Hybrid fiber ultra-high performance concrete and preparation method thereof

Abstract

The invention discloses hybrid fiber ultra-high performance concrete and a preparation method thereof, and belongs to the technical field of concrete.The ultra-high performance concrete is prepared from, by mass, 600-800 parts of a cementing material, 300-500 parts of reinforced fibers, 300-500 parts of quartz sand, 10-20 parts of a water reducing agent and 20-30 parts of nano silicon dioxide. According to the hybrid fiber ultra-high performance concrete and the preparation method thereof, through the reasonable raw material ratio and the synergistic effect of the steel fibers and the PVA fibers, the mechanical property of the concrete is remarkably improved, the porosity is reduced through the industrial waste pretreatment and carbonization curing process, the chloride ion diffusion coefficient is greatly reduced, and the concrete quality is improved. The impermeability and the corrosion resistance of the concrete are enhanced; meanwhile, resource utilization of industrial waste is achieved, the treatment problem of the industrial waste is solved, the production cost is reduced, and the sustainable development concept is met.

Description

Technical Field

[0001] The present invention relates to the technical field of concrete, and in particular to a hybrid fiber ultra-high performance concrete and a preparation method thereof. Background Art

[0002] Currently, concrete technology is constantly evolving. However, ordinary concrete has limitations in key properties such as strength and durability, making it difficult to meet the stringent requirements for high-performance materials in large building structures, marine engineering, infrastructure in harsh environments, etc. In terms of strength improvement, the effects of traditional strengthening methods are gradually reaching a bottleneck, and the application of new strengthening materials has become the key to breakthrough; in terms of durability, concrete is vulnerable to environmental erosion, and problems such as steel bar corrosion caused by chloride ion penetration and structural damage caused by freeze-thaw cycles are prominent. There are also difficulties in the treatment of industrial waste. The large amount of accumulation not only occupies land resources but may also pollute the environment. Summary of the Invention

[0003] The purpose of the present invention is to provide a hybrid fiber ultra-high performance concrete and a preparation method thereof. Through a reasonable raw material ratio, that is, the combination of ordinary Portland cement with specific proportions of fly ash, steel slag powder, and waste glass powder in the cementitious material, and the synergistic effect of steel fibers and PVA fibers, the mechanical properties of the concrete are significantly improved. The pretreatment of industrial waste and the carbonation curing process reduce the porosity, greatly reducing the chloride ion diffusion coefficient and enhancing the impermeability and corrosion resistance of the concrete; at the same time, the resource utilization of industrial waste is realized, which not only solves the problem of its treatment but also reduces production costs, meeting the concept of sustainable development.

[0004] To achieve the above object, the present invention provides a hybrid fiber ultra-high performance concrete, which includes the following components by mass: 600 - 800 parts of cementitious material, 300 - 500 parts of reinforcing fiber, 300 - 500 parts of quartz sand, 10 - 20 parts of water reducer, and 20 - 30 parts of nano-silica.

[0005] Preferably, the cementitious material includes ordinary Portland cement and industrial waste, where the industrial waste includes fly ash, steel slag powder, and waste glass powder, and their mass ratio is (3 - 5):(2 - 4):(1 - 2). The reinforcing fiber includes steel fiber and PVA fiber, and the volume ratio of steel fiber to PVA fiber is (2.5 - 3.5):1.

[0006] The preparation method of the above-mentioned hybrid fiber ultra-high performance concrete includes the following steps: S1. Pretreat the industrial waste; S2. Dry-mix the cementitious material and quartz sand; S3. Incorporate the fiber and wet-mix; S4. Molding and curing.

[0007] Preferably, the specific operation of S1 is as follows: S11. Activate the steel slag powder in two stages: First, ball-mill the steel slag powder with a ball-to-material ratio of 8:1. The specific surface area of the ball-milled steel slag powder is ≥650 m 2 / kg. Then, mix the ball-milled steel slag powder with a sodium sulfate-triethanolamine solution at a mass ratio of 2-3%, and stir and react at 60-70 °C for 2-3 h. Subsequently, dry it until the moisture content ≤1%; S12. Pickle and pre-carbonize the waste glass powder: Crush the waste glass to a particle size ≤0.3 mm to obtain waste glass powder. Then, soak the waste glass powder in 5% citric acid. After soaking for 1-2 h, place the pickled waste glass powder in a closed reactor, and introduce CO2 gas for carbonization. The pressure in the reactor is 0.2-0.3 MPa, and the temperature is 20-30 °C. After carbonization treatment for 5-7 h, a nano-calcium carbonate coating is formed. After carbonization, dry it at 100-120 °C for 2 h, and screen the particles ≤0.15 mm; S13. Pretreat the fly ash: Separate the fly ash through an air classifier, and select the ultrafine fly ash with a particle size ≤20 μm.

[0008] Preferably, the specific operation of S2 is as follows: S21. Put ordinary Portland cement and 30% quartz sand into a planetary mixer for stirring; S22. After the stirring is completed, add the pretreated fly ash, activated steel slag powder, pickled waste glass powder and the remaining quartz sand to the planetary mixer, and increase the speed of the planetary mixer to continue stirring; S23. After the stirring is completed, add nano-silica and pre-carbonized waste glass powder to the planetary mixer, and increase the speed of the planetary mixer to continue stirring until the mixture is uniform.

[0009] Preferably, in S21, the stirring rate of the planetary mixer is 20-30 r / min, and the stirring time is 3-5 min; In S22, the stirring rate of the planetary mixer is 50-70 r / min, and the stirring time is 5-8 min; In S23, the stirring rate of the planetary mixer is 90-100 r / min, and the stirring time is 2-3 min; The stirring temperatures of S21, S22, and S23 are all 25-35 °C.

[0010] Preferably, the specific operation of S3 is as follows: S31. Uniformly sprinkle the steel fibers into the mixture through a vibrating feeder, and start the electromagnetic device in the planetary mixer to perform low-speed stirring so that the steel fibers are oriented along the magnetic field direction; S32. Premix the PVA fibers and water reducer, and spray them into a planetary mixer through a high-pressure atomizing nozzle. At the same time, turn on the ultrasonic generator to break the agglomeration of the PVA fibers, and carry out high-speed stirring to obtain a mixed slurry.

[0011] Preferably, in S31, the ends of the steel fibers are hook-shaped, and the aspect ratio is (60 - 80):1; In S32, the water-binder ratio of the PVA fibers and the water reducer is (0.16 - 0.2):1, the frequency of the ultrasonic generator is 30 - 50 kHz, the power is 5000 - 6000 W, the stirring rate of the planetary mixer is 100 - 130 r / min, and the stirring time is 8 - 10 min.

[0012] Preferably, the specific operation of S4 is as follows: S41. Inject the mixed slurry into the mold and continuously apply pressure; S42. After demolding, place it in a steam curing box for constant temperature curing, then carry out temperature rising curing, and then carry out temperature dropping curing to obtain a specimen; S43. Transfer the specimen to a carbonization chamber for curing. After carbonization, spray a silane coupling agent on the surface to seal the pores.

[0013] Preferably, in S41, the applied pressure is a vertical pressure of 0.3 - 0.5 MPa for 3 - 5 min; In S42, the constant temperature curing temperature is 70 - 90 °C, the constant temperature curing time is 12 - 36 h, the temperature rising curing temperature is 100 - 110 °C, and the temperature rising curing time is 12 - 24 h; the temperature dropping curing temperature is 50 - 70 °C, and the temperature dropping curing time is 12 - 24 h; In S43, the CO2 concentration in the carbonization chamber is 15 - 30%, the temperature is 20 - 30 °C, the humidity is 60 - 80%, the curing time is 36 - 72 h, and the concentration of the silane coupling agent is 4 - 6%.

[0014] Therefore, the present invention adopts the above-mentioned hybrid fiber ultra-high performance concrete and its preparation method, and has the following beneficial effects: (1) By combining ordinary Portland cement in the cementitious material with fly ash, steel slag powder, and waste glass powder in a specific mass ratio, and synergistically strengthening with steel fibers and PVA fibers in an appropriate volume ratio, it can withstand greater loads and is suitable for heavy-duty structures; (2) The industrial waste pretreatment and carbonization curing process reduce the porosity of the concrete, effectively prevent erosion media such as chloride ions from entering, improve the density and impermeability, prevent the corrosion of internal steel bars, enhance the corrosion resistance in harsh environments, and extend the service life of the structure; (3)The reasonable application of industrial waste such as fly ash, steel slag powder and waste glass powder in concrete not only solves the problem of their disposal, but also reduces the production cost of concrete, reduces the dependence on natural resources, and conforms to the concept of green environmental protection and sustainable development.

[0015] The following are examples to further describe in detail the technical solutions of the present invention. Specific embodiments

[0016] The following further illustrates the technical solutions of the present invention through examples.

[0017] Unless otherwise defined, the technical terms or scientific terms used in the present invention should have the ordinary meanings understood by those of ordinary skill in the field to which the present invention pertains.

[0018] Example 1 The present invention provides a hybrid fiber ultra-high performance concrete, which includes the following components by mass: 700 parts of cementitious materials (the mass ratio of cement, fly ash, steel slag powder, and waste glass powder is 5:3:2:1), 400 parts of reinforcing fibers (the volume ratio of steel fibers to PVA fibers is 3:1), 400 parts of quartz sand, 15 parts of water reducing agent, and 25 parts of nano-silica.

[0019] The preparation method includes the following steps: I. Pretreatment: The steel slag powder is ball milled to a specific surface area of 680 m 2 / kg, and 65 °C is activated with 3% sodium sulfate-triethanolamine solution for 2.5 h; The waste glass powder is soaked in 5% citric acid for 1.5 h, pre-carbonized with 0.25 MPa CO2 for 6 h, dried and screened to 0.1 mm; The fly ash is classified by air flow to 15 μm.

[0020] II. Dry mixing: Put ordinary Portland cement and 30% quartz sand into a planetary mixer and stir at 25 r / min for 4 min; After the stirring is completed, add the pretreated fly ash, activated steel slag powder, pickled waste glass powder and the remaining quartz sand to the planetary mixer, and increase the speed of the planetary mixer to 60 r / min and stir for 7 min; After the stirring is completed, add nano-silica and pre-carbonized waste glass powder to the planetary mixer, increase the speed of the planetary mixer to 95 r / min and stir for 3 min, and the mixture is stirred evenly.

[0021] III. Wet mixing: Steel fibers with an aspect ratio of 70:1 are evenly scattered into the mixture through a vibrating feeder, and the electromagnetic device in the planetary mixer is started to provide a magnetic field of 0.4 T, and low-speed stirring is carried out at a rate of 40 r / min to make the steel fibers oriented along the magnetic field direction; PVA fibers and water reducing agent are premixed according to a water-binder ratio of 0.18:1, and sprayed into the planetary mixer through a high-pressure atomizing nozzle. At the same time, the ultrasonic generator is turned on, and ultrasonic waves of 50 kHz and 5500 W are used to break the agglomeration of PVA fibers, and high-speed stirring is carried out at 120 r / min for 9 min to obtain a mixed slurry.

[0022] IV. Curing: Inject the mixed slurry into the mold, and continuously apply a vertical pressure of 0.4 MPa for 4 min; After demolding, it is placed in a steam curing box for constant temperature curing at 80 °C for 24 h, then the temperature is raised to 105 °C for curing for 18 h, and then the temperature is lowered to 60 °C for curing for 18 h to obtain a specimen; Transfer the specimen to a carbonization chamber for curing. The CO2 concentration in the carbonization chamber is 25%, the temperature is 25 °C, and the curing time is 60 h. After carbonization, 5% silane coupling agent is sprayed on the surface to seal the pores.

[0023] Example 2 The present invention provides a hybrid fiber ultra-high performance concrete, which includes the following components by mass: 600 parts of cementitious materials (the mass ratio of cement, fly ash, steel slag powder, and waste glass powder is 4:4:3:1.5), 450 parts of reinforcing fibers (the volume ratio of steel fibers to PVA fibers is 2.8:1), 450 parts of quartz sand, 18 parts of water reducing agent, and 28 parts of nano-silica.

[0024] The preparation method includes the following steps: I. Pretreatment: The steel slag powder is ball milled to a specific surface area of 680 m 2 / kg, and 2% sodium sulfate-triethanolamine solution is added for activation at 70 °C for 3 h; The waste glass powder is soaked in 5% citric acid for 1.5 h, pre-carbonized with 0.3 MPa CO2 for 7 h, dried and screened to 0.1 mm; The fly ash is classified by air flow to 15 μm.

[0025] II. Dry mixing: Put ordinary Portland cement and 30% quartz sand into the planetary mixer and stir at 25 r / min for 4 min; After the stirring is completed, add the pretreated fly ash, activated steel slag powder, pickled waste glass powder and the remaining quartz sand to the planetary mixer, and raise the speed of the planetary mixer to 60 r / min and stir for 7 min; After the stirring is completed, nano-silica and pre-carbonized waste glass powder are added to the planetary mixer, and the speed of the planetary mixer is increased to 95 r / min and stirred for 3 min, and the mixture is stirred evenly.

[0026] III. Wet mixing: Steel fibers with a length-to-diameter ratio of 70:1 are evenly scattered into the mixture through a vibrating feeder, and the electromagnetic device in the planetary mixer is started to provide a magnetic field of 0.4 T, and low-speed stirring is carried out at a rate of 40 r / min to make the steel fibers orientedly distributed along the magnetic field direction; PVA fibers and water reducing agent are premixed according to a water-binder ratio of 0.18:1, and are sprayed into the planetary mixer through a high-pressure atomizing nozzle. At the same time, an ultrasonic generator is turned on, and ultrasonic waves of 50 kHz and 6000 W are used to break the agglomeration of PVA fibers, and high-speed stirring is carried out at 130 r / min for 10 min to obtain a mixed slurry.

[0027] IV. Curing: The mixed slurry is injected into the mold, and a vertical pressure of 0.4 MPa is continuously applied for 4 min; After demolding, it is placed in a steam curing box for constant temperature curing at 90 °C for 36 h, then heated to 110 °C for curing for 24 h, and then cooled to 70 °C for curing for 24 h to obtain a specimen; The specimen is transferred to a carbonization chamber for curing. The CO2 concentration in the carbonization chamber is 25%, the temperature is 25 °C, and the curing time is 60 h. After carbonization, 5% silane coupling agent is sprayed on the surface to seal the pores.

[0028] Example III The present invention provides a hybrid fiber ultra-high performance concrete, which comprises the following components by mass: 800 parts of cementitious material (the mass ratio of cement to industrial waste is 1:1, and the mass ratio of fly ash, steel slag powder, and waste glass powder is 3:4:2), 350 parts of reinforcing fiber (the volume ratio of steel fiber to PVA fiber is 3.5:1), 300 parts of quartz sand, 20 parts of water reducing agent, and 30 parts of nano-silica.

[0029] The preparation method comprises the following steps: I. Pretreatment: The steel slag powder is ball-milled to a specific surface area of 720 m 2 / kg, and 3% sodium sulfate-triethanolamine solution is added for activation at 65 °C for 2.5 h; The waste glass powder is soaked in 5% citric acid for 1.5 h, pre-carbonized with 0.25 MPa CO2 for 6 h, dried and sieved to 0.1 mm; The fly ash is classified by air flow to 15 μm.

[0030] II. Dry mixing: Put ordinary portland cement and 30% quartz sand into a planetary mixer and stir at 25 r / min for 4 min; After stirring, add the pretreated fly ash, activated steel slag powder, pickled waste glass powder and the remaining quartz sand into the planetary mixer, and increase the speed of the planetary mixer to 60 r / min and stir for 7 min; After stirring, add nano-silica and pre-carbonized waste glass powder into the planetary mixer, increase the speed of the planetary mixer to 100 r / min and stir for 3 min to make the mixture evenly stirred.

[0031] III. Wet mixing: Sprinkle steel fibers with a length-to-diameter ratio of 70:1 into the mixture evenly through a vibrating feeder, and start the electromagnetic device in the planetary mixer to provide a magnetic field of 0.4 T, and use a speed of 40 r / min for low-speed stirring to make the steel fibers distributed in the direction of the magnetic field; Premix PVA fibers and water reducing agent according to a water-binder ratio of 0.18:1, and spray them into the planetary mixer through a high-pressure atomizing nozzle. At the same time, turn on the ultrasonic generator, and use 50 kHz ultrasonic waves to break the agglomeration of PVA fibers, and use a high speed of 120 r / min to stir for 9 min to obtain a mixed slurry.

[0032] IV. Curing: Inject the mixed slurry into the mold and continuously apply a vertical pressure of 0.4 MPa for 4 min; After demolding, place it in a steam curing box for constant temperature curing at 80 °C for 24 h, then raise the temperature to 105 °C for curing for 18 h, and then lower the temperature to 60 °C for curing for 18 h to obtain a specimen; Transfer the specimen to a carbonization chamber for curing. The CO2 concentration in the carbonization chamber is 25%, the temperature is 25 °C, and the curing time is 72 h. After carbonization, spray 6% silane coupling agent on the surface to seal the pores.

[0033] Comparative Example 1 The concrete in Comparative Example 1 includes the following components: 700 parts of cementitious material (pure cement), 400 parts of reinforcing fiber (only steel fiber), 400 parts of quartz sand, 15 parts of water reducing agent, and 25 parts of nano-silica.

[0034] The difference in the preparation method from Example 1 is that there is no pretreatment step for industrial waste, and during dry mixing, it is a single stirring at 50 r / min for 10 min, and during curing, it is standard curing without carbonization treatment, and other conditions are the same.

[0035] Test the compressive strength and flexural strength of the concrete obtained from Example 1 to Example 3 and Comparative Example 1 according to the method in GB / T50081-2019 "Standard for Test Methods of Physical and Mechanical Properties of Concrete", and the test results are shown in Table 1.

[0036] Table 1 Test Results of Compressive Strength and Flexural Strength ;

[0037] As can be seen from Table 1, the compressive strengths and flexural strengths of Examples 1 to 3 are higher than those of Comparative Example 1, indicating that the pretreatment of industrial waste and the synergistic effect of steel fiber and PVA fiber significantly improve the mechanical properties of concrete.

[0038] The concrete obtained from Examples 1 to 3 and Comparative Example 1 was subjected to the ASTM C1202 rapid chloride ion penetration method, and the concrete was immersed in 3.5% NaCl solution for 28 days to obtain its chloride ion diffusion coefficient. The results are shown in Table 2.

[0039] Table 2 Chloride Ion Diffusion Coefficient ;

[0040] As can be seen from Table 2, the chloride ion diffusion coefficients of Examples 1 to 3 are much lower than those of Comparative Example 1, indicating that the pretreatment of industrial waste and the carbonation curing process significantly reduce the porosity, improve the compactness and impermeability of concrete, and can also effectively prevent corrosion and improve its corrosion resistance.

[0041] Therefore, the present invention adopts the above-mentioned hybrid fiber ultra-high performance concrete and its preparation method. Through reasonable raw material ratio, that is, the combination of ordinary Portland cement with specific proportions of fly ash, steel slag powder, and waste glass powder in the cementitious material, and the synergistic effect of steel fiber and PVA fiber, the mechanical properties of concrete are significantly improved. The industrial waste pretreatment and carbonation curing process reduce the porosity, greatly reduce the chloride ion diffusion coefficient, enhance the impermeability and corrosion resistance of concrete; at the same time, the resource utilization of industrial waste is realized, which not only solves the problem of its treatment but also reduces the production cost, meeting the concept of sustainable development.

[0042] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that they can still modify or equivalently replace the technical solutions of the present invention, and these modifications or equivalent replacements cannot make the modified technical solutions deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A hybrid fiber ultra-high performance concrete, characterized in that: By mass parts, it includes the following components: 600 - 800 parts of cementitious material, 300 - 500 parts of reinforcing fiber, 300 - 500 parts of quartz sand, 10 - 20 parts of water reducer, and 20 - 30 parts of nano-silica; The cementitious material includes ordinary Portland cement and industrial waste. The industrial waste includes fly ash, steel slag powder, and waste glass powder, and their mass ratio is (3 - 5):(2 - 4):(1 - 2). The reinforcing fiber includes steel fiber and PVA fiber, and the volume ratio of steel fiber to PVA fiber is (2.5 - 3.5):

1.

2. The preparation method of a hybrid fiber ultra-high performance concrete according to claim 1, characterized in that: It includes the following steps: S1. Pretreat the industrial waste. The specific operation of S1 is: S11. Activate the steel slag powder in two stages: First, ball-mill the steel slag powder with a ball-to-material ratio of 8:

1. After ball-milling, the specific surface area of the steel slag powder is ≥ 650 m 2 / kg. Then, mix the ball-milled steel slag powder with a sodium sulfate-triethanolamine solution in a mass ratio of 2 - 3%, and stir and react at 60 - 70 °C for 2 - 3 h. Subsequently, dry it to a moisture content of ≤ 1%; S12. Acid wash - pre - carbonize the waste glass powder: Crush the waste glass to a particle size ≤ 0.3 mm to obtain waste glass powder. Then soak the waste glass powder in 5% citric acid. After soaking for 1 - 2 h, place the acid - washed waste glass powder in a closed reaction kettle and introduce CO2 gas for carbonization. The pressure in the reaction kettle is 0.2 - 0.3 MPa, the temperature is 20 - 30 °C. After carbonization treatment for 5 - 7 h, a nano - calcium carbonate coating is formed. After carbonization, dry at 100 - 120 °C for 2 h and screen the particles ≤ 0.15 mm; S13. Pretreat the fly ash: Separate the fly ash through an air classifier and select the ultra - fine fly ash with a particle size ≤ 20 μm; S2. Dry - mix the cementitious material and quartz sand; S3. Incorporate the fiber and wet - mix; S4. Molding and curing.

3. The preparation method of a hybrid fiber ultra-high performance concrete according to claim 2, characterized in that: The specific operation of S2 is: S21. Put ordinary Portland cement and 30% of quartz sand into a planetary mixer for stirring; S22. After the stirring is completed, add the pretreated fly ash, activated steel slag powder, acid - washed waste glass powder, and the remaining quartz sand to the planetary mixer, and increase the speed of the planetary mixer to continue stirring; S23. After the stirring is completed, add nano - silica and pre - carbonized waste glass powder to the planetary mixer, and increase the speed of the planetary mixer to continue stirring until the mixture is uniform.

4. The preparation method of a hybrid fiber ultra-high performance concrete according to claim 3, wherein: In S21, the stirring rate of the planetary mixer is 20 - 30 r / min, and the stirring time is 3 - 5 min; In S22, the stirring rate of the planetary mixer is 50 - 70 r / min, and the stirring time is 5 - 8 min; In S23, the stirring rate of the planetary mixer is 90 - 100 r / min, and the stirring time is 2 - 3 min; The stirring temperature of S21, S22, and S23 is 25 - 35 °C.

5. The preparation method of a hybrid fiber ultra-high performance concrete according to claim 2, wherein: The specific operation of S3 is: S31. Uniformly sprinkle the steel fiber into the mixture through a vibrating feeder, and start the electromagnetic device in the planetary mixer for low - speed stirring to make the steel fiber distribute in the direction of the magnetic field; S32. Premix the PVA fiber and the water reducer, and spray them into the planetary mixer through a high - pressure atomizing nozzle. At the same time, turn on the ultrasonic generator to break the agglomeration of the PVA fiber and conduct high - speed stirring to obtain a mixed slurry.

6. The preparation method of a hybrid fiber ultra-high performance concrete according to claim 5, characterized in that: In S31, the end of the steel fiber is hook - shaped, and the aspect ratio is (60 - 80):1; In S32, the water-binder ratio of PVA fiber to water reducer is (0.16 - 0.2):1, the frequency of the ultrasonic generator is 30 - 50 kHz, the power is 5000 - 6000 W, the stirring rate of the planetary mixer is 100 - 130 r / min, and the stirring time is 8 - 10 min.

7. The preparation method of a hybrid fiber ultra-high performance concrete according to claim 2, characterized in that: The specific operation of S4 is as follows: S41. Inject the mixed slurry into the mold and continuously apply pressure. S42. After demolding, place it in a steam curing box for constant temperature curing, then carry out temperature rising curing, and then carry out temperature dropping curing to obtain the specimen. S43. Transfer the specimen to the carbonization chamber for curing, and spray silane coupling agent on the surface after carbonization to seal the pores.

8. The preparation method of a hybrid fiber ultra-high performance concrete according to claim 7, characterized in that: In S41, the applied pressure is a vertical pressure of 0.3 - 0.5 MPa for 3 - 5 min. In S42, the constant temperature curing temperature is 70 - 90 °C, the constant temperature curing time is 12 - 36 h, the temperature rising curing temperature is 100 - 110 °C, and the temperature rising curing time is 12 - 24 h; the temperature dropping curing temperature is 50 - 70 °C, and the temperature dropping curing time is 12 - 24 h. In S43, the CO2 concentration in the carbonization chamber is 15 - 30%, the temperature is 20 - 30 °C, the humidity is 60 - 80%, the curing time is 36 - 72 h, and the concentration of the silane coupling agent is 4 - 6%.