Preparation method and application of gelling capillary capillary crystallization type waterproof agent based on nano material

Abstract

The invention discloses a preparation method and application of a gelling capillary capillary crystallization type waterproof agent based on a nano material, and belongs to the technical field of building materials. The waterproof agent is prepared from the following raw materials: carbonate, calcium salt, sodium silicate, disodium ethylene diamine tetraacetate, L-aspartic acid, a cross-linked polymer and water. The cross-linked polymer is composed of an acrylic monomer, a sodium acrylate monomer, N, N '-methylene bisacrylamide, polyvinyl alcohol, distilled water and an initiator. A novel gelatinization capillary crystallization waterproof strategy is provided, the waterproof performance, strength and durability of the cement-based material can be remarkably improved, and the method has the advantages of being simple in preparation process, low in cost, environmentally friendly, harmless and the like.

Description

Technical Field

[0001] The present invention belongs to the technical field of building materials, and particularly relates to a preparation method and application of a cementitious capillary permeation crystallization type waterproof agent based on nanomaterials. Background Art

[0002] As a porous material, concrete has a large number of microcracks and micropores inside, which are defects that cannot be ignored. Due to the porosity of concrete, under capillary action, harmful corrosive ions such as Mg 2+ , Cl - , SO 4 2- etc. can easily penetrate into the concrete through water transportation, thereby forcing the internal environment of the concrete to change, resulting in the loss or decomposition of cement hydration products and generating harmful substances. This kind of penetration damage will ultimately lead to the failure of the concrete.

[0003] Cementitious capillary crystallization waterproof materials (CCCW) provide protection by reducing porosity and improving pore structure. The active chemical substances carried by CCCW materials can diffuse with water and move downward into the cracks or capillaries of the concrete. During this process, the active chemical substances (crystallization and complexing agents) in CCCW will enrich calcium ions and accelerate the formation of calcium carbonate and calcium silicate in the pores. The large consumption of calcium ions will catalyze the hydration of unreacted cement particles. However, traditional materials often have problems such as poor permeability, inability to form an effective deep waterproof layer, and uneven crystallization, thus affecting their waterproof effect and being difficult to meet the high requirements of modern engineering for material performance. Therefore, developing a material with both excellent dispersibility and efficient permeation crystallization has important research value. Summary of the Invention

[0004] In view of the above technical problems, the present invention proposes a preparation method and application of a cementitious capillary permeation crystallization type waterproof agent based on nanomaterials. This cementitious capillary permeation crystallization type waterproof agent develops a new strategy for the application of nano-calcium carbonate in concrete at the nanoscale, which can significantly improve the waterproof performance, strength and durability of cement-based materials, and this method has the advantages of simple preparation process, low cost, environmental protection and harmlessness.

[0005] To achieve the above object, the present invention provides the following technical solutions: A cementitious capillary permeation crystallization type waterproof agent based on nanomaterials, comprising the following raw materials in parts by mass: 20-40 parts of carbonate, 50-100 parts of calcium salt, 20-40 parts of sodium silicate, 2-4 parts of disodium ethylenediaminetetraacetate, 4-8 parts of L-aspartic acid, 10-20 parts of cross-linked polymer and 800-1100 parts of water.

[0006] One strategy for the present invention to improve the waterproof effect of cementitious capillary crystallization is to combine nanotechnology to enhance dispersibility and cooperate with highly permeable cross-linked polymers to ensure that highly dispersed nano-calcium carbonate can penetrate deep into the cement-based material. The swelling effect of the cross-linked polymer causes its molecular chains to stretch and adsorb a large amount of water molecules. Due to its small size effect, the nano-calcium carbonate adsorbed on the molecular chains is more likely to enter tiny pores and cracks. As the nucleation sites for crystallization, the nano-calcium carbonate promotes the growth and connection of crystals, and together with the highly permeable cross-linked polymer, forms a three-dimensional crystal network. This network structure can effectively seal the pores and cracks of the substrate, thereby maximizing the waterproof performance, strength and durability of the cement-based material.

[0007] Further, the carbonate is sodium carbonate, potassium carbonate or ammonium carbonate.

[0008] Further, the calcium salt is calcium nitrate tetrahydrate or calcium chloride.

[0009] Further, the cross-linked polymer is sodium polyacrylate hydrogel.

[0010] Even further, the preparation method of the sodium polyacrylate hydrogel is as follows: Dissolve acrylic acid monomer, sodium acrylate monomer, N,N'-methylenebisacrylamide and polyvinyl alcohol in distilled water and stir, then continue to add an initiator to the stirred solution and continue stirring until fully dissolved; Purge the obtained mixed solution with nitrogen under a low pressure of 0.1 MPa to remove the dissolved oxygen in the solution, then heat it in a water bath to obtain sodium polyacrylate hydrogel, and finally wash, vacuum dry and grind the obtained sodium polyacrylate hydrogel in sequence to obtain sodium polyacrylate hydrogel powder.

[0011] Even further, the sodium polyacrylate hydrogel is composed of the following raw materials in parts by mass: 1-1.5 parts of acrylic acid monomer, 0.2-0.6 parts of sodium acrylate monomer, 0.05-0.15 parts of N,N'-methylenebisacrylamide, 0.05-0.1 parts of polyvinyl alcohol, 10 parts of distilled water and 0.01-0.03 parts of initiator; and / or The initiator is ammonium persulfate or potassium persulfate; and / or The parameters of the water bath heating are: temperature 40-80 °C, time 4-12 h.

[0012] The present invention also provides a method for preparing the nano-material-based gelling capillary penetration crystalline waterproof agent, comprising the following steps: dissolving a cross-linked polymer and a calcium salt in deionized water, dispersing them at a high speed of 5000 - 8000 rpm for 10 min, then adding disodium ethylenediaminetetraacetate and L-aspartic acid, continuing to disperse at a high speed of 5000 - 8000 rpm for 30 min, subsequently dropping a carbonate solution, with the dropping time being 5 - 10 min, regulating the pH of the solution to 10 - 12 during the dropping process, adding sodium silicate after the dropping is completed, continuing to disperse at a high speed of 5000 - 8000 rpm for 10 min, taking out the synthetic solution, performing freeze-drying treatment, and grinding the particle size to less than 10 microns with a grinder to obtain the nano-material-based gelling capillary penetration crystalline waterproof agent.

[0013] Further, the carbonate solution is formed by mixing a carbonate and deionized water.

[0014] The present invention also provides an application of the nano-material-based gelling capillary penetration crystalline waterproof agent in building materials.

[0015] Compared with the prior art, the present invention has the following advantages and technical effects: The present invention proposes a new gelling capillary crystallization waterproof strategy, that is, a gelling capillary crystallization waterproof material with high crystallinity and high permeability of nanotechnology.

[0016] The method of the present invention has low cost, simple preparation process, and is environmentally friendly and harmless. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The accompanying drawings, which form a part of the present invention, are used to provide a further understanding of the present invention. The schematic embodiments and descriptions thereof of the present invention are used to explain the present invention and do not constitute an improper limitation to the present invention. In the drawings: Figure 1 is an optical microscope image of the gelling capillary penetration crystalline waterproof agent prepared in Example 1; Figure 2 is an optical microscope image of the gelling capillary penetration crystalline waterproof agent prepared in Example 2; Figure 3 is an optical microscope image of the gelling capillary penetration crystalline waterproof agent prepared in Example 3. DETAILED DESCRIPTION OF THE INVENTION

[0018] The various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation to the present invention, but rather as a more detailed description of certain aspects, characteristics, and implementation embodiments of the present invention.

[0019] It should be understood that the terms used in the present invention are only for describing specific embodiments and are not intended to limit the present invention. Additionally, for the numerical ranges in the present invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Each intermediate value within any stated value or stated range, as well as each smaller range between any other stated value or intermediate value within the stated range, is also included in the present invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0020] Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. Although the present invention only describes preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the practice or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials related to the documents. In case of conflict with any incorporated document, the content of this specification shall prevail.

[0021] Without departing from the scope or spirit of the present invention, various improvements and variations can be made to the specific embodiments of the present invention's specification, which are obvious to those skilled in the art. Other embodiments obtained from the specification of the present invention are obvious to those skilled in the art. The specification and examples of the present invention are merely exemplary.

[0022] Regarding the use of "comprising", "including", "having", "containing", etc. in this article, they are all open-ended terms, meaning including but not limited to.

[0023] A nano-material-based gelling capillary penetration crystalline waterproofing agent, comprising the following raw materials in parts by mass: 20 - 40 parts of carbonate, 50 - 100 parts of calcium salt, 20 - 40 parts of sodium silicate, 2 - 4 parts of disodium ethylenediaminetetraacetate, 4 - 8 parts of L-aspartic acid, 10 - 20 parts of cross-linked polymer, and 800 - 1100 parts of water. Preferably, it comprises the following raw materials in parts by mass: 20 - 40 parts of carbonate, 50 - 100 parts of calcium salt, 20 - 40 parts of sodium silicate, 2 - 4 parts of disodium ethylenediaminetetraacetate, 4 - 8 parts of L-aspartic acid, 10 - 20 parts of cross-linked polymer, and 860 - 880 parts of water.

[0024] In some preferred embodiments of the present invention, the carbonate is sodium carbonate, potassium carbonate or ammonium carbonate. Exemplarily, in the following examples, sodium carbonate is taken as an example to discuss the product performance.

[0025] In some preferred embodiments of the present invention, the calcium salt is calcium nitrate tetrahydrate or calcium chloride.

[0026] In some preferred embodiments of the present invention, the cross-linked polymer is sodium polyacrylate hydrogel. The preparation method of the sodium polyacrylate hydrogel is as follows: Acrylic acid monomer, sodium acrylate monomer, N,N'-methylenebisacrylamide and polyvinyl alcohol are dissolved in a test tube filled with distilled water and stirred. Then, an initiator is added to the stirred solution and stirred continuously until it is fully dissolved. The test tube is equipped with a nitrogen inlet adapter, and the obtained mixed solution is purged with nitrogen under a low pressure of 0.1 MPa to remove the dissolved oxygen in the solution. Subsequently, it is heated in a water bath to obtain sodium polyacrylate hydrogel. Finally, the obtained sodium polyacrylate hydrogel is washed (with distilled water), vacuum dried, and ground to obtain sodium polyacrylate hydrogel powder.

[0027] The sodium polyacrylate hydrogel is composed of the following raw materials in parts by mass: 1-1.5 parts of acrylic acid monomer, 0.2-0.6 parts of sodium acrylate monomer, 0.05-0.15 parts of N,N'-methylenebisacrylamide, 0.05-0.1 parts of polyvinyl alcohol, 10 parts of distilled water and 0.01-0.03 parts of initiator; preferably, the sodium polyacrylate hydrogel is composed of the following raw materials in parts by mass: 1.2-1.5 parts of acrylic acid monomer, 0.5-0.6 parts of sodium acrylate monomer, 0.1-0.15 parts of N,N'-methylenebisacrylamide, 0.05-0.08 parts of polyvinyl alcohol, 10 parts of distilled water and 0.02-0.03 parts of initiator.

[0028] The initiator is ammonium persulfate or potassium persulfate.

[0029] The temperature of the water bath heating is 40-80 °C. Exemplarily, in the following examples, the product performance is discussed taking the temperature of 40 °C as an example. The time of the water bath heating is 4-12 h, such as 4 h, 6 h or 12 h.

[0030] The vacuum drying means drying to a constant weight in a vacuum oven at 60 °C.

[0031] The preparation method of the nano-material-based gelling capillary infiltration crystalline waterproofing agent comprises the following steps: Dissolve the cross-linked polymer and calcium salt in deionized water, disperse them at a high speed at 5000 - 8000 rpm (such as 5000 rpm or 8000 rpm) for 10 min, then add disodium ethylenediaminetetraacetate and L-aspartic acid, and continue to disperse them at a high speed at 5000 - 8000 rpm (such as 5000 rpm or 8000 rpm) for 30 min. Subsequently, dropwise add the carbonate solution, and the dropping time is 5 - 10 min (such as 10 min). During the dropping process, adjust the pH of the solution to 10 - 12 (such as 10 or 11) with 30% concentration of NaOH solution. After the dropping is completed, add sodium silicate, and continue to disperse them at a high speed at 5000 - 8000 rpm (such as 5000 rpm or 8000 rpm) for 10 min to obtain the nano-material-based gelling capillary infiltration crystalline waterproofing agent.

[0032] The carbonate solution is prepared by mixing 20 - 40 parts of carbonate and 60 - 100 parts of deionized water, preferably by mixing 20 - 40 parts of carbonate and 60 - 80 parts of deionized water. Exemplarily, it is mixed with 40 parts of carbonate and 60 parts of deionized water, or 20 parts of carbonate and 80 parts of deionized water.

[0033] The application of the nano-material-based gelling capillary infiltration crystalline waterproofing agent in building materials.

[0034] In the present invention, "parts" refers to parts by mass, unless otherwise specified.

[0035] All raw materials used in the present invention are obtained by purchasing in the market.

[0036] The technical solution of the present invention is further described below through examples.

[0037] Example 1 Preparation of a nano-material-based gelling capillary infiltration crystalline waterproofing agent: S1. Dissolve 1.2 parts of acrylic acid monomer, 0.5 parts of sodium acrylate monomer, 0.1 part of N,N′-methylenebisacrylamide cross-linking agent and 0.05 part of polyvinyl alcohol in 10 parts of distilled water, and stir in a test tube; then add 0.02 part of free radical initiator (potassium persulfate) to the stirred solution, and stir until it is fully dissolved; this test tube is equipped with a nitrogen inlet adapter, and purge with nitrogen at a low pressure of 0.1 MPa for 10 min to remove the dissolved oxygen in the solution. Subsequently, immerse the reactor in a temperature-controlled water bath and keep it at 40 °C for 6 h to obtain sodium polyacrylate hydrogel; finally, wash the obtained sodium polyacrylate hydrogel with distilled water, dry it to a constant weight in a vacuum oven at 60 °C, and then grind it into powder (grind to a particle size of less than 20 microns) to obtain the cross-linked polymer; S2. Dissolve 20 parts of cross-linked polymer and 100 parts of calcium salt (calcium nitrate tetrahydrate) in 800 parts of deionized water, disperse at a high speed of 8000 rpm for 10 min, then add 4 parts of disodium ethylenediaminetetraacetate and 8 parts of L-aspartic acid, and then disperse at a high speed of 8000 rpm for 30 min. After that, dropwise add a sodium carbonate solution (the sodium carbonate solution is composed of 40 parts of sodium carbonate and 60 parts of deionized water), and the dropping time is 10 min. During the dropping process, adjust the pH of the solution to 11 with a 30% concentration of NaOH solution. After the dropping is completed, add 40 parts of sodium silicate, continue to disperse at a high speed of 8000 rpm for 10 min, take out the synthetic solution, perform freeze-drying treatment, and grind the particle size to less than 20 microns with a grinder to obtain a nano-material-based gelling capillary permeation crystalline waterproofing agent.

[0038] Example 2 Preparation of a nano-material-based gelling capillary permeation crystalline waterproofing agent: S1. Dissolve 1.5 parts of acrylic acid monomer, 0.56 parts of sodium acrylate monomer, 0.15 parts of N,N′-methylenebisacrylamide cross-linking agent and 0.1 part of polyvinyl alcohol in 10 parts of distilled water and stir in a test tube; then add 0.03 parts of free radical initiator (ammonium persulfate) to the stirred solution and stir until fully dissolved; this test tube is equipped with a nitrogen inlet adapter, and purge with nitrogen at a low pressure of 0.1 MPa for 10 min to remove the dissolved oxygen in the solution. Subsequently, immerse the reactor in a temperature-controlled water bath and keep it at 40 °C for 12 h to obtain sodium polyacrylate hydrogel; finally, wash the obtained sodium polyacrylate hydrogel with distilled water, dry it to a constant weight in a vacuum oven at 60 °C, and then grind it into powder with a grinder (grind to a particle size of less than 20 microns) to obtain a cross-linked polymer; S2. Dissolve 20 parts of cross-linked polymer and 100 parts of calcium salt (calcium nitrate tetrahydrate) in 800 parts of deionized water, disperse at a high speed of 8000 rpm for 10 min, then add 4 parts of disodium ethylenediaminetetraacetate and 8 parts of L-aspartic acid, and then disperse at a high speed of 8000 rpm for 30 min. After that, dropwise add a sodium carbonate solution (the sodium carbonate solution is composed of 40 parts of sodium carbonate and 60 parts of deionized water), and the dropping time is 10 min. During the dropping process, adjust the pH of the solution to 10 with a 30% concentration of NaOH solution. After the dropping is completed, add 40 parts of sodium silicate, continue to disperse at a high speed of 8000 rpm for 10 min, take out the synthetic solution, perform freeze-drying treatment, and grind the particle size to less than 20 microns with a grinder to obtain a nano-material-based gelling capillary permeation crystalline waterproofing agent.

[0039] Example 3 Preparation of a nano-material-based gelling capillary permeation crystalline waterproofing agent: S1. Dissolve 1.2 parts of acrylic acid monomer, 0.5 parts of sodium acrylate monomer, 0.1 parts of N,N′-methylenebisacrylamide crosslinking agent and 0.05 parts of polyvinyl alcohol in 10 parts of distilled water, and stir in a test tube; then add 0.02 parts of free radical initiator (ammonium persulfate) to the stirred solution and stir until fully dissolved; this test tube is equipped with a nitrogen inlet adapter, and purge with nitrogen for 10 min under a low pressure of 0.1 MPa to remove the dissolved oxygen in the solution. Subsequently, immerse the reactor in a temperature-controlled water bath and maintain at 40 °C for 6 h to obtain sodium polyacrylate hydrogel; finally, wash the obtained sodium polyacrylate hydrogel with distilled water, dry it to a constant weight in a vacuum oven at 60 °C, and then grind it into powder with a grinder (grind to a particle size of less than 20 microns) to obtain a crosslinked polymer; S2. Dissolve 10 parts of crosslinked polymer and 50 parts of calcium salt (calcium nitrate tetrahydrate) in 800 parts of deionized water, disperse at high speed at 5000 rpm for 10 min, then add 2 parts of disodium ethylenediaminetetraacetate and 4 parts of L-aspartic acid, and then disperse at high speed at 5000 rpm for 30 min. After that, dropwise add a sodium carbonate solution (the sodium carbonate solution is composed of 20 parts of sodium carbonate and 80 parts of deionized water), and the dropping time is 10 min. During the dropping process, adjust the pH of the solution to 11 with a 30% concentration of NaOH solution. After the dropping is completed, add 20 parts of sodium silicate and continue to disperse at high speed at 5000 rpm for 10 min. Take out the synthetic solution, perform freeze-drying treatment, and grind the particle size with a grinder to less than 20 microns to obtain a gel capillary permeable crystalline waterproof agent based on nanomaterials.

[0040] Use a laser particle size analyzer to measure the particle size of the waterproof agents prepared in Examples 1-3. The results show that the particle size of the waterproof agent in Example 1 is 325 nm, the particle size of the waterproof agent in Example 2 is 367 nm, and the particle size of the waterproof agent in Example 3 is 310 nm. The waterproof agents prepared in the examples of the present invention are all nanoscale and can be uniformly dispersed in the pores of concrete.

[0041] Through an optical microscope, observe the dispersion status of nano-calcium carbonate in the gel capillary permeable crystalline waterproof agent. Place the cleaned silicon plate steadily on the stage of the microscope, and gently drop a small amount of the waterproof agents prepared in Examples 1-3 dissolved in water on the surface of the silicon plate with a dropper or pipette, and observe the contour, size and distribution of nano-calcium carbonate particles in the coating with a magnification of 2000 times. As Figures 1 - 3 shown.

[0042] From Figures 1 - 3 it can be seen that in the waterproof agents prepared in Examples 1-3, the crystal morphology of nano-calcium carbonate is calcite and it is uniformly adsorbed on the crosslinked polymer.

[0043] Comparative Example 1 Same as Example 1, except that no cross-linked polymer is added.

[0044] Comparative Example 2 Same as Example 1, except that no disodium ethylenediaminetetraacetate and L-aspartic acid are added in step S2.

[0045] Comparative Example 3 Same as Example 1, except that in step S2, the pH of the solution is adjusted to 7 with 30% NaOH solution during the dropping process.

[0046] Comparative Example 4 Same as Example 1, except that the cross-linked polymer is replaced with cross-linked waterborne polyurethane.

[0047] Comparative Example 5 Same as Example 1, except that 0.05 parts of free radical initiator (potassium persulfate) are added in step S1.

[0048] Comparative Example 6 Same as Example 1, except that 1 part of disodium ethylenediaminetetraacetate and 2 parts of L-aspartic acid are added in step S2.

[0049] Application Example 1 Prepare a reference mortar. The polycarboxylate water reducing agent used for testing is D4 sold on the market, and the dosage is 0.2% of the mass of the cementitious material. The cement used for testing is P•O42.5R cement produced by Esheng Cement Factory, and the sand used is ISO standard sand produced by Xiamen ASO Standard Sand Co., Ltd. The mortar mix ratio is: 900 g of cement, 1450 g of sand, 324 g of water, and 1.8 g of polycarboxylate water reducing agent.

[0050] Adopt the standard GB18445-2012 "Cementitious capillary crystalline waterproofing materials". The reference mortar specimens adopt a circular tabletop, with a lower diameter of 80 mm, an upper diameter of 70 mm, and a height of 30 mm. 6 samples are made in each group. Before demolding, the molded samples are cured for 1 day in a standard environment with a relative humidity of 95% and a temperature of 20°C. The mass ratio of the waterproofing agent powder to water is 4∶1 for batching. Use a stirring tool to fully stir the powder and water until a viscous slurry is formed for coating the coating (the coating thickness is about 1.5 mm, and the waterproofing agent dosage is 2 g). Thoroughly clean the demolded samples before coating the coating on the top surface, then apply the waterproofing agents prepared in the above examples and comparative examples on the surface of the substrate specimens, and place the samples containing the coating in water for 26 days. During this period, the liquid level is maintained at 3 / 4 of the sample height. After curing, dry the samples in the atmospheric environment for 1 day, and then conduct the impermeability strength test. The mortar impermeability strength is measured by the stepwise pressure method (SPM), with an initial pressure of 0.3 MPa and an increase of 0.1 MPa per hour thereafter. The results of the mortar impermeability test are shown in Table 1.

[0051] Blank group: There is no coating on the top surface of the prepared reference mortar specimen.

[0052] Table 1

[0053] Note: The time point of "the first time" is one day after the mortar specimen is cured. The time point of "after removing the coating" is one day after the mortar specimen coated with the coating is dried.

[0054] As shown in Table 1, the effect of the coating on improving the impermeability performance is confirmed. Compared with the uncoated specimens, the impermeability strength of the coated specimens (28 days, including 1 day of curing, 26 days in water, and 1 day of drying, a total of 28 days) has been greatly improved. The impermeability strength ratios of the samples in Examples 1-3 are more than 200%, and the impermeability strength ratio after removing the coating is also more than 200%. This indicates that the coating of the cementitious capillary penetration crystalline waterproofing agent enhances the impermeability of the mortar, and this performance still exists even after the coating is removed. The prepared coating not only has the surface anti-seepage effect, but also improves the microstructure of the matrix due to the penetration of nano-calcium carbonate and silicate into the matrix interior.

[0055] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

Claims

1. A gelling capillary penetration crystalline waterproofing agent based on nanomaterials, characterized in that: The invention comprises the following raw materials in parts by weight: 20-40 parts of carbonate, 50-100 parts of calcium salt, 20-40 parts of sodium silicate, 2-4 parts of disodium ethylenediaminetetraacetate, 4-8 parts of L-aspartic acid, 10-20 parts of cross-linked polymer and 800-1100 parts of water; The preparation method of the nanomaterial-based gelling capillary penetration crystalline waterproofing agent, The method comprises the following steps: dissolving a cross-linked polymer and a calcium salt in deionized water, dispersing the mixture at high speed at a rotation speed of 5000-8000 rpm for 10 minutes, adding disodium ethylenediaminetetraacetic acid and L-aspartic acid, continuing to disperse the mixture at high speed at a rotation speed of 5000-8000 rpm for 30 minutes, then dripping a carbonate solution for 5-10 minutes, regulating the pH value of the solution to 10-12 during the dripping process, adding sodium silicate after the dripping is completed, continuing to disperse the mixture at high speed at a rotation speed of 5000-8000 rpm for 10 minutes, taking out the synthetic solution, performing freeze drying treatment, and grinding the solution to a particle size of less than 20 microns using a grinder to obtain a gelled capillary penetration crystalline waterproofing agent based on nanomaterials.

2. The nanomaterial-based gelling capillary penetration crystalline waterproofing agent according to claim 1, characterized in that: The carbonate is sodium carbonate, potassium carbonate or ammonium carbonate.

3. The nanomaterial-based gelling capillary penetration crystalline waterproofing agent according to claim 1, characterized in that: The calcium salt is calcium nitrate tetrahydrate or calcium chloride.

4. The nanomaterial-based gelling capillary penetration crystalline waterproofing agent according to claim 1, characterized in that: The cross-linked polymer is sodium polyacrylate hydrogel.

5. The nanomaterial-based gelling capillary penetration crystalline waterproofing agent according to claim 4, characterized in that: The preparation method of the sodium polyacrylate hydrogel comprises the following steps: dissolving acrylic acid monomer, sodium acrylate monomer, N,N′-methylenebisacrylamide and polyvinyl alcohol in distilled water and stirring, then continuously adding an initiator into the stirred solution and continuously stirring until the solution is fully dissolved; purging the obtained mixed solution with nitrogen at a low pressure of 0.1 MPa to remove dissolved oxygen in the solution, then heating in a water bath to obtain the sodium polyacrylate hydrogel, and finally sequentially washing, vacuum drying and grinding the obtained sodium polyacrylate hydrogel to obtain the sodium polyacrylate hydrogel powder.

6. The nanomaterial-based gelling capillary penetration crystalline waterproofing agent according to claim 5, characterized in that: The sodium polyacrylate hydrogel is composed of the following raw materials in parts by weight: 1-1.5 parts of acrylic acid monomer, 0.2-0.6 parts of sodium acrylate monomer, 0.05-0.15 parts of N,N′-methylenebisacrylamide, 0.05-0.1 parts of polyvinyl alcohol, 10 parts of distilled water and 0.01-0.03 parts of initiator; and / or The initiator is ammonium persulfate or potassium persulfate; and / or The parameters of the water bath heating are: temperature 40-80°C, time 4-12h.

7. A method for preparing a nanomaterial-based gelling capillary penetration crystalline waterproofing agent according to any one of claims 1 to 6, characterized in that: The method comprises the following steps: dissolving a cross-linked polymer and a calcium salt in deionized water, dispersing the mixture at high speed at a rotation speed of 5000-8000 rpm for 10 minutes, adding disodium ethylenediaminetetraacetic acid and L-aspartic acid, continuing to disperse the mixture at high speed at a rotation speed of 5000-8000 rpm for 30 minutes, then dripping a carbonate solution for 5-10 minutes, regulating the pH value of the solution to 10-12 during the dripping process, adding sodium silicate after the dripping is completed, continuing to disperse the mixture at high speed at a rotation speed of 5000-8000 rpm for 10 minutes, taking out the synthetic solution, performing freeze drying treatment, and grinding the solution to a particle size of less than 20 microns using a grinder to obtain a gelled capillary penetration crystalline waterproofing agent based on nanomaterials.

8. The method for preparing the nanomaterial-based gelling capillary penetration crystalline waterproofing agent according to claim 7, characterized in that: The carbonate solution is prepared by mixing carbonate and deionized water.

9. Use of the nanomaterial-based gelling capillary penetration crystalline waterproofing agent as claimed in any one of claims 1 to 6 in building materials.

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