High-strength impervious concrete waterproofing agent and preparation process thereof

Abstract

The invention relates to a high-strength impervious concrete waterproofing agent and a preparation process thereof, the waterproofing agent is prepared by mixing the raw materials of modified silica fume, nanoscale active SiO2, a composite expanding agent, ettringite crystal matrix, acrylate copolymerized rubber powder, a polycarboxylate superplasticizer, a rare earth activator and hydroxyl silicone oil emulsion through specific process steps. Wherein the modified silica fume, the nano-scale active SiO2, the composite expanding agent and other key components are all prepared by adopting a special preparation method, so that the performance of the modified silica fume, the nano-scale active SiO2 and the composite expanding agent is enhanced. The preparation process comprises the following steps: preheating the modified silica fume, premixing the nano material, forming a complex, mixing at a low speed, adding the rubber powder and the water reducing agent, introducing the rare earth exciting agent, carrying out vacuum degassing, curing and the like, and finally obtaining the high-strength impervious concrete waterproof agent with excellent performance. The waterproof agent has the performance of remarkably improving the compressive strength, breaking strength, wear resistance, chloride ion permeability resistance and the like of concrete, and is suitable for concrete engineering with high-strength anti-permeability requirements.

Description

Technical Field

[0001] The present invention relates to the technical field of building materials, in particular to a high-strength anti-seepage concrete waterproofing agent and a preparation process thereof. Background Art

[0002] Concrete is an indispensable material in modern construction projects, but its poor impermeability and easy cracking problems have always plagued the industry. Once water seepage occurs in a concrete structure, it will not only reduce the durability of the structure, but may also cause serious consequences such as surface erosion and steel corrosion, greatly affecting the quality and service life of the project. Although there are many types of concrete waterproofing agents on the current market, most products are difficult to effectively suppress the cracking tendency of concrete while improving the impermeability of concrete. Especially in high-strength concrete application scenarios, its impermeability and crack prevention effects are even more unsatisfactory. Therefore, it is particularly urgent to develop a high-strength impermeability concrete waterproofing agent that can significantly enhance the impermeability of concrete and has excellent anti-cracking effects. Summary of the Invention

[0003] The present invention aims to provide a high-strength and anti-seepage concrete waterproofing agent and a preparation process thereof, so as to solve the problem that the concrete waterproofing agent in the prior art has poor anti-seepage and anti-cracking effects in high-strength concrete.

[0004] To solve the above technical problems, the present invention provides a high-strength and anti-seepage concrete waterproofing agent, which is characterized by being composed of the following raw materials in parts by weight: 25-35 parts of modified silica fume, 8-12 parts of nano-active SiO2, 10-18 parts of a composite expansion agent, 10-13 parts of an ettringite crystal matrix, 3-8 parts of an acrylate copolymer rubber powder, 0.5-2 parts of a polycarboxylic acid water reducer, 0.1-0.5 parts of a rare earth activator, and 1-3 parts of a hydroxy silicone oil emulsion.

[0005] Preferably, the preparation method of the modified silica fume is as follows: heat-treating silica fume at 1450°C in a nitrogen atmosphere for 1h to obtain crystalline reconstructed silica fume, adding a 5% hydrochloric acid aqueous solution 5 times the weight of the crystalline reconstructed silica fume to a reactor, adding the crystalline reconstructed silica fume under stirring and reacting at room temperature for 20min, filtering, washing with water until neutral, and air-drying at 120°C to constant weight to obtain acid-activated silica fume, adding the acid-activated silica fume to a reactor, adding a THF solution 5 times the weight of the acid-activated silica fume, adding (9E,12E)-9,12-octadecadienoyl chloride 0.5 times the weight of the acid-activated silica fume under stirring, adding triethylamine 0.6 times the weight of the acid-activated silica fume, ultrasonically reacting for 2h under stirring, filtering, rinsing the filter cake with THF twice, each time using 1 times the weight of the acid-activated silica fume, drying at 40°C in vacuum to constant weight, ball-milling, and passing through a 100-mesh sieve to obtain the obtained silica fume.

[0006] Preferably, the preparation method of the nano-scale active SiO2 is as follows: SiO2 and 5% HNO3 solution are mixed in a mass ratio of 1:5, refluxed at 80°C for 2 hours, filtered, the filter cake is washed with water until neutral, and dried at 120°C with air blowing to obtain acid-activated nano-SiO2 with surface impurities removed and hydroxyl density increased, the acid-activated nano-SiO2 is added to a reaction bottle, ethanol is added with a weight twice the weight of the acid-activated nano-SiO2, and ultrasonically treated for 30 minutes (frequency 40 kHz), to obtain an acid-activated nano-SiO2 dispersion; acrylic acid (0.3 times the weight of the acid-activated nano-SiO2) was added to the reaction flask, ethanol (3 times the weight of the acrylic acid) was added, and NaOH (0.5 times the molar number of the acrylic acid) was added for neutralization, the pH was adjusted to 6-7, and N,N'-methylenebisacrylamide (0.1% by weight of the acrylic acid) was added to obtain a monomer solution; ammonium persulfate (1 times the molar number of the acrylic acid) was dissolved in deionized water (50 times the weight of the ammonium persulfate) to obtain an initiator solution, the acid-activated nano-SiO2 dispersion, the monomer solution, and the initiator solution were mixed, heated to 60-70°C under nitrogen protection with constant stirring (300-500 rpm) for a reaction time of 4-6 hours, heated to 80°C for 1 hour, centrifuged, washed three times with a mixture of ethanol / water = 1 / 1 (V:V) to remove unreacted monomers, and dried under vacuum at 60°C to constant weight.

[0007] Preferably, the composite expansion agent is prepared by adding calcium oxide and magnesium oxide whose weight is 0.25 times of the weight of calcium oxide into a ball mill and milling for 30 minutes, and then drying at 500° C. in vacuum for 5 hours to obtain the composite expansion agent.

[0008] Preferably, the ettringite crystal matrix is ​​a ternary compound of CaO·Al2O3·CaSO4, with a particle size D50 of 5-15 μm.

[0009] Preferably, the acrylic copolymer rubber powder is any one of methyl methacrylate-butyl acrylate copolymer, acrylic acid ester-styrene copolymer or acrylic acid ester-vinyl ether copolymer; The polycarboxylic acid water reducer is any one of methacrylic acid-acrylate copolymer, maleic anhydride-acrylate copolymer or polyethylene glycol monomethyl ether acrylate copolymer; The rare earth activator is any one of lanthanum nitrate, cerium sulfate or neodymium chloride; The hydroxy silicone oil emulsion is any one of sodium dodecylbenzenesulfonate modified hydroxy silicone oil emulsion, OP-10 emulsified hydroxy silicone oil or sodium lauryl sulfate composite hydroxy silicone oil emulsion.

[0010] A preparation process of a high-strength anti-seepage concrete waterproofing agent comprises the following steps: S1. Place the modified silica fume in a vacuum drying oven and heat it to 60°C for 30 minutes to remove the surface adsorbed water layer to obtain preheated modified silica fume; S2, adding nano-scale active SiO2 into a high-speed mixer with a rotation speed of 1500 rpm, and premixing with the composite expansion agent for 5 minutes to eliminate nanoparticle agglomeration, thereby obtaining a premixed nano-SiO2 / composite expansion agent; S3, premixing the acrylic copolymer rubber powder and the polycarboxylic acid water reducer in proportion to form a "rubber powder-water reducer complex"; S4, adding the modified silica fume preheated in step S1 and the nano-SiO2 / composite expansion agent premixed in step S2 into a double cone mixer, adding the ettringite crystal matrix, and mixing at a low speed of 20 rpm for 10 minutes; S5. Add the "rubber powder-water reducing agent complex" prepared in step S3 and the hydroxy silicone oil emulsion, raise the temperature to 40±2°C, and mix at 50 rpm for 15 minutes; S6. Dissolve the rare earth activator (lanthanum nitrate / cerium sulfate) in 5 times anhydrous ethanol, spray into the system, mix at high speed for 5 minutes, and vacuum degas until there are no bubbles; S7. Transfer the mixture into a sealed container, mature it at a constant temperature to promote the penetration and coating of hydroxy silicone oil, sieve it, and seal it in an aluminum foil bag filled with nitrogen. Preferably, in step S6, the high-speed mixing speed is 100 rpm, and the vacuum degree of vacuum degassing is -0.08 to -0.09 MPa.

[0011] Preferably, in step S7, the constant temperature aging temperature is 40° C., the constant temperature aging time is 24 hours, and the sieving is through a 200-mesh sieve.

[0012] The concrete waterproofing agent is applied to lightweight concrete to enhance the waterproofing performance of lightweight concrete.

[0013] The beneficial effects of the present invention are: 1. Silica fume undergoes high-temperature crystal reconstruction, acid activation, and surface grafting of octadecadienoyl chloride, significantly improving hydrophobicity and interfacial bonding, thereby enhancing concrete density. Acid washing of nano-active SiO2 increases surface hydroxyl density, and in-situ polymerization of acrylic acid forms an organic-inorganic hybrid structure, solving the problem of nanoparticle agglomeration and improving dispersibility and pore-filling capacity. The composite expansion agent (CaO / MgO = 4:1) uses magnesium oxide's delayed expansion properties to complement calcium oxide's early expansion, compensating for shrinkage in stages and reducing the risk of cracking. Vacuum drying prevents prehydration.

[0014] 2. Four-fold waterproof mechanism synergy: the matrix of ettringite crystals can quickly form a needle-shaped crystal network, thereby blocking the capillary pores; the composite expansion agent can continuously generate ettringite / calcium hydroxide to compensate for shrinkage stress and inhibit cracks; nano-SiO2 / modified silica fume can physically fill nano-pores, thereby reducing porosity; hydroxyl silicone oil emulsion can form a hydrophobic film layer with a contact angle of >110°, blocking the penetration of water molecules.

[0015] 3. High-speed premixing (1500 rpm) of nano-SiO2 and expansion agent can break up nano-agglomerates, and preheating of modified silica fume (60°C) can eliminate the interference of adsorbed water on interfacial reactions. A step-by-step mixing strategy: first mixing inorganic materials (at a low speed of 20 rpm to prevent particle breakage) and then adding organic matter (at a low temperature of 40°C to protect the polymer) can avoid component failure. The spray addition of rare earth activators can achieve atomic-level dispersion and catalyze the improvement of the nucleation efficiency of ettringite. The aging process (40°C×24h) can promote the penetration and coating of hydroxyl silicone oil molecular chains on the particle surface, thereby forming a continuous hydrophobic film, significantly improving the waterproofness, strength and durability of concrete. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is the SEM electron microscope image of the waterproofing agent of the present invention.

[0017] Figure 2 This is a comparison chart of the water absorption curves of concrete with the concrete waterproofing agent of the present invention and original concrete of the same weight, 100g each, after solidification and drying.

[0018] Figure 3 The expansion and contraction curves of the high-strength anti-seepage concrete waterproofing agent of the present invention and the traditional concrete waterproofing agent are shown. DETAILED DESCRIPTION

[0019] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0020] Preparation of modified silica fume: Silica fume is heated at 1450°C in a nitrogen atmosphere for 1 hour to obtain crystalline reconstructed silica fume, a 5% hydrochloric acid aqueous solution 5 times the weight of the crystalline reconstructed silica fume is added to a reactor, the crystalline reconstructed silica fume is added under stirring and reacted at room temperature for 20 minutes, filtered, washed with water until neutral, and air-dried at 120°C to constant weight to obtain acid-activated silica fume, the acid-activated silica fume is added to a reactor, a THF solution 5 times the weight of the acid-activated silica fume is added, (9E,12E)-9,12-octadecadienoyl chloride 0.5 times the weight of the acid-activated silica fume is added under stirring, triethylamine 0.6 times the weight of the acid-activated silica fume is added, ultrasonically reacted for 2 hours under stirring, filtered, the filter cake is rinsed with THF twice, each time using 1 times the weight of the acid-activated silica fume, dried at 40°C in vacuum to constant weight, ball-milled, and passed through a 100-mesh sieve.

[0021] Preparation of nano-scale active SiO2: SiO2 and 5% HNO3 solution were mixed in a mass ratio of 1:5, refluxed at 80℃ for 2 hours, filtered, the filter cake was washed with water until neutral, and dried at 120℃ with air blowing to obtain acid-activated nano-SiO2 with surface impurities removed and hydroxyl density increased. The acid-activated nano-SiO2 was added to a reaction bottle, and ethanol with a weight twice that of the acid-activated nano-SiO2 was added and ultrasonicated for 30 minutes (frequency 40 kHz), to obtain an acid-activated nano-SiO2 dispersion; acrylic acid (0.3 times the weight of the acid-activated nano-SiO2) was added to the reaction flask, ethanol (3 times the weight of the acrylic acid) was added, NaOH (0.5 times the molar number of the acrylic acid) was added for neutralization, the pH was adjusted to 6-7, and N,N'-methylenebisacrylamide (0.1% by weight of the acrylic acid) was added to obtain a monomer solution; ammonium persulfate (1 times the molar number of the acrylic acid) was dissolved in deionized water (50 times the weight of the ammonium persulfate) to obtain an initiator solution, the acid-activated nano-SiO2 dispersion, the monomer solution, and the initiator solution were mixed, heated to 60-70°C under nitrogen protection with constant stirring (300-500 rpm) for a reaction time of 4-6 hours, heated to 80°C for 1 hour, centrifuged, washed 3 times with an ethanol-water mixture (1:1) to remove unreacted monomers, and dried in vacuo at 60°C to a constant weight.

[0022] Preparation of composite expansion agent: Calcium oxide and magnesium oxide whose weight is 0.25 times of the weight of calcium oxide are added into a ball mill and milled for 30 minutes. After ball milling, the composite expansion agent is dried at 500°C in vacuum for 5 hours.

[0023] Example 1 250g of modified silica fume was placed in a vacuum drying oven and heated to 60℃ for 30 minutes to break the surface adsorbed water layer to obtain preheated modified silica fume; 80g of nano-scale active SiO2 was added to a high-speed mixer with a speed of 1500 rpm and premixed with 100g of composite expansion agent for 5 minutes to eliminate the agglomeration of nanoparticles to obtain premixed nano-SiO2 / composite expansion agent; 30g of methyl methacrylate-butyl acrylate copolymer and 5g of methacrylic acid-acrylate copolymer were premixed to form a "rubber powder-water reducer complex"; the preheated modified silica fume and premixed nano-SiO2 / composite expansion agent were added to a double cone mixer, 100g of ettringite crystal matrix were added, and the mixture was mixed at a low speed of 20rpm for 10 minutes; the "rubber powder-water reducer complex" and 10g of sodium dodecylbenzenesulfonate modified hydroxyl silicone oil emulsion were added, the temperature was raised to 40±2℃, 50 rpm and mixed for 15 minutes; 1g of lanthanum nitrate was dissolved in 5g of anhydrous ethanol, sprayed into the system, mixed at a high speed of 100rmp for 5 minutes, and degassed in a vacuum of -0.08MPa until there were no bubbles; the mixture was transferred to a sealed container and aged at a constant temperature of 40°C for 24h to promote the penetration and coating of hydroxyl silicone oil, passed through a 200-mesh sieve, and sealed in an aluminum foil bag filled with nitrogen to obtain the waterproofing agent of the present invention. The SEM electron microscope image of the waterproofing agent of the present invention is attached. Figure 1 . Example 2 300g of modified silica fume was placed in a vacuum drying oven and heated to 60℃ for 30 minutes to break the surface adsorbed water layer to obtain preheated modified silica fume; 100g of nano-scale active SiO2 was added to a high-speed mixer with a speed of 1500 rpm and premixed with 140g of composite expansion agent for 5 minutes to eliminate the agglomeration of nanoparticles to obtain premixed nano-SiO2 / composite expansion agent; 50g of acrylate-styrene copolymer and 13g of maleic anhydride-acrylate copolymer were premixed to form a "rubber powder-water reducer complex"; the preheated modified silica fume and premixed nano-SiO2 / composite expansion agent were added to a double cone mixer, 115g of ettringite crystal matrix was added, and the mixture was mixed at a low speed of 20 rpm for 10 minutes; the "rubber powder-water reducer complex" and 20g of OP-10 emulsified hydroxyl silicone oil were added, the temperature was raised to 40±2℃, 50 rpm for 15 minutes; dissolve 3g of cerium sulfate in 15g of anhydrous ethanol, spray into the system, mix at 100rmp for 5 minutes, and degas in a vacuum of -0.085MPa until there are no bubbles; transfer the mixture into a sealed container, mature at a constant temperature of 40℃ for 24h to promote the penetration and coating of hydroxyl silicone oil, pass through a 200-mesh sieve, and seal the aluminum foil bag with nitrogen.

[0024] Example 3 350g of modified silica fume was placed in a vacuum drying oven and heated to 60℃ for 30 minutes to break the surface adsorbed water layer to obtain preheated modified silica fume; 120g of nano-scale active SiO2 was added to a high-speed mixer with a rotation speed of 1500 rpm and premixed with 180g of composite expansion agent for 5 minutes to eliminate the agglomeration of nanoparticles to obtain premixed nano-SiO2 / composite expansion agent; 80g of acrylate-vinyl ether copolymer and 20g of polyethylene glycol monomethyl ether acrylate copolymer were premixed to form a "rubber powder-water reducer complex"; the preheated modified silica fume and premixed nano-SiO2 / composite expansion agent were added to a double cone mixer, 130g of ettringite crystal matrix was added, and the mixture was mixed at a low speed of 20rpm for 10 minutes; the "rubber powder-water reducer complex" and 30g of sodium lauryl sulfate composite hydroxyl silicone oil emulsion were added, the temperature was raised to 40±2℃, 50 rpm and mix for 15 minutes; dissolve 5g of neodymium chloride in 25g of anhydrous ethanol, spray into the system, mix at a high speed of 100rmp for 5 minutes, and degas in a vacuum of -0.09MPa until there are no bubbles; transfer the mixture into a sealed container, and mature at a constant temperature of 40℃ for 24h to promote the penetration and coating of hydroxyl silicone oil, pass through a 200-mesh sieve, and seal the aluminum foil bag with nitrogen.

[0025] Comparative Example 1 Same as Example 2, except that the modified silica fume is replaced by unmodified silica fume.

[0026] Comparative Example 2 Same as Example 2, except that the nano-active SiO2 is replaced by ordinary SiO2.

[0027] Comparative Example 3 Same as Example 2, except that the ratio of the composite expansion agent is changed from CaO / MgO=4:1 to CaO:MgO=8:1.

[0028] Comparative Example 4 Same as Example 2, except that no ettringite crystal matrix was added.

[0029] Comparative Example 5 Same as Example 2, except that steps S1-S3 are skipped and all raw materials are directly mixed.

[0030] Comparative Example 6 Same as Example 2, except that the aging in step S7 is changed to 25° C.×6 h.

[0031] Comparative Example 7 Same as Example 2, except that no rare earth activator is added.

[0032] Performance test, specific data results statistics are shown in the following table:

[0033] Test results: It can be seen from the embodiment and comparative example 1 (unmodified silica fume) that the impermeability of comparative example 1 decreased by 60%, and the strength increased by only 15%, indicating that the surface grafted hydrophobic chain is the key to improving density and interface bonding; it can be seen from the embodiment and comparative example 2 (ordinary SiO2) that the chloride ion diffusion coefficient of comparative example 2 increased by 200%, indicating that pickling and acrylic acid hybridization are irreplaceable for nano-dispersion and pore filling effects; it can be seen from the embodiment and comparative example 3 (imbalanced expansion agent ratio) that the drying shrinkage rate of comparative example 3 increased by 117%, and microcracks appeared, indicating that CaO / MgO=4:1 ensures a balance between rapid expansion in the early stage and continuous compensation in the later stage; it can be seen from the embodiment and comparative example 4 (without ettringite) that the impermeability grade of comparative example 4 is only P8, and the porosity increases sharply, indicating that the ettringite needle-shaped crystal network (D50=5-15μm) is fast The core of rapid plugging of capillary pores; through the embodiment and comparative example 5 (skipping premixing / preheating), it can be seen that the strength increase of comparative example 5 is reduced by 30%, and the rubber powder is agglomerated, indicating that preheating to break adsorbed water (S1), high-speed premixing to break agglomeration (S2), and rubber powder-water reducer pre-compounding (S3) are indispensable; through the embodiment and comparative example 6 (insufficient aging), it can be seen that the contact angle of comparative example 6 is reduced from 113° to 95°, and the impermeability is reduced by 28%, indicating that 40°C×24h aging is a necessary condition for hydroxy silicone oil to form a continuous hydrophobic film; through the embodiment and comparative example 7 (no rare earth), it can be seen that the chloride ion diffusion coefficient of comparative example 7 is increased by 87%, indicating that rare earth spray dispersion catalyzes the nucleation of ettringite and improves the crystallization efficiency by 50%; wherein the concrete waterproofing agent of the present invention is added to the concrete with the same weight of 100g and the original concrete after solidification and drying is compared in the attached figure. Figure 2 The expansion and contraction curves of the high-strength anti-seepage concrete waterproofing agent of the present invention and the traditional concrete waterproofing agent are shown in the attached Figure 3 .

[0034] The above-described embodiments merely illustrate several implementations of the present invention, and while their descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art would be able to make numerous variations and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be determined by the appended claims.

Claims

1. A high-strength anti-seepage concrete waterproofing agent, characterized in that: The invention is composed of the following raw materials in parts by weight: 25-35 parts of modified silica fume, 8-12 parts of nano-grade active SiO2, 10-18 parts of composite expansion agent, 10-13 parts of ettringite crystal matrix, 3-8 parts of acrylate copolymer rubber powder, 0.5-2 parts of polycarboxylic acid water reducer, 0.1-0.5 parts of rare earth activator and 1-3 parts of hydroxy silicone oil emulsion.

2. The high-strength anti-seepage concrete waterproofing agent according to claim 1, characterized in that: The preparation method of the modified silica fume comprises the following steps: heating silica fume at 1450° C. in a nitrogen atmosphere for 1 hour to obtain crystalline reconstructed silica fume, adding a 5% hydrochloric acid aqueous solution whose weight is 5 times the weight of the crystalline reconstructed silica fume into a reactor, adding the crystalline reconstructed silica fume to react at room temperature for 20 minutes under stirring, filtering, washing with water until neutral, and air-drying at 120° C. to constant weight to obtain acid-activated silica fume, adding the acid-activated silica fume into a reactor, adding a THF solution whose weight is 5 times the weight of the acid-activated silica fume, adding (9E,12E)-9,12-octadecadienoyl chloride whose weight is 0.5 times the weight of the acid-activated silica fume under stirring, adding triethylamine whose weight is 0.6 times the weight of the acid-activated silica fume, ultrasonically reacting for 2 hours under stirring, filtering, rinsing the filter cake with THF twice, each time using 1 times the weight of the acid-activated silica fume, drying at 40° C. in a vacuum environment to constant weight, ball-milling, and passing through a 100-mesh sieve to obtain the modified silica fume.

3. The high-strength anti-seepage concrete waterproofing agent according to claim 1, characterized in that: The nano-scale active SiO2 preparation method comprises the following steps: mixing SiO2 and 5% HNO3 solution at a mass ratio of 1:5, refluxing at 80°C for 2 hours, filtering, washing the filter cake with water until neutral, and drying at 120°C with air blowing to obtain acid-activated nano-SiO2 with surface impurities removed and hydroxyl density increased; adding the acid-activated nano-SiO2 to a reaction flask, adding ethanol twice the weight of the acid-activated nano-SiO2, and ultrasonically treating for 30 minutes to obtain an acid-activated nano-SiO2 dispersion; adding acrylic acid 0.3 times the weight of the acid-activated nano-SiO2 to the reaction flask, adding ethanol three times the weight of the acrylic acid, and neutralizing with NaOH 0.5 times the molar number of the acrylic acid. The pH is adjusted to 6-7, and N,N'-methylenebisacrylamide is added in an amount of 0.1% by weight of acrylic acid to obtain a monomer solution; ammonium persulfate in an amount of 1 times the molar number of acrylic acid is dissolved in deionized water in an amount of 50 times the weight of ammonium persulfate to obtain an initiator solution; the acid-activated nano-SiO2 dispersion, the monomer solution, and the initiator solution are mixed, and the mixture is heated to 60-70°C under nitrogen protection, stirred at a constant temperature, and reacted for 4-6 hours; the mixture is heated to 80°C and kept warm for 1 hour, centrifuged, washed three times with a mixture of ethanol and water in a volume ratio of 1 / 1 to remove unreacted monomers, and dried in vacuo at 60°C to a constant weight.

4. The high-strength anti-seepage concrete waterproofing agent according to claim 1, characterized in that: The composite expansion agent is prepared by adding calcium oxide and magnesium oxide whose weight is 0.25 times of the weight of calcium oxide into a ball mill and milling for 30 minutes, and then drying at 500° C. in vacuum for 5 hours to obtain the composite expansion agent.

5. The high-strength anti-seepage concrete waterproofing agent according to claim 1, characterized in that: The ettringite crystal matrix is ​​a ternary compound of CaO·Al2O3·CaSO4, and the particle size D50 is 5-15 μm.

6. The high-strength anti-seepage concrete waterproofing agent according to claim 1, characterized in that: The acrylic copolymer rubber powder is any one of methyl methacrylate-butyl acrylate copolymer, acrylic acid ester-styrene copolymer or acrylic acid ester-vinyl ether copolymer; The polycarboxylic acid water reducer is any one of methacrylic acid-acrylate copolymer, maleic anhydride-acrylate copolymer or polyethylene glycol monomethyl ether acrylate copolymer; The rare earth activator is any one of lanthanum nitrate, cerium sulfate or neodymium chloride; The hydroxy silicone oil emulsion is any one of sodium dodecylbenzenesulfonate modified hydroxy silicone oil emulsion, OP-10 emulsified hydroxy silicone oil or sodium lauryl sulfate composite hydroxy silicone oil emulsion.

7. A process for preparing a high-strength and anti-seepage concrete waterproofing agent according to any one of claims 1 to 6, characterized in that: The following steps are involved: S1. Place the modified silica fume in a vacuum drying oven and heat it to 60°C for 30 minutes to remove the surface adsorbed water layer to obtain preheated modified silica fume; S2, adding nano-scale active SiO2 into a high-speed mixer with a rotation speed of 1500 rpm, and premixing with the composite expansion agent for 5 minutes to eliminate nanoparticle agglomeration, thereby obtaining a premixed nano-SiO2 / composite expansion agent; S3. Premix the acrylic copolymer rubber powder and the polycarboxylic acid water reducer in proportion to form a "rubber powder-water reducer composite"; S4, adding the modified silica fume preheated in step S1 and the nano-SiO2 / composite expansion agent premixed in step S2 into a double cone mixer, adding the ettringite crystal matrix, and mixing at a low speed of 20 rpm for 10 minutes; S5. Add the "rubber powder-water reducing agent complex" prepared in step S3 and the hydroxy silicone oil emulsion, raise the temperature to 40±2°C, and mix at 50 rpm for 15 minutes; S6. Dissolve the rare earth activator in 5 times anhydrous ethanol, spray into the system, mix at high speed for 5 minutes, and vacuum degas until there are no bubbles; S7. Transfer the mixture into a sealed container, mature it at a constant temperature to promote the penetration and coating of hydroxy silicone oil, sieve it, and seal it in an aluminum foil bag filled with nitrogen.

8. The preparation process of the high-strength anti-seepage concrete waterproofing agent according to claim 7, characterized in that: In step S6, the high-speed mixing speed is 100 rpm, and the vacuum degree of vacuum degassing is -0.08 to -0.09 MPa.

9. The preparation process of the high-strength anti-seepage concrete waterproofing agent according to claim 7, characterized in that: In step S7, the constant temperature aging temperature is 40° C., the constant temperature aging time is 24 hours, and the sieving is through a 200-mesh sieve.

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