High-toughness ultra-high performance concrete and preparation method thereof

Abstract

The present invention discloses a high-toughness ultra-high-performance concrete and a preparation method thereof, and relates to the technical field of polymer modified materials thereof. The concrete is composed of a cementitious material composite system, a fiber reinforcement system and a polymer modifier, wherein the cementitious material comprises silicate cement, nano-silica, rice husk ash-based auxiliary cementitious material and gradient-graded quartz powder, and the fiber system adopts a multi-scale composite reinforcement of steel fiber / basalt fiber / polypropylene fiber, combined with a polyurethane emulsion interface modifier. During preparation, a three-stage process of dry mixing-fiber dispersion-wet mixing is adopted, combined with microfluidization emulsification and segmented polymerization technology to achieve uniform fiber dispersion and matrix-fiber interface reinforcement. The solution has both high strength, high toughness and industrial feasibility, and is suitable for harsh engineering scenarios such as bridge joints and explosion-proof structures.

Description

Technical Field

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

[0002] Ultra-High Performance Concrete (UHPC) is a new material that has rapidly developed in the construction industry in recent years. It is renowned for its excellent mechanical properties, exceptional durability, and good fire resistance. This material has been widely used in bridges, tunnels, high-rise buildings, and other projects requiring high-strength and high-durability structures. UHPC's hallmark features include extremely high compressive strength (typically exceeding 150 MPa), excellent impermeability, and corrosion resistance, making it an indispensable component of modern engineering design. However, despite its outstanding strength and durability, UHPC's limited toughness limits its application in certain environments. In particular, when subjected to impact loads, vibration loads, or high strain rates, UHPC often exhibits pronounced brittle failure characteristics. This brittle failure can lead to structural failure, thereby reducing its reliability in applications such as earthquake and blast resistance. Therefore, improving the toughness of UHPC has become a hot topic of concern in both academia and engineering.

[0003] To address the issue of insufficient toughness in UHPC, researchers have proposed various improvement methods and disclosed a series of related technical solutions in patent literature. The following analysis of representative prior art documents summarizes the current state of research on improving UHPC toughness, identifies its shortcomings, and uses this as a basis to explain the innovative background of this invention. Prior art 1 (CN109553361A) discloses an ultra-high performance concrete and its preparation method. This method optimizes the mix ratio of raw materials and the preparation process to produce UHPC with high compressive and flexural strength. The components include cement, silica fume, fly ash, slag powder, quartz sand, steel fiber, water, and a water reducer. Through rational mix design and process control, the compressive and flexural strengths of this concrete are significantly improved, meeting the requirements of some engineering applications. However, the document does not propose specific improvement measures to address the toughness issues of UHPC, particularly its toughness performance under high strain rates or dynamic loads. Therefore, while this technology has certain advantages in terms of strength improvement, it cannot effectively address the brittle failure of UHPC, limiting its applicability in a wider range of scenarios. For example, prior art 2 (CN110467410A) proposes a high-toughness ultra-high performance concrete and its preparation method, focusing on improving the toughness and crack resistance of concrete through fiber reinforcement technology. This concrete adds polypropylene fibers and steel fibers to traditional UHPC, utilizing the bridging and pull-out effects of the fibers to enhance the material's tensile properties and crack control capabilities. Experimental results show that this method can improve the toughness of UHPC to a certain extent, resulting in better ductility under stress. However, this method relies primarily on the reinforcing effect of the fibers, and the improvement in the toughness of the concrete matrix itself is relatively limited. In addition, the uniformity of fiber dispersion in concrete and the quality of the interfacial bonding with the matrix directly affect its reinforcement effect, and this document does not fully address the problems of uneven fiber dispersion and poor interfacial bonding. Therefore, this technology still faces certain challenges in practical application, especially how to ensure the uniformity of fiber distribution in large-scale production, which requires further research. For example, prior art 3 (CN113185209A) proposes a method for preparing high-toughness ultra-high performance concrete. By using special cementitious materials and aggregate grading, combined with fiber reinforcement technology, the toughness of UHPC is significantly improved. This method innovates in raw material selection and mix design, while utilizing the synergistic effect of fibers to enhance the material's crack resistance and energy absorption capacity. Experimental results show that this concrete has significantly improved toughness indicators compared to traditional UHPC and can better adapt to application requirements under dynamic load conditions. However, the shortcomings of this technology are that it is difficult to obtain special cementitious materials and aggregates, and the preparation process is relatively complex, resulting in high production costs and low production efficiency. These problems have, to a certain extent, limited the promotion and application of this method in actual engineering projects.

[0004] In summary, existing technologies have made certain progress in improving the toughness of UHPC, and a variety of technical routes have been proposed, including fiber reinforcement, nano-modification, and polymer modification. However, these methods still have some common problems: Limitations of fiber reinforcement technology: The problems of uneven fiber dispersion and poor interface bonding are common, which affects the stability of the reinforcement effect. Insufficient improvement in matrix toughness: Most methods only improve toughness by adding external components, but have limited improvement in the ductility of the concrete matrix itself. Cost and process complexity: The introduction of nanomaterials, special cementitious materials or polymers often increases production costs and process difficulty, which is not conducive to large-scale industrial applications. The challenge of performance balance: How to avoid the decline in other key properties such as strength and durability while improving toughness remains an urgent problem to be solved.

[0005] Therefore, developing a new type of high-toughness, ultra-high-performance concrete and its preparation method requires not only overcoming the aforementioned technical difficulties but also finding a balance between performance improvement, cost control, and process feasibility. This new method should be theoretically innovative and have practical application value. Summary of the Invention

[0006] Existing technologies suffer from the following problems: Insufficient toughness: While conventional ultra-high-performance concrete (UHPC) possesses high compressive strength, it is highly brittle, exhibits poor crack resistance, and exhibits poor ductility, making it susceptible to brittle failure under stress or impact. Poor fiber dispersion: In existing technologies, the uneven distribution of fibers within the concrete matrix limits the reinforcement effect and the fibers' ability to fully realize their tensile and crack resistance. Weak interfacial bonding: The poor interfacial bonding between the fibers and the cement matrix limits the overall toughness and durability of the material. Cost and environmental issues: Conventional UHPC often uses expensive raw materials (such as high-purity silica fume) and has a complex preparation process, resulting in high production costs and significant environmental impact. Limited durability: Under extreme environments (such as those with high corrosion, high permeability, or high temperatures), existing UHPC exhibits insufficient durability, making it difficult to meet specific engineering requirements. To address these issues, the present invention improves upon existing technologies through the following innovations: Optimized component design: Introducing a multi-scale fiber reinforcement system and polymer modifiers to enhance toughness and interfacial bonding. New cementitious materials: Rice husk ash-based auxiliary cementitious materials replace some traditional expensive materials, reducing costs and improving environmental friendliness. Improved preparation process: A three-stage process of "dry mixing-fiber dispersion-wet mixing" is used to ensure uniform fiber dispersion and stable material properties.

[0007] To achieve the above-mentioned object, the present invention provides the following technical solution: a high-toughness ultra-high performance concrete, comprising the following components in parts by weight: a cementitious material composite system: 600-800 parts of Portland cement (CAS No.: 65997-15-1), 50-100 parts of nano-silica (CAS No.: 7631-86-9), 80-150 parts of rice husk ash-based auxiliary cementitious material, and 200-300 parts of gradient-graded quartz powder; a fiber reinforcement system: 3-5 parts of steel fiber, 1.5-2.5 parts of basalt fiber, and 0.8-1.2 parts of polypropylene fiber (CAS No.: 9003-07-0); and a polymer modifier: 8-12 parts of polyurethane emulsion (CAS No.: 26680-22-8).

[0008] The high-toughness ultra-high performance concrete is composed of the following components in parts by weight: a cementitious material composite system: 650-750 parts of Portland cement, 70-90 parts of nano-silicon dioxide, 90-130 parts of rice husk ash-based auxiliary cementitious material, and 220-270 parts of gradient-graded quartz powder; a fiber reinforcement system: 3-5 parts of steel fiber, 1.5-2.5 parts of basalt fiber, and 0.8-1.2 parts of polypropylene fiber; and a polymer modifier: 8-12 parts of polyurethane emulsion.

[0009] The high-toughness ultra-high performance concrete is composed of the following components in parts by mass: a cementitious material composite system: 700 parts of Portland cement, 80 parts of nano-silicon dioxide, 110 parts of rice husk ash-based auxiliary cementitious material, and 250 parts of gradient-graded quartz powder; a fiber reinforcement system: 4 parts of steel fiber, 2 parts of basalt fiber, and 1 part of polypropylene fiber; and a polymer modifier: 10 parts of polyurethane emulsion.

[0010] Preferably, the silicate cement is silicate cement of grade 42.5 or above; the particle size of the nano-silica is 10-50 nm; the preparation method of the rice husk ash-based auxiliary cementitious material is as follows: after the rice husk is wind-sorted, the rice husk with a particle size of less than 2 mm is ultrasonically cleaned with a 0.1% by weight citric acid solution for 20-30 minutes, the cleaned rice husk is immersed in a 5% by weight sodium hydroxide solution, wherein the mass ratio of the rice husk to the sodium hydroxide solution is 1: (3-10), the mixture is stirred at a constant temperature of 80-90°C for 2-4 hours, then preheated at 300°C under nitrogen protection for 1 hour, heated to 600°C for 2-3 hours, and cooled to room temperature at a rate of 5°C / min. A zirconia ball mill is used with a ball-to-material ratio of 5:1 and grinding at 200 rpm for 30 minutes until D50 ≤ 8 μm to obtain a ground powder, the ground powder is mixed with a silane coupling agent KH550 at a mass ratio of (3-7): 20, an alkali solution (sodium hydroxide solution) with a pH of 10.5 in an amount 50-100 times the mass of the ground powder is added, followed by ultrasonic treatment at 40 kHz and 300 W for 30-40 minutes, and then spray drying is performed with an inlet temperature of 180°C and an outlet temperature of 80°C to obtain a modified powder, 20-40 times the mass of the modified powder is added with a 0.3% agarose solution by mass percentage, heated to boiling, and cooled to room temperature to obtain a product; the gradient-graded quartz powder is quartz powder with D50 2 μm / 10 μm / 50 μm mixed in a mass ratio of 1:2:1.

[0011] Preferably, the steel fiber has a diameter of 0.18-0.25 mm and a length of 12-15 mm.

[0012] Preferably, the preparation method of the polyurethane emulsion is as follows: bisphenol A epoxy resin (CAS No.: 25068-38-6), waterborne polyurethane prepolymer (Bayhydur®ultra 3100 produced by Covestro), hydroxylated carbon nanotubes (Jiangsu Xianfeng Nanomaterial Technology Co., Ltd., product number 100254, serial number XFM14), acrylate monomer (CAS No.: 5888-33-5) and sulfosuccinate (CAS No.: CAS No. 5138-18-1) emulsifier are added to the mixture of bisphenol A epoxy resin and acrylate monomer in a mass ratio of (20-40): (30-50): (0.1-0.5): (15-25): (1.5-3), and the sulfosuccinate emulsifier is added to the mixture of bisphenol A epoxy resin and acrylate monomer, and the mixture is fully stirred. The above mixture, waterborne polyurethane prepolymer and hydroxylated carbon nanotubes are placed in a microfluidizer and heated at 120 Pre-emulsification is carried out under a pressure of 00-15000psi, and the parameters are: particle size: D90≤150nm, temperature: 25-35℃, time: 30-60min, the pre-emulsified liquid is heated to 65℃, potassium persulfate in an amount of 0.1-0.5 times the mass of the acrylate monomer is added, the polymerization reaction is started, the temperature is gradually raised to 85℃, the reaction is maintained, and the polymerization reaction time is 4-6h. The liquid after polymerization is cooled to 50℃, 1,4-butanediol in an amount of 1-3 times the mass of the acrylate monomer is added, and a post-chain extension reaction is carried out. The reaction time is 2-4h. The emulsion after the reaction is filtered to remove impurities, and then degassed to eliminate bubbles to obtain the product.

[0013] A method for preparing high-toughness ultra-high performance concrete as described above comprises the following steps: (1) raw material preparation: according to the mass parts, respectively weigh the silicate cement, nano-silica, rice husk ash-based auxiliary cementitious material and gradient-graded quartz powder in the cementitious material composite system; respectively weigh the steel fiber, basalt fiber and polypropylene fiber in the fiber reinforcement system; weigh the polymer modifier; (2) dry-mixing cementitious material: add the weighed silicate cement, nano-silica, rice husk ash-based auxiliary cementitious material and gradient-graded quartz powder into a mixer, and dry-mix at a speed of 200-300 rpm for 3-5 minutes to ensure that the components are evenly mixed to obtain a mixture; (3) fiber dispersion: add the steel fiber, basalt fiber and polypropylene fiber into the mixer, and dry-mix at a speed of 200-300 rpm for 3-5 minutes to ensure that the components are evenly mixed to obtain a mixture; (4) Wet mixing and polymer modifier addition: add water to the mixture obtained in step (3), wherein the mass of water is 0.18-0.22 times that of the mixture, and add polyurethane emulsion at the same time, and stir at a speed of 300-400 rpm for 5-8 minutes to form a uniform concrete slurry; (5) Pouring and vibrating: pour the uniformly stirred concrete slurry into a pre-prepared mold, and vibrate it with a vibration table for 30-60 seconds to ensure that the slurry is dense and free of bubbles; (6) Curing: place the cast specimen in a standard curing room for 24 hours and then demould it; after demoulding, continue to cure it under standard curing conditions for 7 days.

[0014] Preferably, the dispersion parameters in step (3) are as follows: stirring at a speed of 100-150 rpm for 2-3 min.

[0015] Preferably, the standard curing parameters in step (6) are as follows: temperature 20±2°C, relative humidity ≥95%.

[0016] Beneficial effects

[0017] Enhanced toughness and crack resistance: By adopting a multi-fiber composite reinforcement system, including a multi-scale combination of steel fiber, basalt fiber and polypropylene fiber, the toughness of concrete is greatly improved, enabling it to exhibit good crack resistance and ductility when subjected to impact loads, vibration loads or high strain rates, avoiding the brittle failure problem of traditional ultra-high performance concrete.

[0018] Improve the interfacial bonding strength between the matrix and the fiber: By introducing polyurethane emulsion interfacial modifier, the interfacial bonding strength between the fiber and the matrix can be effectively improved, making the fiber reinforcement effect more significant, thereby improving the overall mechanical properties and anti-destruction ability of concrete.

[0019] Excellent mechanical properties and durability: While ensuring high strength (compressive strength exceeds 150MPa), this concrete further enhances its anti-permeability, corrosion resistance and fire resistance. It is suitable for engineering projects with extremely high strength and durability requirements, such as bridge joints and explosion-proof structures.

[0020] Industrial feasibility and cost control: This concrete, while maintaining high performance, utilizes a relatively simple preparation process and rationally selected raw materials, making it highly feasible for industrial production. Furthermore, the use of relatively low-cost supplementary cementitious materials, such as rice husk ash-based supplementary cementitious materials, effectively reduces production costs, making this concrete highly economical for large-scale production.

[0021] Broad application prospects: This high-toughness ultra-high performance concrete is suitable for engineering scenarios that require high toughness, high strength, and excellent durability, such as bridge construction, tunnels, industrial facilities, and explosion-resistant structures. It can meet the high requirements of modern construction projects for material performance and has broad market application potential.

[0022] In summary, the high-toughness ultra-high performance concrete of the present invention has significant advantages in mechanical properties, durability, economy, etc., and provides a new type of building material with practical application value for related projects. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a real picture of the concrete prepared in Example 5. DETAILED DESCRIPTION

[0024] In the embodiments of the present invention, parts by weight or parts by mass are equivalently replaced with kilograms (kg) or grams (g), which can be scaled up or down in the same proportion with minimal impact on the experimental results.

[0025] Example 1

[0026] The high-toughness ultra-high performance concrete is composed of the following components in parts by mass: cementitious material composite system: 600 parts of silicate cement, 100 parts of nano-silica, 80 parts of rice husk ash-based auxiliary cementitious material, 300 parts of gradient-graded quartz powder; fiber reinforcement system: 3 parts of steel fiber, 2.5 parts of basalt fiber, 0.8 parts of polypropylene fiber; polymer modifier: 12 parts of polyurethane emulsion.

[0027] The silicate cement is 42.5 grade silicate cement; the particle size of the nano-silica is 10 nm; the preparation method of the rice husk ash-based auxiliary cementitious material is as follows: after the rice husk is wind-sorted, the rice husk with a particle size of less than 2 mm is ultrasonically cleaned with a 0.1% by weight citric acid solution for 20 minutes, and the cleaned rice husk is immersed in a 5% by weight sodium hydroxide solution, wherein the mass ratio between the rice husk and the sodium hydroxide solution is 1:10, and the mixture is stirred at a constant temperature of 80°C for 4 hours, then preheated at 300°C under nitrogen protection for 1 hour, heated to 600°C for 2 hours, cooled to room temperature at a rate of 5°C / min, and used. A zirconia ball mill was used, with a ball-to-material ratio of 5:1, and grinding was performed at 200 rpm for 30 minutes until the D50 value was ≤8 μm. This ground powder was then mixed with a silane coupling agent, KH550, at a mass ratio of 7:20. Alkaline solution with a pH of 10.5 (50 times the mass of the ground powder) was added. The mixture was then ultrasonically treated at 40 kHz and 300 W for 40 minutes. The modified powder was then spray-dried at an inlet temperature of 180°C and an outlet temperature of 80°C. A 0.3% agarose solution (20 times the mass of the ground powder) was added, heated to boiling, and cooled to room temperature to obtain the product. The gradient-graded quartz powder was a mixture of quartz powders with a D50 value of 2 μm / 10 μm / 50 μm (1:2:1). The steel fiber had a diameter of 0.25 mm and a length of 12 mm. The polyurethane emulsion is prepared as follows: bisphenol A epoxy resin, waterborne polyurethane prepolymer, hydroxylated carbon nanotubes, acrylate monomer and sulfosuccinate emulsifier are added to the mixture of bisphenol A epoxy resin and acrylate monomer in a mass ratio of 40:30:0.5:15:3, and the sulfosuccinate emulsifier is fully stirred. The mixture, waterborne polyurethane prepolymer and hydroxylated carbon nanotubes are placed in a microfluidizer and pre-emulsified at a pressure of 12,000 psi. The preparation parameters are as follows: particle size: D 90≤150nm, temperature: 35℃, time: 30min, heat the pre-emulsified liquid to 65℃, add potassium persulfate (0.5 times the mass of acrylate monomer), start the polymerization reaction, gradually heat to 85℃, keep the reaction going, the polymerization reaction time is 4h, cool the liquid after polymerization to 50℃, add 1,4-butanediol (3 times the mass of acrylate monomer) to carry out post-chain extension reaction, the reaction time is 2h, filter the emulsion after reaction to remove impurities, and then degas and eliminate bubbles to obtain the product.

[0028] The method for preparing the high-toughness ultra-high performance concrete comprises the following steps: (1) raw material preparation: according to the mass parts, respectively weigh the silicate cement, nano-silica, rice husk ash-based auxiliary cementitious material and gradient-graded quartz powder in the cementitious material composite system; respectively weigh the steel fiber, basalt fiber and polypropylene fiber in the fiber reinforcement system; weigh the polymer modifier; (2) dry-mixing cementitious material: add the weighed silicate cement, nano-silica, rice husk ash-based auxiliary cementitious material and gradient-graded quartz powder into a mixer, dry-mix at a speed of 200 rpm for 5 minutes to ensure that the components are evenly mixed to obtain a mixture; (3) fiber dispersion: add the steel fiber, basalt fiber and polypropylene fiber into the fiber reinforcement system, and dry-mix at a speed of 200 rpm for 5 minutes to ensure that the components are evenly mixed to obtain a mixture; Rock fiber and polypropylene fiber are added to the dry-mixed cementitious material for dispersion, so that the fibers are evenly dispersed in the mixture; (4) Wet mixing and addition of polymer modifier: water is added to the mixture obtained in step (3), wherein the mass of water is 0.18 times that of the mixture, and polyurethane emulsion is added at the same time, and stirred at a speed of 400 rpm for 5 minutes to form a uniform concrete slurry; (5) Pouring and vibrating: the uniformly stirred concrete slurry is poured into a pre-prepared mold and vibrated using a vibration table for 60 seconds to ensure that the slurry is dense and free of bubbles; (6) Curing: the cast specimen is placed in a standard curing room for curing for 24 hours and then demolded; after demolding, it is continued to be cured under standard curing conditions for 7 days. Among them, the dispersion parameters in step (3) are as follows: stirring at a speed of 100 rpm for 3 minutes; the standard curing parameters in step (6) are as follows: temperature 20±2℃, relative humidity ≥95%.

[0029] Example 2

[0030] The high-toughness ultra-high performance concrete is composed of the following components in parts by mass: cementitious material composite system: 800 parts of silicate cement, 50 parts of nano-silica, 150 parts of rice husk ash-based auxiliary cementitious material, and 200 parts of gradient-graded quartz powder; fiber reinforcement system: 5 parts of steel fiber, 1.5 parts of basalt fiber, and 1.2 parts of polypropylene fiber; polymer modifier: 8 parts of polyurethane emulsion.

[0031] The silicate cement is grade 42.5 silicate cement; the particle size of the nano-silica is 10 nm; the preparation method of the rice husk ash-based auxiliary cementitious material is as follows: after the rice husks are wind-sorted, the rice husks with a particle size of less than 2 mm are ultrasonically cleaned with a 0.1% by weight citric acid solution for 20 minutes, and the cleaned rice husks are immersed in a 5% by weight sodium hydroxide solution, wherein the mass ratio of the rice husks to the sodium hydroxide solution is 1:3, and the mixture is stirred at a constant temperature of 80°C for 2 hours, then preheated at 300°C under nitrogen protection for 1 hour, heated to 600°C for 2 hours, cooled to room temperature at a rate of 5°C / min, and used. A zirconia ball mill was used, with a ball-to-material ratio of 5:1, and grinding at 200 rpm for 30 minutes until the D50 value was ≤8 μm to obtain a ground powder. The ground powder was then mixed with a silane coupling agent, KH550, at a mass ratio of 3:20. Alkaline solution with a pH of 10.5 (50 times the mass of the ground powder) was added. The mixture was then ultrasonically treated at 40 kHz and 300 W for 30 minutes. The modified powder was then spray-dried at an inlet temperature of 180°C and an outlet temperature of 80°C. A 0.3% agarose solution (20 times the mass of the ground powder) was added, heated to boiling, and cooled to room temperature to obtain the product. The gradient-graded quartz powder was a mixture of quartz powders with a D50 value of 2 μm / 10 μm / 50 μm (1:2:1). The steel fiber had a diameter of 0.18 mm and a length of 12 mm. The polyurethane emulsion is prepared as follows: bisphenol A epoxy resin, waterborne polyurethane prepolymer, hydroxylated carbon nanotubes, acrylate monomer and sulfosuccinate emulsifier are added to the mixture of bisphenol A epoxy resin and acrylate monomer at a mass ratio of 20:50:0.1:25:1.5, and the mixture is thoroughly stirred. The mixture, waterborne polyurethane prepolymer and hydroxylated carbon nanotubes are placed in a microfluidizer and pre-emulsified at a pressure of 15,000 psi. Preparation parameters: particle size: D90≤150nm, temperature: 25°C, time: 30min, heat the pre-emulsified liquid to 65°C, add potassium persulfate (0.5 times the mass of the acrylate monomer), start the polymerization reaction, gradually heat to 85°C, keep the reaction going, the polymerization reaction time is 6h, cool the polymerized liquid to 50°C, add 1,4-butanediol (3 times the mass of the acrylate monomer) to carry out post-chain extension reaction, the reaction time is 4h, filter the emulsion after the reaction to remove impurities, and then degas and eliminate bubbles to obtain the product.

[0032] The method for preparing the high-toughness ultra-high performance concrete comprises the following steps: (1) raw material preparation: according to the mass parts, respectively weigh the silicate cement, nano-silica, rice husk ash-based auxiliary cementitious material and gradient-graded quartz powder in the cementitious material composite system; respectively weigh the steel fiber, basalt fiber and polypropylene fiber in the fiber reinforcement system; weigh the polymer modifier; (2) dry-mixing the cementitious material: add the weighed silicate cement, nano-silica, rice husk ash-based auxiliary cementitious material and gradient-graded quartz powder into a mixer, dry-mix at a speed of 300 rpm for 5 minutes to ensure that the components are evenly mixed to obtain a mixture; (3) fiber dispersion: add the steel fiber, basalt fiber and polypropylene fiber into the mixer, dry-mix at a speed of 300 rpm for 5 minutes to ensure that the components are evenly mixed to obtain a mixture; Rock fiber and polypropylene fiber are added to the dry-mixed cementitious material for dispersion, so that the fibers are evenly dispersed in the mixture; (4) Wet mixing and addition of polymer modifier: water is added to the mixture obtained in step (3), wherein the mass of water is 0.18 times that of the mixture, and polyurethane emulsion is added at the same time, and stirred at a speed of 400 rpm for 5 minutes to form a uniform concrete slurry; (5) Pouring and vibrating: the uniformly stirred concrete slurry is poured into a pre-prepared mold and vibrated using a vibration table for 30 seconds to ensure that the slurry is dense and free of bubbles; (6) Curing: the cast specimen is placed in a standard curing room for curing for 24 hours and then demolded; after demolding, it is continued to be cured under standard curing conditions for 7 days. Among them, the dispersion parameters in step (3) are as follows: stirring at a speed of 150 rpm for 2 minutes; the standard curing parameters in step (6) are as follows: temperature 20±2℃, relative humidity ≥95%.

[0033] Example 3

[0034] The high-toughness ultra-high performance concrete is composed of the following components in parts by mass: cementitious material composite system: 650 parts of silicate cement, 70 parts of nano-silicon dioxide, 90 parts of rice husk ash-based auxiliary cementitious material, and 220 parts of gradient-graded quartz powder; fiber reinforcement system: 3 parts of steel fiber, 1.5 parts of basalt fiber, and 0.8 parts of polypropylene fiber; polymer modifier: 8 parts of polyurethane emulsion.

[0035] The silicate cement is 42.5 grade silicate cement; the particle size of the nano-silica is 10 nm; the preparation method of the rice husk ash-based auxiliary cementitious material is as follows: after the rice husk is wind-sorted, the rice husk with a particle size of less than 2 mm is ultrasonically cleaned with a 0.1% by weight citric acid solution for 20 minutes, and the cleaned rice husk is immersed in a 5% by weight sodium hydroxide solution, wherein the mass ratio of the rice husk to the sodium hydroxide solution is 1:3, and the mixture is stirred at a constant temperature of 80°C for 2 hours, then preheated at 300°C under nitrogen protection for 1 hour, heated to 600°C for 2 hours, cooled to room temperature at a rate of 5°C / min, and oxygenated. A zirconium nitride ball mill was used, with a ball-to-material ratio of 5:1, and ground at 200 rpm for 30 minutes until the D50 value was ≤8 μm. This ground powder was then mixed with a silane coupling agent, KH550, at a mass ratio of 3:20. Alkaline solution with a pH of 10.5 (100 times the mass of the ground powder) was added. The mixture was then ultrasonically treated at 40 kHz and 300 W for 40 minutes. The modified powder was then spray-dried at an inlet temperature of 180°C and an outlet temperature of 80°C. A 0.3% agarose solution (40 times the mass of the ground powder) was added, heated to boiling, and cooled to room temperature to obtain the product. The gradient-graded quartz powder was a mixture of quartz powders with a D50 of 2 μm / 10 μm / 50 μm (1:2:1 mass ratio). The steel fiber had a diameter of 0.25 mm and a length of 12 mm. The polyurethane emulsion is prepared as follows: bisphenol A epoxy resin, waterborne polyurethane prepolymer, hydroxylated carbon nanotubes, acrylate monomer and sulfosuccinate emulsifier are added to the mixture of bisphenol A epoxy resin and acrylate monomer in a mass ratio of 20:30:0.1:15:3, and the sulfosuccinate emulsifier is fully stirred. The mixture, waterborne polyurethane prepolymer and hydroxylated carbon nanotubes are placed in a microfluidizer and pre-emulsified under a pressure of 12,000 psi. The preparation parameters are as follows: particle size: D 90≤150nm, temperature: 35℃, time: 30min, heat the pre-emulsified liquid to 65℃, add potassium persulfate (0.1 times the mass of acrylate monomer), start the polymerization reaction, gradually heat to 85℃, keep the reaction going, the polymerization reaction time is 6h, cool the liquid after polymerization to 50℃, add 1,4-butanediol (3 times the mass of acrylate monomer), carry out post-chain extension reaction, the reaction time is 4h, filter the emulsion after reaction to remove impurities, and then degas and eliminate bubbles to obtain the product.

[0036] The method for preparing the high-toughness ultra-high performance concrete comprises the following steps: (1) raw material preparation: according to the mass parts, respectively weigh the silicate cement, nano-silica, rice husk ash-based auxiliary cementitious material and gradient-graded quartz powder in the cementitious material composite system; respectively weigh the steel fiber, basalt fiber and polypropylene fiber in the fiber reinforcement system; weigh the polymer modifier; (2) dry-mixing the cementitious material: add the weighed silicate cement, nano-silica, rice husk ash-based auxiliary cementitious material and gradient-graded quartz powder into a mixer, dry-mix at a speed of 300 rpm for 3 minutes to ensure that the components are evenly mixed to obtain a mixture; (3) fiber dispersion: add the steel fiber, basalt fiber and polypropylene fiber into the mixer, dry-mix at a speed of 300 rpm for 3 minutes to ensure that the components are evenly mixed to obtain a mixture; Rock fiber and polypropylene fiber are added to the dry-mixed cementitious material for dispersion, so that the fibers are evenly dispersed in the mixture; (4) Wet mixing and addition of polymer modifier: water is added to the mixture obtained in step (3), wherein the mass of water is 0.18 times that of the mixture, and polyurethane emulsion is added at the same time, and stirred at a speed of 300 rpm for 5 minutes to form a uniform concrete slurry; (5) Pouring and vibrating: the uniformly stirred concrete slurry is poured into a pre-prepared mold and vibrated using a vibration table for 60 seconds to ensure that the slurry is dense and free of bubbles; (6) Curing: the cast specimen is placed in a standard curing room for curing for 24 hours and then demolded; after demolding, it is continued to be cured under standard curing conditions for 7 days. Among them, the dispersion parameters in step (3) are as follows: stirring at a speed of 100 rpm for 3 minutes; the standard curing parameters in step (6) are as follows: temperature 20±2℃, relative humidity ≥95%.

[0037] Example 4

[0038] The high-toughness ultra-high performance concrete is composed of the following components in parts by mass: cementitious material composite system: 750 parts of silicate cement, 90 parts of nano-silica, 130 parts of rice husk ash-based auxiliary cementitious material, 270 parts of gradient-graded quartz powder; fiber reinforcement system: 5 parts of steel fiber, 2.5 parts of basalt fiber, 1.2 parts of polypropylene fiber; polymer modifier: 12 parts of polyurethane emulsion.

[0039] The silicate cement is 42.5 grade silicate cement; the particle size of the nano-silica is 50 nm; the preparation method of the rice husk ash-based auxiliary cementitious material is as follows: after the rice husk is wind-sorted, the rice husk with a particle size of less than 2 mm is ultrasonically cleaned with a 0.1% by weight citric acid solution for 30 minutes, and the cleaned rice husk is immersed in a 5% by weight sodium hydroxide solution, wherein the mass ratio between the rice husk and the sodium hydroxide solution is 1:10, and the mixture is stirred at a constant temperature of 90°C for 4 hours, then preheated at 300°C under nitrogen protection for 1 hour, heated to 600°C for 3 hours, cooled to room temperature at a rate of 5°C / min, and used. A zirconia ball mill was used, with a ball-to-material ratio of 5:1, and grinding was performed at 200 rpm for 30 minutes until the D50 value was ≤8 μm. This ground powder was then mixed with a silane coupling agent, KH550, at a mass ratio of 7:20. Alkaline solution with a pH of 10.5 (100 times the mass of the ground powder) was added. The mixture was then ultrasonically treated at 40 kHz and 300 W for 40 minutes. The modified powder was then spray-dried at an inlet temperature of 180°C and an outlet temperature of 80°C. A 0.3% agarose solution (40 times the mass of the ground powder) was added, heated to boiling, and cooled to room temperature to obtain the product. The gradient-graded quartz powder was a mixture of quartz powders with a D50 value of 2 μm / 10 μm / 50 μm (1:2:1). The steel fiber had a diameter of 0.25 mm and a length of 15 mm. The polyurethane emulsion is prepared as follows: bisphenol A epoxy resin, waterborne polyurethane prepolymer, hydroxylated carbon nanotubes, acrylate monomer and sulfosuccinate emulsifier are mixed at a mass ratio of 40:50:0.5:25:3, the sulfosuccinate emulsifier is added to the mixture of bisphenol A epoxy resin and acrylate monomer, and the mixture is thoroughly stirred. The mixture, waterborne polyurethane prepolymer and hydroxylated carbon nanotubes are placed in a microfluidizer and pre-emulsified at a pressure of 15,000 psi. The preparation parameters are as follows: particle size: D 90≤150nm, temperature: 35℃, time: 40min, heat the pre-emulsified liquid to 65℃, add potassium persulfate (0.5 times the mass of acrylate monomer), start the polymerization reaction, gradually heat to 85℃, keep the reaction going, the polymerization reaction time is 6h, cool the liquid after polymerization to 50℃, add 1,4-butanediol (1 times the mass of acrylate monomer) to carry out post-chain extension reaction, the reaction time is 4h, filter the emulsion after reaction to remove impurities, then degas and eliminate bubbles to obtain the product.

[0040] The method for preparing the high-toughness ultra-high performance concrete comprises the following steps: (1) raw material preparation: according to the mass parts, respectively weigh the silicate cement, nano-silica, rice husk ash-based auxiliary cementitious material and gradient-graded quartz powder in the cementitious material composite system; respectively weigh the steel fiber, basalt fiber and polypropylene fiber in the fiber reinforcement system; weigh the polymer modifier; (2) dry-mixing the cementitious material: add the weighed silicate cement, nano-silica, rice husk ash-based auxiliary cementitious material and gradient-graded quartz powder into a mixer, dry-mix at a speed of 300 rpm for 5 minutes to ensure that the components are evenly mixed to obtain a mixture; (3) fiber dispersion: add the steel fiber, basalt fiber and polypropylene fiber into the mixer, dry-mix at a speed of 300 rpm for 5 minutes to ensure that the components are evenly mixed to obtain a mixture; Rock fiber and polypropylene fiber are added to the dry-mixed cementitious material for dispersion, so that the fibers are evenly dispersed in the mixture; (4) Wet mixing and addition of polymer modifier: water is added to the mixture obtained in step (3), wherein the mass of water is 0.22 times that of the mixture, and polyurethane emulsion is added at the same time, and stirred at a speed of 400 rpm for 8 minutes to form a uniform concrete slurry; (5) Pouring and vibrating: the uniformly stirred concrete slurry is poured into a pre-prepared mold and vibrated using a vibration table for 60 seconds to ensure that the slurry is dense and free of bubbles; (6) Curing: the cast specimen is placed in a standard curing room for curing for 24 hours and then demolded; after demolding, it is continued to be cured under standard curing conditions for 7 days. Among them, the dispersion parameters in step (3) are as follows: stirring at a speed of 150 rpm for 3 minutes; the standard curing parameters in step (6) are as follows: temperature 20±2℃, relative humidity ≥95%.

[0041] Example 5

[0042] The high-toughness ultra-high performance concrete is composed of the following components in parts by mass: cementitious material composite system: 700 parts of silicate cement, 80 parts of nano-silica, 110 parts of rice husk ash-based auxiliary cementitious material, 250 parts of gradient-graded quartz powder; fiber reinforcement system: 4 parts of steel fiber, 2 parts of basalt fiber, 1 part of polypropylene fiber; polymer modifier: 10 parts of polyurethane emulsion.

[0043] The silicate cement is 42.5 grade silicate cement; the particle size of the nano-silica is 30 nm; the preparation method of the rice husk ash-based auxiliary cementitious material is as follows: after the rice husk is wind-sorted, the rice husk with a particle size of less than 2 mm is ultrasonically cleaned for 25 minutes with a 0.1% by weight citric acid solution, and the cleaned rice husk is immersed in a 5% by weight sodium hydroxide solution, wherein the mass ratio of the rice husk to the sodium hydroxide solution is 1:6, and the mixture is stirred at a constant temperature of 90°C for 4 hours, then preheated at 300°C under nitrogen protection for 1 hour, heated to 600°C for 3 hours, cooled to room temperature at a rate of 5°C / min, and oxygenated. A zirconium nitride ball mill was used, with a ball-to-material ratio of 5:1, and ground at 200 rpm for 30 minutes until the D50 was ≤8 μm to obtain a ground powder. The ground powder was then mixed with a silane coupling agent, KH550, at a mass ratio of 7:20. Alkaline solution with a pH of 10.5 (100 times the mass of the ground powder) was added. The mixture was then ultrasonically treated at 40 kHz and 300 W for 40 minutes. The modified powder was then spray-dried at an inlet temperature of 180°C and an outlet temperature of 80°C. A 0.3% agarose solution (40 times the mass of the ground powder) was added, heated to boiling, and cooled to room temperature to obtain the product. The gradient-graded quartz powder was a mixture of quartz powders with a D50 of 2 μm / 10 μm / 50 μm (1:2:1 mass ratio). The steel fiber had a diameter of 0.25 mm and a length of 15 mm. The polyurethane emulsion is prepared as follows: bisphenol A epoxy resin, waterborne polyurethane prepolymer, hydroxylated carbon nanotubes, acrylate monomer and sulfosuccinate emulsifier are added to the mixture of bisphenol A epoxy resin and acrylate monomer in a mass ratio of 40:50:0.5:25:2, and the sulfosuccinate emulsifier is fully stirred. The mixture, waterborne polyurethane prepolymer and hydroxylated carbon nanotubes are placed in a microfluidizer and pre-emulsified at a pressure of 14,000 psi. The preparation parameters are as follows: particle size: D 90≤150nm, temperature: 30℃, time: 50min, heat the pre-emulsified liquid to 65℃, add potassium persulfate (0.3 times the mass of acrylate monomer), start the polymerization reaction, gradually heat to 85℃, keep the reaction going, the polymerization reaction time is 5h, cool the liquid after polymerization to 50℃, add 1,4-butanediol (2 times the mass of acrylate monomer), carry out post-chain extension reaction, the reaction time is 3h, filter the emulsion after reaction to remove impurities, and then degas and eliminate bubbles to obtain the product.

[0044] The method for preparing high-toughness ultra-high performance concrete comprises the following steps: (1) raw material preparation: according to the mass parts, respectively weigh the silicate cement, nano-silica, rice husk ash-based auxiliary cementitious material and gradient-graded quartz powder in the cementitious material composite system; respectively weigh the steel fiber, basalt fiber and polypropylene fiber in the fiber reinforcement system; weigh the polymer modifier; (2) dry-mixing cementitious material: add the weighed silicate cement, nano-silica, rice husk ash-based auxiliary cementitious material and gradient-graded quartz powder into a mixer, dry-mix at a speed of 250 rpm for 4 minutes to ensure that the components are evenly mixed to obtain a mixture; (3) fiber dispersion: add the steel fiber, basalt fiber and polypropylene fiber into the mixer, dry-mix at a speed of 250 rpm for 4 minutes to ensure that the components are evenly mixed to obtain a mixture; Rock fiber and polypropylene fiber are added to the dry-mixed cementitious material for dispersion, so that the fibers are evenly dispersed in the mixture; (4) Wet mixing and addition of polymer modifier: water is added to the mixture obtained in step (3), wherein the mass of water is 0.2 times that of the mixture, and polyurethane emulsion is added at the same time, and stirred at a speed of 400 rpm for 7 minutes to form a uniform concrete slurry; (5) Pouring and vibrating: the uniformly stirred concrete slurry is poured into a pre-prepared mold, and vibrated using a vibration table for 50 seconds to ensure that the slurry is dense and free of bubbles; (6) Curing: the cast specimen is placed in a standard curing room for curing for 24 hours and then demolded; after demolding, it is continued to be cured under standard curing conditions for 7 days. Among them, the dispersion parameters in step (3) are as follows: stirring at a speed of 130 rpm for 3 minutes; the standard curing parameters in step (6) are as follows: temperature 20±2℃, relative humidity ≥95%, and the prepared product is as follows Figure 1 shown.

[0045] Comparative Example 1: No fiber reinforcement system was added, and the rest was carried out according to the process of Example 5.

[0046] Comparative Example 2: Only steel fibers were used in the fiber reinforcement system, and the rest were carried out according to the process of Example 5.

[0047] Comparative Example 3: No polymer modifier (polyurethane emulsion) was used, and the rest of the process was carried out according to the process of Example 5.

[0048] Comparative Example 4: Silica fume (CAS No.: 69012-64-2) was used to replace the rice husk ash-based auxiliary cementitious material in the cementitious material composite system, and the rest was carried out according to the process of Example 5.

[0049] Comparative Example 5: The fiber dispersion step was not performed, and the rest of the process was carried out according to the process of Example 5.

[0050] Comparative Example 6: Nano-silica was not used in the gelling material composite system, and the rest was carried out according to the process of Example 5.

[0051] Test Plan: Compressive Strength: Cube compression test conducted in accordance with GB / T 50081-2002, "Standard for Test Methods for Mechanical Properties of Ordinary Concrete." Flexural Strength: Four-point bending test conducted in accordance with GB / T 17671-1999, "Test Methods for Strength of Cement Mortar." Tensile Properties: Ultimate tensile strength determined in accordance with CECS13:2009, "Standard for Test Methods for Fiber-Reinforced Concrete." Equivalent Flexural Strength: Flexural toughness index calculated in accordance with CECS13:2009. Crack Control Capacity: Assessed by the area under the load-displacement curve in the three-point bending test. Fiber-matrix interface bond strength: Fiber-matrix interfacial bond strength: Pullout test using a figure-eight specimen (patent CN113816685A). Slump Propagation: Tested in accordance with GB / T 50080-2016.

[0052] Table 1

[0053]

[0054] As shown in Table 1, from the data of Examples 1 to 5, with the optimization of the component ratio, the performance indicators of concrete show a certain upward trend. Taking Example 5 as an example, its performance data are as follows: compressive strength: 152MPa, flexural strength: 28MPa, ultimate tensile strength: 15MPa, slump expansion: 260mm, equivalent bending strength: 45.3MPa, interface bonding strength: 5MPa. These indicators are better than those of other examples, indicating that the ratio of Example 5 has achieved the best performance balance under the synergistic effect of cementitious materials, fibers and modifiers. Next, by comparison with the comparative example, the reasons for its superiority are further revealed.

[0055] Comparative Example 1: No fiber reinforcement system is added, performance data: compressive strength 125MPa, flexural strength 18MPa, ultimate tensile strength 8MPa, slump expansion 180mm, equivalent flexural strength 25.6MPa, interface bonding strength 2.1MPa. Analysis: Compared with Example 5, various indicators are significantly reduced, especially flexural strength, ultimate tensile strength and equivalent flexural strength. This shows that the fiber reinforcement system is crucial to improving the toughness and crack resistance of concrete. Fibers significantly improve the ductility and damage resistance of the material by bridging cracks and dispersing stress. Comparative Example 2: Only steel fibers are used, performance data: compressive strength 129MPa, flexural strength 20MPa, ultimate tensile strength 9MPa, slump expansion 195mm, equivalent flexural strength 28.3MPa, interface bonding strength 2.8MPa. Analysis: The performance is slightly better than that of Comparative Example 1, but still lower than that of Example 5. Although single steel fibers can improve some properties, they cannot achieve the synergistic enhancement effect of multi-scale fibers. The combination of steel fiber, basalt fiber, and polypropylene fiber in Example 5 comprehensively inhibited crack propagation at the macro, micro, and micro scales. Comparative Example 3: No polymer modifier was used. Performance data: compressive strength 118 MPa, flexural strength 16 MPa, ultimate tensile strength 7 MPa, slump expansion 210 mm, equivalent flexural strength 22.4 MPa, and interfacial bonding strength 1.9 MPa. Analysis: Performance was significantly reduced, especially the interfacial bonding strength, which was far lower than that of Example 5. This indicates that the polyurethane emulsion plays a key role in strengthening the interfacial bonding between the fiber and the matrix, and its flexible interfacial layer improves adhesion and overall mechanical properties. Comparative Example 4: Silica fume was used instead of the rice husk ash-based auxiliary cementitious material. Performance data: compressive strength 135 MPa, flexural strength 22 MPa, ultimate tensile strength 11 MPa, slump expansion 230 mm, equivalent flexural strength 30.2 MPa, and interfacial bonding strength 3.2 MPa. Analysis: Performance was better than Comparative Examples 1-3, but still inferior to Example 5. Rice husk ash-based materials undergo special treatments (such as alkali soaking, silane coupling agent modification, and agarose coating) for increased activity and improved compatibility with the matrix, outperforming traditional silica fume. Comparative Example 5: No fiber dispersion step was performed. Performance data: compressive strength 110 MPa, flexural strength 14 MPa, ultimate tensile strength 6 MPa, slump spread 165 mm, equivalent flexural strength 18.7 MPa, and interfacial bonding strength 1.4 MPa. Analysis: The performance was the worst, indicating that the fiber dispersion step is crucial for ensuring uniform fiber distribution. Undispersed fibers tend to agglomerate, leading to localized stress concentrations and reducing overall performance. Comparative Example 6: No nanosilica was used. Performance data: compressive strength 128 MPa, flexural strength 19 MPa, ultimate tensile strength 9 MPa, slump spread 205 mm, equivalent flexural strength 26.5 MPa, and interfacial bonding strength 2.5 MPa. Analysis: Performance was degraded, particularly in compressive strength and equivalent flexural strength.Nanosilica fills voids and reacts with volcanic ash to produce more calcium silicate hydrate (CSH), increasing the matrix's density and strength. The specific mechanism is analyzed as follows: Multi-scale fiber reinforcement mechanism: Steel fibers (macroscale): Resist macrocrack propagation, improving impact and fatigue resistance. Basalt fibers (mesoscale): Inhibit microcrack propagation, improving initial crack resistance. Polypropylene fibers (microscale): Bridge microcracks, delay crack connectivity, and enhance ductility. Synergistic effect: The three fibers form a multi-level crack control mechanism from the micro to macro scale, significantly improving toughness and damage resistance. Interface modification mechanism: The polymer chains in the polyurethane emulsion form chemical bonds or physical entanglements with the fiber surface, enhancing adhesion. This flexible network mitigates stress concentration, increases interfacial toughness, and thus improves fiber pullout resistance and overall mechanical properties. Optimization of the cementitious material system: Alkaline treatment and silane coupling agent modification of the rice husk ash-based material enhance its activity and compatibility. Agarose coating improves dispersibility and stability, preventing agglomeration. Nano-silica is used as a filler to improve the density and enhance the matrix strength through pozzolanic reaction. The three-stage process of dry mixing-fiber dispersion-wet mixing: ensures uniform distribution of fibers to avoid agglomeration. Microfluidization emulsification technology: makes the polyurethane emulsion particle size finer and the distribution more uniform, thereby improving the modification effect. By optimizing the component ratio, introducing a multi-scale fiber reinforcement system and a polyurethane emulsion modifier, and adopting a scientific preparation process, Example 5 successfully prepared high-toughness ultra-high performance concrete. Its performance improvement is due to the synergistic effect of fiber bridging effect, interface strengthening, cementitious material optimization and process improvement. These mechanisms provide a theoretical basis for further optimization and application of this material.

[0056] The above describes in detail the preferred embodiments of this patent, but this patent is not limited to the above embodiments. Various changes can be made within the knowledge of ordinary technicians in this field without departing from the purpose of this patent.

Claims

1. A high-toughness ultra-high performance concrete, characterized in that: The invention is composed of the following components in parts by mass: a cementitious material composite system: 600-800 parts of Portland cement, 50-100 parts of nano-silicon dioxide, 80-150 parts of rice husk ash-based auxiliary cementitious material, and 200-300 parts of gradient-graded quartz powder; Fiber reinforcement system: 3-5 parts of steel fiber, 1.5-2.5 parts of basalt fiber, 0.8-1.2 parts of polypropylene fiber; polymer modifier: 8-12 parts of polyurethane emulsion; the silicate cement is silicate cement of grade 42.5 or above; the particle size of the nano-silica is 10-50nm; the preparation method of the rice husk ash-based auxiliary cementitious material is as follows: after the rice husk is wind-sorted, the rice husk with a particle size of less than 2mm is ultrasonically cleaned with a 0.1% by weight citric acid solution for 20-30 minutes, and the cleaned rice husk is immersed in a 5% by weight sodium hydroxide solution, wherein the mass ratio between the rice husk and the sodium hydroxide solution is 1: (3-10), and the mixture is stirred at a constant temperature of 80-90°C for 2-4 hours, and then incubated at 300°C under nitrogen protection. Preheat for 1 hour, heat to 600℃ and treat for 2-3 hours, cool to room temperature at 5℃ / min, use a zirconia ball mill with a ball-to-material ratio of 5:1, grind at 200rpm for 30 minutes until D50 ≤ 8μm to obtain a ground powder, mix the ground powder with a silane coupling agent KH550 at a mass ratio of (3-7): 20, add 50-100 times the mass of the ground powder and a pH of 10.5 alkali solution, then ultrasonically treat at 40kHz and 300W for 30-40 minutes, and then spray dry with an inlet temperature of 180℃ and an outlet temperature of 80℃ to obtain a modified powder, add 20-40 times its mass of 0.3% agarose solution, heat to boiling, and cool to room temperature to obtain a product; the gradient graded quartz powder is quartz powder with D50 2μm / 10μm / 50μm mixed in a mass ratio of 1:2:

1.

2. The high-toughness ultra-high performance concrete according to claim 1, characterized in that: The invention is composed of the following components in parts by mass: a cementitious material composite system: 650-750 parts of Portland cement, 70-90 parts of nano-silicon dioxide, 90-130 parts of rice husk ash-based auxiliary cementitious material, and 220-270 parts of gradient-graded quartz powder; Fiber reinforcement system: 3-5 parts of steel fiber, 1.5-2.5 parts of basalt fiber, 0.8-1.2 parts of polypropylene fiber; polymer modifier: 8-12 parts of polyurethane emulsion.

3. The high-toughness ultra-high performance concrete according to claim 2, characterized in that: The invention is composed of the following components in parts by mass: cementitious material composite system: 700 parts of Portland cement, 80 parts of nano-silicon dioxide, 110 parts of rice husk ash-based auxiliary cementitious material, and 250 parts of gradient-graded quartz powder; Fiber reinforcement system: 4 parts of steel fiber, 2 parts of basalt fiber, 1 part of polypropylene fiber; polymer modifier: 10 parts of polyurethane emulsion.

4. The high-toughness ultra-high performance concrete according to claim 1, characterized in that: The steel fiber has a diameter of 0.18-0.25 mm and a length of 12-15 mm.

5. The high-toughness ultra-high performance concrete according to claim 1, characterized in that: The polyurethane emulsion is prepared as follows: bisphenol A epoxy resin, waterborne polyurethane prepolymer, hydroxylated carbon nanotubes, acrylate monomer, and sulfosuccinate emulsifier are added to a mixture of bisphenol A epoxy resin and acrylate monomer at a mass ratio of (20-40): (30-50): (0.1-0.5): (15-25): (1.5-3), and the mixture is thoroughly stirred. The mixture, the waterborne polyurethane prepolymer, and the hydroxylated carbon nanotubes are placed in a microfluidizer and pre-emulsified at a pressure of 12,000-15,000 psi. Control parameters: particle size: D90≤150nm, temperature: 25-35℃, time: 30-60min, heat the pre-emulsified liquid to 65℃, add potassium persulfate in an amount of 0.1-0.5 times the mass of the acrylate monomer, start the polymerization reaction, gradually heat to 85℃, keep the reaction going, the polymerization reaction time is 4-6h, cool the liquid after polymerization to 50℃, add 1,4-butanediol in an amount of 1-3 times the mass of the acrylate monomer, carry out post-chain extension reaction, the reaction time is 2-4h, filter the emulsion after reaction to remove impurities, then degas and eliminate bubbles to obtain the product.

6. A method for preparing the high-toughness ultra-high performance concrete according to claim 1, comprising the following steps: (1) Raw material preparation: according to the mass parts described in claim 1, weigh the silicate cement, nano-silica, rice husk ash-based auxiliary cementitious material and gradient-graded quartz powder in the cementitious material composite system respectively; weigh the steel fiber, basalt fiber and polypropylene fiber in the fiber reinforcement system respectively; weigh the polymer modifier; (2) Dry-mixing cementitious material: add the weighed silicate cement, nano-silica, rice husk ash-based auxiliary cementitious material and gradient-graded quartz powder into a blender, and dry-mix at a speed of 200-300 rpm for 3-5 minutes to ensure that the components are evenly mixed to obtain a mixture; (3) Fiber dispersion: add the steel fiber, basalt fiber and polypropylene fiber into the dry-mixed cementitious material and disperse them so that the fibers are evenly dispersed in the mixture; (4) Wet mixing and addition of polymer modifier: add water to the mixture obtained in step (3), wherein the mass of water is 0.18-0.22 times that of the mixture, and add polyurethane emulsion at the same time, and stir at a speed of 300-400 rpm for 5-8 minutes to form a uniform concrete slurry; (5) Pouring and vibrating: pour the uniformly mixed concrete slurry into a pre-prepared mold, and vibrate it using a vibration table for 30-60 seconds to ensure that the slurry is dense and free of bubbles; (6) Curing: place the cast specimen in a standard curing room for 24 hours and then demold it; after demolding, continue to cure it under standard curing conditions for 7 days.

7. The method for preparing high-toughness ultra-high performance concrete according to claim 6, characterized in that: The dispersion parameters in step (3) are as follows: stirring at a speed of 100-150 rpm for 2-3 minutes.

8. The method for preparing high-toughness ultra-high performance concrete according to claim 7, characterized in that: The parameters of standard curing in step (6) are as follows: temperature 20±2°C, relative humidity ≥95%.

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