retarder comprises a complex of sodium gluconate and boric acid, with a mass ratio of 1:1.

[0013] Compared with existing technologies, sodium gluconate, as a hydroxycarboxylic acid salt retarder, can adsorb onto the surface of cement particles and chelate Ca... 2+ The mechanism of action delays cement hydration; boric acid, on the other hand, reacts with cement hydration products to form complexes, further inhibiting the hydration process. The combination of these two substances extends the initial setting time of the cement paste, providing more time for pouring, vibration, and other construction operations of the impact-resistant paste.

[0014] The second aspect of this invention provides a method for preparing the aforementioned anti-impact paste, the process of which is as follows: (1) Weigh each component; (2) The composite lightweight aggregate and nano-attapulgite clay are mixed to obtain the filler; (3) Add sulfoaluminate cement and retarder to the filler, stir, and obtain cement material; (4) After pre-swelling hydrophobically modified hydroxypropyl methylcellulose with 60% water, it is mixed with water-reducing agent and remaining water to prepare a solution; (5) Add the solution to the cementitious material and stir to obtain a mixture; (6) Add acrylamide-acrylic acid copolymer and polyvinyl butyral to the mixture in two batches, with an interval of 1 minute between each batch. Stir, then add composite fiber, stir, defoam, and obtain the finished paste.

[0015] Furthermore, in step (2), the stirring speed is 300-400 rpm and the stirring time is 5-10 min.

[0016] Further, in step (3), the stirring is first stirred at 300-400 rpm for 2-3 minutes, and then stirred at 800-1000 rpm for 4-7 minutes.

[0017] Furthermore, in step (5), the stirring is performed at 600-800 rpm for 10-20 min.

[0018] Furthermore, the stirring is performed at 600-800 rpm for 10-15 minutes; the defoaming is performed by allowing the mixture to stand for 5-10 minutes.

[0019] Compared with existing technologies, the above preparation method results in cement paste with good uniformity and stability. Detailed Implementation

[0020] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0021] Existing cement pastes have poor impact resistance and poor fluidity.

[0022] To overcome the above-mentioned defects, a first aspect of the present invention provides an impact-resistant paste with high impact resistance, the impact-resistant paste comprising the following raw materials in parts by weight: 100-200 parts of sulfoaluminate cement, 30-50 parts of composite lightweight aggregate, 3-8 parts of acrylamide-acrylic acid copolymer, 1-2 parts of polyvinyl butyral, 0.05-0.1 parts of hydrophobically modified hydroxypropyl methylcellulose, 0.3-0.8 parts of polycarboxylate superplasticizer, 0.1-0.3 parts of nano-attapulgite, 1-3 parts of composite fiber, 40-60 parts of water, and 0.01-0.05 parts of retarder.

[0023] For example, an impact-resistant mortar with high impact resistance comprises: 100 parts of sulfoaluminate cement, 50 parts of composite lightweight aggregate, 8 parts of acrylamide-acrylic acid copolymer, 1.5 parts of polyvinyl butyral, 0.08 parts of hydrophobically modified hydroxypropyl methylcellulose, 0.3 parts of polycarboxylate superplasticizer, 0.2 parts of nano-attapulgite, 2.5 parts of composite fiber, 40 parts of water, and 0.05 parts of retarder.

[0024] For example, an impact mortar with high impact resistance comprises: 150 parts of sulfoaluminate cement, 30 parts of composite lightweight aggregate, 3 parts of acrylamide-acrylic acid copolymer, 1 part of polyvinyl butyral, 0.05 parts of hydrophobically modified hydroxypropyl methylcellulose, 0.8 parts of polycarboxylate superplasticizer, 0.1 parts of nano-attapulgite, 1 part of composite fiber, 50 parts of water, and 0.01 parts of retarder.

[0025] For example, an impact mortar with high impact resistance comprises: 200 parts of sulfoaluminate cement, 40 parts of composite lightweight aggregate, 6 parts of acrylamide-acrylic acid copolymer, 2 parts of polyvinyl butyral, 0.1 parts of hydrophobically modified hydroxypropyl methylcellulose, 0.5 parts of polycarboxylate superplasticizer, 0.3 parts of nano-attapulgite, 3 parts of composite fiber, 60 parts of water, and 0.02 parts of retarder.

[0026] The hydrophobic modification process of hydroxypropyl methylcellulose in the three examples is as follows: Add dried HPMC to DMSO and stir at 60°C until completely dissolved to form a clear solution. Palmitic acid was added at a molar ratio of 3:1 to HPMC hydroxyl groups, followed by the catalyst DCC / DMAP, and the mixture was stirred until homogeneous.

[0027] Adding triethylamine neutralizes the water produced in the reaction, promoting a shift in equilibrium toward esterification.

[0028] The reaction system was heated to 100°C and refluxed under nitrogen protection with stirring for 8 hours. During this time, the hydroxyl groups (at 3400 cm⁻¹) could be monitored using infrared spectroscopy (IR). -1 The peak intensity decreased or the ester carbonyl group (1730.cm) -1 The appearance of the peak indicates the progress of the reaction.

[0029] After the reaction was completed, the mixture was poured into an excess of anhydrous ethanol and stirred until the HPMC derivative was completely precipitated (the palmitate modified product has low solubility in ethanol).

[0030] The precipitate was washed three times with an ethanol-water mixture (volume ratio 3:1) to remove unreacted palmitic acid and catalyst residue.

[0031] The product was vacuum dried at 50°C for 24 hours to obtain a white or slightly yellow powder of palmitic acid modified HPMC.

[0032] In the aforementioned technical solution, palmitic acid is used to hydrophobically modify hydroxypropyl methyl, transforming it from a simple hydrophilic thickener into a modifier with multiple functions, including thixotropic regulation, hydrophobic impermeability, and interface enhancement. In impact-resistant slurries, this modification not only improves the material's workability but also significantly enhances its impact resistance through synergistic effects with nano-attapulgite. Furthermore, the linear molecular chains of the acrylamide-acrylic acid copolymer and the flexible chains of polyvinyl butyral intertwine to form a polymer network; nano-attapulgite is embedded in the network through hydrogen bonding and physical adsorption, forming a "polymer-nanofiller" composite network. This network provides the slurry with thixotropy, making it easily broken down by shear forces during mixing and construction, thus improving its flowability; the network recovers upon standing, preventing slurry bleeding and segregation. Meanwhile, the hydrophobic side chains of the hydrophobically modified hydroxypropyl methylcellulose interact with the hydrophobic butyraldehyde groups of polyvinyl butyral, reducing the hydration swelling of the polymer chains and lowering static viscosity. Simultaneously, its hydrophilic backbone synergistically retains water with the hydrophilic groups of the acrylamide-acrylic acid copolymer, preventing excessive water absorption due to the high specific surface area of ​​the nano-attapulgite, thus achieving a balance between water retention and flowability. Furthermore, the rod-like structure of the nano-attapulgite is interwoven within the cement hydration products, forming a "nano-reinforcing skeleton," while polyvinyl butyral and acrylamide-acrylic acid copolymer form a flexible transition layer at the interface, reducing stress concentration in the cement matrix. When the material is subjected to impact, the nano-attapulgite can hinder crack propagation, while the polymer film absorbs energy through plastic deformation; both synergistically improve impact toughness.

[0033] In some embodiments, the composite lightweight aggregate comprises hollow ceramic microspheres and expanded shale with surface silanization treatment, and the mass ratio of the two is 1:(0.5-2); wherein the hollow ceramic microspheres have a particle size of 50-150μm and a wall thickness of 2-5μm; and the expanded shale with surface silanization treatment has a particle size of 0.5-2mm.

[0034] When the above technical solution is adopted, the spherical structure of hollow ceramic microspheres can reduce the viscosity of the slurry, while the porous structure of expanded shale can absorb excess water.

[0035] In some embodiments, the composite fiber comprises ultra-high molecular weight polyethylene fiber treated with silane coupling agent and basalt fiber, and the mass ratio of the two is (1:1) to (3:1); wherein the length of the polyethylene fiber is 3-6 mm and the length of the basalt fiber is 6-12 mm.

[0036] When using the above technical solution, the silane coupling agent used in this invention is KH-550, and the final polyethylene fiber has a molecular weight of 5 million to 8 million Da. When the paste is subjected to impact load, the ultra-high molecular weight polyethylene fiber can absorb kinetic energy through elastic deformation and consume energy through interfacial friction with the cement matrix, thus delaying crack propagation. Its shorter length (3-6 mm) allows it to disperse well in the paste, enabling it to be uniformly distributed at the microscale, forming a flexible network and inhibiting the generation of microcracks. The longer length (6-12 mm) of basalt fiber allows it to cross potential crack surfaces at the macroscale, forming a bridging effect, bearing tensile stress and limiting crack propagation. Its high elastic modulus can quickly transfer impact stress, avoiding local stress concentration, while the rigid structure can enhance the paste's resistance to deformation. When the mass ratio of the two is (1:1) to (3:1), the short fiber and the long fiber form a gradient reinforcement network, resulting in stronger impact energy absorption capacity, suitable for multiple impacts or dynamic loading environments, and the paste has better impact fatigue resistance.

[0037] In some embodiments, the retarder comprises a complex of sodium gluconate and boric acid, wherein the mass ratio of the two is 1:1.

[0038] When the above technical solution is adopted, sodium gluconate, as a hydroxycarboxylic acid salt retarder, can adsorb onto the surface of cement particles and chelate Ca... 2+ The mechanism of action delays cement hydration; boric acid, on the other hand, reacts with cement hydration products to form complexes, further inhibiting the hydration process. The combination of these two substances extends the initial setting time of the cement paste, providing more time for pouring, vibration, and other construction operations of the impact-resistant paste.

[0039] The second aspect of this invention provides a method for preparing anti-impact paste, the process of which is as follows: (1) Weigh each component; (2) The composite lightweight aggregate and nano-attapulgite clay are mixed to obtain the filler; (3) Add sulfoaluminate cement and retarder to the filler, stir, and obtain cement material; (4) After pre-swelling hydrophobically modified hydroxypropyl methylcellulose with 60% water, it is mixed with water-reducing agent and remaining water to prepare a solution; (5) Add the solution to the cementitious material and stir to obtain a mixture; (6) Add acrylamide-acrylic acid copolymer and polyvinyl butyral to the mixture in two batches, with an interval of 1 minute between each batch. Stir, then add composite fiber, stir, defoam, and obtain the finished paste.

[0040] In some embodiments, in step (2), the stirring speed is 300-400 rpm and the stirring time is 5-10 min.

[0041] In some embodiments, in step (3), the stirring is first stirred at 300-400 rpm for 2-3 minutes, and then stirred at 800-1000 rpm for 4-7 minutes.

[0042] In some embodiments, in step (5), the stirring is performed at 600-800 rpm for 10-20 min.

[0043] In some embodiments, the stirring is performed at 600-800 rpm for 10-15 min; the defoaming is performed by allowing the mixture to stand for 5-10 min to defoam.

[0044] To better illustrate the technical solution of the present invention, the following embodiments are provided. It should be understood that, unless otherwise stated, all materials used are commercially available.

[0045] Example 1: An impact-resistant mortar with high impact resistance, comprising: 100 parts of sulfoaluminate cement, 50 parts of composite lightweight aggregate, 8 parts of acrylamide-acrylic acid copolymer, 1.5 parts of polyvinyl butyral, 0.08 parts of hydrophobically modified hydroxypropyl methylcellulose, 0.3 parts of polycarboxylate superplasticizer, 0.2 parts of nano-attapulgite, 2.5 parts of composite fiber, 40 parts of water, and 0.05 parts of retarder.

[0046] The composite lightweight aggregate comprises hollow ceramic microspheres and expanded shale with surface silanization treatment, with a mass ratio of 1:0.5; the hollow ceramic microspheres have a particle size of 50-150μm and a wall thickness of 2-5μm; the expanded shale with surface silanization treatment has a particle size of 0.5-2mm. The composite fiber consists of KH-550 treated ultra-high molecular weight polyethylene fiber and basalt fiber, with a mass ratio of 1:1; the polyethylene fiber has a length of 3-6 mm and the basalt fiber has a length of 6-12 mm; the final polyethylene fiber has a molecular weight of 5 million-8 million Da. The retarder consists of a complex of sodium gluconate and boric acid, with a mass ratio of 1:1.

[0047] The preparation process of the above-mentioned ointment is as follows: (1) Weigh each component; (2) Mix the composite lightweight aggregate and nano-attapulgite at 300 rpm for 5 min to obtain the filler; (3) Add sulfoaluminate cement and retarder to the filler, stir at 300 rpm for 2 min, and then stir at 800 rpm for 4 min to obtain cement material; (4) After pre-swelling hydrophobically modified hydroxypropyl methylcellulose with 60% water, it is mixed with water-reducing agent and remaining water to prepare a solution; (5) Add the solution to the cementitious material and stir at 600 rpm for 10 min to obtain a mixture; (6) Add acrylamide-acrylic acid copolymer and polyvinyl butyral to the mixture in two batches, with an interval of 1 min between each batch, at 600 rpm for 10 min. Then add composite fiber, at 600 rpm for 10 min, and let stand for 5 min to defoam to obtain the finished paste.

[0048] Example 2: An impact-resistant mortar with high impact resistance, comprising: 150 parts of sulfoaluminate cement, 30 parts of composite lightweight aggregate, 3 parts of acrylamide-acrylic acid copolymer, 1 part of polyvinyl butyral, 0.05 parts of hydrophobically modified hydroxypropyl methylcellulose, 0.8 parts of polycarboxylate superplasticizer, 0.1 parts of nano-attapulgite, 1 part of composite fiber, 50 parts of water, and 0.01 parts of retarder.

[0049] The composite lightweight aggregate comprises hollow ceramic microspheres and expanded shale with surface silanization treatment, with a mass ratio of 1:2; the hollow ceramic microspheres have a particle size of 50-150 μm and a wall thickness of 2-5 μm; the expanded shale with surface silanization treatment has a particle size of 0.5-2 mm. The composite fiber consists of KH-550 treated ultra-high molecular weight polyethylene fiber and basalt fiber, with a mass ratio of 3:1; the polyethylene fiber has a length of 3-6 mm and the basalt fiber has a length of 6-12 mm; the final polyethylene fiber has a molecular weight of 5 million-8 million Da. The retarder consists of a complex of sodium gluconate and boric acid, with a mass ratio of 1:1.

[0050] The preparation process of the above-mentioned ointment is as follows: (1) Weigh each component; (2) Mix the composite lightweight aggregate and nano-attapulgite at 400 rpm for 10 min to obtain the filler; (3) Add sulfoaluminate cement and retarder to the filler, stir at 400 rpm for 3 min, and then stir at 1000 rpm for 7 min to obtain cement material; (4) After pre-swelling hydrophobically modified hydroxypropyl methylcellulose with 60% water, it is mixed with water-reducing agent and remaining water to prepare a solution; (5) Add the solution to the cementitious material and stir at 800 rpm for 20 min to obtain a mixture; (6) Add acrylamide-acrylic acid copolymer and polyvinyl butyral to the mixture in two batches, with an interval of 1 min between each batch, at 800 rpm for 15 min. Then add composite fiber, at 800 rpm for 15 min. Let stand for 10 min to defoam and obtain the finished paste.

[0051] Example 3: An impact-resistant mortar with high impact resistance, comprising: 200 parts of sulfoaluminate cement, 40 parts of composite lightweight aggregate, 6 parts of acrylamide-acrylic acid copolymer, 2 parts of polyvinyl butyral, 0.1 parts of hydrophobically modified hydroxypropyl methylcellulose, 0.5 parts of polycarboxylate superplasticizer, 0.3 parts of nano-attapulgite, 3 parts of composite fiber, 60 parts of water, and 0.02 parts of retarder.

[0052] The composite lightweight aggregate comprises hollow ceramic microspheres and expanded shale with surface silanization treatment, with a mass ratio of 1:1; the hollow ceramic microspheres have a particle size of 50-150 μm and a wall thickness of 2-5 μm; the expanded shale with surface silanization treatment has a particle size of 0.5-2 mm. The composite fiber consists of KH-550 treated ultra-high molecular weight polyethylene fiber and basalt fiber, with a mass ratio of 2:1; the polyethylene fiber has a length of 3-6 mm and the basalt fiber has a length of 6-12 mm; the final polyethylene fiber has a molecular weight of 5 million-8 million Da. The retarder consists of a complex of sodium gluconate and boric acid, with a mass ratio of 1:1.

[0053] The preparation process of the above-mentioned ointment is as follows: (1) Weigh each component; (2) Mix the composite lightweight aggregate and nano-attapulgite at 350 rpm for 8 min to obtain the filler; (3) Add sulfoaluminate cement and retarder to the filler, stir at 350 rpm for 3 min, and then stir at 900 rpm for 6 min to obtain cement material; (4) After pre-swelling hydrophobically modified hydroxypropyl methylcellulose with 60% water, it is mixed with water-reducing agent and remaining water to prepare a solution; (5) Add the solution to the cementitious material and stir at 700 rpm for 15 min to obtain a mixture; (6) Add acrylamide-acrylic acid copolymer and polyvinyl butyral to the mixture in two batches, with an interval of 1 min between each batch, at 700 rpm for 13 min. Then add composite fiber, at 700 rpm for 13 min, and let stand for 8 min to defoam to obtain the finished paste.

[0054] To further verify the effectiveness of the present invention, the inventors set up the following comparative examples, wherein comparative examples 1 to 3 were used to verify the synergistic effect of nano-attapulgite, acrylamide-acrylic acid copolymer, and polyvinyl butyral; comparative examples 4 to 5 were used to verify the synergistic effect of hydrophobically modified hydroxypropyl methylcellulose and attapulgite; comparative example 6 was used to demonstrate the advantages of hydrophobically modified hydroxypropyl methylcellulose; and comparative example 7 was used to demonstrate the advantages of composite fibers.

[0055] Comparative Example 1 Compared to Example 3, acrylamide-acrylic acid was removed, increasing the total mass fraction of polyvinyl butyral to 8 parts, while the remaining components and preparation process remained unchanged.

[0056] Comparative Example 2 Compared with Example 3, polyvinyl butyral was removed, increasing the total mass fraction of acrylamide-acrylic acid to 8 parts, while the remaining components and preparation process remained unchanged.

[0057] Comparative Example 3 Compared to Example 3, the attapulgite clay was removed, increasing the total mass fraction of acrylamide-acrylic acid to 6.3 parts, while the remaining components and preparation process remained unchanged.

[0058] Comparative Example 4 Compared with Example 3, the attapulgite clay was removed, and the mass fraction of hydrophobically modified hydroxypropyl methylcellulose was increased to 0.4 parts, while the remaining components and preparation process remained unchanged.

[0059] Comparative Example 5 Compared with Example 3, the hydrophobically modified hydroxypropyl methylcellulose was removed, increasing the mass fraction of attapulgite to 0.4 parts, while the remaining components and preparation process remained unchanged.

[0060] Comparative Example 6 Compared with Example 3, the hydrophobically modified hydroxypropyl methylcellulose was replaced with an equal amount of hydroxypropyl methylcellulose, while the other components and preparation process remained unchanged.

[0061] Comparative Example 7 Compared with Example 3, steel fibers and polyvinyl alcohol fibers were replaced with composite fibers in an equal mass ratio of 12:1, while the remaining components and preparation process remained unchanged.

[0062] Impact resistance test: Place the experimental setup on a stable surface. Pour water into the storage tank, ensuring the water level is approximately 5cm below the steel filter screen. Lay three layers of filter cloth flat on the screen. Connect the water pump to the intelligent controller and turn on the power. Then adjust the tailgate opening. Note that both the flow meter and the grouting point should be located in the middle of the water tank. This distance from the water inlet ensures a stable flow velocity, while the distance from the tailgate facilitates observation of the erosion morphology. The preparation phase is now complete.

[0063] Turn on the smart controller to pump water from the water tank into the water tank. At this time, use a flow meter to detect the water flow velocity in the tank at its location. Adjust the output power of the smart controller and the opening of the tailgate appropriately to achieve the expected flow velocity. Once this value is reached, do not change the setting of the smart controller or the opening of the tailgate. Then turn off the power of the controller and stop the water intake.

[0064] The slurry from Examples 1 to 3 and Comparative Examples 1 to 7 were placed in an annular container inside a water tank. The container was then lifted upwards, and the slurry began to diffuse. After the diffusion stabilized, the power of the intelligent controller was turned on, allowing water to flow into the tank at the expected flow rate to create specific dynamic water conditions. Note that the position of the slurry and the position of the flow meter should be kept parallel to ensure that the actual flow rate of the slurry being washed is consistent with the reading of the flow meter. The initial mass of the slurry can be reflected by the slurry injection volume, which can be reflected by the change in the scale value inside the slurry storage tank of the grouting equipment.

[0065] The grouting process can be completed in a short time. During the flushing process, the morphology of the grout under pressure can be observed and recorded in real time. After a predetermined flushing time, the power is turned off to prepare for the determination of grout retention rate and flushing range. After the measurement is completed, the bottom of the tank is cleaned, and the next round of testing can begin. After all tests are completed, the power is turned off, the faucet at the drain outlet is opened to drain the water in the device, and all test equipment and the site are cleaned. The water flow velocity during the test was 0.5 m / s and 1.0 m / s; the flushing time was 120 s and 180 s respectively; the morphology of the grout in different groups was observed; the final results show that the grout in Examples 1 to 3 showed little change in morphology after being flushed by water at different speeds, while the grout in Comparative Examples 1 to 7 showed a complete change in morphology after flushing, and even grout loss occurred.

[0066] Meanwhile, the residual slurry rate after 180s of flushing at a flushing rate of 0.5m / s was calculated using the following method: η = m / M; where: m is the mass of the remaining slurry after flushing (g); M is the mass of 50ml of slurry (g); and η is the retention rate.

[0067] The results are shown in Table 1; Table 1 Results of paste residue test

[0068] As shown in Table 1 and the above descriptions of impact resistance properties, attapulgite, polyvinyl butyral, and acrylamide-acrylic acid exhibit synergistic effects. Furthermore, the hydrophobically modified hydroxypropyl methylcellulose synergistically enhances the impact resistance of the paste with attapulgite. Moreover, as shown in Comparative Examples 6 and 7, the modified hydroxypropyl methylcellulose significantly improves the impact resistance of the paste, and the composite fiber of this invention also plays a certain auxiliary role in improving impact resistance.

[0069] Liquidity test Pour the pastes from Examples 1 to 3 and Comparative Examples 1 to 7 into a truncated conical mold. After lifting the mold, measure the diameter of the paste after it expands.

[0070] step: Use a truncated cone mold with a top diameter of 70mm, a bottom diameter of 100mm, and a height of 60mm, and place it on a glass base plate. Pour in the mixed paste, smooth it out, and then lift the mold vertically to allow the paste to flow freely.

[0071] Measure the maximum and minimum diameters of the grout after expansion, and take the average value as the flowability (mm); the larger the expansion diameter, the stronger the flowability, which is suitable for grouting materials that require high flowability.

[0072] The results are shown in Table 2. Table 2 Liquidity Detection Results

[0073] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0074] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An impact-resistant paste with high impact resistance, characterized in that, The impact-resistant slurry comprises the following raw materials in parts by weight: 100-200 parts of sulfoaluminate cement, 30-50 parts of composite lightweight aggregate, 3-8 parts of acrylamide-acrylic acid copolymer, 1-2 parts of polyvinyl butyral, 0.05-0.1 parts of hydrophobically modified hydroxypropyl methylcellulose, 0.3-0.8 parts of polycarboxylate superplasticizer, 0.1-0.3 parts of nano-attapulgite, 1-3 parts of composite fiber, 40-60 parts of water, and 0.01-0.05 parts of retarder; The composite lightweight aggregate comprises hollow ceramic microspheres and expanded shale with surface silanization treatment, and the mass ratio of the two is 1:(0.5~2); the hollow ceramic microspheres have a particle size of 50~150μm and a wall thickness of 2~5μm; the expanded shale with surface silanization treatment has a particle size of 0.5~2mm; The composite fiber comprises ultra-high molecular weight polyethylene fiber treated with silane coupling agent and basalt fiber, and the mass ratio of the two is (1:1) to (3:1); wherein the length of the ultra-high molecular weight polyethylene fiber is 3-6 mm and the length of the basalt fiber is 6-12 mm; The process of hydrophobic modification of hydroxypropyl methylcellulose is as follows: Add dried HPMC to DMSO and stir at 60°C until completely dissolved to form a transparent solution; Palmitic acid was added at a molar ratio of 3:1 to HPMC hydroxyl groups, followed by the catalyst DCC / DMAP, and the mixture was stirred until homogeneous. Triethylamine was then added dropwise, and the reaction system was heated to 100°C and stirred under nitrogen protection for 8 hours. After the reaction was completed, the mixture was poured into excess anhydrous ethanol and stirred until the HPMC derivative was completely precipitated. The precipitate was washed three times with a 3:1 volume ratio ethanol-water mixture, and the product was vacuum dried at 50°C for 24 hours to obtain white or slightly yellow powdered palmitic acid-modified HPMC.

2. The impact-resistant paste with high impact resistance according to claim 1, characterized in that, The retarder comprises a complex of sodium gluconate and boric acid, with a mass ratio of 1:

1.

3. The method for preparing the anti-impact paste according to any one of claims 1-2, characterized in that, The process is as follows: (1) Weigh each component according to any one of claims 1-2; (2) The composite lightweight aggregate and nano-attapulgite clay are mixed to obtain the filler; (3) Add sulfoaluminate cement and retarder to the filler, stir, and obtain cement material; (4) After pre-swelling hydrophobically modified hydroxypropyl methylcellulose with 60% water, it is mixed with polycarboxylate superplasticizer and the remaining water to prepare a solution; (5) Add the solution to the cementitious material and stir to obtain a mixture; (6) Add acrylamide-acrylic acid copolymer and polyvinyl butyral to the mixture in two batches, with an interval of 1 minute between each batch. Stir, then add composite fiber, stir, defoam, and obtain the finished paste.

4. The preparation method according to claim 3, characterized in that, In step (2), the stirring speed is 300-400 rpm and the stirring time is 5-10 min.

5. The preparation method according to claim 3, characterized in that, In step (3), the stirring is first stirred at 300-400 rpm for 2-3 minutes, and then stirred at 800-1000 rpm for 4-7 minutes.

6. The preparation method according to claim 3, characterized in that, In step (5), the stirring is performed at 600-800 rpm for 10-20 minutes.

7. The preparation method according to claim 5, characterized in that, In step (6), the stirring is at 600-800 rpm and the stirring time is 10-15 min; the defoaming is performed by standing for 5-10 min.

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