An ultra-high performance concrete (UHPC) for water conservancy and hydropower and a preparation method thereof

Abstract

The application relates to the technical field of building materials, in particular to super-high-performance UHPC concrete for water conservancy and hydropower and a preparation method thereof, which comprises the following raw materials in parts by weight: 100-110 parts of sulphoaluminate cement, 13-15 parts of silica ash, 10-14 parts of slag powder, 110-120 parts of filler, 12-14 parts of additive, 12-14 parts of steel fiber, 3-5 parts of polycarboxylate superplasticizer, 3-5 parts of expanding agent, 0.4-0.6 parts of defoaming agent and 28-32 parts of mixing water. In the application, the cashew nut shell extract in the composite agent forms a chemical adsorption layer after reaction, blocks the diffusion channel of chloride ions, the introduced triethylamine can promote the loss of migration activity of chloride ions, the modified bentonite and coal gangue can fill the gaps between the cement, and the surface-absorbed organic molecules can exchange and adsorb the chloride ions, so that the permeation path is reduced, and the chloride ion penetration resistance of the concrete is improved.

Description

Technical Field

[0001] This invention relates to the field of building materials technology, specifically to an ultra-high performance UHPC concrete for water conservancy and hydropower and its preparation method. Background Technology

[0002] Ultra-high performance UHPC concrete, also known as reactive powder concrete, is a new type of cement-based composite material based on cement and fine aggregate, composed of active mineral admixtures, water-reducing agents, and fibers. It is widely used in water conservancy projects such as bridge construction.

[0003] In the prior art, although ordinary concrete can meet the basic strength requirements, its high internal porosity and insufficient density make it easy for corrosive media such as chloride ions to penetrate into the structure through capillary channels, accelerating steel corrosion and concrete deterioration. Based on this, the present invention provides an ultra-high performance UHPC concrete for water conservancy and hydropower and its preparation method. Summary of the Invention

[0004] The purpose of this invention is to provide an ultra-high performance UHPC concrete for water conservancy and hydropower and its preparation method. The concrete prepared by this invention not only has good resistance to chloride ion penetration, but also has excellent compressive strength, effectively improving the performance of concrete.

[0005] To achieve the above objectives, the present invention provides the following technical solution: an ultra-high performance UHPC concrete for water conservancy and hydropower, comprising the following raw materials in parts by weight: 100-110 parts of sulfoaluminate cement, 13-15 parts of silica fume, 10-14 parts of slag powder, 110-120 parts of filler, 12-14 parts of additives, 12-14 parts of steel fiber, 3-5 parts of polycarboxylate superplasticizer, 3-5 parts of expansion agent, 0.4-0.6 parts of defoamer, and 28-32 parts of mixing water; The raw materials for the additives include compounding agents, polyaspartic acid esters, and sodium octenyl succinate starch; The raw materials for the compound agent include slurry, powder, and triethylamine; Furthermore, the additive is prepared by the following method: Step 1: Take the composite agent and polyaspartic acid ester and mix them at a mass ratio of (6-8):3. Stir at 300-400 rpm for 20-30 min to obtain the first mixture. Step 2: Mix sodium octenyl succinate starch and deionized water at a mass ratio of 1:(8-10), and stir at 60-70℃ and 200-300rpm for 25-35 minutes to obtain the second mixture; Step 3: Add the first mixture to the second mixture and stir for 30-40 minutes at 45-50℃ and 400-500 rpm. The resulting product is spray-dried at an inlet air temperature of 160-180℃ and an outlet air temperature of 80-90℃ to obtain the additive. The mass ratio of the first mixture to the second mixture is 1:(3-4).

[0006] Further, the composite agent is prepared by the following method: take a slurry, heat it to 75-80℃, add powder, stir at 100-200 rpm for 5-10 min, add triethylamine, stir at 75-80℃ and 100-200 rpm for 3-4 h, and heat at 55-65℃ and 0.07-0.09 MPa for 1 h to obtain the composite agent, wherein the mass of powder is 25% of the mass of slurry, and the mass of triethylamine is 2-3% of the mass of slurry.

[0007] Further, the slurry is prepared by the following method: take washed and dried cashew shells, crush them through an 8-10 mesh sieve, dry them at 100-110℃ for 3-4 hours, cool them to room temperature, add anhydrous ethanol, stir at 300-400 rpm for 1 hour, soak them for 22-26 hours, add sodium hydroxide, stir at 55-65℃ and 300-400 rpm for 2 hours, centrifuge the obtained product at 3000 rpm for 10-20 minutes, take the supernatant, and heat it at 70℃ and 0.1 MPa for 2 hours to obtain the slurry.

[0008] Furthermore, the mass of the anhydrous ethanol is 3-4 times the mass of the cashew shell, and the mass of the sodium hydroxide is 1.5-2.5% of the mass of the cashew shell.

[0009] Furthermore, the powder is prepared by the following method: Step a: Take the additives, bentonite and talc powder and mix them in a mass ratio of 5:3:2. Grind them through an 80-100 mesh sieve and stir them at 200-300 rpm for 10-15 min to obtain a mixed powder. Add 25-35% anhydrous ethanol by mass of the mixture and continue stirring for 20-30 min. Dry it at 85-95℃ for 3-4 h to obtain a dried product. Grind it through a 120 mesh sieve to obtain a dried powder. Step b: Mix the dried powder with propylene oxide at a mass ratio of (6-8):4, add 30-40% of the total mass of deionized water, stir at 250-350 rpm for 15-25 min, dry at 90-100℃ for 3-4 h, cool and grind through a 200-300 mesh sieve to obtain the powder.

[0010] Further, the additive is prepared by the following method: coal gangue is crushed and passed through a 60-80 mesh sieve to obtain coal gangue powder, calcium carbonate and silica powder are added, stirred at 200-300 rpm for 10-15 min, and then calcined at 600-700℃ for 1.5-2.5 h and cooled to obtain the additive. The mass ratio of coal gangue powder, calcium carbonate and silica powder is (3-5):(2-4):(2-4).

[0011] Furthermore, the expanding agent is a calcium sulfoaluminate expanding agent, and the defoamer is an organosilicon defoamer.

[0012] Further, the filler is prepared by the following method: Magnesite that has passed through a 2-4 mesh sieve is taken, sodium carbonate and quartz sand are added, and the mixture is roasted at 600-750℃ for 1.5-2.5 hours. The mixture is then pulverized to pass through an 80-100 mesh sieve and roasted again at 800-900℃ for 1-2 hours to obtain the roasted product. The roasted product, calcined kaolin, and calcium stearate are mixed at a mass ratio of (7-8):2:0.1 and stirred at 200-300 rpm for 15-25 minutes. The resulting product is dried at 100-120℃ for 1.5-2.5 hours to obtain the filler, wherein the mass of sodium carbonate is 7-9% of the mass of magnesite and the mass of quartz sand is 4-6% of the mass of magnesite.

[0013] Furthermore, the preparation method of the ultra-high performance UHPC concrete for water conservancy and hydropower includes the following steps: S1: Take sulfoaluminate cement, silica fume, slag powder, filler, additives, expanding agent and defoamer as needed and mix them. Stir at 40-60 rpm for 2-4 minutes to obtain the first batch. S2: Mix the mixing water and polycarboxylate superplasticizer, add the first batching material, stir at 60-80 rpm for 3-5 min, add steel fibers, stir at 80-100 rpm for 4-6 min, pour the resulting product into the mold, and then steam cure at 50-70℃ for 8-10 h to obtain ultra-high performance UHPC concrete.

[0014] Compared with the prior art, the beneficial effects of the present invention are: 1. In this invention, the coating layer formed by sodium octenyl succinate starch in the additive hydrates and swells in an alkaline environment, effectively preventing water penetration. The cashew nut shell extract in the composite agent forms a dense chemical adsorption layer after reaction, blocking the chloride ion diffusion channels. At the same time, the triethylamine introduced in the composite agent can cause the invading chloride ions to lose their migration activity. The modified bentonite and coal gangue in the powder not only fill the cement gaps with fine particles to refine the pore structure, but also exchange and adsorb with chloride ions, further reducing the penetration path. The double-calcined and activated magnesite and quartz sand in the filler are densely packed, which greatly reduces the capillary porosity and cuts off the connecting channels. All of these work together to improve the chloride ion penetration resistance of concrete.

[0015] 2. In this invention, the cashew nut shell extract in the additive is rich in phenolic compounds, which polymerize in an alkaline environment to form a reinforcing phase that is evenly distributed in the cement stone, effectively dispersing stress and inhibiting the propagation of microcracks. The bentonite and coal gangue components in the powder, which have been calcined and organically modified, fill the gaps between cement particles with fine particles, reducing porosity and microcracks, making the matrix denser. Magnesite, after double calcination, produces lightly calcined magnesium oxide, which reacts with water to generate an expansive component that can fill the interface transition zone between aggregate and cement stone, enhancing the density and integrity of the matrix and improving the compressive strength of concrete. Attached Figure Description

[0016] Figure 1 The present invention provides a flowchart of an ultra-high performance UHPC concrete for water conservancy and hydropower and its preparation method. Detailed Implementation

[0017] 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.

[0018] It should be noted that the raw materials used in the following embodiments are all commercially available.

[0019] Example 1

[0020] A type of ultra-high performance UHPC concrete for water conservancy and hydropower includes the following raw materials in parts by weight: 100 parts of sulfoaluminate cement, 13 parts of silica fume, 10 parts of slag powder, 110 parts of filler, 12 parts of additive, 12 parts of steel fiber, 3 parts of polycarboxylate superplasticizer, 3 parts of expansion agent, 0.4 parts of defoamer, and 28 parts of mixing water. The raw materials for the additives include compounding agents, polyaspartic acid esters, and sodium octenyl succinate starch; The raw materials for the compound agent include slurry, powder, and triethylamine; The additives are prepared by the following methods: Step 1: Mix the composite agent and polyaspartic acid ester at a mass ratio of 6:3 and stir at 300 rpm for 20 minutes to obtain the first mixture; Step 2: Mix sodium octenyl succinate starch and deionized water at a mass ratio of 1:8, and stir at 60℃ and 200 rpm for 25 min to obtain the second mixture; Step 3: Mix the first mixture and the second mixture at a mass ratio of 1:3, stir at 45℃ and 400rpm for 30min, and spray dry the resulting product at an inlet air temperature of 160℃ and an outlet air temperature of 80℃ to obtain the additive.

[0021] The composite agent was prepared by the following method: the slurry was heated to 75°C, 25% of the slurry mass of powder was added, and the mixture was stirred at 100 rpm for 5 min. Then, 2% of the slurry mass of triethylamine was added, and the mixture was stirred at 75°C and 100 rpm for 3 h. Finally, the composite agent was prepared by heating at 55°C and 0.07 MPa for 1 h.

[0022] The slurry was prepared by the following method: cashew shells were washed, dried, crushed and passed through an 8-mesh sieve, dried at 100℃ for 3 hours, cooled to room temperature, and anhydrous ethanol was added in an amount equal to 3 times the weight of the cashew shells. The mixture was stirred at 300 rpm for 1 hour and then soaked for 22 hours. Sodium hydroxide was added and the mixture was stirred at 55℃ and 300 rpm for 2 hours. The resulting product was centrifuged at 3000 rpm for 10 minutes. The supernatant was collected and heated at 70℃ and 0.1 MPa for 2 hours to obtain the slurry. The mass of sodium hydroxide was 1.5% of the mass of the cashew shells.

[0023] The powder is prepared by the following method: Step a: Mix the additives, bentonite, and talc, pulverize, pass through an 80-mesh sieve, stir at 200 rpm for 10 min to obtain a mixed powder, add anhydrous ethanol, continue stirring for 20 min, dry at 85℃ for 3 h to obtain a dried product, pulverize and pass through a 120-mesh sieve to obtain a dried powder. The mass ratio of the additives, bentonite, and talc is 5:3:2, and the mass of anhydrous ethanol is 25% of the mass of the mixture. Step b: Mix the dried powder with propylene oxide, add 30% of the total mass of deionized water, stir at 250 rpm for 15 min, dry at 90℃ for 3 h, cool and grind through a 200 mesh sieve to obtain powder. The mass ratio of dried powder to propylene oxide is 6:4.

[0024] The additive is prepared by the following method: coal gangue is crushed and passed through a 60-mesh sieve to obtain coal gangue powder. The coal gangue powder, calcium carbonate and silica powder are mixed in a mass ratio of 3:2:2, stirred at 200 rpm for 10 min, and then calcined at 600℃ for 1.5 h and cooled to obtain the additive.

[0025] The expanding agent is a calcium sulfoaluminate expanding agent, and the defoamer is an organosilicon defoamer.

[0026] The filler was prepared by the following method: Magnesite, sodium carbonate and quartz sand that had passed through a 2-mesh sieve were mixed in a mass ratio of 100:7:4, calcined at 600℃ for 1.5h, pulverized to pass through an 80-mesh sieve, and then calcined at 800℃ for 1h to obtain the calcined product. The calcined product, calcined kaolin and calcium stearate were mixed in a mass ratio of 7:2:0.1 and stirred at 200rpm for 15min. The resulting product was dried at 100℃ for 1.5h to obtain the filler.

[0027] Preparation method of ultra-high performance UHPC concrete for water conservancy and hydropower: S1: Take sulfoaluminate cement, silica fume, slag powder, filler, additives, expanding agent and defoamer as needed and mix them. Stir at 40 rpm for 2 minutes to obtain the first batch. S2: Mix the mixing water and polycarboxylate superplasticizer, add the first batching material, stir at 60 rpm for 3 min, add steel fibers, stir at 80 rpm for 4 min, pour the resulting product into the mold, and then steam cure at 50℃ for 8 h to obtain ultra-high performance UHPC concrete.

[0028] Example 2

[0029] A type of ultra-high performance UHPC concrete for water conservancy and hydropower includes the following raw materials in parts by weight: 105 parts of sulfoaluminate cement, 14 parts of silica fume, 12 parts of slag powder, 115 parts of filler, 13 parts of additive, 13 parts of steel fiber, 4 parts of polycarboxylate superplasticizer, 4 parts of expansion agent, 0.5 parts of defoamer, and 30 parts of mixing water. The raw materials for the additives include compounding agents, polyaspartic acid esters, and sodium octenyl succinate starch; The raw materials for the compound agent include slurry, powder, and triethylamine; The additives are prepared by the following methods: Step 1: Mix the composite agent and polyaspartic acid ester at a mass ratio of 7:3 and stir at 350 rpm for 25 minutes to obtain the first mixture; Step 2: Mix sodium octenyl succinate starch and deionized water at a mass ratio of 1:9, and stir at 65°C and 250 rpm for 30 min to obtain the second mixture; Step 3: Mix the first mixture and the second mixture at a mass ratio of 1:3.5, stir at 47℃ and 450rpm for 35min, and spray dry the resulting product at an inlet air temperature of 170℃ and an outlet air temperature of 85℃ to obtain the additive.

[0030] The composite agent was prepared by the following method: the slurry was heated to 77°C, 25% of the slurry mass of powder was added, and the mixture was stirred at 150 rpm for 7 min. Then, 2.5% of the slurry mass of triethylamine was added, and the mixture was stirred at 77°C and 150 rpm for 3.5 h. Finally, the mixture was heated at 60°C and 0.08 MPa for 1 h to obtain the composite agent.

[0031] The slurry was prepared by the following method: cashew shells were washed, dried, crushed and passed through a 9-mesh sieve, dried at 105℃ for 3.5h, cooled to room temperature, and anhydrous ethanol was added at 3.5 times the weight of the cashew shells. The mixture was stirred at 350rpm for 1h and then soaked for 24h. Sodium hydroxide was added and the mixture was stirred at 60℃ and 350rpm for 2h. The resulting product was centrifuged at 3000rpm for 15min, and the supernatant was collected and heated at 70℃ and 0.1MPa for 2h to obtain the slurry. The mass of sodium hydroxide was 2% of the mass of the cashew shells.

[0032] The powder is prepared by the following method: Step a: Mix the additives, bentonite, and talc, pulverize, pass through a 90-mesh sieve, and stir at 250 rpm for 12 minutes to obtain a mixed powder. Add anhydrous ethanol, continue stirring for 25 minutes, and dry at 90℃ for 3.5 hours to obtain a dried product. Pulverize and pass through a 120-mesh sieve to obtain a dried powder. The mass ratio of the additives, bentonite, and talc is 5:3:2, and the mass of anhydrous ethanol is 30% of the mass of the mixture. Step b: Mix the dried powder with propylene oxide, add 35% of the total mass of deionized water, stir at 300 rpm for 20 min, dry at 95℃ for 3.5 h, cool and grind through a 250 mesh sieve to obtain powder. The mass ratio of dried powder to propylene oxide is 7:4.

[0033] The additive is prepared by the following method: coal gangue is crushed and passed through a 70-mesh sieve to obtain coal gangue powder. The coal gangue powder, calcium carbonate and silica powder are mixed in a mass ratio of 4:3:3, stirred at 250 rpm for 12 min, and then calcined at 650℃ for 2 h and cooled to obtain the additive.

[0034] The expanding agent is a calcium sulfoaluminate expanding agent, and the defoamer is an organosilicon defoamer.

[0035] The filler was prepared by the following method: Magnesite, sodium carbonate and quartz sand that had passed through a 3-mesh sieve were mixed in a mass ratio of 100:8:5, calcined at 675℃ for 2 hours, pulverized to pass through a 90-mesh sieve, and then calcined at 850℃ for 1.5 hours to obtain the calcined product. The calcined product, calcined kaolin and calcium stearate were mixed in a mass ratio of 7.5:2:0.1 and stirred at 250 rpm for 20 minutes. The resulting product was dried at 110℃ for 2 hours to obtain the filler.

[0036] Preparation method of ultra-high performance UHPC concrete for water conservancy and hydropower: S1: Take sulfoaluminate cement, silica fume, slag powder, filler, additives, expanding agent and defoamer as needed and mix them. Stir at 50 rpm for 3 minutes to obtain the first batch. S2: Mix the mixing water and polycarboxylate superplasticizer, add the first batching material, stir at 70 rpm for 4 min, add steel fibers, stir at 90 rpm for 5 min, pour the resulting product into the mold, and then steam cure at 60℃ for 9 h to obtain ultra-high performance UHPC concrete.

[0037] Example 3

[0038] A type of ultra-high performance UHPC concrete for water conservancy and hydropower includes the following raw materials in parts by weight: 110 parts of sulfoaluminate cement, 15 parts of silica fume, 14 parts of slag powder, 120 parts of filler, 14 parts of additive, 14 parts of steel fiber, 5 parts of polycarboxylate superplasticizer, 5 parts of expansion agent, 0.6 parts of defoamer and 32 parts of mixing water. The raw materials for the additives include compounding agents, polyaspartic acid esters, and sodium octenyl succinate starch; The raw materials for the compound agent include slurry, powder, and triethylamine; The additives are prepared by the following methods: Step 1: Mix the composite agent and polyaspartic acid ester at a mass ratio of 8:3 and stir at 400 rpm for 30 minutes to obtain the first mixture; Step 2: Mix sodium octenyl succinate starch and deionized water at a mass ratio of 1:10, and stir at 70℃ and 300 rpm for 35 min to obtain the second mixture; Step 3: Mix the first mixture and the second mixture at a mass ratio of 1:4, stir at 50℃ and 500rpm for 40min, and spray dry the resulting product at an inlet air temperature of 180℃ and an outlet air temperature of 90℃ to obtain the additive.

[0039] The composite agent was prepared by the following method: the slurry was heated to 80°C, 25% of the slurry mass of powder was added, and the mixture was stirred at 200 rpm for 10 min. Then, 3% of the slurry mass of triethylamine was added, and the mixture was stirred at 80°C and 200 rpm for 4 h. Finally, the composite agent was prepared by heating at 65°C and 0.09 MPa for 1 h.

[0040] The slurry was prepared by the following method: cashew shells were washed, dried, crushed and passed through a 10-mesh sieve, dried at 110℃ for 4 hours, cooled to room temperature, and anhydrous ethanol was added in an amount equal to 4 times the weight of the cashew shells. The mixture was stirred at 400 rpm for 1 hour and then soaked for 26 hours. Sodium hydroxide was added and the mixture was stirred at 65℃ and 400 rpm for 2 hours. The resulting product was centrifuged at 3000 rpm for 20 minutes. The supernatant was collected and heated at 70℃ and 0.1 MPa for 2 hours to obtain the slurry. The mass of sodium hydroxide was 2.5% of the mass of the cashew shells.

[0041] The powder is prepared by the following method: Step a: Mix the additives, bentonite, and talc, pulverize, pass through a 100-mesh sieve, stir at 300 rpm for 15 minutes to obtain a mixed powder, add anhydrous ethanol, continue stirring for 30 minutes, dry at 95℃ for 4 hours to obtain a dried product, pulverize and pass through a 120-mesh sieve to obtain a dried powder. The mass ratio of the additives, bentonite, and talc is 5:3:2, and the mass of anhydrous ethanol is 35% of the mass of the mixture. Step b: Mix the dried powder with propylene oxide, add 40% of the total mass of deionized water, stir at 350 rpm for 25 min, dry at 100℃ for 4 h, cool and grind through a 300 mesh sieve to obtain powder. The mass ratio of dried powder to propylene oxide is 8:4.

[0042] The additive is prepared by the following method: coal gangue is crushed and passed through an 80-mesh sieve to obtain coal gangue powder. The coal gangue powder, calcium carbonate and silica powder are mixed in a mass ratio of 5:4:4, stirred at 300 rpm for 15 min, and then calcined at 700℃ for 2.5 h and cooled to obtain the additive.

[0043] The expanding agent is a calcium sulfoaluminate expanding agent, and the defoamer is an organosilicon defoamer.

[0044] The filler was prepared by the following method: Magnesite, sodium carbonate and quartz sand that had passed through a 4-mesh sieve were mixed in a mass ratio of 100:9:6, calcined at 750℃ for 2.5h, pulverized to pass through a 100-mesh sieve, and then calcined at 900℃ for 2h to obtain the calcined product. The calcined product, calcined kaolin and calcium stearate were mixed in a mass ratio of 8:2:0.1, stirred at 300rpm for 25min, and the resulting product was dried at 120℃ for 2.5h to obtain the filler.

[0045] Preparation method of ultra-high performance UHPC concrete for water conservancy and hydropower: S1: Take sulfoaluminate cement, silica fume, slag powder, filler, additives, expanding agent and defoamer as needed and mix them. Stir at 60 rpm for 4 minutes to obtain the first batch. S2: Mix the mixing water and polycarboxylate superplasticizer, add the first batching material, stir at 80 rpm for 5 min, add steel fibers, stir at 100 rpm for 6 min, pour the resulting product into the mold, and then steam cure at 70℃ for 10 h to obtain ultra-high performance UHPC concrete.

[0046] Comparative Example 1: The difference between this comparative example and Example 1 is that this comparative example does not contain any additives.

[0047] Comparative Example 2 differs from Example 1 in that it does not contain powder.

[0048] Comparative Example 3 differs from Example 1 in that it does not contain filler.

[0049] Performance testing: Performance tests were conducted on the concrete treated in Examples 1-3 and Comparative Examples 1-3, and the test data are recorded in the table below: Table 1

[0050] In the performance test, the chloride ion penetration resistance was tested according to GB / T50082-2009. The lower the value, the better the chloride ion penetration resistance. The compressive strength was tested according to GB / T31387-2025. The higher the value, the better the compressive strength.

[0051] Among them, the compressive strength and chloride ion penetration resistance of the concrete treated in Comparative Examples 1-3 were lower than those in Examples 1-3, which illustrates the importance of additives and fillers. In the preparation of additives, sodium octenyl succinate starch is spray-dried to form a coating layer, which encapsulates the composite agent and polyaspartic acid ester. This starch derivative not only acts as a carrier to control the release of active components, but also slowly hydrates and swells in an alkaline environment. The cashew nut shell extract of the composite agent is rich in phenolic compounds, which react in the alkaline cement environment to form a dense chemical adsorption layer that adheres tightly to the capillary walls and the interface between cement stone and aggregate. This layer is not only dense itself, but also effectively blocks the fine interconnected pores, blocking the physical diffusion channels of chloride ions. At the same time, it effectively disperses stress and inhibits the propagation of microcracks. Meanwhile, the composite agent introduces triethylamine to promote the generation of products with ion adsorption capacity, so that the invading chloride ions lose their activity of migrating inward. The bentonite and coal gangue components in the powder, after calcination and modification, not only have high specific surface area. The fine particle size and compact size allow them to physically fill the gaps between cement particles. These modified mineral particles have good compatibility with the cement matrix, reducing porosity and microcracks, and improving compressive strength. They can also undergo ion adsorption with chloride ions, reducing the chloride ion penetration path. Therefore, the control example 1, which lacks additives, shows the most significant decrease in chloride ion penetration resistance and compressive strength. The control example 2, which lacks powder, also shows a decrease in all properties. Magnesite, after double calcination, produces light-calcined magnesium oxide, which reacts with water to generate an expansive component that can fill the interface transition zone between aggregate and cement stone, enhancing the density and integrity of the matrix. In terms of chloride ion penetration resistance, calcined magnesite and quartz sand particles can be tightly packed between cement particles, physically reducing capillary porosity and cutting off connecting channels. Calcium stearate can form a hydrophobic film on the pore wall, effectively hindering the wetting of water molecules and the migration of chloride ions. Therefore, the control example 3, which lacks fillers, shows a decrease in chloride ion penetration resistance and compressive strength.

[0052] By comparing and analyzing the relevant data in the table, it can be seen that the ultra-high performance UHPC concrete for water conservancy and hydropower in this invention not only has good compressive strength but also excellent resistance to chloride ion penetration. This indicates that the ultra-high performance UHPC concrete for water conservancy and hydropower provided by this invention has a broader market prospect and is more suitable for widespread application.

[0053] 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.

[0054] 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 type of ultra-high performance UHPC concrete for water conservancy and hydropower, characterized in that, The raw materials include the following parts by weight: 100-110 parts of sulfoaluminate cement, 13-15 parts of silica fume, 10-14 parts of slag powder, 110-120 parts of filler, 12-14 parts of additives, 12-14 parts of steel fiber, 3-5 parts of polycarboxylate superplasticizer, 3-5 parts of expansion agent, 0.4-0.6 parts of defoamer, and 28-32 parts of mixing water; The raw materials for the additives include compounding agents, polyaspartic acid esters, and sodium octenyl succinate starch; The raw materials for the compound agent include slurry, powder and triethylamine.

2. The ultra-high performance UHPC concrete for water conservancy and hydropower according to claim 1, characterized in that, The additive is prepared by the following method: Step 1: Take the composite agent and polyaspartic acid ester and mix them at a mass ratio of (6-8):

3. Stir at 300-400 rpm for 20-30 min to obtain the first mixture. Step 2: Mix sodium octenyl succinate starch and deionized water at a mass ratio of 1:(8-10), and stir at 60-70℃ and 200-300rpm for 25-35 minutes to obtain the second mixture; Step 3: Add the first mixture to the second mixture and stir for 30-40 minutes at 45-50℃ and 400-500 rpm. The resulting product is spray-dried at an inlet air temperature of 160-180℃ and an outlet air temperature of 80-90℃ to obtain the additive. The mass ratio of the first mixture to the second mixture is 1:(3-4).

3. The ultra-high performance UHPC concrete for water conservancy and hydropower according to claim 2, characterized in that, The composite agent is prepared by the following method: take a slurry, heat it to 75-80℃, add powder, stir at 100-200 rpm for 5-10 min, add triethylamine, stir at 75-80℃ and 100-200 rpm for 3-4 h, and heat at 55-65℃ and 0.07-0.09 MPa for 1 h to obtain the composite agent, wherein the mass of powder is 25% of the mass of slurry, and the mass of triethylamine is 2-3% of the mass of slurry.

4. The ultra-high performance UHPC concrete for water conservancy and hydropower according to claim 3, characterized in that, The slurry is prepared by the following method: take clean and dried cashew shells, crush them through an 8-10 mesh sieve, dry them at 100-110℃ for 3-4 hours, cool them to room temperature, add ethanol, stir at 300-400 rpm for 1 hour, soak them for 22-26 hours, add sodium hydroxide, stir at 55-65℃ and 300-400 rpm for 2 hours, centrifuge the obtained product at 3000 rpm for 10-20 minutes, take the supernatant, and heat it at 70℃ and 0.1 MPa for 2 hours to obtain the slurry.

5. The ultra-high performance UHPC concrete for water conservancy and hydropower according to claim 4, characterized in that, The mass of ethanol is 3-4 times the mass of cashew nut shells, and the mass of sodium hydroxide is 1.5-2.5% of the mass of cashew nut shells.

6. The ultra-high performance UHPC concrete for water conservancy and hydropower according to claim 3, characterized in that, The powder is prepared by the following method: Step a: Take the additives, bentonite and talc powder and mix them in a mass ratio of 5:3:

2. Grind them through an 80-100 mesh sieve and stir them at 200-300 rpm for 10-15 min to obtain a mixed powder. Add 25-35% anhydrous ethanol by mass of the mixture and continue stirring for 20-30 min. Dry it at 85-95℃ for 3-4 h to obtain a dried product. Grind it through a 120 mesh sieve to obtain a dried powder. Step b: Mix the dried powder with propylene oxide at a mass ratio of (6-8):4, add 30-40% of the total mass of deionized water, stir at 250-350 rpm for 15-25 min, dry at 90-100℃ for 3-4 h, cool and grind through a 200-300 mesh sieve to obtain the powder.

7. The ultra-high performance UHPC concrete for water conservancy and hydropower according to claim 6, characterized in that, The additive is prepared by the following method: coal gangue is crushed and passed through a 60-80 mesh sieve to obtain coal gangue powder. Calcium carbonate and silica powder are added, and the mixture is stirred at 200-300 rpm for 10-15 min. Then, it is calcined at 600-700℃ for 1.5-2.5 h and cooled to obtain the additive. The mass ratio of coal gangue powder, calcium carbonate and silica powder is (3-5):(2-4):(2-4).

8. The ultra-high performance UHPC concrete for water conservancy and hydropower according to claim 1, characterized in that, The expanding agent is a calcium sulfoaluminate expanding agent, and the defoamer is an organosilicon defoamer.

9. The ultra-high performance UHPC concrete for water conservancy and hydropower according to claim 1, characterized in that, The filler is prepared by the following method: Magnesite that has passed through a 2-4 mesh sieve is taken, sodium carbonate and quartz sand are added, and the mixture is roasted at 600-750℃ for 1.5-2.5 hours. The mixture is then pulverized to pass through an 80-100 mesh sieve and roasted again at 800-900℃ for 1-2 hours to obtain the roasted product. The roasted product, calcined kaolin, and calcium stearate are mixed at a mass ratio of (7-8):2:0.1 and stirred at 200-300 rpm for 15-25 minutes. The resulting product is dried at 100-120℃ for 1.5-2.5 hours to obtain the filler. The mass of sodium carbonate is 7-9% of the mass of magnesite, and the mass of quartz sand is 4-6% of the mass of magnesite.

10. The method for preparing ultra-high performance UHPC concrete for water conservancy and hydropower according to any one of claims 1-9, characterized in that, Includes the following steps: S1: Take sulfoaluminate cement, silica fume, slag powder, filler, additives, expanding agent and defoamer as needed and mix them. Stir at 40-60 rpm for 2-4 minutes to obtain the first batch. S2: Mix the mixing water and polycarboxylate superplasticizer, add the first batching material, stir at 60-80 rpm for 3-5 minutes, add steel fibers, stir at 80-100 rpm for 4-6 minutes, and pour the resulting product into the mold to obtain ultra-high performance UHPC concrete.

Images