Low-carbon cement concrete as well as preparation method and application thereof

Abstract

The invention relates to low-carbon cement concrete as well as a preparation method and application thereof. The low-carbon cement concrete comprises the following components in parts by mass: 600-700 parts of clinker cement, 150-200 parts of rice hull ash, 200-300 parts of fly ash and 80-160 parts of a resin system, the resin system comprises epoxy resin, modified carbon fibers, composite boron nitride and carbon nanotubes, and raw materials of the composite boron nitride comprise boron nitride and benzimidazole. The method has the effect of improving the corrosion resistance and strength of the concrete.

Description

Technical Field

[0001] This application relates to the field of concrete, and in particular to a low-carbon cement concrete, its preparation method, and its application. Background Technology

[0002] Cement concrete is an artificial stone material made by mixing cement, water, sand, gravel, etc. in a certain proportion and then processing it through mixing, molding, and curing. It is widely used in construction engineering and other fields.

[0003] Currently, the global building materials industry faces severe environmental pressures, particularly the significant CO2 emissions generated during concrete manufacturing, which have become a major problem urgently needing to be addressed. Traditional cement concrete relies on energy-intensive and high-emission production methods, with clinker firing being the primary source of carbon dioxide emissions. With the increasing awareness of sustainable development, developing low-carbon, high-performance cement concrete has become an urgent need for the building materials industry. Summary of the Invention

[0004] To address the aforementioned issues, this application provides a low-carbon cement concrete, its preparation method, and its application.

[0005] Firstly, this application provides a low-carbon cement concrete solution using the following technical solution: A low-carbon cement concrete comprises the following components in parts by weight: 600-700 parts clinker cement, 150-200 parts rice husk ash, 200-300 parts fly ash, and 80-160 parts resin system; The resin system includes epoxy resin, modified carbon fiber, composite boron nitride and carbon nanotubes, and the composite boron nitride raw material includes boron nitride and benzimidazole.

[0006] By adopting the above technical solution, low-calcium cement is combined with biomass carbon and other fillers as mineral admixtures. After mixing, carbon emissions can be effectively reduced, and the physical properties of the cement can be stably maintained. Rice husk ash is a potentially active material obtained after burning rice husks. It has a high specific surface area and activity, which can improve the density of the cement, thereby increasing its strength. It can also improve the pore structure of the cement, reduce porosity, and replace part of the cement clinker, thereby reducing carbon emissions. At the same time, a small amount of resin system is added to the system, which can further fill the pores of the cement, making the cement denser and improving its mechanical properties such as compressive strength. Epoxy resin has good corrosion resistance, which can improve the overall corrosion resistance of the cement. After adding epoxy resin, modified carbon fiber and composite boron nitride as a resin system, the durability of the cement can be further improved, thereby increasing the overall service life of the cement.

[0007] Preferably, the composite boron nitride is prepared by the following method: Boron nitride was mixed with methanol and ultrasonically dispersed to obtain a boron nitride dispersion. Zinc nitrate hexahydrate and 2-methylimidazole were added to methanol to obtain a mixture. Benzimidazole was added to methanol and ultrasonically dispersed to obtain a benzimidazole dispersion. The benzimidazole dispersion was mixed with the boron nitride dispersion and then added to the mixture. After stirring, centrifugation and washing, and drying, composite boron nitride was obtained.

[0008] By employing the above technical solution, a dense hydroxide layer is grown using boron nitride as the matrix through a two-step method, and benzimidazole is embedded to prepare a composite boron nitride, thereby further improving the overall corrosion resistance of boron nitride. The hydroxide can adsorb Cl... - It can improve the dispersion performance of boron nitride in epoxy resin systems, thereby enhancing the overall stability of the prepared resin system.

[0009] Preferably, the mass ratio of boron nitride, 2-methylimidazole and benzylimidazole is 1:5:(2.4-3).

[0010] By adopting the above technical solution, and preferably within the above range the mass ratio of boron nitride, 2-methylimidazole and benzylimidazole, the overall stability of the prepared composite boron nitride can be further improved.

[0011] Preferably, the modified carbon fiber comprises boron nitride, tannic acid, and (3-glycidyloxypropyl)trimethoxysilane.

[0012] By adopting the above technical solution, tannic acid, a secondary metabolite of plants, is a polyphenol structure. By complexing and depositing tannic acid on the surface of carbon fibers, a large number of phenolic hydroxyl groups can be added to the surface of carbon fibers, resulting in good interfacial compatibility. Furthermore, it can react with the epoxy groups on the surface of epoxy resin to form chemical bonds. Grafting (3-glycidyloxypropyl)trimethoxysilane can further establish a strong medium on the surface of carbon fibers, thereby further improving the bonding performance with epoxy resin.

[0013] Preferably, the modified carbon fiber is prepared by the following method: Tannic acid and ferric chloride hexahydrate were mixed and added to Tris buffer to obtain a reaction solution. Carbon fibers were immersed in the reaction solution and stirred to react. After the reaction, the carbon fibers were filtered, washed and dried to obtain tannic acid composite carbon fibers. (3-glycidyloxypropyl)trimethoxysilane was mixed with ethanol to obtain a silane solution. The prepared tannic acid composite carbon fibers were immersed in the silane solution and stirred to react. After the reaction, the carbon fibers were filtered, washed and dried to obtain modified carbon fibers.

[0014] Preferably, the reaction time of the tannic acid composite carbon fiber with the silane solution is 18-22 hours.

[0015] By adopting the above technical solution, and preferably within the above-mentioned range the stirring reaction time between tannic acid and silane solution, the stability of the prepared modified carbon fiber can be further improved.

[0016] Preferably, the resin system is prepared by the following method: Composite boron nitride, modified carbon fiber and carbon nanotubes were mixed and added to water, and ultrasonically dispersed to obtain a dispersion. The dispersion was placed in a vacuum tube furnace, sintered, cooled and crushed to obtain a composite. The composite, epoxy resin and curing agent were mixed and stirred evenly to obtain a resin system.

[0017] By adopting the above technical solution, a stable three-dimensional network structure is formed between composite boron nitride, modified carbon fiber and carbon nanotubes, which can further improve the stability of the system. After being combined with epoxy resin, the mechanical properties of the system can be further improved, and the various components in the cement system can be further combined, thereby improving the comprehensive performance of concrete.

[0018] Preferably, the mass ratio of the composite boron nitride, modified carbon fiber, carbon nanotubes and epoxy resin is 0.04:(0.06-0.08):0.02:1.

[0019] By adopting the above technical solution, and preferably within the above-mentioned range the mass ratio of composite boron nitride, modified carbon fiber, carbon nanotube and epoxy resin, the overall stability of the prepared resin system can be further improved.

[0020] Secondly, this application provides a method for preparing low-carbon concrete, employing the following technical solution: A method for preparing low-carbon concrete includes the following preparation steps: After mixing clinker cement, rice husk ash, fly ash, and resin system, a concrete mixture is obtained. The concrete mixture is then poured into a mold, vibrated to remove air, and cured to obtain low-carbon concrete.

[0021] Thirdly, this application provides an application of low-carbon concrete, employing the following technical solution: An application of low-carbon concrete, which is used in roads, bridges and building construction.

[0022] In summary, this application includes at least one of the following beneficial technical effects: 1. Using low-calcium cement combined with biomass carbon and other fillers as mineral admixtures can effectively reduce carbon emissions. The addition of rice husk ash and fly ash can replace part of the low-calcium cement to reduce carbon emissions. Fly ash has volcanic activity, which can reduce the high energy consumption generated during the high-temperature calcination of cement. Rice husk ash has a high specific surface area and activity, which can improve the density of cement and thus improve its strength. A resin system is also added to the system to increase the porosity of cement, thereby making the cement more compact. 2. By embedding benzimidazole into boron nitride, the overall corrosion resistance and dispersion properties of the boron nitride system are improved. A layer of hydroxide is generated on the surface of boron nitride, which can adsorb Cl. - This further enhances the overall performance of the resin system. 3. By modifying the carbon fiber surface with tannic acid, a large number of phenolic hydroxyl groups are added to the carbon fiber surface, giving the carbon fiber good interfacial compatibility. Then, (3-glycidyloxypropyl)trimethoxysilane is grafted onto the surface to further establish a strong medium on the carbon fiber surface, thereby improving the bonding performance with epoxy resin. Detailed Implementation

[0023] The present application will be further described in detail below with reference to the embodiments: Raw material description: All raw materials used in the examples are commercially available; Example 1 Preparation of composite boron nitride: 7g of boron nitride was mixed with 500mL of methanol and ultrasonically dispersed for 2h to obtain a boron nitride dispersion. 20g of zinc nitrate hexahydrate and 35g of 2-methylimidazole (CAS No.: 693-98-1) were added to 200mL of methanol to obtain a mixture. 16.8g of benzimidazole (CAS No.: 51-17-2) was added to 200mL of methanol and ultrasonically dispersed to obtain a benzimidazole dispersion. The benzimidazole dispersion was mixed with the boron nitride dispersion and then added to the mixture. The mixture was stirred at 25℃ for 8h, centrifuged at 12000rpm for 15min, washed repeatedly with methanol 3 times, and then vacuum dried at 50℃ for 24h to obtain composite boron nitride.

[0024] Preparation of modified carbon fibers: Tannic acid (CAS No.: 1401-55-4) and ferric chloride hexahydrate were mixed and added to 300 mL of Tris buffer to obtain a reaction solution. The concentration of tannic acid in the reaction solution was 0.1 mg / mL, and the concentration of ferric chloride hexahydrate was 4.2 mg / mL. The reaction solution was stirred at 200 rpm for 15 min. Then, 15 g of carbon fiber was immersed in the reaction solution and stirred at 150 rpm. After the reaction, the carbon fiber was filtered, washed with deionized water, and dried in an oven at 80 °C for 4 h. Tannic acid composite carbon fibers were obtained. (3-glycidyloxypropyl)trimethoxysilane (CAS No.: 2530-83-8) was mixed with ethanol to obtain a silane solution with a mass concentration of 2% (3-glycidyloxypropyl)trimethoxysilane. The prepared tannic acid composite carbon fibers were immersed in 300 mL of the silane solution and stirred at 25 °C for 18 h. After the reaction, the mixture was filtered, and the reacted carbon fibers were washed with deionized water and then dried in an oven at 80 °C for 4 h to obtain modified carbon fibers.

[0025] Preparation of resin system: 5.09 g of composite boron nitride, 6.78 g of modified carbon fiber, and 3.38 g of carbon nanotubes were mixed and added to deionized water. After ultrasonic dispersion, a dispersion was obtained. The dispersion was placed in a vacuum tube furnace and sintered at 300 °C for 20 min under nitrogen protection, held at that temperature for 5 min, then heated to 800 °C within 80 min and held at that temperature for 5 min. After cooling to 25 °C, the mixture was crushed to obtain a composite. The composite, 84.75 g of epoxy resin, and 40 g of curing agent were mixed and stirred evenly to obtain a resin system.

[0026] Preparation of low-carbon cement concrete: Mix 600g of clinker cement, 150g of rice husk ash, 200g of fly ash and 80g of resin system to obtain a concrete mixture. Pour the concrete mixture into a mold, vibrate to remove air, and cure to obtain low-carbon concrete.

[0027] Example 2 Preparation of composite boron nitride: 7g of boron nitride was mixed with 500mL of methanol and ultrasonically dispersed for 2h to obtain a boron nitride dispersion. 20g of zinc nitrate hexahydrate and 35g of 2-methylimidazole were added to 200mL of methanol to obtain a mixture. 18.9g of benzimidazole was added to 200mL of methanol and ultrasonically dispersed to obtain a benzimidazole dispersion. The benzimidazole dispersion was mixed with the boron nitride dispersion and then added to the mixture. The mixture was stirred at 25℃ for 8h, centrifuged at 12000rpm for 15min, washed repeatedly with methanol 3 times, and then vacuum dried at 50℃ for 24h to obtain composite boron nitride.

[0028] Preparation of modified carbon fibers: Tannic acid and ferric chloride hexahydrate were mixed and added to 300 mL of Tris buffer to obtain a reaction solution with a tannic acid concentration of 0.1 mg / mL and a ferric chloride hexahydrate concentration of 4.4 mg / mL. The reaction solution was stirred at 200 rpm for 15 min. Then, 15 g of carbon fiber was immersed in the reaction solution and stirred at 150 rpm. After the reaction, the carbon fiber was filtered, washed with deionized water, and dried in an oven at 80 °C for 4 h to obtain tannic acid composite carbon fiber. (3-glycidyloxypropyl)trimethoxysilane was mixed with ethanol to obtain a silane solution with a (3-glycidyloxypropyl)trimethoxysilane mass concentration of 2%. The prepared tannic acid composite carbon fiber was immersed in 300 mL of silane solution and stirred at 25 °C for 22 h. After the reaction, the carbon fiber was filtered, washed with deionized water, and dried in an oven at 80 °C for 4 h to obtain modified carbon fiber.

[0029] Preparation of resin system: 5g of composite boron nitride, 8.33g of modified carbon fiber, and 3.34g of carbon nanotubes were mixed and added to deionized water. After ultrasonic dispersion, a dispersion was obtained. The dispersion was placed in a vacuum tube furnace and sintered at 300℃ for 20min under nitrogen protection, held for 5min, then heated to 800℃ within 80min, held for 5min, and then cooled to 25℃ and crushed to obtain a composite. The composite, 83.33g of epoxy resin, and 40g of curing agent were mixed and stirred evenly to obtain a resin system.

[0030] Preparation of low-carbon cement concrete: 750g of clinker cement, 200g of rice husk ash, 300g of fly ash and 160g of resin system are mixed to obtain a concrete mixture. The concrete mixture is poured into a mold, vibrated to remove air, and cured to obtain low-carbon concrete.

[0031] Example 3 Preparation of composite boron nitride: 7g of boron nitride was mixed with 500mL of methanol and ultrasonically dispersed for 2h to obtain a boron nitride dispersion. 20g of zinc nitrate hexahydrate and 35g of 2-methylimidazole were added to 200mL of methanol to obtain a mixture. 21g of benzimidazole was added to 200mL of methanol and ultrasonically dispersed to obtain a benzimidazole dispersion. The benzimidazole dispersion was mixed with the boron nitride dispersion and then added to the mixture. The mixture was stirred at 25℃ for 8h, centrifuged at 12000rpm for 15min, washed repeatedly with methanol 3 times, and then vacuum dried at 50℃ for 24h to obtain composite boron nitride.

[0032] Preparation of modified carbon fibers: Tannic acid and ferric chloride hexahydrate were mixed and added to 300 mL of Tris buffer to obtain a reaction solution with a tannic acid concentration of 0.1 mg / mL and a ferric chloride hexahydrate concentration of 4.3 mg / mL. The reaction solution was stirred at 200 rpm for 15 min. Then, 15 g of carbon fiber was immersed in the reaction solution and stirred at 150 rpm. After the reaction, the carbon fiber was filtered, washed with deionized water, and dried in an oven at 80 °C for 4 h to obtain tannic acid composite carbon fiber. (3-glycidyloxypropyl)trimethoxysilane was mixed with ethanol to obtain a silane solution with a (3-glycidyloxypropyl)trimethoxysilane mass concentration of 2%. The prepared tannic acid composite carbon fiber was immersed in 300 mL of silane solution and stirred at 25 °C for 20 h. After the reaction, the carbon fiber was filtered, washed with deionized water, and dried in an oven at 80 °C for 4 h to obtain modified carbon fiber.

[0033] Preparation of resin system: 5.04 g of composite boron nitride, 7.56 g of modified carbon fiber, and 3.37 g of carbon nanotubes were mixed and added to deionized water. After ultrasonic dispersion, a dispersion was obtained. The dispersion was placed in a vacuum tube furnace and sintered at 300 °C for 20 min under nitrogen protection, held at that temperature for 5 min, then heated to 800 °C within 80 min and held at that temperature for 5 min. After cooling to 25 °C, the mixture was crushed to obtain a composite. The composite, 84.03 g of epoxy resin, and 40 g of curing agent were mixed and stirred evenly to obtain a resin system.

[0034] Preparation of low-carbon cement concrete: Mix 700g of clinker cement, 170g of rice husk ash, 250g of fly ash and 120g of resin system to obtain a concrete mixture. Pour the concrete mixture into a mold, vibrate to remove air, and cure to obtain low-carbon concrete.

[0035] Example 4 Example 4 is based on Example 3. In Example 4, 14g of benzimidazole was used in the preparation of the composite boron nitride.

[0036] Example 5 Example 5 is based on Example 3. In Example 5, 23.8g of benzimidazole was used in the preparation of the composite boron nitride.

[0037] Example 6 Example 6 is based on Example 3, except that benzimidazole was not added when preparing the composite boron nitride in Example 6.

[0038] Example 7 Example 7 is based on Example 3. In Example 7, the concentration of ferric chloride hexahydrate in the reaction solution during the preparation of modified carbon fiber is 4 mg / mL.

[0039] Example 8 Example 8 is based on Example 3. In Example 8, the concentration of ferric chloride hexahydrate in the reaction solution during the preparation of modified carbon fiber is 4.6 mg / mL.

[0040] Example 9 Example 9 is based on Example 3. In Example 9, the reaction time between tannic acid composite carbon fiber and silane solution is 14 hours when preparing modified carbon fiber.

[0041] Example 10 Example 10 is based on Example 3. In Example 10, the reaction time between tannic acid composite carbon fiber and silane solution is 24 hours when preparing modified carbon fiber.

[0042] Example 11 Example 11 is based on Example 3, and the modified carbon fiber in Example 11 is tannic acid composite carbon fiber.

[0043] Example 12 Example 12 is based on Example 3. In Example 12, when preparing the resin system, the amount of composite boron nitride used is 5.17g, the amount of modified carbon fiber used is 5.17g, the amount of carbon nanotube used is 3.45g, and the amount of epoxy resin used is 86.21g.

[0044] Example 13 Example 13 is based on Example 3. In Example 13, when preparing the resin system, the amount of composite boron nitride used is 4.92g, the amount of modified carbon fiber used is 9.84g, the amount of carbon nanotube used is 3.27g, and the amount of epoxy resin used is 81.97g.

[0045] Example 14 Example 14 is based on Example 3, but no carbon nanotubes were added when preparing the resin system in Example 14.

[0046] Comparative Example 1 Comparative Example 1 is based on Example 3, but no composite boron nitride was added when preparing the resin system in Comparative Example 1.

[0047] Comparative Example 2 Comparative Example 2 is based on Example 3, but no modified carbon fiber was added when preparing the resin system in Comparative Example 2.

[0048] Performance testing The following performance tests were performed on the samples of Examples 1-14 and Comparative Examples 1-2: (1) Corrosion resistance test The compressive strength of each sample after 150 cycles of sulfate corrosion was tested according to the standard GB / T 50082-2009 Test Method for Long-Term Performance and Durability of Ordinary Concrete. Each sample was tested 3 times, and the average value was taken. The test results were recorded in Table 1.

[0049] (2) Strength performance testing was conducted according to the "GB / T 50081-2002 Standard for Test Methods of Mechanical Properties of Ordinary Concrete". After each example and comparative example concrete was formed, it was placed in a mold with a side length of 150 mm and cured at a temperature of 20±5℃ until final setting. After 24 hours, the concrete was demolded and then placed in a standard environment with a temperature of 20±2℃ and a relative humidity of 95% or higher for curing. After 7 days of curing, the concrete was removed and the compressive strength of the samples was tested. Table 1 Performance test results of Examples 1-14 and Comparative Examples 1-2 As shown in Table 1, the compressive strength of the samples in Examples 1-3 after wet-dry cycles of sulfate corrosion is 34.5 MPa or higher, indicating that the concrete prepared in this application has good corrosion resistance. The compressive strength of the samples in Examples 1-3 after 7 days of protection is 48.0 MPa or higher, indicating that the low-carbon cement concrete prepared in this application has good mechanical strength.

[0050] In Examples 4 and 5, the mass ratios of boron nitride, 2-methylimidazole, and benzimidazole during the preparation of the composite boron nitride were not within the range specified in this application. When the content of benzimidazole was too low, the sustained-release performance was difficult to improve further, so the corrosion resistance of Example 4 was difficult to improve further. When the content of benzimidazole was too high, the boron nitride was also difficult to load benzimidazole, so the corrosion resistance was difficult to improve further, and the stability of the system decreased. Therefore, the performance of Example 5 was reduced.

[0051] In Example 6, benzylimidazole was not added during the preparation of the composite boron nitride. Without the addition of benzylimidazole, the corrosion resistance of boron nitride is difficult to be further improved, so the corrosion resistance of Example 6 is reduced.

[0052] In Examples 7 and 8, the mass ratio of tannic acid to ferric chloride hexahydrate in the reaction solution during the preparation of modified carbon fibers was not within the range specified in this application. When the concentration of ferrous chloride hexahydrate was too low, the reaction was not fully carried out, and the complexation modification effect of tannic acid and iron ions on the carbon fiber surface was difficult to further improve. The tannic acid complex on the carbon fiber surface was unevenly distributed and agglomerated, affecting the overall stability of the system. When the concentration of ferrous chloride hexahydrate was too high, the complexation reaction was already in a complete state, making it difficult to further improve the overall performance of the prepared modified carbon fibers. Therefore, the performance of Example 8 was difficult to further improve.

[0053] In Examples 9 and 10, the reaction time between the tannic acid composite carbon fiber and the silane solution during the preparation of modified carbon fiber was not within the range specified in this application. When the reaction time was too short, the polymer content on the surface of the tannic acid composite carbon fiber was too low, making it difficult to further cover the carbon fiber surface and further improve the bonding performance with the epoxy resin, thus reducing the strength of the system. When the reaction time was too long, the polymer content on the surface of the prepared carbon fiber was too high, which affected the overall stability of the system. Therefore, the performance of Examples 9 and 10 was reduced.

[0054] In Example 11, (3-glycidyloxypropyl)trimethoxysilane was not used to modify the carbon fiber, making it difficult to further improve the bonding performance between the carbon fiber and the epoxy resin, thus reducing the stability of the system.

[0055] In Examples 12 and 13, the mass ratios of composite boron nitride, modified carbon fiber, carbon nanotubes, and epoxy resin during the preparation of the resin system were not within the range specified in this application. When the mass ratio of fillers in the system changed, it affected the performance of the epoxy resin, resulting in a decrease in the overall performance of the resin system. Therefore, the performance of Examples 12 and 13 both decreased.

[0056] In Example 14, no carbon nanotubes were added to the resin system. Without carbon nanotubes, it is difficult to form a stable three-dimensional network structure, and the strength of the system is difficult to be further improved. Therefore, the performance of Example 14 is reduced.

[0057] In Comparative Example 1, the corrosion resistance decreased without the addition of composite boron nitride, and the three-dimensional network structure in the resin system was also affected. Therefore, the performance of Comparative Example 1 was reduced.

[0058] In Comparative Example 2, no modified carbon fiber was added during the preparation of the resin system. Without the addition of modified carbon fiber, it is difficult for the system to form a stable three-dimensional structure in the epoxy resin, so the performance of Comparative Example 2 is reduced.

[0059] This specific embodiment is merely an explanation of this application and is not intended to limit it. Based on the above description, those skilled in the art can make various changes and modifications without departing from the technical concept of this application. The technical scope of this application is not limited to the contents of the specification but must be determined according to the scope of the claims.

Claims

1. A low-carbon cement concrete, characterized in that: The components include the following parts by weight: 600-700 parts clinker cement, 150-200 parts rice husk ash, 200-300 parts fly ash, and 80-160 parts resin system; The resin system includes epoxy resin, modified carbon fiber, composite boron nitride and carbon nanotubes, and the composite boron nitride raw material includes boron nitride and benzimidazole.

2. The low-carbon cement concrete according to claim 1, characterized in that: The composite boron nitride was prepared by the following method: Boron nitride was mixed with methanol and ultrasonically dispersed to obtain a boron nitride dispersion. Zinc nitrate hexahydrate and 2-methylimidazole were added to methanol to obtain a mixture. Benzimidazole was added to methanol and ultrasonically dispersed to obtain a benzimidazole dispersion. The benzimidazole dispersion was mixed with the boron nitride dispersion and then added to the mixture. After stirring, centrifugation and washing, and drying, composite boron nitride was obtained.

3. The low-carbon cement concrete according to claim 2, characterized in that: The mass ratio of boron nitride, 2-methylimidazole and benzylimidazole is 1:5:(2.4-3).

4. The low-carbon cement concrete according to claim 1, characterized in that: The modified carbon fiber comprises boron nitride, tannic acid, and (3-glycidyloxypropyl)trimethoxysilane.

5. The low-carbon cement concrete according to claim 4, characterized in that: The modified carbon fiber was prepared by the following method: Tannic acid and ferric chloride hexahydrate were mixed and added to Tris buffer to obtain a reaction solution. Carbon fibers were immersed in the reaction solution and stirred to react. After the reaction, the carbon fibers were filtered, washed and dried to obtain tannic acid composite carbon fibers. (3-glycidyloxypropyl)trimethoxysilane was mixed with ethanol to obtain a silane solution. The prepared tannic acid composite carbon fibers were immersed in the silane solution and stirred to react. After the reaction, the carbon fibers were filtered, washed and dried to obtain modified carbon fibers.

6. The low-carbon cement concrete according to claim 5, characterized in that: The reaction time between the tannic acid composite carbon fiber and the silane solution is 18-22 hours.

7. The low-carbon cement concrete according to claim 1, characterized in that: The resin system was prepared using the following method: Composite boron nitride, modified carbon fiber and carbon nanotubes were mixed and added to water, and ultrasonically dispersed to obtain a dispersion. The dispersion was placed in a vacuum tube furnace, sintered, cooled and crushed to obtain a composite. The composite, epoxy resin and curing agent were mixed and stirred evenly to obtain a resin system.

8. The low-carbon cement concrete according to claim 7, characterized in that: The mass ratio of the composite boron nitride, modified carbon fiber, carbon nanotubes and epoxy resin is 0.04:(0.06-0.08):0.02:

1.

9. A method for preparing low-carbon concrete according to any one of claims 1-8, characterized in that: The preparation methods include the following: After mixing clinker cement, rice husk ash, fly ash, and resin system, a concrete mixture is obtained. The concrete mixture is then poured into a mold, vibrated to remove air, and cured to obtain low-carbon concrete.

10. An application of the low-carbon concrete according to any one of claims 1-8, characterized in that: The low-carbon concrete is used in roads, bridges, and building construction.

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