Structural compactness self-waterproofing material for underground engineering concrete and application thereof

Abstract

The application relates to the technical field of building materials, and discloses a structural compactness self-waterproof material for underground engineering concrete and application thereof, raw materials of which include, in terms of weight parts, 10-14 parts of konjak dry gel, 20-25 parts of modified expansive agent, 10-15 parts of fluorosilicate, 2-5 parts of aluminum sulfate, 10-12 parts of porous powder, 7-9 parts of dispersant and 8-10 parts of water reducing agent. The structural compactness self-waterproof material can realize good self-waterproof function and structural compactness of the concrete, the konjak dry gel and the modified expansive agent can make the concrete slurry moderately expand in the plastic and hardening stages, can compensate early shrinkage and later self-generated volume change, and can improve the volume stability; the modified expansive agent can also serve as a reinforcing phase, effectively plays a skeleton support and reinforcing role, improves the compressive strength of the concrete, and further improves the waterproofness of the concrete.

Description

Technical Field

[0001] This invention relates to the field of building materials technology, and in particular to a structurally dense self-waterproofing material for underground engineering concrete and its application. Background Technology

[0002] Waterproofing of basements and other underground building projects is characterized by high quality requirements, poor construction conditions, a wide variety of materials, difficulty in protecting finished products, and many weak points. Therefore, it is generally carried out by combining structural self-waterproofing and additional waterproofing. The reinforced concrete structure itself has self-waterproofing function, and flexible waterproofing materials are added for external waterproofing.

[0003] Self-waterproofing of concrete structures is a waterproofing method that utilizes the inherent density and crack resistance of the structural material to achieve waterproofing. It integrates structural load-bearing and waterproofing into a single process, relying on the concrete's wall thickness, water repellency, and density to achieve waterproofing. Self-waterproofing of concrete structures is a crucial line of defense in engineering waterproofing, characterized by low cost, simple procedures, convenient construction, and abundant and widely available materials, making it the preferred method.

[0004] During the project implementation, the additional waterproofing layer was laid using the loose-lay method with SBS modified bitumen waterproofing membrane. This resulted in numerous joints, and if any damage or leakage occurred during construction, groundwater could easily seep into the outer waterproofing layer under pressure, rendering it ineffective. Furthermore, due to the increased overall load on the building, and with deformation and settlement of the foundation and subgrade, the outer waterproofing layer would be subjected to tens of tons of pressure per square meter, making the flexible materials within it susceptible to damage.

[0005] Therefore, while the waterproofing effect of an additional external waterproofing layer in underground structures exists in theory, it is not fully realized in practice. In reality, the self-waterproofing function of reinforced concrete must be relied upon more heavily. The key to ensuring the waterproofing of underground structures is to guarantee the density and self-waterproofing function of the concrete structure. Summary of the Invention

[0006] In order to solve the above-mentioned technical problems, the purpose of this invention is to provide a structurally dense self-waterproofing material for underground engineering concrete and its application. Through the optimization of each component, a better synergistic effect can be achieved, which can realize the good self-waterproofing function and structural density of concrete.

[0007] The objective of this invention is achieved through the following technical solutions.

[0008] In a first aspect, the present invention provides a structurally dense self-waterproofing material for underground engineering concrete, the raw materials of which, by weight, include: 10-14 parts konjac dry gel, 20-25 parts modified expansion agent, 10-15 parts fluorosilicate, 2-5 parts aluminum sulfate, 10-12 parts porous powder, 7-9 parts dispersant and 8-10 parts water-reducing agent.

[0009] This invention achieves a good synergistic effect through the optimal selection of its components. When applied to concrete, this material provides excellent self-waterproofing and structural density. Fluorosilicate, acting as a coagulant and corrosion inhibitor, effectively extends the setting time of concrete, resulting in good impermeability and durability. The alkali-silicic acid reaction is a crucial factor affecting concrete durability; aluminum ions in aluminum sulfate inhibit the alkali-silicic acid reaction and effectively prevent the expansion that has already occurred. The porous powder, with its porosity, large specific surface area, and adsorption capacity, enhances the compatibility between the components and concrete. It can also work in conjunction with dispersants to quickly penetrate the concrete, filling capillary pores and increasing density. The water-reducing agent reduces the amount of mixing water and can be directionally adsorbed onto the surface of cement particles, dispersing them and releasing some of the trapped water, effectively increasing the fluidity of the concrete during mixing.

[0010] Konjac dry gel can absorb water and swell. As a dual-effect expansion source, it, along with modified expansion agents, allows the paste to expand moderately during both the plastic and hardening stages. This compensates for the early shrinkage of cement paste, preventing early shrinkage, and also mitigates later volume changes, thus improving its volume stability. Konjac dry gel also possesses water-retention properties, simultaneously improving the water retention of concrete, filling cracks, reducing capillary pores, improving internal hydrophobicity, and enhancing impermeability.

[0011] Preferably, the preparation method of the modified expanding agent includes the following steps:

[0012] (1) Add polyacrylonitrile to acetone, then add silicon carbide whiskers for dispersion, and then perform wet ball milling.

[0013] (2) After ball milling, the product is dried and dispersed in an aqueous solution of potassium hydroxide for hydrolysis.

[0014] (3) Next, add triethanolamine and stir, then add sodium methylsilicate and heat to react;

[0015] (4) After the reaction is complete, cool the mixture, add methanol and adjust the pH to neutral, and then perform vacuum distillation to obtain the modified swelling agent.

[0016] The modified expansive agent in this invention is obtained by coating polyacrylonitrile polymer chains onto the surface of silicon carbide whiskers, followed by grafting sodium methylsilicate with triethanolamine. The silanol groups in sodium methylsilicate can react with the silanol groups in concrete materials to dehydrate and crosslink, achieving a reverse capillary effect and simultaneously generating expansion, increasing the density of the concrete structure. The silicon carbide whiskers can act as a reinforcing phase in the concrete, and with the expansion effect of the surface-loaded material, they can better fill cracks, effectively playing their skeletal support and reinforcement role, and improving the compressive strength of the concrete. Furthermore, the hydrolysis of polyacrylonitrile generates carboxyl groups, which not only facilitate the grafting of triethanolamine and sodium methylsilicate, but also allow the carboxyl groups on the extended long molecular chains to adsorb onto the surface of cement particles, improving compatibility and dispersibility, and promoting rapid penetration into the concrete interior. Together with sodium methylsilicate, a stable waterproof membrane is formed inside the concrete after solidification. Sodium methylsilicate also has extremely strong water resistance and reinforcing properties; therefore, this modified expansive agent can effectively improve the density and waterproofness of the concrete structure.

[0017] Preferably, in step (1), the mass-to-volume ratio of polyacrylonitrile, silicon carbide whiskers and acetone is 10-20g: 0.5-0.7g: 50mL; the diameter of the silicon carbide whiskers is 0.1-2μm and the length is 10-30μm; the wet ball milling time is 30-60min and the ball-to-material ratio is 1:3-4.

[0018] The size parameters of silicon carbide whiskers affect the surface coating properties of polyacrylonitrile.

[0019] Preferably, in step (2), the mass ratio of the obtained product to potassium hydroxide is 1:0.5 to 0.8; the hydrolysis treatment is performed by heating to 100 to 105°C for 6 to 8 hours.

[0020] Preferably, in step (3), the mass ratio of polyacrylonitrile, triethanolamine and sodium methylsilicate is 10-20:1:2-3; the heating reaction is carried out by stirring at 35-40°C for 1-2 hours.

[0021] If the grafting ratio of sodium methylsilicate is too high, it will cause an imbalance in its proportion on the polyacrylonitrile molecular chain. Sodium methylsilicate will form a waterproof film too early and will not be able to work with the hydrophilic long molecular chain to achieve a better internal penetration effect in concrete, affecting the penetration depth, compatibility and early dispersion of cement particles.

[0022] Preferably, the preparation method of the konjac dried gel includes the following steps: mixing konjac powder and water at a mass ratio of 1 to 2:100, heating to 95 to 100°C and stirring for 5 to 6 hours, then adding a sodium hydroxide aqueous solution with a mass concentration of 25 to 30% and stirring, so that the mass ratio of sodium hydroxide to konjac powder is 0.5 to 0.6:1, then dehydrating and drying in a ventilated environment, freeze-drying, and then pulverizing to obtain konjac dried gel.

[0023] Konjac flour contains abundant konjac glucomannan, which contains a large number of active hydroxyl groups. Under alkaline conditions, it will lose acetyl groups, intensify intermolecular entanglement, and form konjac gel with high water absorption.

[0024] Preferably, the fluorosilicate is sodium fluorosilicate.

[0025] Preferably, the porous powder is diatomaceous earth, hydrotalcite powder, or zeolite powder.

[0026] Preferably, the dispersant is sodium gluconate, oxidized polyethylene wax, sodium pyrophosphate, or sodium dodecylbenzenesulfonate.

[0027] Preferably, the water-reducing agent is a polycarboxylate water-reducing agent, a lignin sulfonate water-reducing agent, an aminosulfonate water-reducing agent, or a naphthalene sulfonate water-reducing agent.

[0028] Secondly, the present invention also provides an application of the above-mentioned structurally dense self-waterproofing material in concrete structures, wherein the structurally dense self-waterproofing material is added to concrete at 2-3% of the weight of cement to obtain a concrete structure.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] (1) Konjac dry gel and modified expansion agent are used as dual expansion sources, which can make the concrete paste expand moderately in both the plastic and hardening stages, which can compensate for early shrinkage and the volume change generated by itself in the later stage, thus improving its volume stability.

[0031] (2) Modified expansive agents have good compatibility and dispersibility in concrete materials. They can also be used as reinforcing phases to effectively play their role in skeleton support and reinforcement, improve the compressive strength of concrete, and form an effective waterproof membrane to enhance the waterproofness of concrete.

[0032] (3) Fluorosilicates serve as coagulants and corrosion inhibitors for concrete, giving it good impermeability and durability. Aluminum ions in aluminum sulfate can inhibit the occurrence of alkali-silicic acid reaction and improve the durability of concrete. Porous powders have porosity, large specific surface area and adsorption properties, which can improve the compatibility between components and concrete. They can also work with dispersants to quickly penetrate into the interior of concrete and fill the capillary pores of concrete to increase the density of concrete. Water-reducing agents can reduce the amount of mixing water and effectively increase the fluidity of concrete during mixing. Detailed Implementation

[0033] The technical solution of the present invention is illustrated below with specific embodiments, but the scope of protection of the present invention is not limited thereto:

[0034] General Implementation Examples

[0035] 1. Structurally dense self-waterproofing material

[0036] By weight, the raw materials include: 10-14 parts konjac dried gel, 20-25 parts modified expanding agent, 10-15 parts fluorosilicate (sodium fluorosilicate), 2-5 parts aluminum sulfate, 10-12 parts porous powder, 7-9 parts dispersant, and 8-10 parts water-reducing agent. The porous powder is diatomaceous earth, hydrotalcite powder, or zeolite powder. The dispersant is sodium gluconate, oxidized polyethylene wax, sodium pyrophosphate, or sodium dodecylbenzene sulfonate. The water-reducing agent is polycarboxylate water-reducing agent, lignin sulfonate water-reducing agent, aminosulfonate water-reducing agent, or naphthalene sulfonate water-reducing agent.

[0037] The preparation method of konjac dried gel includes the following steps:

[0038] Konjac powder and water are mixed at a mass ratio of 1 to 2:100, heated to 95 to 100°C and stirred for 5 to 6 hours. Then, a sodium hydroxide aqueous solution with a mass concentration of 25 to 30% is added and stirred to make the mass ratio of sodium hydroxide to konjac powder 0.5 to 0.6:1. After dehydration and drying in a ventilated environment, the mixture is freeze-dried and then pulverized to obtain konjac dry gel.

[0039] The preparation method of the modified expanding agent includes the following steps:

[0040] (1) Add polyacrylonitrile to acetone, then add silicon carbide whiskers (0.1-2 μm in diameter and 10-30 μm in length) for dispersion, wherein the mass-volume ratio of polyacrylonitrile, silicon carbide whiskers and acetone is 10-20 g: 0.5-0.7 g: 50 mL; then perform wet ball milling for 30-60 min, with a ball-to-material ratio of 1:3-4;

[0041] (2) After ball milling, the product is dried and dispersed in an aqueous solution of potassium hydroxide. The mass ratio of the product to potassium hydroxide is 1:0.5 to 0.8. Then, hydrolysis is carried out and the product is heated to 100 to 105°C for 6 to 8 hours.

[0042] (3) Next, add triethanolamine and stir, then add sodium methylsilicate. The mass ratio of polyacrylonitrile, triethanolamine and sodium methylsilicate is 10-20:1:2-3. Then, heat the reaction and stir at 35-40°C for 1-2 hours.

[0043] (4) After the reaction is complete, cool the mixture, add methanol and adjust the pH to neutral, and then perform vacuum distillation to obtain the modified swelling agent.

[0044] 2. Application

[0045] The above-mentioned structurally dense self-waterproofing material is used in the concrete structure of underground engineering. Specifically, the structurally dense self-waterproofing material is added to the concrete at 2-3% of the cement weight to obtain the concrete structure.

[0046] Example 1

[0047] By weight, the raw materials of the structurally dense self-waterproofing material include: 13 parts konjac dry gel, 24 parts modified expansion agent, 12 parts sodium fluorosilicate, 5 parts aluminum sulfate, 12 parts diatomaceous earth, 7 parts sodium dodecylbenzene sulfonate and 9 parts polycarboxylate superplasticizer.

[0048] The preparation method of konjac dried gel includes the following steps:

[0049] Konjac powder and water were mixed at a mass ratio of 1.6:100, heated to 95°C and stirred for 6 hours. Then, a 25% sodium hydroxide aqueous solution was added and stirred to make the mass ratio of sodium hydroxide to konjac powder 0.55:1. After dehydration and drying in a ventilated environment, the mixture was freeze-dried and then pulverized to obtain konjac dry gel.

[0050] The preparation method of the modified expanding agent includes the following steps:

[0051] (1) Add polyacrylonitrile to acetone, then add silicon carbide whiskers (diameter 0.1-2 μm, length 10-30 μm) for dispersion, wherein the mass-volume ratio of polyacrylonitrile, silicon carbide whiskers and acetone is 17 g: 0.6 g: 50 mL; then perform wet ball milling for 50 min, with a ball-to-material ratio of 1:3.

[0052] (2) After ball milling, the product is dried and dispersed in an aqueous solution of potassium hydroxide, so that the mass ratio of the product to potassium hydroxide is 1:0.7. Then, hydrolysis is carried out and the product is heated to 103°C for 7 hours.

[0053] (3) Next, triethanolamine was added and stirred, and then sodium methylsilicate was added. The mass ratio of polyacrylonitrile, triethanolamine and sodium methylsilicate was 17:1:2.5. Then the reaction was heated and stirred at 40°C for 1.5 h.

[0054] (4) After the reaction is complete, cool the mixture, add methanol and adjust the pH to neutral, and then perform vacuum distillation to obtain the modified swelling agent.

[0055] Example 2

[0056] By weight, the raw materials of the structurally dense self-waterproofing material include: 14 parts konjac dry gel, 21 parts modified expansion agent, 13 parts sodium fluorosilicate, 4 parts aluminum sulfate, 12 parts diatomaceous earth, 9 parts sodium dodecylbenzene sulfonate and 8 parts polycarboxylate superplasticizer.

[0057] The preparation method of konjac dried gel includes the following steps:

[0058] Konjac powder and water were mixed at a mass ratio of 1.6:100, heated to 95°C and stirred for 6 hours. Then, a 25% sodium hydroxide aqueous solution was added and stirred to make the mass ratio of sodium hydroxide to konjac powder 0.55:1. After dehydration and drying in a ventilated environment, the mixture was freeze-dried and then pulverized to obtain konjac dry gel.

[0059] The preparation method of the modified expanding agent includes the following steps:

[0060] (1) Add polyacrylonitrile to acetone, then add silicon carbide whiskers (diameter 0.1-2 μm, length 10-30 μm) for dispersion, wherein the mass-volume ratio of polyacrylonitrile, silicon carbide whiskers and acetone is 16 g: 0.6 g: 50 mL; then perform wet ball milling for 50 min, with a ball-to-material ratio of 1:3.

[0061] (2) After ball milling, the product is dried and dispersed in an aqueous solution of potassium hydroxide, so that the mass ratio of the product to potassium hydroxide is 1:0.8. Then, hydrolysis is carried out and the product is heated to 103°C for 8 hours.

[0062] (3) Next, add triethanolamine and stir, then add sodium methylsilicate, wherein the mass ratio of polyacrylonitrile, triethanolamine and sodium methylsilicate is 16:1:3. Then, heat the reaction and stir at 40°C for 1.5 h.

[0063] (4) After the reaction is complete, cool the mixture, add methanol and adjust the pH to neutral, and then perform vacuum distillation to obtain the modified swelling agent.

[0064] Example 3

[0065] By weight, the raw materials of the structurally dense self-waterproofing material include: 13 parts konjac dry gel, 24 parts modified expansion agent, 12 parts sodium fluorosilicate, 5 parts aluminum sulfate, 12 parts diatomaceous earth, 7 parts sodium dodecylbenzene sulfonate and 9 parts polycarboxylate superplasticizer.

[0066] The preparation method of konjac dried gel includes the following steps:

[0067] Konjac powder and water were mixed at a mass ratio of 1.6:100, heated to 95°C and stirred for 6 hours. Then, a 25% sodium hydroxide aqueous solution was added and stirred to make the mass ratio of sodium hydroxide to konjac powder 0.55:1. After dehydration and drying in a ventilated environment, the mixture was freeze-dried and then pulverized to obtain konjac dry gel.

[0068] The preparation method of the modified expanding agent includes the following steps:

[0069] (1) Add polyacrylonitrile to acetone, then add silicon carbide whiskers (diameter 0.1-2 μm, length 10-30 μm) for dispersion, wherein the mass-volume ratio of polyacrylonitrile, silicon carbide whiskers and acetone is 20 g: 0.7 g: 50 mL; then perform wet ball milling for 60 min, with a ball-to-material ratio of 1:4.

[0070] (2) After ball milling, the product is dried and dispersed in an aqueous solution of potassium hydroxide, so that the mass ratio of the product to potassium hydroxide is 1:0.8. Then, hydrolysis is carried out and the product is heated to 103°C for 8 hours.

[0071] (3) Next, add triethanolamine and stir, then add sodium methylsilicate, wherein the mass ratio of polyacrylonitrile, triethanolamine and sodium methylsilicate is 20:1:2. Then, heat the reaction and stir at 35°C for 2 hours.

[0072] (4) After the reaction is complete, cool the mixture, add methanol and adjust the pH to neutral, and then perform vacuum distillation to obtain the modified swelling agent.

[0073] Comparative Example 1

[0074] The difference from Example 1 is that no modified expanding agent is added.

[0075] By weight, the raw materials of the structurally dense self-waterproofing material include: 13 parts konjac dry gel, 12 parts sodium fluorosilicate, 5 parts aluminum sulfate, 12 parts diatomaceous earth, 7 parts sodium dodecylbenzene sulfonate and 9 parts polycarboxylate superplasticizer.

[0076] Comparative Example 2

[0077] The difference from Example 1 is that the modified expanding agent is not hydrolyzed in its preparation method.

[0078] By weight, the raw materials of the structurally dense self-waterproofing material include: 13 parts konjac dry gel, 24 parts modified expansion agent, 12 parts sodium fluorosilicate, 5 parts aluminum sulfate, 12 parts diatomaceous earth, 7 parts sodium dodecylbenzene sulfonate and 9 parts polycarboxylate superplasticizer.

[0079] The preparation method of konjac dried gel includes the following steps:

[0080] Konjac powder and water were mixed at a mass ratio of 1.6:100, heated to 95°C and stirred for 6 hours. Then, a 25% sodium hydroxide aqueous solution was added and stirred to make the mass ratio of sodium hydroxide to konjac powder 0.55:1. After dehydration and drying in a ventilated environment, the mixture was freeze-dried and then pulverized to obtain konjac dry gel.

[0081] The preparation method of the modified expanding agent includes the following steps:

[0082] (1) Add polyacrylonitrile to acetone, then add silicon carbide whiskers (diameter 0.1-2 μm, length 10-30 μm) for dispersion, wherein the mass-volume ratio of polyacrylonitrile, silicon carbide whiskers and acetone is 17 g: 0.6 g: 50 mL; then perform wet ball milling for 50 min, with a ball-to-material ratio of 1:3.

[0083] (2) After ball milling, the product is dried, dispersed in water, triethanolamine is added and stirred, and then sodium methylsilicate is added. The mass ratio of polyacrylonitrile, triethanolamine and sodium methylsilicate is 17:1:2.5. Then the product is heated and stirred at 40°C for 1.5 h.

[0084] (3) After the reaction is complete, cool the mixture, add methanol and adjust the pH to neutral, and then perform vacuum distillation to obtain the modified swelling agent.

[0085] Comparative Example 3

[0086] The difference from Example 1 is that the hydrolysis treatment is incomplete in the preparation method of the modified expanding agent.

[0087] By weight, the raw materials of the structurally dense self-waterproofing material include: 13 parts konjac dry gel, 24 parts modified expansion agent, 12 parts sodium fluorosilicate, 5 parts aluminum sulfate, 12 parts diatomaceous earth, 7 parts sodium dodecylbenzene sulfonate and 9 parts polycarboxylate superplasticizer.

[0088] The preparation method of konjac dried gel includes the following steps:

[0089] Konjac powder and water were mixed at a mass ratio of 1.6:100, heated to 95°C and stirred for 6 hours. Then, a 25% sodium hydroxide aqueous solution was added and stirred to make the mass ratio of sodium hydroxide to konjac powder 0.55:1. After dehydration and drying in a ventilated environment, the mixture was freeze-dried and then pulverized to obtain konjac dry gel.

[0090] The preparation method of the modified expanding agent includes the following steps:

[0091] (1) Add polyacrylonitrile to acetone, then add silicon carbide whiskers (diameter 0.1-2 μm, length 10-30 μm) for dispersion, wherein the mass-volume ratio of polyacrylonitrile, silicon carbide whiskers and acetone is 17 g: 0.6 g: 50 mL; then perform wet ball milling for 50 min, with a ball-to-material ratio of 1:3.

[0092] (2) After ball milling, the product is dried and dispersed in an aqueous solution of potassium hydroxide, so that the mass ratio of the product to potassium hydroxide is 1:0.7. Then, hydrolysis is carried out and the product is heated to 90°C for 3 hours.

[0093] (3) Next, triethanolamine was added and stirred, and then sodium methylsilicate was added. The mass ratio of polyacrylonitrile, triethanolamine and sodium methylsilicate was 17:1:2.5. Then the reaction was heated and stirred at 40°C for 1.5 h.

[0094] (4) After the reaction is complete, cool the mixture, add methanol and adjust the pH to neutral, and then perform vacuum distillation to obtain the modified swelling agent.

[0095] Comparative Example 4

[0096] The difference from Example 1 is that excessive amounts of sodium methylsilicate were added in the preparation method of the modified expanding agent.

[0097] By weight, the raw materials of the structurally dense self-waterproofing material include: 13 parts konjac dry gel, 24 parts modified expansion agent, 12 parts sodium fluorosilicate, 5 parts aluminum sulfate, 12 parts diatomaceous earth, 7 parts sodium dodecylbenzene sulfonate and 9 parts polycarboxylate superplasticizer.

[0098] The preparation method of konjac dried gel includes the following steps:

[0099] Konjac powder and water were mixed at a mass ratio of 1.6:100, heated to 95°C and stirred for 6 hours. Then, a 25% sodium hydroxide aqueous solution was added and stirred to make the mass ratio of sodium hydroxide to konjac powder 0.55:1. After dehydration and drying in a ventilated environment, the mixture was freeze-dried and then pulverized to obtain konjac dry gel.

[0100] The preparation method of the modified expanding agent includes the following steps:

[0101] (1) Add polyacrylonitrile to acetone, then add silicon carbide whiskers (diameter 0.1-2 μm, length 10-30 μm) for dispersion, wherein the mass-volume ratio of polyacrylonitrile, silicon carbide whiskers and acetone is 17 g: 0.6 g: 50 mL; then perform wet ball milling for 50 min, with a ball-to-material ratio of 1:3.

[0102] (2) After ball milling, the product is dried and dispersed in an aqueous solution of potassium hydroxide, so that the mass ratio of the product to potassium hydroxide is 1:0.7. Then, hydrolysis is carried out and the product is heated to 103°C for 7 hours.

[0103] (3) Next, add triethanolamine and stir, then add sodium methylsilicate, wherein the mass ratio of polyacrylonitrile, triethanolamine and sodium methylsilicate is 17:1:4. Then, heat the reaction and stir at 40°C for 3 hours.

[0104] (4) After the reaction is complete, cool the mixture, add methanol and adjust the pH to neutral, and then perform vacuum distillation to obtain the modified swelling agent.

[0105] Concrete structures were prepared using the structurally dense self-waterproofing materials obtained in Examples 1-3 and Comparative Examples 1-4, and their performance was tested accordingly. The specific results are shown in Table 1. Concrete material: Cement 270 kg / m³ 3 1200 kg / m³ of gravel 3 600kg / m³ of river sand 3 Silica fume 35kg / m 3 180kg / m of water 3 The structurally dense self-waterproofing material is added to the concrete material at 2.5% of the cement weight, and then mixed, poured, vibrated, and cured to obtain a concrete structure.

[0106] Table 1

[0107] Test Project Compressive strength (MPa, 28d) Shrinkage rate ratio (%, 28 days) Maximum seepage resistance pressure (MPa) Example 1 40.2 92 13.5 Example 2 42.4 91 12.6 Example 3 39.6 95 12.9 Comparative Example 1 31.7 113 9.4 Comparative Example 2 35.8 108 11.2 Comparative Example 3 37.3 102 12.1 Comparative Example 4 37.9 97 11.5

[0108] As shown in Table 1, the structurally dense self-waterproofing material of this invention can achieve good self-waterproofing function and structural density of concrete. In conjunction with Example 1 and Comparative Example 1, the absence of a modified expansive agent leads to poorer compensating shrinkage and structural density of the concrete, and also reduces compressive strength. In conjunction with Example 1 and Comparative Examples 2-3, the lack of hydrolysis treatment of polyacrylonitrile results in poor dispersion and binding of the modified expansive agent in the concrete material, and it cannot better synergize with sodium methylsilicate to achieve good internal permeability of the concrete, thus worsening waterproofing. In conjunction with Example 1 and Comparative Example 4, excessive grafting of sodium methylsilicate leads to an imbalance in its proportion on the polyacrylonitrile molecular chain, causing premature formation of a waterproof membrane, affecting penetration depth, compatibility, and early dispersion of cement particles.

[0109] The above are merely preferred embodiments of the present invention and do not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made using the present invention specification, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. The application of a structurally dense self-waterproofing material in concrete structures, characterized in that, The raw materials of the structurally dense self-waterproofing material, by weight, include: 10-14 parts konjac dry gel, 20-25 parts modified expansion agent, 10-15 parts fluorosilicate, 2-5 parts aluminum sulfate, 10-12 parts porous powder, 7-9 parts dispersant, and 8-10 parts water-reducing agent; the structurally dense self-waterproofing material is added to concrete at 2-3% of the cement weight to obtain a concrete structure; Konjac powder and water were mixed at a mass ratio of 1~2:100 and stirred at 95~100℃ for 5~6 hours. Then, a sodium hydroxide aqueous solution with a mass concentration of 25~30% was added and stirred. The mass ratio of sodium hydroxide to konjac powder was 0.5~0.6:

1. After dehydration and drying in a ventilated environment, the mixture was freeze-dried and pulverized to obtain konjac dry gel. Polyacrylonitrile was added to acetone, followed by the addition of silicon carbide whiskers for dispersion, and then wet ball milling was performed. After ball milling, the mixture was dried, and the resulting product was dispersed in an aqueous solution of potassium hydroxide and hydrolyzed at 100-105°C for 6-8 hours. Triethanolamine was then added and stirred, followed by sodium methylsilicate. The mass ratio of polyacrylonitrile, triethanolamine, and sodium methylsilicate was 10-20:1:2-3, and the mixture was heated for reaction. After the reaction was completed, the mixture was cooled, methanol was added, and the pH was adjusted to neutral. The mixture was then subjected to vacuum distillation to obtain the modified expanding agent.

2. The application of the structurally dense self-waterproofing material as described in claim 1 in concrete structures, characterized in that, The mass-to-volume ratio of polyacrylonitrile, silicon carbide whiskers, and acetone is 10-20 g: 0.5-0.7 g: 50 mL; the diameter of the silicon carbide whiskers is 0.1-2 μm and the length is 10-30 μm; the wet ball milling time is 30-60 min and the ball-to-material ratio is 1:3-4; the mass ratio of the obtained product to potassium hydroxide is 1:0.5-0.

8.

3. The application of the structurally dense self-waterproofing material as described in claim 1 in concrete structures, characterized in that, The heating reaction is carried out by stirring at 35~40℃ for 1~2 hours.

4. The application of the structurally dense self-waterproofing material as described in claim 1 in concrete structures, characterized in that, The mass ratio of polyacrylonitrile, triethanolamine, and sodium methylsilicate is 20:1:

2.

5. The application of the structurally dense self-waterproofing material as described in any one of claims 1-3 in concrete structures, characterized in that, The fluorosilicate is sodium fluorosilicate.

6. The application of the structurally dense self-waterproofing material as described in any one of claims 1-3 in concrete structures, characterized in that, The porous powder is diatomaceous earth, hydrotalcite powder, or zeolite powder.

7. The application of the structurally dense self-waterproofing material as described in any one of claims 1-3 in concrete structures, characterized in that, The dispersant is sodium gluconate, oxidized polyethylene wax, sodium pyrophosphate, or sodium dodecylbenzenesulfonate.

8. The application of the structurally dense self-waterproofing material as described in any one of claims 1-3 in concrete structures, characterized in that, The water-reducing agent is a polycarboxylate water-reducing agent, a lignin sulfonate water-reducing agent, an aminosulfonate water-reducing agent, or a naphthalene sulfonate water-reducing agent.