Self-repairing impervious concrete

Abstract

The invention relates to the technical field of concrete, in particular to self-repairing impervious concrete, which is prepared from the following raw materials in parts by weight: 260 to 300 parts of cement, 60 to 80 parts of fly ash, 20 to 40 parts of silica fume, 400 to 500 parts of machine-made sand, 80 to 100 parts of quartz sand, 400 to 600 parts of melon-seed-shaped sheets, 15 to 25 parts of additives, 10 to 20 parts of metakaolin and 2 to 4 parts of water reducing agents. The additive is prepared from the following raw materials: a base material, zinc nitrate, cupric tartrate, manganese dioxide, waterborne polyurethane, a fiber material and a silane coupling agent KH-550. According to the invention, when the concrete cracks to generate stress, the outer layer is broken, and the supporting material of the inner layer is exposed in a concrete system, so that the directional repairing and filling effects are achieved, namely, the self-repairing performance of the concrete is improved, and the service life of the concrete is effectively prolonged.

Description

Technical Field

[0001] This invention relates to the field of concrete technology, specifically to a self-healing, impermeable concrete. Background Technology

[0002] Impermeable concrete refers to concrete with an impermeability grade equal to or greater than P6 (capable of resisting 0.6MPa hydrostatic pressure). It improves its density, water repellency and impermeability by adjusting the mix proportion, adding admixtures or using special cement, so as to reduce the seepage channels. Impermeable concrete has both load-bearing and waterproof functions, and the materials are widely available, low in cost and have good durability.

[0003] Existing impermeable concrete technologies mostly rely on adjusting water-reducing agents to achieve impermeability, without fundamentally improving its microstructure. This inevitably leads to the formation of microcracks during use. These cracks cannot self-repair and become channels for the intrusion of harmful substances such as moisture and chloride ions, resulting in a need to extend the service life of the concrete. Therefore, this invention provides a self-healing impermeable concrete. Summary of the Invention

[0004] The purpose of this invention is to provide a self-healing, impermeable concrete to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a self-healing impermeable concrete, comprising the following raw materials in parts by weight: 260-300 parts cement, 60-80 parts fly ash, 20-40 parts silica fume, 400-500 parts manufactured sand, 80-100 parts quartz sand, 400-600 parts dried melon seed chips, 15-25 parts additives, 10-20 parts metakaolin, and 2-4 parts water-reducing agent; The raw materials for the additives include base material, zinc nitrate, copper tartrate, manganese dioxide, waterborne polyurethane, fiber material, and silane coupling agent KH-550. The raw materials for the fiber material include tetraneedle-shaped zinc oxide whiskers, acetone solution, silane coupling agent Z-6011, sodium dodecyl sulfate, deionized water, butyl acrylate, potassium persulfate, ethylene glycol dimethacrylate, and ammonia.

[0006] Preferably, the additive is prepared by the following method: the base material is fed into a tube furnace, heated to 550-600°C at a rate of 5-10°C / min, held for 10-20 min, and then cooled to room temperature. Zinc nitrate, copper tartrate, and manganese dioxide are added and mixed. Acetylene gas is then introduced at a rate of 3-5 L / min, and the temperature is raised to 800-1000°C at a rate of 10-20°C, held for 6-10 min, and then the acetylene is turned off. Nitrogen gas is introduced and cooled to room temperature to obtain a mixture. The mixture is then ground to a particle size of 10-40 μm to obtain a powder. The powder and waterborne polyurethane are mixed to obtain a preliminary mixture. The preliminary mixture, fiber material, and silane coupling agent KH-550 are added to a mixer, which is set to 200-400 rpm and stirred for 40-60 min. The mixture is then sent to an oven and dried at 60-80°C for 3-5 h to obtain the additive.

[0007] Preferably, the base material is prepared by mixing carbon black, copper oxide, aluminum oxide and titanium oxide, and the mass ratio of carbon black, copper oxide, aluminum oxide and titanium oxide is 1:(0.2~0.4):(0.1~0.2):(0.1~0.2).

[0008] Preferably, the mass of zinc nitrate is 2-4% of the mass of the base material, and the mass ratio of zinc nitrate, copper tartrate, and manganese dioxide is 1:(0.4-0.6):(0.2-0.4).

[0009] Preferably, the mass ratio of powder to waterborne polyurethane is 1:(0.4-0.6), and the mass ratio of primary mix, fiber material, and silane coupling agent KH-550 is 1:(0.4-0.6):(0.06-0.08).

[0010] Preferably, the fiber material is prepared by the following method: tetraneedle-shaped zinc oxide whiskers, acetone solution, and silane coupling agent Z-6011 are added to a mixer, which is set to 400-600 rpm for 20-40 minutes. The resulting product is then ultrasonically dispersed at room temperature at 60-80 Hz for 10-20 minutes. The resulting product is then added to an oven and dried at 80-100°C for 2-4 hours to obtain coarse material. The coarse material, sodium dodecyl sulfate, and deionized water are added to a reaction vessel, and the mixer is set to 100-200 rpm for stirring. After stirring for 20–40 minutes, butyl acrylate, potassium persulfate, and ethylene glycol dimethacrylate are added to the reactor. The reactor temperature is set to 80–90°C, and the stirring speed is 60–80 rpm. The mixture is stirred at this constant temperature for 20–40 minutes. After cooling to room temperature, ammonia water is added to the reactor, and the mixture is stirred evenly and allowed to stand for 2–4 hours. The resulting product is centrifuged to obtain a precipitate. The precipitate is washed with deionized water and then placed in an oven at 60–80°C for 4–6 hours to dry, thus obtaining the fiber material.

[0011] Preferably, the mass ratio of tetraneedle-shaped zinc oxide whiskers, acetone solution, and silane coupling agent Z-6011 is 1:(10-20):(0.06-0.08); the mass ratio of crude material, sodium dodecyl sulfate, and deionized water is 1:(0.1-0.2):(8-10); the mass of butyl acrylate is 50-70% of the mass of crude material; the mass ratio of butyl acrylate, potassium persulfate, and ethylene glycol dimethacrylate is 1:(0.08-0.12):(0.06-0.08); the mass of ammonia is 10-14% of the mass of butyl acrylate; the mass concentration of ammonia is 5-10%; and the concentration of acetone solution is 13.5 mol / L.

[0012] Preferably, the cement is silicate cement.

[0013] Preferably, the water-reducing agent is a polycarboxylate water-reducing agent.

[0014] Preferably, a method for preparing self-healing impermeable concrete includes the following steps: Step 1: Weigh out the cement, fly ash, silica fume, manufactured sand, quartz sand, corn kernels, additives, metakaolin, and water-reducing agent as needed and add them to the mixer. Set the mixer to 40-60 rpm and mix for 10-20 minutes to obtain the premix. Step 2: After mixing the premixed materials at a water-cement ratio of 0.45 to 0.55, a slurry is prepared. Step 3: Pour the slurry into the mold, vibrate to compact it, cover with plastic wrap, and let it stand for curing at 20-25℃ for 24-48 hours before demolding. After demolding, cure for 5-7 days to obtain self-healing impermeable concrete.

[0015] Compared with the prior art, the beneficial effects of the present invention are: In this invention, during the preparation of the additive, the tubular furnace is initially heated to remove impurities from the base material and activate the surface. Then, acetylene gas is introduced, and under a second high-temperature condition, the acetylene decomposes to generate carbon deposit material. Under the action of zinc nitrate and copper tartrate, copper ions catalyze the reaction, forming a support material with good mechanical properties in conjunction with the carbon deposit material. Subsequently, under the mixing treatment of waterborne polyurethane, the waterborne polyurethane acts as an encapsulation and protection agent, causing a microfilm structure to form on the surface of the support material. This allows the support material to maintain a stable state in the concrete system. When the concrete cracks and generates stress, the outer layer breaks, exposing the inner support material to the concrete system, thus playing a directional repair and filling role, thereby improving the self-healing performance of the concrete and effectively extending its service life. Attached Figure Description

[0016] Figure 1 This invention provides a flowchart for the preparation of self-healing impermeable concrete.

[0017] Figure 2 This invention provides a flowchart for the preparation of fiber materials for self-healing impermeable concrete. Detailed Implementation

[0018] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0019] It should be noted that the raw materials used in the following embodiments are all commercially available. Example

[0020] A self-healing impermeable concrete comprises the following raw materials in parts by weight: 260 parts silicate cement, 60 parts fly ash, 20 parts silica fume, 400 parts manufactured sand, 80 parts quartz sand, 400 parts dried melon seed chips, 15 parts additives, 10 parts metakaolin, and 2 parts polycarboxylate superplasticizer. The raw materials for the additive include base material, zinc nitrate, copper tartrate, manganese dioxide, waterborne polyurethane, fiber material, and silane coupling agent KH-550. The base material is prepared by mixing carbon black, copper oxide, aluminum oxide, and titanium oxide in a mass ratio of 1:0.2:0.1:0.1. The raw materials for the fiber material include tetraneedle-shaped zinc oxide whiskers, acetone solution, silane coupling agent Z-6011, sodium dodecyl sulfate, deionized water, butyl acrylate, potassium persulfate, ethylene glycol dimethacrylate, and ammonia.

[0021] The additive is prepared by the following method: The base material is fed into a tube furnace, heated to 550℃ at a rate of 5℃ / min, held for 10 min, and then cooled to room temperature. Zinc nitrate, copper tartrate, and manganese dioxide are added and mixed. Acetylene gas is then introduced at a rate of 3 L / min, and the temperature is raised to 800℃ at a rate of 10℃, held for 6 min, and then the acetylene is turned off. Nitrogen gas is introduced and the mixture is cooled to room temperature to obtain a mixture. The mixture is then ground to a particle size of 10 μm to obtain a powder. The powder and water-based... Polyurethane was mixed at a mass ratio of 1:0.4 to obtain a preliminary mixture. The preliminary mixture, fiber material, and silane coupling agent KH-550 were added to a mixer at a mass ratio of 1:0.4:0.06. The mixer was set to 200 rpm and stirred for 40 minutes. Then, it was sent to an oven and dried at 60°C for 3 hours to obtain an additive. The mass of zinc nitrate was 2% of the mass of the base material, and the mass ratio of zinc nitrate, copper tartrate, and manganese dioxide was 1:0.4:0.2.

[0022] The fiber material was prepared by the following method: Tetraneous zinc oxide whiskers, acetone solution, and silane coupling agent Z-6011 were added to a mixer at a mass ratio of 1:10:0.06. The mixer was set to 400 rpm and stirred for 20 minutes. The resulting product was then ultrasonically dispersed at 60 Hz for 10 minutes at room temperature. The product was then placed in an oven and dried at 80°C for 2 hours to obtain coarse material. The coarse material, sodium dodecyl sulfate, and deionized water were added to a reaction vessel at a mass ratio of 1:0.1:8. The mixer was set to 100 rpm and stirred for 20 minutes. Then, butyl acrylate, potassium persulfate, and ethylene glycol dimethacrylate were added to the reaction vessel. The reaction vessel was then set to... The temperature was 80℃, the stirring speed was 60 rpm, and the constant temperature stirring was carried out for 20 min. After cooling to room temperature, ammonia water was added to the reactor, stirred evenly, and allowed to stand for 2 h. The obtained product was centrifuged to obtain precipitate. The precipitate was washed with deionized water and then sent to an oven set at 60℃ for 4 h to obtain fiber material. The mass of butyl acrylate was 50% of the mass of the crude material, the mass ratio of butyl acrylate, potassium persulfate, and ethylene glycol dimethacrylate was 1:0.08:0.06, the mass of ammonia water was 10% of the mass of butyl acrylate, the mass concentration of ammonia water was 5%, and the concentration of acetone solution was 13.5 mol / L.

[0023] A method for preparing self-healing impermeable concrete includes the following steps: Step 1: Weigh out the cement, fly ash, silica fume, manufactured sand, quartz sand, corn kernels, additives, metakaolin, and water-reducing agent as needed and add them to the mixer. Set the mixer to 40 rpm and mix for 10 minutes to obtain the premix. Step 2: After mixing the premixed materials at a water-cement ratio of 0.45, a slurry is prepared. Step 3: Pour the slurry into the mold, vibrate to compact it, cover with plastic wrap, and let it stand for 24 hours at 20℃ before demolding. After demolding, cure for 5 days to obtain self-healing impermeable concrete. Example

[0024] A self-healing impermeable concrete comprises the following raw materials in parts by weight: 280 parts silicate cement, 70 parts fly ash, 30 parts silica fume, 450 parts manufactured sand, 90 parts quartz sand, 500 parts dried melon seed chips, 20 parts additives, 15 parts metakaolin, and 3 parts polycarboxylate superplasticizer. The raw materials for the additive include base material, zinc nitrate, copper tartrate, manganese dioxide, waterborne polyurethane, fiber material, and silane coupling agent KH-550. The base material is prepared by mixing carbon black, copper oxide, aluminum oxide, and titanium oxide in a mass ratio of 1:0.3:0.15:0.15. The raw materials for the fiber material include tetraneedle-shaped zinc oxide whiskers, acetone solution, silane coupling agent Z-6011, sodium dodecyl sulfate, deionized water, butyl acrylate, potassium persulfate, ethylene glycol dimethacrylate, and ammonia.

[0025] The additive is prepared by the following method: The base material is fed into a tube furnace, heated to 580℃ at a rate of 8℃ / min, held for 15 min, and then cooled to room temperature. Zinc nitrate, copper tartrate, and manganese dioxide are added and mixed. Acetylene gas is then introduced at a rate of 4 L / min, and the temperature is raised to 900℃ at 15℃, held for 8 min, then the acetylene is turned off, nitrogen is introduced, and the mixture is cooled to room temperature to obtain a mixture. The mixture is then ground to a particle size of 25 μm to obtain a powder. The powder and water-based... Polyurethane was mixed at a mass ratio of 1:0.5 to obtain a preliminary mixture. The preliminary mixture, fiber material, and silane coupling agent KH-550 were added to a mixer at a mass ratio of 1:0.5:0.07. The mixer was set to 300 rpm and stirred for 50 minutes. Then, it was sent to an oven and dried at 70°C for 4 hours to obtain an additive. The mass of zinc nitrate was 3% of the mass of the base material, and the mass ratio of zinc nitrate, copper tartrate, and manganese dioxide was 1:0.5:0.3.

[0026] The fiber material was prepared by the following method: Tetraneous zinc oxide whiskers, acetone solution, and silane coupling agent Z-6011 were added to a mixer at a mass ratio of 1:15:0.07. The mixer was set to 500 rpm and stirred for 30 minutes. The resulting product was then ultrasonically dispersed at 70 Hz for 15 minutes at room temperature. The resulting product was then placed in an oven and dried at 90°C for 3 hours to obtain coarse material. The coarse material, sodium dodecyl sulfate, and deionized water were added to a reaction vessel at a mass ratio of 1:0.15:9. The mixer was set to 150 rpm and stirred for 30 minutes. Then, butyl acrylate, potassium persulfate, and ethylene glycol dimethacrylate were added to the reaction vessel. The reaction vessel was set to... The temperature was set at 85℃, the stirring speed at 70 rpm, and the mixture was stirred at this constant temperature for 30 minutes. After cooling to room temperature, ammonia water was added to the reactor, and the mixture was stirred evenly and allowed to stand for 3 hours. The resulting product was centrifuged to obtain a precipitate. The precipitate was washed with deionized water and then placed in an oven at 70℃ for 5 hours to dry, thus obtaining the fiber material. The butyl acrylate content was 60% of the crude material content, the mass ratio of butyl acrylate, potassium persulfate, and ethylene glycol dimethacrylate was 1:0.1:0.07, the ammonia water content was 12% of the butyl acrylate content, the ammonia water concentration was 8%, and the acetone solution concentration was 13.5 mol / L.

[0027] A method for preparing self-healing impermeable concrete includes the following steps: Step 1: Weigh out the cement, fly ash, silica fume, manufactured sand, quartz sand, corn kernels, additives, metakaolin, and water-reducing agent as needed and add them to the mixer. Set the mixer to 50 rpm and mix for 115 minutes to obtain the premix. Step 2: After mixing the premixed materials at a water-cement ratio of 0.5, a slurry is obtained; Step 3: Pour the slurry into the mold, vibrate to compact it, cover with plastic wrap, and let it stand at 22℃ for 36 hours before demolding. After demolding, cure for 6 days to obtain self-healing impermeable concrete. Example

[0028] A self-healing impermeable concrete comprises the following raw materials in parts by weight: 300 parts silicate cement, 80 parts fly ash, 40 parts silica fume, 500 parts manufactured sand, 100 parts quartz sand, 600 parts dried melon seed chips, 25 parts additives, 20 parts metakaolin, and 4 parts polycarboxylate superplasticizer. The raw materials for the additive include base material, zinc nitrate, copper tartrate, manganese dioxide, waterborne polyurethane, fiber material, and silane coupling agent KH-550. The base material is prepared by mixing carbon black, copper oxide, aluminum oxide, and titanium oxide in a mass ratio of 1:0.4:0.2:0.2. The raw materials for the fiber material include tetraneedle-shaped zinc oxide whiskers, acetone solution, silane coupling agent Z-6011, sodium dodecyl sulfate, deionized water, butyl acrylate, potassium persulfate, ethylene glycol dimethacrylate, and ammonia.

[0029] The additive is prepared by the following method: The base material is fed into a tube furnace, heated to 600℃ at a rate of 10℃ / min, held for 20 min, and then cooled to room temperature. Zinc nitrate, copper tartrate, and manganese dioxide are added and mixed. Acetylene gas is then introduced at a rate of 5 L / min, and the temperature is raised from 20℃ to 1000℃ and held for 10 min. The acetylene is then turned off, and nitrogen is introduced to cool to room temperature, yielding a mixture. This mixture is then ground to a particle size of 40 μm to obtain a powder. The powder and water are then... Polyurethane was mixed at a mass ratio of 1:0.6 to obtain a preliminary mixture. The preliminary mixture, fiber material, and silane coupling agent KH-550 were added to a mixer at a mass ratio of 1:0.6:0.08. The mixer was set to 400 rpm and stirred for 60 minutes. Then, it was sent to an oven and dried at 80°C for 5 hours to obtain an additive. The mass of zinc nitrate was 4% of the mass of the base material, and the mass ratio of zinc nitrate, copper tartrate, and manganese dioxide was 1:0.6:0.4.

[0030] The fiber material was prepared by the following method: Tetraneous zinc oxide whiskers, acetone solution, and silane coupling agent Z-6011 were added to a mixer at a mass ratio of 1:20:0.08. The mixer was set to 600 rpm and stirred for 40 minutes. The resulting product was then ultrasonically dispersed at 80 Hz for 20 minutes at room temperature. The resulting product was then placed in an oven and dried at 100℃ for 4 hours to obtain coarse material. The coarse material, sodium dodecyl sulfate, and deionized water were added to a reaction vessel at a mass ratio of 1:0.2:10. The mixer was set to 200 rpm and stirred for 40 minutes. Then, butyl acrylate, potassium persulfate, and ethylene glycol dimethacrylate were added to the reaction vessel. The reaction vessel was set to... The mixture was stirred at 90℃ and 80 rpm for 40 minutes. After cooling to room temperature, ammonia was added to the reactor and stirred until homogeneous. The mixture was then allowed to stand for 4 hours. The resulting product was centrifuged to obtain a precipitate. The precipitate was washed with deionized water and then placed in an oven at 80℃ for 6 hours to obtain fiber material. The butyl acrylate content was 70% of the crude material content. The mass ratio of butyl acrylate, potassium persulfate, and ethylene glycol dimethacrylate was 1:0.12:0.08. The ammonia content was 14% of the butyl acrylate content and the ammonia concentration was 10%. The acetone solution concentration was 13.5 mol / L.

[0031] A method for preparing self-healing impermeable concrete includes the following steps: Step 1: Weigh out the cement, fly ash, silica fume, manufactured sand, quartz sand, corn kernels, additives, metakaolin, and water-reducing agent as needed and add them to the mixer. Set the mixer to 60 rpm and mix for 20 minutes to obtain the premix. Step 2: After mixing the premixed materials at a water-cement ratio of 0.55, a slurry is prepared. Step 3: Pour the slurry into the mold, vibrate to compact it, cover with plastic wrap, and let it stand for 48 hours at 25℃ before demolding. After demolding, cure for 7 days to obtain self-healing impermeable concrete.

[0032] Comparative Example 1: The difference between this comparative example and Example 1 is that this comparative example does not contain any additives.

[0033] Comparative Example 2: The difference between this comparative example and Example 1 is that no fiber material is added during the preparation of the additive in this comparative example.

[0034] Comparative Example 3: The difference between this comparative example and Example 1 is that acetylene gas is not introduced during the preparation of the additive in this comparative example.

[0035] Mechanical property testing: Referring to GB / T50081-2019 standard, concrete prepared by the methods in Examples 1-3 was selected and made into cubic specimens of 150mm×150mm×150mm. The compressive strength at 3d, 7d, 14d, 21d and 28d was tested and recorded in Table 1. Table 1: Mechanical Properties Analysis of the data in the comparison table shows that the strength data of the impermeable concrete prepared by the preparation method of Examples 1-3 after standard curing for 3d, 7d, 14d, 21d and 28d are all better than those of Comparative Examples 1-3. This indicates that the impermeable concrete prepared by Examples 1-3 has better performance in the early, middle and late stages than the impermeable concrete prepared by Comparative Examples 1-3. Among them, Comparative Example 1 showed the worst strength data, indicating that the additive system is the core of improving the mechanical properties of concrete. Without additives, concrete relies solely on the hydration reaction of the cementitious matrix, resulting in more porosity and defects in the microstructure. Comparative Example 2 had a higher strength than Comparative Example 1 but lower than Examples 1-3, confirming the reinforcing effect of fiber materials. It also demonstrates that the three-dimensional structure of tetraneedle-shaped zinc oxide whiskers can form an interlocking network in concrete, effectively transferring loads and inhibiting microcrack propagation. Without fiber materials, stress concentration is more likely to lead to crack initiation and propagation. Although Comparative Example 3 only omitted the step of introducing acetylene gas, it still showed some improvement. However, this directly results in strength data that is only higher than that of the control group with the actual additive. This is because acetylene decomposes at high temperature and deposits on the surface of the base material to form a nano-carbon layer. This carbon layer has a high specific surface area and conductivity, which can effectively adsorb and promote the dispersion and activity of catalysts such as zinc nitrate and copper tartrate. Without acetylene treatment, the base material is just a simple mixture, and its catalytic activity and interfacial bonding ability with the cement matrix are greatly reduced. Metal oxide particles are prone to agglomeration and it is difficult to form a uniform multiphase catalytic center, resulting in insufficient hydration reaction and decreased microstructure density, which leads to a significant decrease in the strength of the impermeable concrete.

[0036] Self-healing performance test: Concrete prepared using the methods in Examples 1-3 and Comparative Examples 1-3 was used to fabricate frustum-shaped impermeable specimens with an upper diameter of 175 mm, a lower diameter of 185 mm, and a height of 150 mm. Following Appendix A of GB / T18445-2022 "Cement-based Penetrating Crystalline Waterproofing Materials," the specimens were cured for 28 days. A crack 0.3 mm wide and 40-50 mm deep was pre-placed in the middle of the specimens for the first impermeability test (water pressure started at 0.1 MPa, increasing by 0.1 MPa every 8 hours until water seeped through to the top surface; the pressure was recorded). At this point, the pressure is the initial anti-seepage pressure. After standard curing for 56 days, a second anti-seepage test is conducted, and the second anti-seepage pressure is recorded. Furthermore, after the pre-formed crack and after 56 days of curing, the same crack area is photographed, and the crack pixel area is calculated after image binarization. Then, the crack closure rate is calculated. The calculation formula is: closure rate (%) = (initial crack area - crack area after 56 days) / initial crack area × 100%. At the same time, the crack width is observed periodically, and the time (d) required to reach a 90% closure rate is recorded. The obtained data are recorded in Table 2.

[0037] Table 2: Self-healing performance Analysis of the data in the comparison table shows that the self-healing performance of the impermeable concrete prepared by the methods of Examples 1-3 is significantly better than that of Comparative Examples 1-3. In Example 1, the initial impermeability pressure reached 1.48 MPa, significantly higher than the 0.82-1.05 MPa of Comparative Examples 1-3. This indicates that the synergistic effect of the additives and fibers resulted in a denser microstructure in the early stages of concrete forming. The additive's matrix particles filled the cement stone pores, and the three-dimensional network structure formed by the fibers blocked potential seepage channels, providing excellent initial impermeability for the concrete. Example 1 maintained a high secondary impermeability pressure of 1.36 MPa, with an impermeability pressure ratio of 91.8%, demonstrating that the concrete's impermeability was greatly restored after 56 days of self-healing. In contrast, the secondary impermeability pressure of Comparative Examples 1-3 was only 0.65-0.89 MPa, with a pressure ratio of only 79.2%-84.7%, indicating significantly insufficient repair effect. Furthermore, Comparative Example 1, lacking the additives, showed significantly lower performance across all indicators. The worst result demonstrates that the additive is the core of the entire self-healing system. The data from Comparative Example 2, lacking fiber material, reflects limited repair effectiveness, indicating that the fiber material plays a crucial supporting and guiding role in the repair process. Comparative Example 3, without acetylene gas treatment, showed significantly worse repair performance than the Example 1, demonstrating that acetylene treatment is essential for forming highly efficient catalytic centers. Example 1 achieved a crack closure rate of 93%, reaching 90% closure within just 35 days, showcasing rapid and efficient repair capabilities. In contrast, Comparative Examples 1-3 had closure rates of only 10-40%, requiring over 75 days to reach 90% closure, indicating slow repair speed and limited effectiveness. This result fully demonstrates that the additive provides the active substances and catalytic centers required for the repair reaction, the fiber material provides the attachment framework and growth guidance for the repair products, and the carbon layer formed by acetylene treatment greatly enhances catalytic efficiency and ion migration ability.

[0038] As can be seen from the above, the self-healing impermeable concrete and its preparation method provided in this application form a self-healing network inside the concrete through the synergistic effect of additives and fibers in a specific ratio. When microcracks occur, a repair reaction is triggered, which has the advantages of effectively sealing microcracks, improving impermeability, and enhancing long-term durability through a self-healing mechanism. Therefore, the self-healing impermeable concrete provided by this invention has a broader market prospect and is more suitable for widespread application.

[0039] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0040] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A self-healing, impermeable concrete, characterized in that, The raw materials include the following parts by weight: 260-300 parts cement, 60-80 parts fly ash, 20-40 parts silica fume, 400-500 parts manufactured sand, 80-100 parts quartz sand, 400-600 parts dried melon seed chips, 15-25 parts additives, 10-20 parts metakaolin, and 2-4 parts water-reducing agent; The raw materials for the additives include base material, zinc nitrate, copper tartrate, manganese dioxide, waterborne polyurethane, fiber material, and silane coupling agent KH-550. The raw materials for the fiber material include tetraneedle-shaped zinc oxide whiskers, acetone solution, silane coupling agent Z-6011, sodium dodecyl sulfate, deionized water, butyl acrylate, potassium persulfate, ethylene glycol dimethacrylate, and ammonia.

2. The self-healing impermeable concrete according to claim 1, characterized in that, The additive is prepared by the following method: the base material is fed into a tube furnace, heated to 550-600℃ at a rate of 5-10℃ / min, held for 10-20min, and then cooled to room temperature. Zinc nitrate, copper tartrate, and manganese dioxide are added and mixed. Acetylene gas is then introduced at a rate of 3-5L / min, and the temperature is raised to 800-1000℃ at a rate of 10-20℃, held for 6-10min, and then the acetylene is turned off. Nitrogen gas is introduced and cooled to room temperature to obtain a mixture. The mixture is then ground to a particle size of 10-40μm to obtain a powder. The powder and waterborne polyurethane are mixed to obtain a preliminary mixture. The preliminary mixture, fiber material, and silane coupling agent KH-550 are added to a mixer and stirred at 200-400rpm for 40-60min. The mixture is then placed in an oven and dried at 60-80℃ for 3-5h to obtain the additive.

3. The self-healing impermeable concrete according to claim 2, characterized in that, The base material is prepared by mixing carbon black, copper oxide, aluminum oxide and titanium oxide, with the mass ratio of carbon black, copper oxide, aluminum oxide and titanium oxide being 1:(0.2~0.4):(0.1~0.2):(0.1~0.2).

4. The self-healing impermeable concrete according to claim 2, characterized in that, The mass of zinc nitrate is 2-4% of the mass of the base material, and the mass ratio of zinc nitrate, copper tartrate, and manganese dioxide is 1:(0.4-0.6):(0.2-0.4).

5. The self-healing impermeable concrete according to claim 2, characterized in that, The mass ratio of powder to waterborne polyurethane is 1:(0.4-0.6), and the mass ratio of primary mix, fiber material, and silane coupling agent KH-550 is 1:(0.4-0.6):(0.06-0.08).

6. The self-healing impermeable concrete according to claim 1, characterized in that, The fiber material is prepared by the following method: tetraneedle-shaped zinc oxide whiskers, acetone solution, and silane coupling agent Z-6011 are added to a mixer, which is set to 400-600 rpm for 20-40 minutes. The resulting product is then ultrasonically dispersed at room temperature at 60-80 Hz for 10-20 minutes. The resulting product is then added to an oven and dried at 80-100℃ for 2-4 hours to obtain coarse material. The coarse material, sodium dodecyl sulfate, and deionized water are added to a reaction vessel, and the mixer is set to 100-200 rpm for stirring. After 20-40 minutes of stirring, butyl acrylate, potassium persulfate, and ethylene glycol dimethacrylate are added to the reactor. The reactor temperature is set to 80-90℃, and the stirring speed is 60-80 rpm. The mixture is stirred at this constant temperature for 20-40 minutes. After cooling to room temperature, ammonia water is added to the reactor, and the mixture is stirred evenly and allowed to stand for 2-4 hours. The resulting product is centrifuged to obtain a precipitate. The precipitate is washed with deionized water and then placed in an oven at 60-80℃ for 4-6 hours to dry, thus obtaining the fiber material.

7. The self-healing impermeable concrete according to claim 6, characterized in that, The mass ratio of tetraneedle-shaped zinc oxide whiskers, acetone solution, and silane coupling agent Z-6011 is 1:(10-20):(0.06-0.08). The mass ratio of crude material, sodium dodecyl sulfate, and deionized water is 1:(0.1-0.2):(8-10). The mass of butyl acrylate is 50-70% of the mass of crude material. The mass ratio of butyl acrylate, potassium persulfate, and ethylene glycol dimethacrylate is 1:(0.08-0.12):(0.06-0.08). The mass of ammonia water is 10-14% of the mass of butyl acrylate, and the mass concentration of ammonia water is 5-10%. The concentration of acetone solution is 13.5 mol / L.

8. The self-healing impermeable concrete according to claim 1, characterized in that, The cement used is silicate cement.

9. The self-healing impermeable concrete according to claim 1, characterized in that, The water-reducing agent used is a polycarboxylate water-reducing agent.

10. The method for preparing self-healing impermeable concrete according to any one of claims 1 to 9, characterized in that, Includes the following steps: Step 1: Weigh out the cement, fly ash, silica fume, manufactured sand, quartz sand, corn kernels, additives, metakaolin, and water-reducing agent as needed and add them to the mixer. Set the mixer to 40-60 rpm and mix for 10-20 minutes to obtain the premix. Step 2: After mixing the premixed materials at a water-cement ratio of 0.45 to 0.55, a slurry is prepared. Step 3: Pour the slurry into the mold, vibrate to compact it, cover with plastic wrap, and let it stand for curing at 20-25℃ for 24-48 hours before demolding. After demolding, cure for 5-7 days to obtain self-healing impermeable concrete.

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