High-performance anti-freezing grouting material and use method thereof

Abstract

The invention relates to the technical field of building materials, in particular to a high-performance anti-freezing grouting material and a using method thereof.The high-performance anti-freezing grouting material is prepared from, by weight, 30-45 parts of cement, 5-10 parts of silica fume, 4-8 parts of microbeads, 40-60 parts of sand, 0.2-1 part of a water reducing agent, 0.5-2 parts of a composite anti-freezing agent and 0.1-0.6 part of polymer rubber powder; the sum of the parts by weight of the components is 100 parts. Wherein the composite antifreeze agent comprises an air entraining agent, calcium nitrite and sodium sulfate. The concrete has the advantages of good mechanical properties and fluidity, no shrinkage and excellent frost resistance, and can be applied to high-latitude and high-altitude severe cold areas.

Description

Technical Field

[0001] This invention relates to the field of building materials technology, and in particular to a high-performance antifreeze grouting material and its application method. Background Technology

[0002] Cement-based grouting material is a dry-mixed material made from cement, mineral admixtures, aggregates, and additives in a specific ratio. It is simply mixed with water according to the ratio before use. Due to its excellent mechanical properties and fluidity, it is commonly used for structural filling, reinforcement, and repair in road and bridge construction, rail transit, and wind power industries.

[0003] However, traditional cement-based grouting materials have significant disadvantages in the application of cold regions (especially freeze-thaw cycles). In cold environments, the water in the capillary pores inside the material freezes and expands in volume, generating huge internal stress, which leads to the propagation of internal microcracks, surface peeling, and pulverization, resulting in a sharp decline in strength and durability, affecting the overall strength and durability of the structure.

[0004] Therefore, developing high-performance, freeze-resistant cement-based grouting materials that can be applied to frigid regions at high latitudes and altitudes has become an urgent technical problem to be solved. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art. This invention provides a high-performance antifreeze grouting material with good mechanical properties and fluidity, no shrinkage, and excellent antifreeze performance, which can be applied to cold regions at high latitudes and high altitudes.

[0006] To address the above problems, this invention proposes a high-performance antifreeze grouting material, comprising the following raw materials in parts by weight: The ingredients are: 30-45 parts cement, 5-10 parts silica fume, 4-8 parts microspheres, 40-60 parts sand, 0.2-1 part water-reducing agent, 0.5-2 parts composite antifreeze agent, and 0.1-0.6 parts polymer powder; the total weight of the above components is 100 parts; wherein the composite antifreeze agent includes an air-entraining agent, calcium nitrite, and sodium sulfate.

[0007] As an improvement to the above technical solution, the ratio of the air-entraining agent, calcium nitrite, and sodium sulfate is 1:(150~200):(50~100); The average particle size of the microspheres is ≤10μm, and the maximum particle size is ≤20μm.

[0008] As an improvement to the above technical solution, the sandbag contains 6~10wt% first quartz sand, 40~48wt% second quartz sand, 40~48wt% third quartz sand and 2~6wt% fourth quartz sand; The first quartz sand is 8-16 mesh quartz sand, the second quartz sand is 16-40 mesh quartz sand, the third quartz sand is 40-70 mesh quartz sand, and the fourth quartz sand is 100-200 mesh quartz sand.

[0009] As an improvement to the above technical solution, the silica fume has an amorphous silica content of ≥95% and a specific surface area of ​​20,000~30,000 m². 2 / kg.

[0010] As an improvement to the above technical solution, the polymer powder is an acrylate copolymer, the glass transition temperature of the acrylate copolymer is -5℃ to 5℃, the average particle size is 50~150μm, the ash content is 8%±2%, and its 2% aqueous solution has a viscosity of 200~400 mPa·s at 25℃.

[0011] As an improvement to the above technical solution, the air-entraining agent is a saponin-based air-entraining agent or a slow-release air-entraining nanomaterial. The slow-release air-entraining nanomaterial is obtained by adsorbing an air-entraining agent onto modified silica nanospheres, and the particle size of the slow-release air-entraining nanomaterial is 50 nm to 500 nm.

[0012] As an improvement to the above technical solution, the sustained-release gas-entraining nanomaterial is made from the following raw materials: 10-20 parts by weight of modified silica nanospheres Thickener 10-20 parts by weight 5-10 parts by weight of foam stabilizer 70-100 parts by weight of air-entraining agent 200-300 parts by volume of deionized water 200-300 parts by volume of ethanol.

[0013] As an improvement to the above technical solution, the modified silica nanospheres are made from the following raw materials: 0.2~1.0 parts by weight of cationic surfactant 1-3 parts by volume of ammonia water 100-200 parts by volume of deionized water 280-600 parts by volume of ethanol 4-10 parts by volume of alkyl orthosilicate 5-10 parts by volume of silane coupling agent 8-15 parts by weight of sodium gluconate.

[0014] As an improvement to the above technical solution, the modified silica nanospheres are prepared by the following method: Mix 0.2 to 1.0 parts by weight of cationic surfactant, 1 to 3 parts by volume of ammonia, 100 to 200 parts by volume of deionized water and 200 to 400 parts by volume of ethanol, and heat to 45°C to 50°C and stir thoroughly to obtain the first mixture; Add 4-10 parts by volume of alkyl orthosilicate to the first mixture, stir continuously, and filter to obtain the second mixture; The second mixture was placed in a high-pressure reactor at a pressure of 50 MPa to 150 MPa and heated to 145°C to 160°C for 35 to 45 hours. The precipitate was then washed. The precipitate was extracted to remove the cationic surfactant, yielding hollow porous silica nanospheres. 15-30 parts by weight of the silica nanospheres, 80-200 parts by volume of ethanol, 5-10 parts by volume of silane coupling agent and 8-15 parts by weight of sodium gluconate are mixed and stirred continuously at room temperature. After filtration and drying, the modified silica nanospheres with sodium gluconate grafted on the inner and outer walls are obtained.

[0015] Accordingly, the present invention also provides a method for using a high-performance antifreeze grout, comprising mixing 30-45 parts cement, 5-10 parts silica fume, 4-8 parts microspheres, 40-60 parts sand, 0.2-1 parts water-reducing agent, 0.5-2 parts composite antifreeze agent, and 0.1-0.6 parts polymer powder in a specified ratio, and adding water at a water-to-material ratio of 0.13-0.15 to obtain the grout. The well-mixed grout is poured into the structural parts that need to be reinforced, repaired, or filled.

[0016] The implementation of this invention has the following beneficial effects: This invention relates to a high-performance antifreeze grouting material comprising cement, silica fume, microspheres, sand, a water-reducing agent, a composite antifreeze agent, and polymer powder. Specifically, the introduction of silica fume enhances the density of the grout matrix through its filling and pozzolanic effects, promoting strength improvement. The microspheres introduced in this high-performance antifreeze grouting material provide a ball-bead effect, improving grout fluidity. The composite antifreeze agent used in this high-performance antifreeze grouting material includes an air-entraining agent, calcium nitrite, and sodium sulfate, formulated from air-entraining components, freezing point lowering components, and early-strength components; its incorporation improves early strength and enhances antifreeze resistance. The polymer powder introduced in this high-performance antifreeze grouting material exhibits strong hydrophobicity and imparts excellent deformability to the grout, effectively absorbing and dissipating stress generated by freeze-thaw cycles, thus improving durability.

[0017] Furthermore, the sand used in the high-performance antifreeze grout of the present invention is a mixture of quartz sand with a specific particle size, which acts as a skeleton and is beneficial to improving strength.

[0018] Furthermore, the slow-release air-entraining nanomaterial is obtained by adsorbing an air-entraining agent onto modified silica nanospheres. Both the inner and outer walls of the modified silica nanospheres are grafted with sodium gluconate, which controls the slow-release rate of the air-entraining agent. The resulting bubbles within the grout exhibit high uniformity, thus providing better antifreeze performance and making it suitable for low-pressure, frigid environments. Moreover, the particle size of the slow-release air-entraining nanomaterial ranges from 50nm to 500nm, ensuring a sufficient supply of the air-entraining agent and stable dispersion, preventing nanoscale agglomeration or sedimentation, and guaranteeing the homogeneity of the grout. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be described in further detail below.

[0020] This invention proposes a high-performance antifreeze grouting material, comprising the following raw materials in parts by weight: The ingredients are: 30-45 parts cement, 5-10 parts silica fume, 4-8 parts microspheres, 40-60 parts sand, 0.2-1 part water-reducing agent, 0.5-2 parts composite antifreeze agent, and 0.1-0.6 parts polymer powder; the total weight of the above components is 100 parts; wherein the composite antifreeze agent includes an air-entraining agent, calcium nitrite, and sodium sulfate.

[0021] Preferred high-performance antifreeze grouting material comprises the following raw materials in parts by weight: The ingredients are: 30-42 parts cement, 5-10 parts silica fume, 4-8 parts microspheres, 45-55 parts sand, 0.2-1 part water-reducing agent, 0.5-2 parts composite antifreeze agent, and 0.1-0.5 parts polymer powder; the total weight of the above components is 100 parts; wherein the composite antifreeze agent includes an air-entraining agent, calcium nitrite, and sodium sulfate.

[0022] The high-performance antifreeze grouting material of this invention includes cement, silica fume, microspheres, sand, water-reducing agent, composite antifreeze agent and polymer powder. It has good mechanical properties and fluidity, no shrinkage and excellent antifreeze performance, and can be applied to cold regions at high latitudes and high altitudes.

[0023] Cement is the main source of strength in the high-performance frost-resistant grout. In the formulation of the high-performance frost-resistant grout of this invention, the amount of cement is 30 to 45 parts, exemplarily 30, 35, 40, or 45 parts, but not limited thereto. In some preferred embodiments, the cement is preferably silicate cement with a strength grade greater than or equal to 52.5.

[0024] Silica fume's main component is amorphous silica, which possesses extremely strong pozzolanic activity and micro-aggregate filling effect, beneficial for enhancing the density and strength of the grout matrix. In the formulation of the high-performance antifreeze grout of this invention, the amount of silica fume is 5-10 parts, exemplarily 6, 7, 8, or 9 parts, but not limited thereto. In some preferred embodiments, the silica fume has an amorphous silica content ≥95% and a specific surface area of ​​20,000-30,000 m². 2 / kg, which can effectively fill micropores and react with calcium hydroxide during the cement hydration process to generate additional hydrated calcium silicate gel, significantly improving strength.

[0025] The microspheres are spherical in shape, which can act as a "ball bearing" effect, improving the fluidity of the grout and reducing water demand. Their high fineness and high pozzolanic activity also contribute to improving the strength and durability of the grout. Specifically, in the formulation of the high-performance antifreeze grout of this invention, the amount of microspheres is 4 to 8 parts, exemplarily 5, 6, 7, or 8 parts, but not limited to these.

[0026] In some preferred embodiments, the average particle size of the microspheres is ≤10μm and the maximum particle size is ≤20μm. They can be combined with cement, silica fume, sand, polymer powder, etc. to effectively improve the fluidity of the grout and further enhance the strength and durability of the grout.

[0027] The sand is a mixture of quartz sand with a specific particle size, exhibiting high hardness, high strength, and good wear resistance, primarily serving as a skeleton. Specifically, in the formulation of the high-performance antifreeze grouting material of this invention, the amount of sand is 40-60 parts, exemplarily 40 parts, 45 parts, 50 parts, or 55 parts, but not limited to these.

[0028] In some preferred embodiments, the sand comprises 6-10 wt% first quartz sand, 40-48 wt% second quartz sand, 40-48 wt% third quartz sand, and 2-6 wt% fourth quartz sand, wherein the first quartz sand is 8-16 mesh, the second quartz sand is 16-40 mesh, the third quartz sand is 40-70 mesh, and the fourth quartz sand is 100-200 mesh. This specific particle size combination of sand can reduce porosity through close packing, thereby improving the strength, durability, and toughness of the grout.

[0029] Water-reducing agents are mainly used to reduce the amount of water used, improve the fluidity of the grout, and increase its strength. Specifically, in the formulation of the high-performance antifreeze grout of this invention, the amount of water-reducing agent is 0.2 to 1 part, exemplarily 0.3 parts, 0.5 parts, 0.7 parts, or 0.9 parts, but not limited to these.

[0030] The water-reducing agent can be any commercially available water-reducing agent commonly used for grouting. Specifically, it can be a polycarboxylate-based water-reducing agent, a naphthalene-based high-efficiency water-reducing agent, an aminosulfonate-based water-reducing agent, an aliphatic high-efficiency water-reducing agent, a melamine-based water-reducing agent, or a lignin sulfonate.

[0031] The composite antifreeze agent is a compound of air-entraining agent, calcium nitrite, and sodium sulfate, which helps to improve the antifreeze performance of the grouting material. Specifically, in the formulation of the high-performance antifreeze grouting material of the present invention, the amount of composite antifreeze agent is 0.5 to 2 parts, exemplarily 0.6 parts, 0.9 parts, 1.2 parts, or 1.5 parts, but not limited thereto.

[0032] In some preferred embodiments, the ratio of the air-entraining agent, calcium nitrite, and sodium sulfate is 1:(150-200):(50-100), wherein the amounts of calcium nitrite and sodium sulfate are relatively large, with the amount of calcium nitrite being 150-200 times that of the air-entraining agent and the amount of sodium sulfate being 50-100 times that of the air-entraining agent. The air-entraining agent, as an air-entraining component, can generate microbubbles, improving filling performance and reducing shrinkage while ensuring the long-term freeze resistance of the grout. Calcium nitrite, as a major component, lowers the freezing point, which helps to lower the freezing point of the liquid phase in the pores of the grout, preventing early freezing from affecting strength. Sodium sulfate, as a minor component, is an early-strength component and can help improve early strength. More preferably, the ratio of the air-entraining agent, calcium nitrite, and sodium sulfate is 1:(180-200):(60-100). More preferably, the ratio of the air-entraining agent, calcium nitrite, and sodium sulfate is 1:200:100.

[0033] In some preferred embodiments, the air-entraining agent is a saponin-based air-entraining agent. Saponin-based air-entraining agents can introduce a large number of microbubbles with a diameter of less than 200 μm. These bubbles act as "ball bearings" in the concrete mixture, significantly reducing inter-aggregate friction and improving fluidity, cohesion, and water retention. The bubbles fill the seepage channels, preventing external moisture from penetrating and improving impermeability. The elastic bubbles buffer freeze-thaw expansion forces, greatly enhancing freeze-thaw resistance. They also isolate harmful substances from contact with the concrete structure, enhancing resistance to chemical erosion.

[0034] Examples of saponin-based air-entraining agents include triterpenoid saponins, tea saponins, gypenosides L, and notoginsenoside R2, but are not limited to these.

[0035] In some preferred embodiments, the air-entraining agent is a slow-release air-entraining nanomaterial.

[0036] The slow-release air-entraining nanomaterial is obtained by adsorbing an air-entraining agent onto modified silica nanospheres, and the particle size of the slow-release air-entraining nanomaterial is 50 nm to 500 nm.

[0037] The aforementioned particle size ensures a sufficient supply and stable dispersion of the air-entraining agent, preventing nanoscale agglomeration or sedimentation and guaranteeing the homogeneity of the grout. Furthermore, the slow-release air-entraining nanomaterial has channels for the escape of the air-entraining agent, with pore sizes ranging from 1 nm to 20 nm. Capillary forces delay the migration of the air-entraining agent, and the release half-life is appropriately extended to ensure smooth diffusion and prevent pore blockage.

[0038] In some preferred embodiments, the sustained-release gas-entraining nanomaterial is made from the following raw materials: 10-20 parts by weight of modified silica nanospheres Thickener 10-20 parts by weight 5-10 parts by weight of foam stabilizer 70-100 parts by weight of air-entraining agent 200-300 parts by volume of deionized water 200-300 parts by volume of ethanol.

[0039] The modified silica nanospheres are made from the following raw materials: 0.2~1.0 parts by weight of cationic surfactant 1-3 parts by volume of ammonia water 100-200 parts by volume of deionized water 280-600 parts by volume of ethanol 4-10 parts by volume of alkyl orthosilicate 5-10 parts by volume of silane coupling agent 8-15 parts by weight of sodium gluconate.

[0040] It should be noted that the above correspondence between parts by weight and parts by volume is in g / ml.

[0041] The modified silica nanospheres were prepared by the following method: Mix 0.2 to 1.0 parts by weight of cationic surfactant, 1 to 3 parts by volume of ammonia, 100 to 200 parts by volume of deionized water and 200 to 400 parts by volume of ethanol, and heat to 45°C to 50°C and stir thoroughly to obtain the first mixture; Add 4-10 parts by volume of alkyl orthosilicate to the first mixture, stir continuously, and filter to obtain the second mixture; The second mixture was placed in a high-pressure reactor at a pressure of 50 MPa to 150 MPa and heated to 145°C to 160°C for 35 to 45 hours. The precipitate was then washed. The precipitate was extracted to remove the cationic surfactant, yielding hollow porous silica nanospheres. 15-30 parts by weight of the silica nanospheres, 80-200 parts by volume of ethanol, 5-10 parts by volume of silane coupling agent and 8-15 parts by weight of sodium gluconate are mixed and stirred continuously at room temperature. After filtration and drying, the modified silica nanospheres with sodium gluconate grafted on the inner and outer walls are obtained.

[0042] The polyhydroxyl groups of sodium gluconate form a hydrogen bond network with the polar groups of the air-entraining agent, effectively increasing the loading capacity of the modified silica nanospheres. Furthermore, the mesoporous structure synergistically enhances adsorption efficiency through capillary action. The hydrophobic alkyl chains adsorb oily air-entraining agents via van der Waals forces, while the hydrophilicity of sodium gluconate maintains the dispersion stability of the microspheres in the slurry, preventing aggregation and sedimentation.

[0043] Specifically, the sustained-release air-entraining nanomaterial is prepared by the following method: Ethanol and deionized water were mixed in a 1:1 volume ratio to obtain an ethanol-water mixed solvent. The air-entraining agent was then mixed with the ethanol-water mixed solvent to prepare an air-entraining agent solution with a concentration of 10 g / L to 20 g / L. Modified silica nanospheres and air-entraining agent solution were mixed at a weight ratio of 1:10 and ultrasonically dispersed for 30-60 minutes. Then, the mixture was stirred at a constant temperature of 40-50℃ and a stirring speed of 180-300 rpm for 12-24 hours. Subsequently, thickener and foam stabilizer were added slowly in sequence and stirred for 1-2 hours to obtain slow-release air-entraining nanomaterials.

[0044] An ethanol-water mixed solvent is used to adjust the solution polarity, promoting the diffusion of gas-entraining agent molecules into the mesopores of the microspheres. Ultrasonic dispersion is combined to ensure uniform loading and avoid localized enrichment. Isothermal stirring provides appropriate molecular kinetic energy, accelerating the diffusion of the gas-entraining agent through the microsphere pore channels while preventing high temperatures from damaging the hydrogen bond structure. This gas-entraining agent adsorption method simultaneously addresses the problems of low adsorption efficiency and poor dispersion stability through the mesopore confinement effect of sodium gluconate grafting and a stepwise loading strategy.

[0045] Preferably, the thickener can be a commercially available thickener commonly used for concrete grouting. Examples include hydroxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl methyl cellulose, polyacrylamide, and SF-3 thickener, but are not limited thereto.

[0046] Preferably, the foam stabilizer includes one or more of the following: modified silicone resin polyether emulsion, ammonium oxide fluorocarbon surfactant, and coconut oil diethanolamide.

[0047] The polymer powder can form a highly elastic polymer film with a low glass transition temperature. It is highly hydrophobic and imparts excellent deformability to the grout, effectively absorbing and dissipating stress generated by freeze-thaw cycles and mitigating freeze-thaw damage. Specifically, in the formulation of the high-performance antifreeze grout of this invention, the amount of polymer powder is 0.1 to 0.6 parts, exemplarily 0.2 parts, 0.3 parts, 0.4 parts, or 0.5 parts, but not limited thereto.

[0048] In some preferred embodiments, the polymer powder is an acrylate copolymer. Exemplary acrylate copolymers include, but are not limited to, butyl acrylate (nBA)-methyl methacrylate (MMA) copolymer, ethyl acrylate (EA)-methyl methacrylate (MMA) copolymer, and carbomer SF-1. The acrylate copolymer has a glass transition temperature of -5°C to 5°C, an average particle size of 50~150 μm, an ash content of 8%±2%, and a viscosity of 2% aqueous solution at 25°C of 200~400 mPa·s. After the acrylate copolymer forms a film in the grout slurry, the resulting polymer film possesses high elasticity, effectively absorbing and dissipating the micro-stress generated by freeze-thaw cycles, reducing the intrusion of freezeable water, and mitigating freeze-thaw damage.

[0049] Accordingly, the present invention also provides a method for using a high-performance antifreeze grout, comprising mixing 30-45 parts of cement, 5-10 parts of silica fume, 4-8 parts of microspheres, 40-60 parts of sand, 0.2-1 parts of water-reducing agent, 0.5-2 parts of composite antifreeze agent, and 0.1-0.6 parts of polymer powder in a specified ratio, and adding water at a water-to-material ratio of 0.13-0.15 to obtain the grout. The well-mixed grout is poured into the structural parts that need to be reinforced, repaired, or filled.

[0050] The method of using the high-performance antifreeze grout of the present invention can effectively control the internal stress of the material in a cold environment, avoid the propagation of internal microcracks, surface peeling and pulverization, improve the strength and durability of the structure, and extend the service life of the structure. It is suitable for cold regions at high latitudes and high altitudes.

[0051] The present invention will be further illustrated below with specific embodiments. Example 1 This embodiment provides a high-performance antifreeze grouting material, comprising the following raw materials in parts by weight: The ingredients are: 38 parts silicate cement, 7 parts silica fume, 5 parts microspheres, 48 ​​parts sand, 0.5 parts polycarboxylate superplasticizer, 1.2 parts composite antifreeze agent, and 0.3 parts polymer powder. The water-to-material ratio is 0.14. The composite antifreeze agent includes an air-entraining agent, calcium nitrite, and sodium sulfate, with the ratio of the air-entraining agent, calcium nitrite, and sodium sulfate being 1:200:100. The air-entraining agent is a saponin-based air-entraining agent.

[0052] The average particle size of the microspheres is ≤10μm, and the maximum particle size is ≤20μm.

[0053] The sand comprises 8wt% first quartz sand, 44wt% second quartz sand, 44wt% third quartz sand, and 4wt% fourth quartz sand; wherein the first quartz sand is 8-16 mesh quartz sand, the second quartz sand is 16-40 mesh quartz sand, the third quartz sand is 40-70 mesh quartz sand, and the fourth quartz sand is 100-200 mesh quartz sand.

[0054] The polymer powder is carbomer SF-1.

[0055] Example 2 The difference between this embodiment and Embodiment 1 is that: The ratio of the air-entraining agent, calcium nitrite, and sodium sulfate is 1:100:100.

[0056] Example 3 The difference between this embodiment and Embodiment 1 is that: High-performance antifreeze grouting material comprises the following raw materials in parts by weight: 45 parts silicate cement, 5 parts silica fume, 4 parts microspheres, 43 parts sand, 0.6 parts water-reducing agent, 2 parts composite antifreeze agent, and 0.4 parts polymer powder.

[0057] The sand comprises 10wt% first quartz sand, 42wt% second quartz sand, 42wt% third quartz sand, and 6wt% fourth quartz sand.

[0058] Example 4 The difference between this embodiment and Embodiment 1 is that: High-performance antifreeze grouting material comprises the following raw materials in parts by weight: 30 parts silicate cement, 10 parts silica fume, 8 parts microspheres, 49 parts sand, 1 part water-reducing agent, 1.5 parts composite antifreeze agent, and 0.5 parts polymer powder.

[0059] The sand comprises 4.5 wt% first quartz sand, 45 wt% second quartz sand, 45 wt% third quartz sand, and 5.5 wt% fourth quartz sand.

[0060] Example 5 The difference between this embodiment and Embodiment 1 is that the air-entraining agent is a slow-release air-entraining nanomaterial; The slow-release air-entraining nanomaterial is obtained by adsorbing an air-entraining agent onto modified silica nanospheres, and the particle size of the slow-release air-entraining nanomaterial is 50 nm to 500 nm.

[0061] The modified silica nanospheres were prepared by the following method: Mix 0.4g of CTAB, 3ml of ammonia, 150ml of deionized water and 300ml of ethanol, and heat to 50°C while stirring thoroughly to obtain the first mixture; Add 6 ml of TEOS dropwise to the first mixture above, stir continuously for 3 hours, filter, and obtain the second mixture; The second mixture was placed in a high-pressure reactor and heated to 150°C under a pressure of 100 MPa for 40 h. The precipitate was then thoroughly washed with 500 ml of deionized water and 500 ml of methanol. The precipitate was extracted for 50 hours to remove CTAB, yielding silica nanospheres to be grafted. 20g of silica nanospheres to be grafted, 100ml of ethanol, 10ml of KH570 and 10g of sodium gluconate were mixed and stirred continuously at room temperature (25℃) for 24h. The mixture was then filtered and dried at 60℃ to obtain the modified silica nanospheres with sodium gluconate grafted on both the inner and outer walls.

[0062] The sustained-release, gas-entraining nanomaterial is composed of the following raw materials: 15 parts by weight of modified silica nanospheres Thickener 15 parts by weight 7 parts by weight of foam stabilizer 85 parts by weight of air-entraining agent 250 parts by volume of deionized water 250 parts by volume of ethanol.

[0063] The sustained-release, air-entraining nanomaterial was prepared by the following method: Ethanol and deionized water were mixed in a 1:1 volume ratio to obtain an ethanol-water mixed solvent. The ethanol-water mixed solvent was then mixed with an air-entraining agent and stirred to prepare a 15 g / L air-entraining agent solution. Modified silica nanospheres and air-entraining agent solution were mixed at a weight ratio of 1:10 and ultrasonically dispersed for 45 min. Then, the mixture was stirred at a stirring speed of 250 rpm for 18 h at a constant temperature of 45 °C. Subsequently, thickener and foam stabilizer were added slowly in sequence and stirred for 1.5 h to obtain slow-release air-entraining nanomaterials.

[0064] Comparative Example 1 This comparative example provides a grouting material that differs from Example 1 above in that it does not contain a composite antifreeze agent.

[0065] Comparative Example 2 This comparative example provides a grouting material that differs from Example 1 above in that it does not contain composite antifreeze and polymer powder.

[0066] Comparative Example 3 This comparative example provides a grouting material that differs from Example 1 above in that it does not contain polymer powder.

[0067] The grouting materials of Examples 1-5 and Comparative Examples 1-3 were mixed, molded, cured, and tested for strength according to the methods specified in the "Technical Specification for Application of Cement-Based Grouting Materials" (GB / T 50448). The freeze-thaw cycle temperature was -40℃ to 40℃: one cycle consisted of maintaining the material at -40℃ for 4 hours and then at 40℃ for 4 hours.

[0068] The specific test results are as follows:

[0069] Comparison of the results of each embodiment and comparative example shows that the incorporation of composite antifreeze agent has a significant effect on improving the frost resistance of grouting material, and the incorporation of polymer powder can also play a positive role in improving the frost resistance of grouting material. The high-performance frost-resistant grouting materials provided in Examples 1-5 have good workability, mechanical properties and freeze-thaw resistance, and can be used for structural reinforcement, repair and filling in severely cold regions during winter.

[0070] It should be noted that the testing of initial fluidity, 28-day compressive strength, and compressive strength after 150 and 300 freeze-thaw cycles is based on the "Technical Specification for Application of Cement-based Grouting Materials" (GB / T 50448).

[0071] The above description represents the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A high-performance antifreeze grouting material, characterized in that, Including the following parts by weight of raw materials: The ingredients are: 30-45 parts cement, 5-10 parts silica fume, 4-8 parts microspheres, 40-60 parts sand, 0.2-1 part water-reducing agent, 0.5-2 parts composite antifreeze agent, and 0.1-0.6 parts polymer powder; the total weight of the above components is 100 parts; wherein the composite antifreeze agent includes an air-entraining agent, calcium nitrite, and sodium sulfate.

2. The high-performance antifreeze grouting material as described in claim 1, characterized in that, The ratio of the air-entraining agent, calcium nitrite, and sodium sulfate is 1:(150~200):(50~100); The average particle size of the microspheres is ≤10μm, and the maximum particle size is ≤20μm.

3. The high-performance antifreeze grouting material as described in claim 1, characterized in that, The sandbag contains 6-10 wt% first quartz sand, 40-48 wt% second quartz sand, 40-48 wt% third quartz sand, and 2-6 wt% fourth quartz sand; The first quartz sand is 8-16 mesh quartz sand, the second quartz sand is 16-40 mesh quartz sand, the third quartz sand is 40-70 mesh quartz sand, and the fourth quartz sand is 100-200 mesh quartz sand.

4. The high-performance antifreeze grouting material as described in claim 1, characterized in that, The silica fume is composed of amorphous silica with a content ≥95% and a specific surface area of ​​20,000~30,000 m². 2 / kg.

5. The high-performance antifreeze grouting material as described in claim 1, characterized in that, The polymer powder is an acrylate copolymer with a glass transition temperature of -5℃ to 5℃, an average particle size of 50~150μm, an ash content of 8%±2%, and a viscosity of 2% aqueous solution of acrylate at 25℃ of 200~400 mPa·s.

6. The high-performance antifreeze grouting material as described in claim 1, characterized in that, The air-entraining agent is a saponin-based air-entraining agent or a slow-release air-entraining nanomaterial. The slow-release air-entraining nanomaterial is obtained by adsorbing an air-entraining agent onto modified silica nanospheres, and the particle size of the slow-release air-entraining nanomaterial is 50 nm to 500 nm.

7. The high-performance antifreeze grouting material as described in claim 6, characterized in that, The sustained-release, gas-entraining nanomaterial is made from the following raw materials: 10-20 parts by weight of modified silica nanospheres Thickener 10-20 parts by weight 5-10 parts by weight of foam stabilizer 70-100 parts by weight of air-entraining agent 200-300 parts by volume of deionized water 200-300 parts by volume of ethanol.

8. The high-performance antifreeze grouting material as described in claim 7, characterized in that, The modified silica nanospheres are made from the following raw materials: 0.2~1.0 parts by weight of cationic surfactant 1-3 parts by volume of ammonia water 100-200 parts by volume of deionized water 280-600 parts by volume of ethanol 4-10 parts by volume of alkyl orthosilicate 5-10 parts by volume of silane coupling agent 8-15 parts by weight of sodium gluconate.

9. The high-performance antifreeze grouting material as described in claim 8, characterized in that, The modified silica nanospheres were prepared by the following method: Mix 0.2 to 1.0 parts by weight of cationic surfactant, 1 to 3 parts by volume of ammonia, 100 to 200 parts by volume of deionized water and 200 to 400 parts by volume of ethanol, and heat to 45°C to 50°C and stir thoroughly to obtain the first mixture; Add 4-10 parts by volume of alkyl orthosilicate to the first mixture, stir continuously, and filter to obtain the second mixture; The second mixture was placed in a high-pressure reactor at a pressure of 50 MPa to 150 MPa and heated to 145°C to 160°C for 35 to 45 hours. The precipitate was then washed. The precipitate was extracted to remove the cationic surfactant, yielding hollow porous silica nanospheres. 15-30 parts by weight of the silica nanospheres, 80-200 parts by volume of ethanol, 5-10 parts by volume of silane coupling agent and 8-15 parts by weight of sodium gluconate are mixed and stirred continuously at room temperature. After filtration and drying, the modified silica nanospheres with sodium gluconate grafted on the inner and outer walls are obtained.

10. A method of using a high-performance antifreeze grouting material as described in any one of claims 1 to 9, characterized in that, Mix 30-45 parts cement, 5-10 parts silica fume, 4-8 parts microspheres, 40-60 parts sand, 0.2-1 parts water-reducing agent, 0.5-2 parts composite antifreeze agent, and 0.1-0.6 parts polymer powder according to the specified ratio, and add water at a water-to-material ratio of 0.13-0.15 to obtain the slurry. The well-mixed grout is poured into the structural parts that need to be reinforced, repaired, or filled.

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