Preparation method and application of high frost resistance and hydrophobic functionalized foam concrete

Abstract

The application relates to the technical field of lightweight concrete, and particularly discloses a preparation method of high-anti-freezing and hydrophobic functionalized foam concrete and application thereof. The preparation method comprises the following steps: (1) adding a coupling agent and a hydrogel raw material into a dispersion liquid of inorganic nanoparticles, stirring to form a mixed liquid; (2) adding an animal protein foaming agent into water to whip to form a foam-like substance, then adding the mixed liquid into the foam-like substance and continuing to whip, adding a hydrophobic substance and a crosslinking agent capable of crosslinking the hydrogel raw material to form a hydrogel, and continuing to whip to obtain a modified foaming agent; and (3) mixing the modified foaming agent with a cement-based slurry uniformly to obtain the foam concrete. The method can avoid direct contact of the hydrophobic agent with the foam and the cement slurry, thereby reducing the adverse influence of the hydrophobic agent on the foam mechanism and the hydration degree of the foam concrete.

Description

Technical Field

[0001] This invention relates to the field of lightweight concrete technology, specifically to a method for preparing highly frost-resistant and hydrophobic functionalized foamed concrete and its application. Background Technology

[0002] The information disclosed in this background section is intended only to enhance understanding of the overall background of the invention and is not necessarily to be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art.

[0003] Freeze-thaw damage is prevalent in northern my country, posing a significant challenge to the safety of concrete structures in many cold climates due to freeze-thaw cycles. Prolonged freeze-thaw cycles can lead to serious problems such as reduced strength, decreased impermeability, and surface spalling in concrete structures. Furthermore, microcracks generated by freeze-thaw cycles can become channels for moisture transport within the concrete, accelerating the deterioration process and reducing the lifespan of concrete structures in freeze-thaw environments. Foamed concrete, with its advantages of good thermal insulation, seismic resistance, lightweight yet high strength, ease of processing, and convenient construction, is widely used in embankment filling, tunnel void filling, road insulation layers in cold regions, retaining walls, building exterior walls, and foundation pit backfilling.

[0004] However, due to the large number of artificially introduced macroscopic pores in foamed concrete, it easily traps moisture from the outside. When the outside temperature is low, this moisture stored in the pores freezes, generating ice expansion pressure. Once this expansion pressure exceeds the tensile strength of the pore walls, the walls will break down. With each freeze-thaw cycle, the foamed concrete structure eventually fails. Currently, methods to improve the freeze-thaw resistance of foamed concrete mainly include adding admixtures, increasing dry density, and adding additives, but these methods cannot fundamentally prevent water intrusion. While adding hydrophobic agents can solve the above problems, these agents degrade the foam structure in the foamed concrete and hinder cement hydration, leading to a significant deterioration in the mechanical properties of the foamed concrete. Summary of the Invention

[0005] To address the aforementioned problems, this invention discloses a method for preparing highly freeze-thaw resistant, hydrophobic functionalized foamed concrete and its application. This method effectively avoids direct contact between the hydrophobic agent and the foam and cement paste, thereby reducing the adverse effects of the hydrophobic agent on the foam structure and hydration degree of the foamed concrete. Specifically, the technical solution of this invention is as follows.

[0006] First, this invention discloses a method for preparing highly freeze-resistant and hydrophobic functionalized foamed concrete, comprising the following steps: (1) Add coupling agent and hydrogel raw material to the dispersion of inorganic nanoparticles, stir evenly to form a mixture, and set aside.

[0007] (2) Add the foaming agent to water and whip to form a foamy substance. Then add the mixture and continue whipping. After completion, add a hydrophobic substance and a crosslinking agent that can crosslink the hydrogel raw material to form a hydrogel and continue whipping to obtain a modified foaming agent for later use.

[0008] (3) Mix the modified foaming agent with the cement-based slurry evenly to obtain foamed concrete.

[0009] Further, in step (1), the dispersion is formed by mixing inorganic nanoparticles and water at a ratio of 1g:80~120ml. The inorganic nanoparticles include at least one of nano-silica, nano-alumina, etc. Optionally, the particle size of the inorganic nanoparticles is 30~100nm.

[0010] Further, in step (1), the ratio of the inorganic nanoparticles, coupling agent, and hydrogel raw material is 0.5~2 parts by weight: 0.1~0.5 parts by weight: 2~10 parts by weight. Optionally, the coupling agent includes any one of γ-aminopropyltriethoxysilane, 3-glycidylpropoxytrimethoxysilane, and γ-methacryloyloxypropyltrimethoxysilane. The hydrogel raw material includes any one of polyacrylamide and polyethylene glycol.

[0011] Further, in step (2), the ratio of the foaming agent to water is in the range of 1g:30~60ml. Optionally, the foaming agent includes animal protein foaming agents, plant protein foaming agents, and anionic foaming agents.

[0012] Further, in step (2), the mixture is added to the foamy substance in a ratio of 3-15 parts by weight to 0.5-2 parts by weight of the foaming agent and inorganic nanoparticles.

[0013] Further, in step (2), the ratio of the hydrophobic material to the inorganic nanoparticles is 5-10 parts by weight: 0.5-2 parts by weight. Optionally, the hydrophobic material includes at least one of silane hydrophobic agents, siloxane hydrophobic agents, etc.

[0014] Further, in step (2), the ratio of the crosslinking agent to the inorganic nanoparticles is 0.1~1 parts by weight: 0.5~2 parts by weight. Optionally, the crosslinking agent includes at least one of N-hydroxypropaneamide, 1-acetyl-2-thioacrylacetic acid ester, etc.

[0015] Further, in step (3), the ratio of the modified foaming agent dosage to the cement in the cement-based slurry is 8.7~28.5 parts by weight: 60~80 parts by weight.

[0016] Optionally, the cement-based slurry comprises the following components: 60-80 parts by weight of cement, 20-40 parts by weight of admixture, 0.15-2 parts by weight of water-reducing agent, and mixing water, wherein the mixing water is added at a water-cement ratio of 0.25-0.5.

[0017] Optionally, the cement includes at least one of ordinary silicate cement, sulfoaluminate cement, white cement, etc.

[0018] Optionally, the admixture includes at least one of silica fume, fly ash, mineral powder, etc.

[0019] Optionally, the water-reducing agent includes at least one of polycarboxylate water-reducing agents, naphthalene-based water-reducing agents, and lignosulfonate water-reducing agents.

[0020] Secondly, this invention discloses the application of the highly frost-resistant and hydrophobic functionalized foamed concrete in building exterior walls, embankment filling, tunnel void filling, road insulation layers in cold regions, retaining walls, etc.

[0021] Compared with the prior art, the present invention has at least the following beneficial technical effects: This invention first forms a mixture of inorganic nanoparticles, a coupling agent, and hydrogel raw materials. During this process, the inorganic nanoparticles react with the coupling agent to generate amphiphilic inorganic nanoparticles, both of which exist on the foam walls and play a role in stabilizing the foam. Then, this mixture is added to a foam-like substance formed by a foaming agent. The hydrogel raw materials, inorganic nanoparticles, and coupling agent are densely distributed around the foam walls. When a hydrophobic substance and a crosslinking agent are added, the hydrogel raw materials crosslink under the action of the crosslinking agent to form a hydrogel. This hydrogel encapsulates the hydrophobic substance within it. The inorganic nanoparticles distributed within the hydrogel enhance its rigidity, thus helping to maintain the stability of the hydrogel structure in the early stages of concrete mixing, ensuring the morphology of the formed foam structure is stable, and preventing the premature release of the internal hydrophobic substance, which could affect cement hydration. Simultaneously, it avoids direct contact between the hydrophobic substance and the bubble structure formed by the foaming agent, preventing damage to the bubble structure.

[0022] Furthermore, since the hydrogel forms synchronously with the foam and ultimately resides within the foam gaps, the problem of difficulty in foaming caused by the high viscosity of the hydrogel when added directly is solved. When the modified foaming agent obtained by the above method is mixed with cement-based slurry, direct contact between the hydrophobic substance and the cement components in the slurry can be effectively avoided, preventing insufficient contact between the cement components and the mixing water, which could lead to incomplete hydration and deterioration of concrete strength. This is because the release of the hydrophobic substance exerts a hydrophobic effect on the remaining hydrogel shell as the hydrogel releases water, rather than interacting with the cement surface.

[0023] The foamed concrete prepared by the above method not only has good strength but also good hydrophobicity, thus possessing high frost resistance. Furthermore, the inorganic nanoparticles (nano silica, nano alumina) will undergo a secondary hydration reaction with calcium hydroxide, a hydration product of cement in the concrete, to form cementitious products such as hydrated calcium silicate and hydrated calcium aluminate, thereby enhancing the strength of the foamed concrete. Attached Figure Description

[0024] The accompanying drawings, which form part of this specification, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. Hereinafter, embodiments of the invention will be described in detail with reference to the accompanying drawings, wherein: Figure 1 The image shows a sample of the modified foaming agent prepared in Example 1 below.

[0025] Figure 2 This is a macroscopic illustration of the internal hydrophobicity of the foamed concrete specimen prepared in Example 1 below. Detailed Implementation

[0026] The present invention is further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Experimental methods in the following embodiments, unless otherwise specified, are generally performed under conventional conditions or as recommended by the manufacturer.

[0027] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of skill in the art. The reagents and raw materials used in this invention are readily available through conventional means, and unless otherwise specified, they shall be used in accordance with conventional methods or product instructions. Furthermore, any methods and materials similar to or equivalent to those described herein may be applied to the methods of this invention. The preferred embodiments and materials described herein are for illustrative purposes only.

[0028] Example 1 A method for preparing highly freeze-resistant and hydrophobic functionalized foamed concrete includes the following steps: (1) Inorganic nanoparticles (nano silica) with a particle size distribution between 60 and 100 nm were mixed with water at a ratio of 1 g: 100 ml and ultrasonically dispersed for 15 min to obtain a nano silica dispersion. Then, a coupling agent (γ-aminopropyltriethoxysilane) and a hydrogel material (polyethylene glycol) were added to the dispersion, and the ratio of the inorganic nanoparticles, coupling agent, and hydrogel material was 1.5 parts by weight: 0.3 parts by weight: 7 parts by weight. The mixture was then stirred for 20 min to form a mixture for later use.

[0029] (2) Mix the animal protein foaming agent with water at a ratio of 1g:50ml and foam at a speed of 100rad / min. After foaming for 1 minute, add the animal protein foaming agent to the inorganic nanoparticles at a weight ratio of 10 parts by weight: 1.5 parts by weight. Continue foaming for 2 minutes, then add a silane hydrophobic agent (n-octyltriethoxysilane) and a crosslinking agent (N-hydroxypropaneamide), with the weight ratio of the hydrophobic agent, crosslinking agent, and inorganic nanoparticles being 8:1.5:0.7. Then continue foaming for 10 minutes to obtain a modified foaming agent (such as...). Figure 1 (As shown), for later use.

[0030] (3) Take the following raw materials: 70 parts by weight of 42.5 ordinary Portland cement, 30 parts by weight of silica fume admixture, and 1 part by weight of polycarboxylate superplasticizer. Mix the above raw materials and add mixing water at a water-cement ratio of 0.45. Stir for 2 minutes to obtain cement-based slurry.

[0031] (3) The modified foaming agent is mixed with the cement-based slurry at a ratio of 20:70 by weight of cement to the modified foaming agent, and then stirred for 5 minutes to obtain foamed concrete slurry.

[0032] The foamed concrete slurry prepared in this embodiment was poured into a mold and cured for 28 days to obtain foamed concrete specimens. The compressive strength of the foamed concrete was then tested according to GB / T 43487-2023 "Test Methods for Foamed Concrete and Products," and its frost resistance was tested according to JGJ / T 341-2014 "Technical Specification for Application of Foamed Concrete." The test results for each performance indicator are shown in Table 1 below. Additionally, the internal hydrophobicity of the foamed concrete specimens was also tested. Figure 2 This is a macroscopic view of the internal hydrophobicity of the specimen, and its water contact angle is shown in the table below: .

[0033] Example 2 A method for preparing highly freeze-resistant and hydrophobic functionalized foamed concrete includes the following steps: (1) Inorganic nanoparticles (nano silica) with a particle size distribution between 30 and 50 nm were mixed with water at a ratio of 1 g: 120 ml and ultrasonically dispersed for 20 min to obtain a nano silica dispersion. Then, a coupling agent (3-glycidylpropoxytrimethoxysilane) and a hydrogel raw material (polyacrylamide) were added to the dispersion, and the ratio of the inorganic nanoparticles, coupling agent and hydrogel raw material was 2 parts by weight: 0.5 parts by weight: 10 parts by weight. The mixture was then stirred for 15 min to form a mixture for later use.

[0034] (2) Mix the plant protein foaming agent with water at a ratio of 1g:60ml and foam at a speed of 110rad / min. After foaming for 1 minute, add the mixture to the solution at a ratio of 15 parts by weight to 2 parts by weight of the plant protein foaming agent and inorganic nanoparticles. Continue foaming for 2 minutes, then add the siloxane hydrophobic agent (polydimethylsiloxane) and crosslinking agent (N-hydroxypropaneamide), with the weight ratio of the hydrophobic agent, crosslinking agent and inorganic nanoparticles being 10:2:1. Continue foaming for 8 minutes to obtain the modified foaming agent for later use.

[0035] (3) Take the following raw materials: 80 parts by weight of white cement, 40 parts by weight of fly ash admixture, and 2 parts by weight of sodium lignosulfonate water-reducing agent. Mix the above raw materials and add mixing water at a water-cement ratio of 0.5. Stir for 2 minutes to obtain cement-based slurry.

[0036] (3) The modified foaming agent is mixed with the cement-based slurry in a ratio of 28.5:80 by weight of white cement in the cement-based slurry, and then stirred for 10 minutes to obtain foamed concrete slurry.

[0037] The foamed concrete slurry prepared in this embodiment was poured into a mold and cured for 28 days to obtain foamed concrete specimens. The compressive strength, frost resistance, and water contact angle of the foamed concrete specimens were then tested according to the method described in Example 1 above. The results are shown in the table below: .

[0038] Example 3 A method for preparing highly freeze-resistant and hydrophobic functionalized foamed concrete includes the following steps: (1) Inorganic nanoparticles (nano silica and nano alumina, with a mass ratio of 1:1) with a particle size distribution between 50 and 80 nm were mixed with water at a ratio of 1 g: 80 ml and ultrasonically dispersed for 15 min to obtain a nano silica dispersion. Then, a coupling agent (γ-methacryloyloxypropyltrimethoxysilane) and a hydrogel material (polyethylene glycol) were added to the dispersion, and the ratio of the inorganic nanoparticles, coupling agent, and hydrogel material was 0.5 parts by weight: 0.1 parts by weight: 2 parts by weight. The mixture was then stirred for 10 min to form a mixture for later use.

[0039] (2) The anionic foaming agent and water were mixed at a ratio of 1g:30ml and foamed at a speed of 120rad / min. After foaming for 1 minute, the mixture was added at a ratio of 3 parts by weight of the anionic foaming agent to 0.5 parts by weight of the inorganic nanoparticles. After foaming for another 2 minutes, a silane hydrophobic agent (isobutyltriethoxysilane) and a crosslinking agent (1-acetyl-2-thioacrylacetic acid ester) were added, with the weight ratio of the hydrophobic agent, crosslinking agent and inorganic nanoparticles being 5:0.5:0.1. Then, the mixture was foamed for another 10 minutes to obtain the modified foaming agent for later use.

[0040] (3) Take the following raw materials: 60 parts by weight of sulfoaluminate cement, 20 parts by weight of mineral powder admixture, and 0.15 parts by weight of naphthalene-based water-reducing agent. Mix the above raw materials and add mixing water at a water-cement ratio of 0.25. Stir for 2 minutes to obtain cement-based slurry.

[0041] (3) The modified foaming agent is mixed with the cement-based slurry at a ratio of 8.7:60 by weight of cement in the cement-based slurry, and then stirred for 5 minutes to obtain foamed concrete slurry.

[0042] The foamed concrete slurry prepared in this embodiment was poured into a mold and cured for 28 days to obtain foamed concrete specimens. The compressive strength, frost resistance, and water contact angle of the foamed concrete specimens were then tested according to the method described in Example 1 above. The results are shown in the table below: .

[0043] Example 4 A method for preparing highly frost-resistant and hydrophobic functionalized foamed concrete is described, similar to Example 1 above, except that the inorganic nanoparticles used in Example 1 are removed. The foamed concrete slurry prepared in this example is poured into a mold and cured for 28 days to obtain foamed concrete specimens. The compressive strength, frost resistance, and water contact angle of the foamed concrete specimens are then tested according to the method described in Example 1 above. The results are shown in the table below. .

[0044] Example 5 A method for preparing highly freeze-resistant and hydrophobic functionalized foamed concrete includes the following steps: (1) Inorganic nanoparticles (nano-calcium carbonate) with a particle size distribution between 60 and 100 nm were mixed with water at a ratio of 1 g: 100 ml and ultrasonically dispersed for 15 min to obtain a nano-calcium carbonate dispersion. Then, a coupling agent (γ-aminopropyltriethoxysilane) and a hydrogel material (polyethylene glycol) were added to the dispersion, and the ratio of nano-calcium carbonate, coupling agent, and hydrogel material was 1.5 parts by weight: 0.3 parts by weight: 7 parts by weight. The mixture was then stirred for 20 min to form a mixture for later use.

[0045] (2) Mix the animal protein foaming agent with water at a ratio of 1g:50ml and foam at a speed of 100rad / min. After foaming for 1 minute, add the animal protein foaming agent to the nano-calcium carbonate at a ratio of 10 parts by weight: 1.7 parts by weight. Continue foaming for 2 minutes, then add a silane hydrophobic agent (n-octyltriethoxysilane) and a crosslinking agent (N-hydroxypropaneamide), with the weight ratio of the hydrophobic agent, crosslinking agent and inorganic nanoparticles being 8:1.5:0.7. Then continue foaming for 10 minutes to obtain the modified foaming agent for later use.

[0046] (3) Take the following raw materials: 70 parts by weight of 42.5 ordinary Portland cement, 30 parts by weight of silica fume admixture, and 1 part by weight of polycarboxylate superplasticizer. Mix the above raw materials and add mixing water at a water-cement ratio of 0.45. Stir for 2 minutes to obtain cement-based slurry.

[0047] (3) The modified foaming agent is mixed with the cement-based slurry at a ratio of 20:70 by weight of cement to the modified foaming agent, and then stirred for 5 minutes to obtain foamed concrete slurry.

[0048] The foamed concrete slurry prepared in this embodiment was poured into a mold and cured for 28 days to obtain foamed concrete specimens. The compressive strength, frost resistance, and water contact angle of the foamed concrete specimens were then tested according to the method described in Example 1 above. The results are shown in the table below: .

[0049] Example 6 A method for preparing highly freeze-resistant and hydrophobic functionalized foamed concrete is the same as in Example 2 above, except that the mixture in this example is prepared using the following steps: Inorganic nanoparticles (nano-silica) with a particle size distribution between 30 and 50 nm are mixed with water at a ratio of 1 g: 120 ml and then ultrasonically dispersed for 20 min to obtain a nano-silica dispersion. Then, hydrogel raw material (polyacrylamide) is added to the dispersion, with the ratio of inorganic nanoparticles to hydrogel raw material being 2 parts by weight: 10 parts by weight. The mixture is then stirred for 15 min to form a mixture.

[0050] The foamed concrete slurry prepared in this embodiment was poured into a mold and cured for 28 days to obtain foamed concrete specimens. The compressive strength, frost resistance, and water contact angle of the foamed concrete specimens were then tested according to the method described in Example 1 above. The results are shown in the table below: .

[0051] Example 7 A method for preparing highly freeze-resistant and hydrophobic functionalized foamed concrete is the same as in Example 3 above, except that the mixture in this example is prepared using the following steps: Inorganic nanoparticles (nano silica and nano alumina, with a mass ratio of 1:1) with a particle size distribution between 50 and 80 nm are mixed with water at a ratio of 1 g: 80 ml and then ultrasonically dispersed for 15 min to obtain a nano silica dispersion. Then, a coupling agent (γ-methacryloyloxypropyltrimethoxysilane) is added to the dispersion, and the ratio of the inorganic nanoparticles to the coupling agent is 0.5 parts by weight: 0.1 parts by weight. The mixture is then stirred for 10 min to form a final mixture for later use.

[0052] The foamed concrete slurry prepared in this embodiment was poured into a mold and cured for 28 days to obtain foamed concrete specimens. The compressive strength, frost resistance, and water contact angle of the foamed concrete specimens were then tested according to the method described in Example 1 above. The results are shown in the table below: .

[0053] Example 8 A method for preparing highly freeze-resistant and hydrophobic functionalized foamed concrete is the same as in Example 2 above, except that the modified foaming agent in this example is prepared using the following steps: A plant protein foaming agent is mixed with water at a ratio of 1g:60ml, and then foamed at a speed of 110 rad / min. After foaming for 1 minute, the plant protein foaming agent is mixed with inorganic nanoparticles (nano silica), a coupling agent (3-glycidylpropoxytrimethoxysilane), and a hydrogel raw material (polyacrylamide) in a ratio of 15 parts by weight: 2 parts by weight: 0.5 parts by weight: 10 parts by weight. Foaming continues for another 2 minutes. Then, a silane-based hydrophobic agent (n-octyltriethoxysilane) and a crosslinking agent (N-hydroxypropaneamide) are added, with the weight ratio of the hydrophobic agent, crosslinking agent, and inorganic nanoparticles being 10:2:1. Foaming continues for another 8 minutes to obtain the modified foaming agent, which is then ready for use.

[0054] The foamed concrete slurry prepared in this embodiment was poured into a mold and cured for 28 days to obtain foamed concrete specimens. The compressive strength, frost resistance, and water contact angle of the foamed concrete specimens were then tested according to the method described in Example 1 above. The results are shown in the table below: .

[0055] Example 9 A method for preparing highly freeze-resistant and hydrophobic functionalized foamed concrete is the same as in Example 3 above, except that the modified foaming agent in this example is prepared using the following steps: Anionic foaming agent and water are mixed at a ratio of 1g:30ml, and foamed at a speed of 120rad / min. After foaming for 1 minute, the anionic foaming agent is mixed with inorganic nanoparticles (nano silica), coupling agent (γ-methacryloyloxypropyltrimethoxysilane), and hydrogel raw material (polyethylene glycol) in a ratio of 3 parts by weight: 0.5 parts by weight: 0.1 parts by weight: 2 parts by weight. Foaming continues for another 2 minutes. Then, isobutyltriethoxysilane and a crosslinking agent (1-acetyl-2-thioacrylacetic acid ester) are added, with the weight ratio of the hydrophobic agent, crosslinking agent, and inorganic nanoparticles being 5:0.5:0.1. Foaming continues for another 10 minutes to obtain the modified foaming agent, which is then ready for use.

[0056] The foamed concrete slurry prepared in this embodiment was poured into a mold and cured for 28 days to obtain foamed concrete specimens. The compressive strength, frost resistance, and water contact angle of the foamed concrete specimens were then tested according to the method described in Example 1 above. The results are shown in the table below: .

[0057] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing highly freeze-thaw resistant and hydrophobic functionalized foamed concrete, characterized in that, Includes the following steps: (1) Add coupling agent and hydrogel raw material to the dispersion of inorganic nanoparticles, stir evenly to form a mixture, and set aside; the ratio of inorganic nanoparticles, coupling agent and hydrogel raw material is 0.5~2 parts by weight: 0.1~0.5 parts by weight: 2~10 parts by weight; (2) Add the foaming agent to water and beat it to form a foamy substance. Then add the mixture and continue beating. After completion, add the hydrophobic substance and the crosslinking agent that can crosslink the hydrogel raw material to form a hydrogel and continue beating to obtain the modified foaming agent for later use. The ratio of the hydrophobic substance to the inorganic nanoparticles is 5-10 parts by weight: 0.5-2 parts by weight. (3) Mix the modified foaming agent with the cement-based slurry evenly to obtain foamed concrete.

2. The method for preparing highly frost-resistant and hydrophobic functionalized foamed concrete according to claim 1, characterized in that, In step (1), the dispersion is formed by mixing inorganic nanoparticles and water in a ratio of 1g:80~120ml.

3. The method for preparing highly frost-resistant and hydrophobic functionalized foamed concrete according to claim 1, characterized in that, In step (1), the inorganic nanoparticles include at least one of nano-silica and nano-alumina.

4. The method for preparing highly frost-resistant and hydrophobic functionalized foamed concrete according to claim 1, characterized in that, In step (1), the coupling agent includes any one of γ-aminopropyltriethoxysilane, 3-glycidylpropoxytrimethoxysilane, and γ-methacryloyloxypropyltrimethoxysilane.

5. The method for preparing highly frost-resistant and hydrophobic functionalized foamed concrete according to claim 1, characterized in that, In step (2), the ratio of the foaming agent to water is 1g: 30~60ml.

6. The method for preparing highly frost-resistant and hydrophobic functionalized foamed concrete according to claim 1, characterized in that, The foaming agent includes animal protein foaming agents, plant protein foaming agents, and anionic foaming agents.

7. The method for preparing highly frost-resistant and hydrophobic functionalized foamed concrete according to claim 1, characterized in that, In step (2), the mixture is added to the foamy substance in a ratio of 3-15 parts by weight to 0.5-2 parts by weight of the foaming agent and inorganic nanoparticles.

8. The method for preparing highly frost-resistant and hydrophobic functionalized foamed concrete according to claim 1, characterized in that, In step (2), the hydrophobic substance includes at least one of silane hydrophobic agents and siloxane hydrophobic agents.

9. The method for preparing highly frost-resistant and hydrophobic functionalized foamed concrete according to claim 1, characterized in that, In step (2), the ratio of the crosslinking agent to the inorganic nanoparticles is 0.1~1 parts by weight: 0.5~2 parts by weight.

10. The method for preparing highly frost-resistant and hydrophobic functionalized foamed concrete according to claim 1, characterized in that, The crosslinking agent includes at least one of N-hydroxypropaneamide and 1-acetyl-2-thioacrylacetic acid ester.

11. The method for preparing highly frost-resistant and hydrophobic functionalized foamed concrete according to claim 1, characterized in that, The hydrogel raw material includes any one of polyacrylamide and polyethylene glycol.

12. The method for preparing highly frost-resistant and hydrophobic functionalized foamed concrete according to any one of claims 1-11, characterized in that, In step (3), the ratio of the modified foaming agent dosage to the cement in the cement-based slurry is 8.7~28.5 parts by weight: 60~80 parts by weight.

13. The method for preparing highly frost-resistant and hydrophobic functionalized foamed concrete according to claim 1, characterized in that, The cement-based slurry comprises the following components: 60-80 parts by weight of cement, 20-40 parts by weight of admixture, 0.15-2 parts by weight of water-reducing agent, and mixing water, wherein the mixing water is added at a water-cement ratio of 0.25-0.

5.

14. The method for preparing highly frost-resistant and hydrophobic functionalized foamed concrete according to claim 13, characterized in that, The cement includes at least one of ordinary silicate cement, sulfoaluminate cement, and white cement.

15. The method for preparing highly frost-resistant and hydrophobic functionalized foamed concrete according to claim 13, characterized in that, The admixture includes at least one of silica fume, fly ash, and mineral powder.

16. The method for preparing highly frost-resistant and hydrophobic functionalized foamed concrete according to claim 13, characterized in that, The water-reducing agent includes at least one of polycarboxylate water-reducing agents, naphthalene-based water-reducing agents, and lignosulfonate water-reducing agents.

17. The application of the high freeze-resistant and hydrophobic functionalized foamed concrete obtained by the preparation method according to any one of claims 1-16 in building exterior walls, embankment filling, tunnel void filling, road insulation layer or retaining wall in cold regions.

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