A nano-hexagonal boron nitride modified cement-based two-component grouting material and its preparation method

Abstract

This invention discloses a cement-based two-component grouting material modified with nano-hexagonal boron nitride. The grouting material raw materials include component A and component B. Component A includes cement, retarder, micro-expansion agent, and nano-modified h-BN. Component B includes water glass. The nano-modified h-BN is obtained by ball milling and modification of h-BN. Non-ionic hydrophilic covalently grafted nano-hexagonal boron nitride is used as an external modified filler in the cement-water glass two-component grouting material. It works together with retarders, expansion agents, and other additives to improve the dispersion stability of nano-boron nitride in the cement-based grouting material slurry (high electrolyte environment), thereby improving the dispersion uniformity of nano-hexagonal boron nitride in the stone body. It can retain effective stone components, improve the overall density of the grout after molding, reduce slurry dissolution, inhibit ion permeation rate, reduce environmental damage during grouting, and help maintain ecological balance.

Description

Technical Field

[0001] This invention relates to the field of grouting materials, specifically to a nano-hexagonal boron nitride modified cement-based two-component grouting material and its preparation method. Background Technology

[0002] Cement-based grouting materials can be categorized into single-component and two-component grouting materials based on the type of grout used. Single-component cement-based grouting materials include cement grout, silicate grout, mortar, and fine cement grout. Two-component cement-based grouting materials include cement-based two-component grouting materials, with the cement-water glass two-component grout system being the most comprehensive. Single-component cement-based grouting materials are typically used for reinforcing rocks, foundations, or structures, as well as for seepage prevention and plugging, joint treatment of dams, grouting of ducts in post-tensioned prestressed concrete, and the production of pressurized concrete. Two-component cement-based grouting materials are used for seepage prevention in sandy soils, grouting of large structural cracks, and repair and seepage prevention of structures requiring impermeability. During the grouting process, cement-based grouting materials are prone to leakage due to accidents, especially in water-rich tunnels. During the grouting construction phase, soluble ions such as calcium and chloride ions diffuse into the surrounding water, causing water pollution; after the formation of grout, the migration of water in the external environment often changes with the seasons. In existing technologies, the performance of grouting materials has been effectively controlled by changing the proportion of admixtures, such as adding nanomaterials. For example, by adding graphene oxide to cement-based grouting materials, a graphene oxide nano-modified cement-based grouting material has been developed. The graphene oxide fills the micropores formed during the hydration process of the grouting material, creating a bridging effect, which significantly improves the impermeability and service life of the cement-based grouting material.

[0003] However, using graphene oxide as an admixture to improve grouting materials also presents some significant problems:

[0004] 1. Mismatch between hydrophilicity and hydrophobicity: Although graphene oxide contains a large number of functional groups, such as hydroxyl and carboxyl groups, which makes it highly hydrophilic in water, the surfaces of cement particles in cement slurry are usually hydrophobic. This makes it difficult for graphene oxide to form good contact and adhesion with the cement particle surfaces.

[0005] 2. Particle Aggregation: Graphene oxide tends to form aggregates in cement slurry through forces such as van der Waals forces and hydrogen bonds. This aggregation reduces the uniform distribution of graphene oxide in cement-based materials, thus affecting its performance.

[0006] 3. Cement hydration reaction: When cement hydrates in water, it releases a large amount of heat of hydration and hydration products, such as ettringite and calcium silicate hydration products. These hydration products may deposit on the surface of graphene oxide, affecting its dispersibility. All of the above factors can affect the application of graphene oxide materials in cement-based grouting materials, leading to damage to the material's properties.

[0007] Existing literature utilizes nano-hexagonal boron nitride for the modification of two-liquid slurries. However, the method employed involves mechanical ball milling to nano-size the boron nitride, followed by the addition of surfactants to physically adsorb the nano-hexagonal boron nitride and improve dispersion uniformity. The main problem with this approach is that the adsorption of surfactants by the cement hydrates in the two-liquid slurry, coupled with the strongly alkaline electrolyte environment, prevents the nano-hexagonal boron nitride from meeting the required dispersion uniformity. Given the significant impact of nanomaterial dispersibility on performance, this method has not achieved satisfactory performance improvement for the grouting material, and the full potential of the nano-hexagonal boron nitride is not realized. Chemical grafting of nano-hexagonal boron nitride can effectively address this issue.

[0008] Chemically grafted nano-hexagonal boron nitride can avoid dispersant loss, improve the dispersion uniformity and consistency of nano-hexagonal boron nitride in two-component grouts, and efficiently modify cement-based grouting materials. This not only ensures that the mechanical properties of the grouting material are not affected, but also improves its durability; at the same time, it achieves an eco-friendly effect. Summary of the Invention

[0009] In view of this, the purpose of this invention is to provide a nano-hexagonal boron nitride modified cement-based two-component grouting material and its preparation method, which can ensure that the mechanical properties of the grouting material itself are not affected, improve the durability of the grouting material, and achieve an eco-friendly effect.

[0010] The present invention relates to a nano-hexagonal boron nitride modified cement-based two-component grouting material. The raw materials of the grouting material include component A and component B. The raw materials of component A include cement, retarder, micro-expansion agent and nano-modified h-BN. The raw materials of component B include water glass. The nano-modified h-BN is obtained by ball milling and modification of h-BN.

[0011] Furthermore, the nano-modified h-BN is obtained by dry ball milling followed by wet ball milling of h-BN. The thickness of the nano-modified h-BN sheets is 1-10 nm, the length is 1-100 nm, the width is 1-100 nm, and the mass grafting yield of the nano-h-BN is 5%-10%.

[0012] Furthermore, the preparation method of the modified h-BN includes the following steps: mixing h-BN with B2O3 and then ball milling, then adding 2Na2CO3·3H2O for secondary ball milling, then adding a mixture of dimethyl sulfoxide and glucose crystals for wet ball milling, and finally filtering, centrifuging and drying the ball-milled sample to obtain modified h-BN.

[0013] Furthermore, ball milling is carried out in a zirconia ball mill jar with a ball-to-material ratio of 60:1-75:1;

[0014] Furthermore, component B is a mixture of sodium silicate and potassium silicate;

[0015] Furthermore, the raw material of component A includes the following components by weight: 900-1000 parts of ordinary Portland cement, 900-1000 parts of water, 20-30 parts of retarder, 40-60 parts of expansion agent, and 0.1-1 parts of modified h-BN; the raw material of component B includes the following components by volume: 340-400 parts of sodium silicate and 160-200 parts of potassium silicate.

[0016] Furthermore, the sodium silicate has a Baume degree of 35-40 Bé and a density of 1.3-1.4 g / cm³. 3 The sodium oxide content is 8%-9%, the silicon dioxide content is 27%-28%, and the modulus is 3.2-3.3; the potassium silicate has a Baume degree of 35-40 Bé and a density of 1.3-1.4 g / cm³. 3 Potassium oxide content is 12%-13%, silicon dioxide content is 26%-27%, and modulus is 3.2-3.3;

[0017] Furthermore, the retarder is disodium hydrogen phosphate; the micro-expansion agent is SCEA-II high-performance concrete expansion agent.

[0018] This invention also discloses a method for preparing a nano-hexagonal boron nitride modified cement-based two-component grouting material, comprising the following steps:

[0019] S1, the modified h-BN powder is dissolved in water and ultrasonically treated to fully disperse it in water, thus obtaining a nano-modified h-BN mixed solution;

[0020] S2, component A is prepared by mixing cement, water, retarder, micro-expansion agent and h-BN mixed aqueous solution; S3, component B is prepared by mixing sodium silicate and potassium silicate.

[0021] This invention also discloses a method for using a nano-hexagonal boron nitride modified cement-based two-component grouting material, characterized in that: during on-site grouting, component A and component B are mixed using a pipeline and then used for grouting repair and penetration grouting of concrete cracks.

[0022] The beneficial effects of this invention are as follows: The nano-hexagonal boron nitride modified cement-based two-component grouting material and its preparation method of this invention use non-ionic hydrophilic covalently grafted nano-hexagonal boron nitride as an external modified filler in the cement-water glass two-component grouting material. It works in conjunction with retarders, expansion agents, and other additives to improve the dispersion stability of nano-boron nitride in the cement-based grouting material slurry (in a high electrolyte environment), thereby improving the dispersion uniformity of nano-hexagonal boron nitride in the stone body. This allows for the retention of effective stone components, increases the overall density of the grout after molding, reduces slurry dissolution, inhibits ion permeation rate, reduces environmental damage during the grouting process, and is conducive to maintaining ecological balance. Attached Figure Description

[0023] The present invention will be further described below with reference to the accompanying drawings and embodiments:

[0024] Figure 1 This is a process flow diagram of the construction method of the present invention.

[0025] Figure 2 This is a graph showing the changing trends of electrical conductivity and exudated ions in the grouting material of the present invention. Detailed Implementation

[0026] This embodiment describes a nano-hexagonal boron nitride modified cement-based two-component grouting material. The grouting material raw materials include component A and component B. Component A includes cement, a retarder, a micro-expansion agent, and nano-modified h-BN. Component B includes water glass. The nano-modified h-BN is obtained by ball milling and modification of h-BN. Hexagonal boron nitride is a graphene-like two-dimensional sheet material. Due to its unique lattice structure, it possesses excellent mechanical strength and chemical stability. The nano-sized BNNSs, due to their large surface area, can adsorb into the micropores of the grouting aggregate, effectively adsorbing, capturing, and blocking various micro-ions. By using non-ionic, hydrophilic, covalently grafted nano-h-BN, only a small amount is added to the cement-based grouting material, which can significantly reduce various interactions between the grouting material and the external environment. When applied to grouting systems with high fluidity, it can retain effective stone components, improve the overall density of the grout after molding, reduce grout dissolution, inhibit ion seepage rate, and reduce environmental damage during grouting, thus contributing to maintaining ecological balance. The use of non-ionic, hydrophilic, covalently grafted nano-h-BN can reduce the degradation of the grouted stone's durability, such as dissolution and carbonization, and also minimize the impact of grouting construction on surrounding water and soil environments.

[0027] In this embodiment, the nano-modified h-BN is prepared by dry ball milling followed by wet ball milling of h-BN. The nano-modified h-BN has a sheet thickness of 1-10 nm, a length of 1-100 nm, and a width of 1-100 nm, with a mass grafting yield of 5%-10%. The prepared nano-modified h-BN has extremely small particle size and a large specific surface area, enabling it to adsorb into the micropores of the grouting stone body, thereby improving the overall density of the stone body. h-BN can also block and capture ions in the pores of the grouting stone body, reducing the leaching of harmful ions and protecting the construction environment.

[0028] In this embodiment, the preparation method of the modified h-BN includes the following steps: mixing h-BN with B2O3 and ball milling, then adding 2Na2CO3·3H2O for secondary ball milling, then adding a mixture of dimethyl sulfoxide and glucose crystals for wet ball milling, and filtering, centrifuging, and drying the ball-milled sample to obtain modified h-BN; using a one-pot ball milling method to modify commercially available h-BN results in high efficiency in the exfoliation and modification of h-BN, and the process is mainly carried out under closed conditions to avoid interference from external factors, achieving the purpose of stable and controllable procedure, and the obtained modified BNNSs has a complete structure.

[0029] In this embodiment, ball milling is performed in a zirconia ball mill jar with a ball-to-material ratio of 60:1 to 75:1. The ball-to-material ratio refers to the ratio of the mass of material to the mass of the grinding media within the ball mill. It is a crucial parameter affecting the ball milling process. Too few balls result in fewer impacts and grinding cycles, leading to low efficiency; too many balls hinder the impact between the balls, preventing the full realization of the crushing effect. The ball-to-material ratio setting of this invention ensures that the h-BN retains its complete lamellar structure to the greatest extent possible after ball milling.

[0030] In this embodiment, component B is a mixture of sodium silicate and potassium silicate.

[0031] In this embodiment, component A comprises the following components by weight: 900-1000 parts ordinary Portland cement, 900-1000 parts water, 20-30 parts retarder, 40-60 parts expanding agent, and 0.1-1 parts modified h-BN; component B comprises the following components by volume: 340-400 parts sodium silicate and 160-200 parts potassium silicate. The retarder delays the precipitation of Ca(OH)2, CSH, and CASH during hydration, thus slowing down the rapid hydration of the grouting material after the addition of water glass slurry and increasing its workability. The expanding agent improves the pore structure of the grouting material during molding, making it more uniform, thereby increasing the density and mechanical strength of the hydrated stone body. Ordinary Portland cement (42.5R) is preferably used. The retarder is preferably disodium hydrogen phosphate; the expanding agent is SCEA-II high-performance concrete expanding agent.

[0032] In this embodiment, the sodium silicate has a Baume degree of 35-40 Bé and a density of 1.3-1.4 g / cm³. 3 The sodium oxide content is 8%-9%, the silicon dioxide content is 27%-28%, and the modulus is 3.2-3.3; the potassium silicate has a Baume degree of 35-40 Bé and a density of 1.3-1.4 g / cm³. 3 It contains 12%-13% potassium oxide and 26%-27% silicon dioxide, with a modulus of 3.2-3.3; sodium silicate is a slightly yellowish viscous liquid; potassium silicate is a high-definition transparent viscous liquid.

[0033] The preparation method of the nano-hexagonal boron nitride modified cement-based two-component grouting material in this embodiment includes the following steps:

[0034] S1, the modified h-BN powder is dissolved in water and ultrasonically treated to fully disperse it in water, thus obtaining a nano-modified h-BN mixed solution;

[0035] S2, component A is prepared by mixing cement, water, retarder, micro-expansion agent and h-BN mixed aqueous solution;

[0036] S3 is prepared by mixing sodium silicate and potassium silicate to obtain component B. It has the characteristics of simple method, low cost and environmental friendliness. It can not only ensure that the mechanical properties of the grouting material itself are not affected, but also improve the durability of the grouting material, thus achieving an ecologically friendly effect.

[0037] The method of using the nano-hexagonal boron nitride modified cement-based two-component grouting material in this embodiment involves mixing component A and component B during on-site grouting for concrete crack repair and penetrating grouting. The pre-preserved component A and component B solutions are transported to the construction site, where they are mixed before grouting. This on-site forming process eliminates the need for pre-forming, optimizing the construction steps. The grouting material is suitable for concrete crack repair and penetrating grouting.

[0038] Example 1

[0039] The nano-hexagonal boron nitride modified cement-based two-component grouting material of this embodiment includes the following components by weight: 900 parts of ordinary silicate cement, 900 parts of water, 20 parts of retarder (disodium hydrogen phosphate), 40 parts of SCEA-II high-performance concrete expansion agent, and 0.1 parts of modified h-BN; and the following components by volume: 340 parts of sodium silicate and 160 parts of potassium silicate.

[0040] The method for using nano-hexagonal boron nitride modified cement-based grouting material in this embodiment includes the following steps:

[0041] 1) Commercial h-BN (average size ≈ 74 μm) was first mixed with B₂O₃ at a molar ratio of 1:0.5 and then placed in a 100 ml zirconia ball mill jar. The mixture was ball-milled for 2 hours at a ball-to-material ratio of 60:1. After the initial milling, 0.15 times the molar ratio of h-BN to 2Na₂CO₃·3H₂O was added for a second milling process of 4 hours. Following the dry milling step, a mixture of 2.3 times the molar ratio of h-BN to DMSO and 0.6 times the molar ratio of glucose crystals was stirred thoroughly and then wet-milled in the ball mill jar for 6 hours. The final sample was filtered, centrifuged, and dried to obtain the final sample. After thorough ball milling and exfoliation, the h-BN sheet thickness was 10 nm, the length was 60 nm, and the width was 80 nm. The mass grafting yield of nano-h-BN was 8%.

[0042] 2) Dissolve the modified h-BN powder in water and sonicate for 10 minutes to fully disperse it in water and obtain a mixed solution.

[0043] 3) Mix cement, water, retarder, micro-expansion agent, and mixed aqueous solution in proportion to obtain fresh cement paste component A, and store it in a container.

[0044] 4) Mix sodium silicate and potassium silicate to obtain fresh silicate solution component B, and store it in a container.

[0045] 5) Transport the stored liquid A and liquid B to the construction site. When grouting on site, mix liquid A and liquid B before grouting.

[0046] Example 2

[0047] The nano-hexagonal boron nitride modified cement-based two-component grouting material of this embodiment includes the following components by weight: 1000 parts of ordinary silicate cement, 1000 parts of water, 30 parts of retarder (disodium hydrogen phosphate), 60 parts of SCEA-II high-performance concrete expansion agent, and 1 part of modified h-BN; and the following components by volume: 400 parts of sodium silicate and 200 parts of potassium silicate.

[0048] The method for using nano-hexagonal boron nitride modified cement-based grouting material in this embodiment includes the following steps:

[0049] 1) Commercial h-BN (average size ≈ 74 μm) was first mixed with B₂O₃ at a molar ratio of 1:0.5 and then placed in a 100 ml zirconia ball mill jar. The mixture was ball-milled for 2 hours at a ball-to-material ratio of 75:1. After the initial milling, 0.15 times the molar ratio of h-BN to 2Na₂CO₃·3H₂O was added for a second milling process of 4 hours. Following the dry milling step, a mixture of 2.3 times the molar ratio of h-BN to DMSO and 0.6 times the molar ratio of glucose crystals was stirred thoroughly and then wet-milled in the ball mill jar for 6 hours. The final sample was filtered, centrifuged, and dried to obtain the final sample. The modified h-BN sheets had a thickness of 5 nm, a length of 10 nm, and a width of 10 nm. The mass grafting yield of nano-h-BN was 5%.

[0050] 2) Dissolve the modified h-BN powder in water and sonicate for 10 minutes to fully disperse it in water and obtain a mixed solution.

[0051] 3) Mix cement, water, retarder, micro-expansion agent, and mixed aqueous solution in proportion to obtain fresh cement paste component A, and store it in a container.

[0052] 4) Mix sodium silicate and potassium silicate to obtain fresh silicate solution component B, and store it in a container.

[0053] 5) Transport the stored liquid A and liquid B to the construction site. When grouting on site, mix liquid A and liquid B before grouting.

[0054] Example 3

[0055] The nano-hexagonal boron nitride modified cement-based two-component grouting material of this embodiment comprises, by weight, the following components in component A: 910 parts of ordinary silicate cement, 950 parts of water, 28 parts of retarder (disodium hydrogen phosphate), 50 parts of SCEA-II high-performance concrete expansion agent, and 0.7 parts of modified h-BN; and by volume, the following components in component B: 350 parts of sodium silicate and 190 parts of potassium silicate.

[0056] The method for using nano-hexagonal boron nitride modified cement-based grouting material in this embodiment includes the following steps:

[0057] 1) Commercial h-BN (average size ≈ 74 μm) was first mixed with B₂O₃ at a molar ratio of 1:0.7 and then placed in a 100 ml zirconia ball mill jar. The mixture was ball-milled for 2.5 h at a ball-to-material ratio of 60:1-75:1. After the initial milling, 0.15 times the molar ratio of h-BN to 2Na₂CO₃·3H₂O was added for a second milling process of 4.1 h. Following the dry milling step, a mixture of 2.3 times the molar ratio of h-BN to DMSO and 0.6 times the molar ratio of glucose crystals was stirred thoroughly and then wet-milled in the ball mill jar for 6 h. The final sample was filtered, centrifuged, and dried to obtain the final sample. After thorough ball milling and exfoliation, the h-BN sheets had a thickness of 10 nm, a length of 100 nm, and a width of 100 nm. The mass grafting yield of nano-h-BN was 10%.

[0058] 2) Dissolve the modified h-BN powder in water and sonicate for 14 minutes to fully disperse it in water and obtain a mixed solution.

[0059] 3) Mix cement, water, retarder, micro-expansion agent, and mixed aqueous solution in proportion to obtain fresh cement paste component A, and store it in a container.

[0060] 4) Mix sodium silicate and potassium silicate to obtain fresh silicate solution component B, and store it in a container.

[0061] 5) Transport the stored liquid A and liquid B to the construction site. When grouting on site, mix liquid A and liquid B before grouting.

[0062] Example 4

[0063] The nano-hexagonal boron nitride modified cement-based two-component grouting material of this embodiment comprises, by weight, the following components in component A: 980 parts of ordinary silicate cement, 950 parts of water, 21 parts of retarder (disodium hydrogen phosphate), 55 parts of SCEA-II high-performance concrete expansion agent, and 0.1 parts of modified h-BN; and by volume, the following components in component B: 400 parts of sodium silicate and 160 parts of potassium silicate.

[0064] The method for using nano-hexagonal boron nitride modified cement-based grouting material in this embodiment includes the following steps:

[0065] 1) Commercial h-BN (average size ≈ 74 μm) was first mixed with B₂O₃ at a molar ratio of 1.1:0.5 and then placed in a 100 ml zirconia ball mill jar. The mixture was ball-milled for 2.3 h at a ball-to-material ratio of 70:1. After the initial milling, 2Na₂CO₃·3H₂O (0.15 times the molar ratio of h-BN) was added for a second milling process of 4 h. Following the dry milling step, a mixture of DMSO (2.4 times the molar ratio of h-BN) and glucose crystals (0.7 times the molar ratio) was stirred thoroughly and then wet-milled in the ball mill jar for 7 h. The final sample was then filtered, centrifuged, and dried. After thorough ball milling and exfoliation, the h-BN sheets had a thickness of 8 nm, a length of 80 nm, and a width of 80 nm. The mass grafting yield of nano-h-BN was 7%.

[0066] 2) Dissolve the modified h-BN powder in water and sonicate for 8 minutes to fully disperse it in water and obtain a mixed solution.

[0067] 3) Mix cement, water, retarder, micro-expansion agent, and mixed aqueous solution in proportion to obtain fresh cement paste component A, and store it in a container.

[0068] 4) Mix sodium silicate and potassium silicate to obtain fresh silicate solution component B, and store it in a container.

[0069] 5) Transport the stored liquid A and liquid B to the construction site. When grouting on site, mix liquid A and liquid B before grouting.

[0070] Example 5

[0071] The nano-hexagonal boron nitride modified cement-based two-component grouting material of this embodiment comprises, by weight, the following components in component A: 970 parts of ordinary silicate cement, 950 parts of water, 23 parts of retarder (disodium hydrogen phosphate), 55 parts of SCEA-II high-performance concrete expansion agent, and 0.5 parts of modified h-BN; and by volume, the following components in component B: 380 parts of sodium silicate and 180 parts of potassium silicate.

[0072] The method for using nano-hexagonal boron nitride modified cement-based grouting material in this embodiment includes the following steps:

[0073] 1) Commercial h-BN (average size ≈ 74 μm) was first mixed with B₂O₃ at a molar ratio of 1.5:0.7 and then placed in a 100 ml zirconia ball mill jar. The mixture was ball-milled for 2.5 h at a ball-to-material ratio of 68:1. After the initial milling, 0.2 times the molar ratio of h-BN to 2Na₂CO₃·3H₂O was added for a second milling process of 4.3 h. Following the dry milling step, a mixture of 2.6 times the molar ratio of DMSO and 0.8 times the molar ratio of glucose was stirred thoroughly and then wet-milled in the ball mill jar for 6.8 h. The final sample was filtered, centrifuged, and dried to obtain the final sample. After thorough ball milling and exfoliation, the h-BN sheets had a thickness of 3 nm, a length of 30 nm, and a width of 30 nm. The mass grafting yield of nano-h-BN was 6%.

[0074] 2) Dissolve the modified h-BN powder in water and sonicate for 16 minutes to fully disperse it in water and obtain a mixed solution.

[0075] 3) Mix cement, water, retarder, micro-expansion agent, and mixed aqueous solution in proportion to obtain fresh cement paste component A, and store it in a container.

[0076] 4) Mix sodium silicate and potassium silicate to obtain fresh silicate solution component B, and store it in a container.

[0077] 5) Transport the stored liquid A and liquid B to the construction site. When grouting on site, mix liquid A and liquid B before grouting.

[0078] Example 6

[0079] The nano-hexagonal boron nitride modified cement-based two-component grouting material of this embodiment comprises, by weight, the following components in component A: 950 parts of ordinary silicate cement, 950 parts of water, 25 parts of retarder (disodium hydrogen phosphate), 50 parts of SCEA-II high-performance concrete expansion agent, and 0.6 parts of modified h-BN; and by volume, the following components in component B: 370 parts of sodium silicate and 180 parts of potassium silicate.

[0080] The method for using nano-hexagonal boron nitride modified cement-based grouting material in this embodiment includes the following steps:

[0081] 1) Commercial h-BN (average size ≈ 74 μm) was first mixed with B₂O₃ at a molar ratio of 1:0.5 and then placed in a 100 ml zirconia ball mill jar. The mixture was ball-milled for 2 hours at a ball-to-material ratio of 70:1. After the initial milling, 0.15 times the molar ratio of h-BN to 2Na₂CO₃·3H₂O was added for a second milling process of 4 hours. Following the dry milling step, a mixture of 2.3 times the molar ratio of DMSO and 0.6 times the molar ratio of glucose crystals was stirred thoroughly and then wet-milled in the ball mill jar for 6 hours. The final sample was filtered, centrifuged, and dried to obtain the final sample. After thorough ball milling and exfoliation, the h-BN sheets had a thickness of 5 nm, a length of 50 nm, and a width of 50 nm. The mass grafting yield of nano-h-BN was 8%.

[0082] 2) Dissolve the modified h-BN powder in water and sonicate for 10 minutes to fully disperse it in water and obtain a mixed solution.

[0083] 3) Mix cement, water, retarder, micro-expansion agent, and mixed aqueous solution in proportion to obtain fresh cement paste component A, and store it in a container.

[0084] 4) Mix sodium silicate and potassium silicate to obtain fresh silicate solution component B, and store it in a container.

[0085] 5) Transport the stored liquid A and liquid B to the construction site. When grouting on site, mix liquid A and liquid B before grouting.

[0086] In the above embodiments, the sodium silicate has a Baume degree of 35-40 Bé and a density of 1.3-1.4 g / cm³. 3 The sodium oxide content is 8%-9%, the silicon dioxide content is 27%-28%, and the modulus is 3.2-3.3; the potassium silicate has a Baume degree of 35-40 Bé and a density of 1.3-1.4 g / cm³. 3 It contains 12%-13% potassium oxide, 26%-27% silicon dioxide, and has a modulus of 3.2-3.3.

[0087] In the above embodiments, h-BN refers to hexagonal boron nitride, and DMSO is dimethyl sulfoxide. Additionally, in step 2), before ultrasonic treatment, a suitable nonionic dispersant can be added to aid in the dispersion of the h-BN modified material, such as alkylphenol polyvinyl ether, sorbitol alkylate, polyoxyethylene alkylphenol ether, etc.

[0088] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A nano-hexagonal boron nitride modified cement-based dual liquid slurry grouting material, characterized in that: The grouting material raw materials include component A and component B. Component B includes water glass. Component A raw materials include the following components by weight: 900-1000 parts of ordinary silicate cement, 900-1000 parts of water, 20-30 parts of retarder, 40-60 parts of micro-expansion agent, and 0.1-1 parts of nano-modified h-BN. Component B includes the following components by volume: 340-400 parts of sodium water glass and 160-200 parts of potassium water glass. The nano-modified h-BN is obtained by ball milling and modification of h-BN. The preparation method of the nano-modified h-BN includes the following steps: mixing h-BN with B2O3 and ball milling, then adding 2Na2CO3•3H2O for secondary ball milling, then adding a mixture of dimethyl sulfoxide and glucose for wet ball milling, and filtering, centrifuging, and drying the ball-milled sample to obtain modified h-BN.

2. The nanohexagonal boron nitride modified cement-based dual-liquid paste grouting material according to claim 1, characterized in that: The thickness of the nano-modified h-BN sheets is 1-10 nm, the planar size is in the range of nanometer to micrometer, and the mass grafting yield of nano-h-BN is 5%-10%.

3. The nanohexagonal boron nitride modified cement-based dual-liquid slurry grouting material according to claim 1, characterized in that: Ball milling was carried out in a zirconia ball mill jar with a ball-to-material ratio of 60:1-75:

1.

4. The nano-hexagonal boron nitride modified cement-based two-component grouting material according to claim 1, characterized in that: The sodium water glass has a Baume degree of 35-40Be, a density of 1.3-1.4 g / cm 3 , a sodium oxide content of 8%-9%, a silicon dioxide content of 27%-28%, and a modulus of 3.2-3.3; and the potassium water glass has a Baume degree of 35-40Be, a density of 1.3-1.4 g / cm 3 , a potassium oxide content of 12%-13%, a silicon dioxide content of 26%-27%, and a modulus of 3.2-3.

3.

5. The nano-hexagonal boron nitride modified cement-based two-component grouting material according to claim 1, characterized in that: The retarder is disodium hydrogen phosphate; the micro-expansion agent is SCEA-II high-performance concrete expansion agent.

6. The preparation method of the nano-hexagonal boron nitride modified cement-based two-component grouting material according to claim 1, characterized in that: Includes the following steps: S1, the modified h-BN powder is dissolved in water and ultrasonically treated to fully disperse it in water to obtain a nano-modified h-BN mixed solution, wherein the nano-modified h-BN content in the nano-modified h-BN mixed solution is 7mg / ml-9.8mg / ml; S2, component A is prepared by mixing cement, water, retarder, micro-expansion agent and h-BN mixed solution; S3, component B is prepared by mixing sodium silicate and potassium silicate.

7. The method of using the nano-hexagonal boron nitride modified cement-based two-component grouting material according to claim 1, characterized in that: When grouting on site, components A and B are mixed and used for grouting repair and penetration grouting of concrete cracks.

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