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

Abstract

The invention discloses 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-reinforced system and a polymer modifier, the cementitious material comprises Portland cement, nano-silica, a rice hull ash-based auxiliary cementitious material and gradient grading quartz powder, and the fiber system adopts steel fiber / basalt fiber / polypropylene fiber multi-scale composite reinforcement. And a polyurethane emulsion interface modifier is matched. During preparation, a dry mixing-fiber dispersion-wet mixing three-stage process is combined with a microfluidization emulsification and segmented polymerization technology, so that uniform dispersion of fibers and matrix-fiber interface reinforcement are realized. The scheme has high strength, high toughness and industrial feasibility, and is suitable for harsh engineering scenes such as bridge joints and explosion-proof structures.

Description

Technical Field

[0001] The 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 type of material that has developed rapidly in the field of construction engineering in recent years. It is known for its excellent mechanical properties, outstanding durability and good fire resistance. This material has been widely used in bridges, tunnels, high-rise buildings and other projects that require high-strength and high-durability structures. The typical characteristics of UHPC include extremely high compressive strength (usually exceeding 150MPa), excellent permeability resistance and corrosion resistance, which make it an indispensable part of modern engineering design. However, despite the excellent performance of UHPC in strength and durability, its insufficient toughness limits its application in certain special environments. In particular, when subjected to impact loads, vibration loads or high strain rates, UHPC often exhibits obvious brittle failure characteristics, which may lead to structural failure, thereby reducing its reliability in earthquake resistance, explosion resistance and other fields. Therefore, how to improve the toughness of UHPC has become a hot issue of common concern in the current academic and engineering communities.

[0003] In order to solve the problem of insufficient toughness of UHPC, researchers have proposed a variety of improvement methods and disclosed a series of related technical solutions in patent documents. The following analyzes typical comparative documents in the prior art, sorts out the current research status of UHPC toughness improvement, points out its shortcomings, and uses this as a basis to explain the innovative background of the present invention. Prior art 1 (CN109553361A) discloses an ultra-high performance concrete and a preparation method thereof. The method prepares a UHPC with high compressive strength and flexural strength by optimizing the mix ratio and preparation process of raw materials. Its components include cement, silica fume, fly ash, slag powder, quartz sand, steel fiber, water and water reducer. Through reasonable mix design and process control, the compressive strength and flexural strength of the concrete have been significantly improved, meeting the needs of some engineering applications. However, the document does not propose specific improvement measures for the toughness problem of UHPC, especially the toughness performance under high strain rate or dynamic load is not mentioned. Therefore, although this technology has certain advantages in strength improvement, it cannot effectively solve the problem of brittle failure of UHPC, limiting its applicability in a wider range of scenarios. Another example is that prior art 2 (CN110467410A) proposes a high-toughness ultra-high performance concrete and its preparation method, which focuses on improving the toughness and crack resistance of concrete through fiber reinforcement technology. This concrete adds polypropylene fibers and steel fibers to the traditional UHPC, and uses the bridging effect and pulling effect of the fibers to enhance the tensile properties and crack control ability of the material. The experimental results show that this method can improve the toughness of UHPC to a certain extent, so that it exhibits better ductility during the stress process. However, this method mainly relies on the reinforcement effect of the fiber, and the improvement of the toughness of the concrete matrix itself is relatively limited. In addition, the uniformity of fiber dispersion in concrete and the quality of interface bonding with the matrix directly affect its reinforcement effect, and this document does not fully solve the problems of uneven fiber dispersion and poor interface bonding. Therefore, this technology still faces certain challenges in practical applications, especially how to ensure the uniformity of fiber distribution in large-scale production still needs further research. Another example is prior art 3 (CN113185209A), which proposes a method for preparing high-toughness ultra-high performance concrete. By adopting special cementitious materials and aggregate grading, combined with fiber reinforcement technology, the toughness of UHPC is significantly improved. This method has made innovations in raw material selection and mix design, and at the same time uses the synergistic effect of fibers to enhance the material's crack resistance and energy absorption capacity. The experimental results show that the concrete has significantly improved in toughness indicators compared with traditional UHPC, and can better adapt to application requirements under dynamic load conditions. However, the disadvantage of this technology is that it is difficult to obtain special cementitious materials and aggregates, and the preparation process is relatively complicated, resulting in high production costs and low production efficiency. These problems have limited the promotion and application of this method in actual engineering to a certain extent.

[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, polymer modification, etc. 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 the improvement in the ductility of the concrete matrix itself is limited. Cost and process complexity: The introduction of nanomaterials, special cementitious materials or polymers often increases production costs and process difficulties, 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 a problem that needs to be solved urgently.

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

[0006] The existing technology has the following problems: Insufficient toughness: Although traditional ultra-high performance concrete (UHPC) has high compressive strength, it is relatively brittle, has poor crack resistance and ductility, and is prone to brittle failure under force or impact. Poor fiber dispersion: In the existing technology, the distribution of fibers in the concrete matrix is ​​not uniform enough, resulting in limited reinforcement effect, and it is difficult to give full play to the tensile and crack resistance of the fibers. Weak interface bonding: The interface bonding performance between the fiber and the cement matrix is ​​poor, which limits the overall toughness and durability of the material. Cost and environmental protection issues: Traditional UHPC mostly uses expensive raw materials (such as high-purity silica fume), and the preparation process is complicated, resulting in high production costs and a greater impact on the environment. Durability limitations: In extreme environments (such as high corrosion, high permeability or high temperature conditions), the durability of existing UHPC is insufficient and it is difficult to meet special engineering requirements. In response to the above problems, the present invention improves the existing technology through the following innovations: Optimized component design: Introducing a multi-scale fiber reinforcement system and a polymer modifier to improve toughness and interface bonding. New cementitious materials: Rice husk ash-based auxiliary cementitious materials are used to replace some traditional expensive materials, reducing costs and improving environmental protection. Improved preparation process: The "dry mixing-fiber dispersion-wet mixing" three-stage process is adopted to ensure uniform fiber dispersion and stability of material performance.

[0007] To achieve the above-mentioned purpose, the present invention provides the following technical scheme: a high-toughness ultra-high performance concrete, composed of the following components in parts by weight: a cementitious material composite system: 600-800 parts of silicate cement (CAS No.: 65997-15-1), 50-100 parts of nano-silicon dioxide (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); 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 silicate cement, 70-90 parts of nano-silicon dioxide, 90-130 parts of rice husk ash-based auxiliary cementitious materials, 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 silicate cement, 80 parts of nano-silicon dioxide, 110 parts of rice husk ash-based auxiliary cementitious materials, 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 silicon dioxide 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 for 20-30min using 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: (3-10), and the mixture is stirred at a constant temperature of 80-90°C for 2-4h, then preheated at 300°C under nitrogen protection for 1h, heated to 600°C for 2-3h, and cooled to room temperature at 5°C / min. A zirconium oxide ball mill is used with a ball-to-material ratio of 5:1, and the powder is ground 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 of 50-100 times the mass of the ground powder is added, and then an ultrasonic treatment is performed at 40 kHz and 300 W for 30-40 minutes, followed by spray drying at an inlet temperature of 180°C and an outlet temperature of 80°C to obtain a modified powder, and a 0.3% agarose solution in a mass percentage of 20-40 times the mass of the agarose solution is added, heated to boiling, and cooled to room temperature to obtain a product; the gradient graded quartz powder is a quartz powder with a D50 of 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., item No. 100254, code No. XFM14), acrylate monomer (CAS No.: 5888-33-5) and sulfosuccinate (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, and the mixture is placed in a microfluidizer together with the waterborne polyurethane prepolymer and the hydroxylated carbon nanotubes, and heated at 120 The pre-emulsification is carried out under a pressure of 00-15000psi, and the parameters are as follows: particle size: D90≤150nm, temperature: 25-35℃, time: 30-60min, the pre-emulsified liquid is heated to 65℃, potassium persulfate with 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, the polymerization reaction time is 4-6h, the liquid after polymerization is cooled to 50℃, 1,4-butanediol with an amount of 1-3 times the mass of the acrylate monomer is added, 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 a degassing treatment is carried out to remove bubbles to obtain the product.

[0013] A method for preparing the 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-silicon dioxide, 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-silicon dioxide, 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 then stir the mixture for 3-5 minutes. The fibers and polypropylene fibers 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 the water is 0.18-0.22 times that of the mixture, and polyurethane emulsion is added at the same time, and stirred at a speed of 300-400 rpm for 5-8 min to form a uniform concrete slurry; (5) Pouring and vibrating: the uniformly stirred concrete slurry is poured into a pre-prepared mold, and vibrated on a vibration table for 30-60 s 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 h and then demolded; after demolding, it is continued to be cured 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 variety of fiber composite reinforcement systems, including a multi-scale combination of steel fiber, basalt fiber and polypropylene fiber, the toughness of concrete is greatly improved, so that it exhibits 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 improves its anti-permeability, corrosion resistance and fire resistance. It is suitable for engineering projects with high strength and extremely high durability requirements, such as bridge joints, explosion-proof structures, etc.

[0020] Industrial feasibility and cost control: While ensuring high performance, the present invention adopts a relatively simple preparation process, and the raw materials are reasonably selected, which has strong industrial production feasibility. In terms of cost control, the use of low-cost auxiliary cementitious materials such as rice husk ash-based auxiliary cementitious materials effectively reduces the production cost, making the concrete highly economical in 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-proof 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] For 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 little effect 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-silicon dioxide, 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 silicon dioxide 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 for 20 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 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 5°C / min, and used Zirconia ball mill, ball-to-material ratio of 5:1, 200rpm grinding for 30min, until D50≤8μm, to obtain ground powder, the ground powder and silane coupling agent KH550 are mixed at a mass ratio of 7:20, 50 times the mass of the ground powder is added with an alkali solution with a pH of 10.5, then ultrasonically treated at 40kHz and 300W for 40min, and then spray dried, the inlet temperature is 180℃, the outlet temperature is 80℃, to obtain a modified powder, 20 times the mass of the 0.3% agarose solution is added, heated to boiling, cooled to room temperature, and the product is obtained; the gradient graded quartz powder is D50 2μm / 10μm / 50μm quartz powder mixed at a mass ratio of 1:2:1. The diameter of the steel fiber is 0.25mm and the length is 12mm. The preparation method of the polyurethane emulsion is 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 40:30:0.5:15:3, and the sulfosuccinate emulsifier is fully stirred. The mixture, the waterborne polyurethane prepolymer and the hydroxylated carbon nanotubes are placed in a microfluidizer and pre-emulsified at a pressure of 12000psi. Preparation parameters: particle size: D 90≤150nm, temperature: 35℃, time: 30min, heat the pre-emulsified liquid to 65℃, add potassium persulfate with a mass of 0.5 times that of the acrylate monomer, start the polymerization reaction, gradually heat to 85℃, keep the reaction going, the polymerization reaction time is 4h, cool the polymerized liquid to 50℃, add 1,4-butanediol with a mass of 3 times that of the acrylate monomer, carry out post-chain extension reaction, the reaction time is 2h, filter the emulsion after the reaction to remove impurities, then degas and remove bubbles to obtain the product.

[0028] 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-silicon dioxide, 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-silicon dioxide, rice husk ash-based auxiliary cementitious material and gradient-graded quartz powder into a mixer, and 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 a mixer, and then stir the mixture for 5 minutes. 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 polymer modifier addition: 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 a vibration table is used to vibrate 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, continue to cure 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-silicon dioxide, 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 42.5 grade silicate cement; the particle size of the nano silicon dioxide 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 for 20 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 between the rice husk and 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 5°C / min, and used Zirconia ball mill, ball-to-material ratio of 5:1, 200rpm grinding for 30min, until D50≤8μm, to obtain ground powder, the ground powder and silane coupling agent KH550 are mixed at a mass ratio of 3:20, 50 times the mass of the ground powder is added with an alkali solution with a pH of 10.5, then ultrasonically treated at 40kHz and 300W for 30min, and then spray dried, the inlet temperature is 180℃, the outlet temperature is 80℃, to obtain the modified powder, add 20 times the mass of 0.3% agarose solution, heat to boiling, cool to room temperature, and obtain the product; the gradient graded quartz powder is D50 2μm / 10μm / 50μm quartz powder mixed at a mass ratio of 1:2:1. The diameter of the steel fiber is 0.18mm and the length is 12mm. The preparation method of the polyurethane emulsion is 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 20:50:0.1:25:1.5, 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 15000 psi. Preparation parameters: particle size: D90≤150nm, temperature: 25℃, time: 30min, heat the pre-emulsified liquid to 65℃, add potassium persulfate with the mass of 0.5 times of the acrylate monomer, start the polymerization reaction, gradually heat to 85℃, keep the reaction going, the polymerization time is 6h, cool the liquid after polymerization to 50℃, add 1,4-butanediol with the mass of 3 times of the acrylate monomer, carry out post-chain extension reaction, the reaction time is 4h, filter the emulsion after reaction to remove impurities, then degas and remove bubbles to obtain the product.

[0032] 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-silicon dioxide, 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-silicon dioxide, rice husk ash-based auxiliary cementitious material and gradient-graded quartz powder into a mixer, and 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 a mixer, and 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 polymer modifier addition: 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 on 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, continue to cure 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 silicon dioxide is 10nm; 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 for 20 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 1:3, and the mixture is stirred at a constant temperature of 80°C for 2h, then preheated at 300°C under nitrogen protection for 1h, heated to 600°C for 2h, cooled to room temperature at 5°C / min, and oxygen is used. Zirconium ball mill, ball-to-material ratio of 5:1, 200rpm grinding for 30min, until D50≤8μm, to obtain ground powder, the ground powder and silane coupling agent KH550 are mixed at a mass ratio of 3:20, 100 times the mass of the ground powder is added with an alkali solution with a pH of 10.5, then ultrasonically treated at 40kHz and 300W for 40min, and then spray dried, the inlet temperature is 180℃, the outlet temperature is 80℃, to obtain a modified powder, 40 times the mass of the 0.3% agarose solution is added, heated to boiling, cooled to room temperature, and the product is obtained; the gradient graded quartz powder is D50 2μm / 10μm / 50μm quartz powder mixed at a mass ratio of 1:2:1. The diameter of the steel fiber is 0.25mm and the length is 12mm. The preparation method of the polyurethane emulsion is 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 20:30:0.1:15:3, and the sulfosuccinate emulsifier is fully stirred. The mixture, waterborne polyurethane prepolymer and hydroxylated carbon nanotubes are placed in a microfluidizer and pre-emulsified at a pressure of 12000psi. Preparation parameters: particle size: D 90≤150nm, temperature: 35℃, time: 30min, heat the pre-emulsified liquid to 65℃, add potassium persulfate with the mass of 0.1 times of the acrylate monomer, start the polymerization reaction, gradually heat to 85℃, keep the reaction going, the polymerization time is 6h, cool the liquid after polymerization to 50℃, add 1,4-butanediol with the mass of 3 times of the acrylate monomer, carry out post-chain extension reaction, the reaction time is 4h, filter the emulsion after reaction to remove impurities, then degas and remove bubbles to obtain the product.

[0036] 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-silicon dioxide, 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-silicon dioxide, rice husk ash-based auxiliary cementitious material and gradient-graded quartz powder into a mixer, and 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 a mixer, and 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 polymer modifier addition: 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 a vibration table is used to vibrate 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, continue to cure 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-silicon dioxide, 130 parts of rice husk ash-based auxiliary cementitious materials, and 270 parts of gradient-graded quartz powder; fiber reinforcement system: 5 parts of steel fiber, 2.5 parts of basalt fiber, and 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 silicon dioxide is 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 for 30 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 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 5°C / min, and used Zirconia ball mill, ball-to-material ratio of 5:1, 200rpm grinding for 30min, until D50≤8μm, to obtain ground powder, the ground powder and silane coupling agent KH550 are mixed at a mass ratio of 7:20, 100 times the mass of the ground powder with pH 10.5 alkali solution is added, then ultrasonic treatment is carried out at 40kHz, 300W for 40min, and then spray drying is carried out, the inlet temperature is 180℃, the outlet temperature is 80℃, to obtain modified powder, 40 times the mass of 0.3% agarose solution is added, heated to boiling, cooled to room temperature, and the product is obtained; the gradient graded quartz powder is D50 2μm / 10μm / 50μm quartz powder is mixed at a mass ratio of 1:2:1. The diameter of the steel fiber is 0.25mm and the length is 15mm. The preparation method of the polyurethane emulsion is 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 40:50:0.5:25:3, 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 15000 psi. Preparation parameters: particle size: D 90≤150nm, temperature: 35℃, time: 40min, heat the pre-emulsified liquid to 65℃, add potassium persulfate with the mass of 0.5 times of acrylate monomer, start the polymerization reaction, gradually heat to 85℃, keep the reaction going, the polymerization time is 6h, cool the liquid after polymerization to 50℃, add 1,4-butanediol with the mass of 1 times of acrylate monomer, carry out post-chain extension reaction, the reaction time is 4h, filter the emulsion after reaction to remove impurities, then degas and remove bubbles to obtain the product.

[0040] 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-silicon dioxide, 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-silicon dioxide, rice husk ash-based auxiliary cementitious material and gradient-graded quartz powder into a mixer, and 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 a mixer, and 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 polymer modifier addition: 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 a vibration table is used to vibrate 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-silicon dioxide, 110 parts of rice husk ash-based auxiliary cementitious materials, and 250 parts of gradient-graded quartz powder; fiber reinforcement system: 4 parts of steel fiber, 2 parts of basalt fiber, and 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 silicon dioxide is 30nm; 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 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 5°C / min, and oxygenated. Zirconium ball mill, ball-to-material ratio of 5:1, 200rpm grinding for 30min, until D50≤8μm, to obtain ground powder, the ground powder and silane coupling agent KH550 are mixed at a mass ratio of 7:20, 100 times the mass of the ground powder with pH 10.5 alkali solution is added, then ultrasonic treatment is carried out at 40kHz, 300W for 40min, and then spray drying is carried out, the inlet temperature is 180℃, the outlet temperature is 80℃, to obtain modified powder, 40 times the mass of 0.3% agarose solution is added, heated to boiling, cooled to room temperature, and the product is obtained; the gradient graded quartz powder is D50 2μm / 10μm / 50μm quartz powder is mixed at a mass ratio of 1:2:1. The diameter of the steel fiber is 0.25mm and the length is 15mm. The preparation method of the polyurethane emulsion is 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 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 14000 psi. Preparation parameters: particle size: D 90≤150nm, temperature: 30℃, time: 50min, heat the pre-emulsified liquid to 65℃, add potassium persulfate with a mass of 0.3 times of the acrylate monomer, start the polymerization reaction, gradually heat to 85℃, keep the reaction going, the polymerization time is 5h, cool the liquid after polymerization to 50℃, add 1,4-butanediol with a mass of 2 times of the acrylate monomer, carry out post-chain extension reaction, the reaction time is 3h, filter the emulsion after the reaction to remove impurities, then degas and remove 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-silicon dioxide, 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-silicon dioxide, rice husk ash-based auxiliary cementitious material and gradient-graded quartz powder into a mixer, and 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 a mixer, and then stir the mixture for 4 minutes. 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: Add water to the mixture obtained in step (3), wherein the mass of water is 0.2 times that of the mixture, and add polyurethane emulsion at the same time, stir at a speed of 400rpm for 7 minutes to form a uniform concrete slurry; (5) Pouring and vibrating: Pour the evenly stirred concrete slurry into a pre-prepared mold, and vibrate on a vibration table for 50 seconds to ensure that the slurry is dense and free of bubbles; (6) Curing: Place the cast specimen in a standard curing room for curing for 24 hours and then demold; after demolding, continue to cure under standard curing conditions for 7 days. Among them, the dispersion parameters in step (3) are as follows: stir at a speed of 130rpm for 3 minutes; the standard curing parameters in step (6) are as follows: temperature 20±2℃, relative humidity ≥95%, 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 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 was carried out according to the process of Example 5.

[0050] Comparative Example 6: Nano-silicon dioxide is not used in the cementitious material composite system, and the rest is carried out according to the process of Example 5.

[0051] Test plan: Compressive strength: Cube compression test is carried out according to GB / T 50081-2002 "Standard for Test Methods of Mechanical Properties of Ordinary Concrete". Flexural strength: Four-point bending test is carried out according to GB / T 17671-1999 "Test Methods for Strength of Cement Mortar". Tensile properties: Ultimate tensile strength, according to CECS13:2009 "Standard for Test Methods of Fiber Concrete". Equivalent flexural strength: Calculate the flexural toughness index according to CECS13:2009 standard. Crack control ability: Evaluate by the area under the load-displacement curve in the three-point bending test. Fiber-matrix interface bonding strength: Use 8-shaped specimen pull-out test (patent CN113816685A). Slump expansion: Tested according to GB / T 50080-2016 standard.

[0052] Table 1

[0053]

[0054] As shown in Table 1, from the data of Example 1 to Example 5, with the optimization of the component ratio, the performance indicators of concrete show a certain improvement 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 other embodiments, 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 comparing 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 bending 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 bending 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 materials 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 bending 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 a single steel fiber can improve some properties, it cannot achieve the synergistic enhancement effect of multi-scale fibers. The combination of steel fiber, basalt fiber and polypropylene fiber in Example 5 fully inhibits crack expansion at the macro, micro and micro scales. Comparative Example 3: No polymer modifier is used, performance data: compressive strength 118MPa, flexural strength 16MPa, ultimate tensile strength 7MPa, slump expansion 210mm, equivalent bending strength 22.4MPa, interface bonding strength 1.9MPa. Analysis: The performance is greatly reduced, especially the interface bonding strength is much lower than that of Example 5. This shows that polyurethane emulsion plays a key role in reinforcing the interface between fiber and matrix, and its flexible interface layer improves the bonding force and overall mechanical properties. Comparative Example 4: Using silica fume to replace rice husk ash-based auxiliary cementitious material, performance data: compressive strength 135MPa, flexural strength 22MPa, ultimate tensile strength 11MPa, slump expansion 230mm, equivalent bending strength 30.2MPa, interface bonding strength 3.2MPa. Analysis: The performance is better than that of Comparative Examples 1-3, but still inferior to that of Example 5. The rice husk ash-based material has been specially treated (such as alkali soaking, silane coupling agent modification, and agarose coating) to have higher activity and better compatibility with the matrix, which is better than traditional silica ash. Comparative Example 5: No fiber dispersion step, performance data: compressive strength 110MPa, flexural strength 14MPa, ultimate tensile strength 6MPa, slump expansion 165mm, equivalent bending strength 18.7MPa, interface bonding strength 1.4MPa. Analysis: The performance is the worst, indicating that the fiber dispersion step is crucial to ensure uniform fiber distribution. Undispersed fibers are prone to agglomeration, resulting in local stress concentration and reducing overall performance. Comparative Example 6: No nano-silica is used, performance data: compressive strength 128MPa, flexural strength 19MPa, ultimate tensile strength 9MPa, slump expansion 205mm, equivalent bending strength 26.5MPa, interface bonding strength 2.5MPa. Analysis: Performance is reduced, especially compressive strength and equivalent bending strength.Nano-silica generates more calcium silicate hydrate (CSH) by filling voids and reacting with volcanic ash, which improves the density and strength of the matrix. The above specific mechanism analysis is as follows: Multi-scale fiber reinforcement mechanism, steel fiber (macroscale): resists the extension of macro cracks and improves impact resistance and fatigue resistance. Basalt fiber (mesoscale): inhibits the extension of micro cracks and improves initial crack resistance. Polypropylene fiber (microscale): bridges micro cracks, delays crack connectivity, and enhances ductility. Synergistic effect: The three types of fibers form a multi-level crack control mechanism from micro to macro, greatly improving toughness and damage resistance. Interface modification mechanism: The polymer chain segments in the polyurethane emulsion form chemical bonds or physical entanglements with the fiber surface to enhance adhesion. Its flexible network relieves stress concentration and improves interface toughness, thereby improving fiber pull-out resistance and overall mechanical properties. The gelling material system is optimized. After the rice husk ash-based material is treated with alkali and modified with a silane coupling agent, its activity and compatibility are enhanced. Agarose coating improves dispersibility and stability and prevents agglomeration. Nano-silica is used as a filler to improve the density and enhance the strength of the matrix through volcanic ash reaction. Three-stage process of dry mixing-fiber dispersion-wet mixing: ensure 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 stems from 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 implementation of this patent, but this patent is not limited to the above implementation. Various changes can be made within the knowledge scope 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 weight: a cementitious material composite system: 600-800 parts of silicate 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.

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 weight: a cementitious material composite system: 650-750 parts of silicate 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: It is composed of the following components in parts by mass: cementitious material composite system: 700 parts of silicate 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 silicate cement is silicate cement of grade 42.5 or above; the particle size of the nano silicon dioxide 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 for 20-30min using 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 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 2-4h, then preheated at 300°C under nitrogen protection for 1h, heated to 600°C for 2-3h, and cooled to room temperature at 5°C / min. , using a zirconium oxide ball mill with a ball-to-material ratio of 5:1, grinding at 200rpm for 30min until D50≤8μm, obtaining a ground powder, mixing the ground powder with a silane coupling agent KH550 at a mass ratio of (3-7):20, adding an alkali solution with a pH of 10.5 in an amount 50-100 times the mass of the ground powder, then ultrasonically treating at 40kHz and 300W for 30-40min, and then spray drying with an inlet temperature of 180°C and an outlet temperature of 80°C to obtain a modified powder, adding a 0.3% agarose solution in a mass percentage of 20-40 times the mass thereof, heating to boiling, and cooling to room temperature to obtain a product; the gradient graded quartz powder is a quartz powder with a D50 of 2μm / 10μm / 50μm mixed in a mass ratio of 1:2:

1.

5. 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.

6. The high-toughness ultra-high performance concrete according to claim 1, characterized in that: The preparation method of the polyurethane emulsion is 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 (20-40): (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, and the mixture, waterborne polyurethane prepolymer and hydroxylated carbon nanotubes are placed in a microfluidizer and pre-emulsified at a pressure of 12000-15000 psi. , Preparation parameters: particle size: D90≤150nm, temperature: 25-35℃, time: 30-60min, heat the pre-emulsified liquid to 65℃, add potassium persulfate with a mass of 0.1-0.5 times of the acrylate monomer, start the polymerization reaction, gradually heat to 85℃, keep the reaction going, the polymerization time is 4-6h, cool the polymerized liquid to 50℃, add 1,4-butanediol with a mass of 1-3 times of the acrylate monomer, carry out post-chain extension reaction, the reaction time is 2-4h, filter the emulsion after the reaction to remove impurities, then degas and remove bubbles to obtain the product.

7. 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 of 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 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 dry-mixed cementitious material for dispersion, 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 of that of the mixture, and add polyurethane emulsion at the same time, and stir at a speed of 300-400 rpm for 5-8 min to form a uniform concrete slurry; (5) Casting and vibrating: cast the uniformly stirred concrete slurry into a pre-prepared mold, and vibrate it on a vibration table for 30-60 s to ensure that the slurry is dense and free of bubbles; (6) Curing: place the cast specimen in a standard curing room for 24 h and then demold it; after demolding, continue to cure it under standard curing conditions for 7 days.

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

9. The method for preparing high-toughness ultra-high performance concrete according to claim 8, 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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