High-performance anti-crack and anti-seepage concrete for hydraulic structure and preparation method thereof

Abstract

The invention relates to the field of high-performance anti-cracking and anti-seepage concrete, in particular to high-performance anti-cracking and anti-seepage concrete for hydraulic structures and a preparation method thereof. The high-performance anti-cracking and anti-seepage concrete for the hydraulic structure comprises the following substances in parts by weight: 25-30 parts of cement; 80 to 100 parts of coarse aggregate; 70 to 80 parts of fine aggregate; 10 to 15 parts of water; 3-5 parts of an anti-crack and anti-permeability modifier; the anti-crack and anti-permeability modifier comprises a silicon-aluminum base material, and the silicon-aluminum base material comprises fly ash, slag and metakaolin which are mixed according to the mass ratio of (4-5): (2.5-3.5): (2-3). The anti-cracking and anti-seepage performance is synergistically improved through the silicon-aluminum base material composite modifier. Compared with a single mineral admixture, the composite system can more efficiently refine the pore size distribution and reduce the permeability coefficient of the concrete; meanwhile, Ca (OH) 2 crystals are consumed through a volcanic ash reaction, interface stress concentration caused by crystal oriented growth is reduced, microcrack initiation is inhibited from the source, and crack resistance and permeability resistance are improved.

Description

Technical Field

[0002] This invention relates to the field of high-performance crack-resistant and impermeable concrete, specifically to a high-performance crack-resistant and impermeable concrete for hydraulic structures and its preparation method. Background Technology

[0004] Hydraulic structures, as the core carriers of water conservancy projects, encompass key facilities such as dams, sluices, water conveyance tunnels, and coastal breakwaters. Their concrete structures must withstand complex environmental effects such as high water head pressure, freeze-thaw cycles, sulfate erosion, and chloride ion penetration over long periods. Crack resistance and impermeability are core indicators determining the durability of hydraulic concrete: cracks not only directly cause leakage but also become channels for the intrusion of corrosive media such as water and salt, accelerating steel corrosion and concrete deterioration; while insufficient impermeability weakens the structure's resistance to water pressure, exacerbating the accumulation of internal damage. Traditional silicate cement concrete, due to its high shrinkage and brittleness, is prone to micro-cracks under long-term load and environmental coupling effects, and its impermeability decreases significantly with service time, making it difficult to meet the high durability requirements of modern water conservancy projects for a century-long lifespan. Therefore, developing hydraulic concrete materials with both excellent crack resistance and impermeability has become a key technical challenge for ensuring the safety of water conservancy projects and reducing life-cycle maintenance costs.

[0005] Currently, the industry mainly adopts fiber reinforcement technology to improve the crack resistance and impermeability of hydraulic concrete. By adding steel fibers, polypropylene fibers or basalt fibers, the bridging effect of the fibers is used to disperse stress and inhibit the propagation of macroscopic cracks, in an attempt to achieve a synergistic improvement in crack resistance and impermeability.

[0006] Regarding the aforementioned existing technologies, the inventors have discovered that while some technologies have improved the crack resistance and impermeability of hydraulic concrete to a certain extent, their limitations remain significant. In fiber-reinforced technologies, single fibers are prone to settling and clumping due to their high density, resulting in poor dispersion uniformity. High admixture levels can also reduce the workability of concrete, making it difficult to simultaneously achieve full-chain performance optimization of "inhibiting micro-crack generation - hindering media penetration - preventing macro-crack propagation." Consequently, these technologies cannot meet the long-term service requirements of demanding scenarios such as high-head dams and highly erosive coastal structures. Summary of the Invention

[0008] Based on the technical problems existing in the prior art, the present invention provides a high-performance crack-resistant and impermeable concrete for hydraulic structures and a method for preparing the same.

[0009] In the first aspect, this application provides a high-performance crack-resistant and impermeable concrete for hydraulic structures, employing the following technical solution: A high-performance crack-resistant and impermeable concrete for hydraulic structures comprises the following components by weight: 25-30 parts cement; 80-100 parts coarse aggregate; 70-80 parts fine aggregate; 10-15 parts water; 3-5 parts of crack-resistant and seepage-resistant modifier; The crack-resistant and impermeable modifier includes a silica-alumina matrix, which comprises fly ash, slag and metakaolin mixed in a mass ratio of (4-5):(2.5-3.5):(2-3).

[0010] Through the above technical solution, this application achieves a synergistic improvement in crack resistance and impermeability through a silica-alumina matrix composite modifier. Fly ash, slag, and metakaolin are all industrial solid wastes rich in SiO2 and Al2O3. In the alkaline environment of Ca(OH)2 generated during cement hydration, their active components react with Ca... 2+ The reaction generates additional CSH gel, filling the capillary and gel pores inside the concrete. Simultaneously, the particle size distribution of the three materials forms a complementary gradation, further optimizing the pore structure. In terms of effect, compared to single mineral admixtures, this composite system can more efficiently refine the pore size distribution and reduce the permeability coefficient of concrete. Furthermore, the pozzolanic reaction consumes Ca(OH)2 crystals, reducing interfacial stress concentration caused by directional crystal growth, thus inhibiting the initiation of microcracks at the source and achieving a "dual improvement" in crack resistance and impermeability.

[0011] Furthermore, the crack-resistant and seepage-resistant modifier also includes an interface coating layer, which is formed by coating and curing a polymer emulsion. The polymer emulsion is prepared by mixing an acrylic emulsion and a silane coupling agent at a mass ratio of (20:1-1.5).

[0012] Through the above technical solution, this application strengthens the interfacial bonding between the modifier and the cement matrix through an interface coating layer. After the acrylic emulsion forms a film, it creates a continuous elastic interface layer that can absorb the internal stress generated during cement hydration due to shrinkage or temperature changes, preventing microcracks from forming in the interface transition zone due to stress concentration. The alkoxy groups of the silane coupling agent hydrolyze to generate -Si-OH groups, which react with the hydroxyl groups on the aggregate surface to form -Si-O- covalent bonds, while the amino group at the other end combines with the carboxyl groups of the acrylic emulsion to form chemical bond bridging. This flexible film buffer composite interface design with enhanced chemical bonds reduces the initial defect density of the interface and improves the bonding strength, thereby significantly improving the impermeability and crack resistance of the concrete.

[0013] Furthermore, the crack-resistant and impermeable modifier is prepared using the following technical solution: Fly ash, slag, and metakaolin were mixed with an activator, stirred, and collected to obtain a mixed slurry. The mixed slurry was taken and spray-dried to obtain dried microspheres; The crack-resistant and impermeable modifier can be prepared by taking dried microspheres, immersing them in a polymer emulsion, ultrasonically dispersing them, and then drying and curing them.

[0014] Through the above technical solution, this application optimizes the preparation process of "core-shell microspheres" for crack-resistant and impermeable modifiers. The structure of an active core and a functional outer shell is achieved through spray drying and emulsion coating. The slurry formed by mixing the silica-alumina matrix with the activator is spray-dried into micron-sized microspheres, increasing the specific surface area and improving the reaction efficiency between the active component and cement hydration products. The polymer emulsion coating layer on the surface of the microspheres gradually swells during concrete mixing, forming a "slow-release" effect, ensuring the uniform distribution of the interface modifier at the cement-aggregate interface. Compared with directly adding powder, core-shell microspheres avoid the problem of localized modification failure caused by agglomeration. The active core fills the pores through continuous pozzolanic reaction, while the polymer film on the outer shell forms a continuous barrier layer at the interface, ultimately achieving a stable improvement in impermeability. Simultaneously, the spherical shape of the microspheres also improves the workability of concrete and reduces construction difficulty.

[0015] Furthermore, the high-performance crack-resistant and impermeable concrete for hydraulic structures also includes 10-15 parts by weight of nano-modified grout, wherein the nano-modified grout comprises the following substances in parts by weight: 3-6 parts of nano-silica; 1.5-2.5 parts of carbon nanotubes; Polyethylene glycol-400 6-15 parts; 60-80 parts deionized water.

[0016] Through the above technical solution, this application introduces a nano-modified slurry for modification. Nano-SiO2 fills the nanoscale pores between CSH gels, refining the gel pore structure. Carbon nanotubes, with their ultra-high aspect ratio and strength, bridge gel particles, forming a nano-reinforcement-gel network composite structure, enhancing the toughness of the gel phase. Polyethylene glycol, as a dispersant, prevents nanoparticle aggregation through steric hindrance, ensuring uniform dispersion in concrete. Thus, the nano-modified slurry significantly reduces the nanoporosity of concrete while increasing the fracture energy of the gel phase, effectively suppressing nanoscale microcracks caused by shrinkage or load, providing a fundamental microscopic guarantee for the crack resistance and impermeability of concrete.

[0017] Furthermore, the high-performance crack-resistant and impermeable concrete for hydraulic structures also includes 3-8 parts by weight of toughening fibers, which are basalt fibers and steel fibers mixed in a mass ratio of 2-3:1.

[0018] Furthermore, the toughening fibers contain basalt fibers of 10-20 mm in diameter and steel fibers of 0.3-0.5 mm in diameter and 15-20 mm in length.

[0019] Through the above technical solution, this application achieves full-scale crack control using a composite toughening system of basalt fiber and steel fiber. Basalt fiber has high strength and good alkali resistance, and can disperse stress at micro-cracks through a bridging effect, inhibiting crack propagation. Steel fiber has high stiffness and high tensile strength, and can withstand tensile stress at macro-cracks, preventing rapid crack extension. After being mixed in a certain proportion, a gradient reinforcement network of "micro-fiber crack inhibition + coarse fiber load bearing" is formed. This composite fiber system covers full-scale control from micro-cracks to macro-cracks, and avoids the limitations of single fibers, significantly improving the crack resistance and toughness of concrete.

[0020] Secondly, this application provides a method for preparing high-performance crack-resistant and impermeable concrete for hydraulic structures, employing the following technical solution: A method for preparing high-performance crack-resistant and impermeable concrete for hydraulic structures includes the following preparation steps: Take cement and nano-modified slurry, mix them at low speed and collect the mixture; After adding coarse and fine aggregates to the mixture, add crack-resistant and impermeable modifier, stir at medium speed, and collect the mixture liquid; After taking the mixed liquid and adding toughening fibers, it is stirred at high speed and poured into a mold. It is then vibrated to compact the mixture and sprayed with a protective emulsion layer. After curing for 24 weeks, the film is removed and allowed to cure naturally, thus producing high-performance crack-resistant and impermeable concrete for hydraulic structures.

[0021] Furthermore, the low-speed stirring rate is 50-70 r / min; the medium-speed stirring rate is 90-150 r / min; and the high-speed stirring rate is 180-250 r / min.

[0022] Through the above technical solution, this application adopts a staged mixing preparation process. By controlling the mixing rate, the dispersion effect of each component is optimized, and the long-term impermeability is enhanced through surface protection. Low-speed mixing ensures that the nano-modified slurry uniformly coats cement particles, preventing nanoparticle agglomeration; medium-speed mixing ensures that coarse and fine aggregates are fully mixed with core-shell microspheres, with microspheres filling the gaps between aggregates; high-speed mixing ensures that fibers are uniformly dispersed, forming a continuous fiber network. The staged mixing process ensures the uniform distribution of nanomaterials, microspheres, and fibers in concrete, fully utilizing the modification efficiency of each component.

[0023] Furthermore, the protective emulsion layer is a fluorocarbon resin emulsion, and the spraying amount of the fluorocarbon resin emulsion is 0.15-0.25 kg / m². 2 .

[0024] Through the above technical solution, this application constructs a long-lasting and stable hydrophobic barrier on the surface of hydraulic concrete using fluorocarbon resin emulsion surface protection. This design not only directly improves the impermeability and corrosion resistance of the concrete, but also indirectly assists the crack resistance of the internal modification system by delaying the intrusion of external corrosive media, forming a closed-loop protection mechanism of internal modification inhibiting crack formation and surface protection blocking media intrusion. This overcomes the limitations of traditional concrete relying solely on internal modification, providing crucial surface protection technology support for the long-term safe service of highly durable hydraulic structures.

[0025] In summary, this application has the following beneficial effects: First, this application utilizes a nanoscale-filled composite micron-level interface enhancement technology, further enhanced by a multi-scale synergistic scheme designed with macro-level fiber crack prevention, to cover the full-scale defect control of concrete, from nanopores to macro-cracks: Nano-modified slurry fills the nanopores between gels, refining the pore size distribution and enhancing gel toughness; micron-level core-shell microspheres fill the capillaries between aggregates, strengthening the cement-aggregate interface bond; macro-toughening fibers, through a microfiber crack prevention composite with coarse fiber load-bearing technology, inhibit the propagation of cracks larger than 0.05 mm. This multi-scale modification system forms a closed-loop control mechanism that inhibits micro-crack initiation, hinders media penetration, and prevents macro-crack extension. Compared to traditional single-modification technologies, this achieves a synergistic breakthrough in impermeability and crack resistance.

[0026] Secondly, this application achieves dual reinforcement of the cement matrix and aggregate interface through a core-shell microsphere structure combining an active core with a polymer shell and an interfacial coating layer of acrylic emulsion: the active core consumes Ca(OH)2 crystals through a pozzolanic reaction, reducing interfacial stress concentration; the polymer shell forms an elastic buffer layer to absorb shrinkage stress; and the silane coupling agent enhances interfacial adhesion through chemical bonds. This improved interfacial bond strength fundamentally reduces the risk of early cracking in concrete caused by interfacial defects, significantly enhancing structural stability.

[0027] Third, this application employs a staged mixing process to ensure that nanomaterials, core-shell microspheres, and fibers are uniformly dispersed in concrete, fully maximizing the modification efficiency of each component. Simultaneously, the fluorocarbon resin emulsion sprayed on the surface forms a hydrophobic film, blocking the penetration of corrosive media such as water and salt. This staged process not only ensures material performance but also reduces construction difficulty. Surface protection, through physical barriers, delays external erosion, forming a synergistic long-term protective mechanism with internal modification. This significantly extends the service life of concrete under harsh environments such as high water heads and strong erosion, substantially reducing the life-cycle maintenance costs of water conservancy projects. Detailed Implementation

[0028] The present application will be further described in detail below with reference to the embodiments.

[0029] Preparation Example 1 Crack-resistant and seepage-resistant modifier 1 Take 4 kg of fly ash, 2.5 kg of slag and 2 kg of metakaolin, stir and mix them, and collect the siliceous alumina matrix. Take the siliceous alumina matrix and add 0.15 kg of water glass and 0.15 kg of sodium hydroxide. Stir and mix them and add water until the solid content is 50%. Then place it in a spray drying device, adjust the inlet air temperature to 220℃ and the outlet air temperature to 100℃, spray dry, and collect the dried microspheres of 10-50 μm to prepare crack-resistant and impermeable modifier 1.

[0030] Preparation Example 2 Crack-resistant and seepage-resistant modifier 2 Take 4.5 kg of fly ash, 3 kg of slag and 2.5 kg of metakaolin, stir and mix them to obtain a silica-alumina matrix. Take the silica-alumina matrix and add 0.15 kg of water glass and 0.15 kg of sodium hydroxide. Stir and mix them and add water until the solid content is 50%. Place it in a spray drying device, adjust the inlet air temperature to 220℃ and the outlet air temperature to 100℃, spray dry and collect the dried microspheres of 10-50 μm to prepare crack-resistant and impermeable modifier 2.

[0031] Preparation Example 3 Crack-resistant and seepage-resistant modifier 3 Take 5 kg of fly ash, 3.5 kg of slag and 3 kg of metakaolin, stir and mix them, and collect the siliceous alumina matrix. Take the siliceous alumina matrix and add 0.15 kg of water glass and 0.15 kg of sodium hydroxide. Stir and mix them and add water until the solid content is 50%. Then place it in a spray drying device, adjust the inlet air temperature to 220℃ and the outlet air temperature to 100℃, spray dry, and collect the dried microspheres of 10-50 μm to prepare crack-resistant and impermeable modifier 3.

[0032] Preparation Example 4 Crack-resistant and impermeable modification 4 Take 4.5 kg of fly ash, 3 kg of slag, and 2.5 kg of metakaolin, mix them, and collect the silicoaluminate matrix. Add 0.15 kg of water glass and 0.15 kg of sodium hydroxide to the silicoaluminate matrix, mix them, and add water until the solid content is 50%. Place it in a spray drying device, adjust the inlet air temperature to 220℃ and the outlet air temperature to 100℃, spray dry, and collect 10-50 μm dry microspheres. Then, mix acrylic emulsion and silane coupling agent KH-550 at a mass ratio of 20:1 to prepare a polymer emulsion. Immerse the dry microspheres in the polymer emulsion, ultrasonically disperse them at a frequency of 40 kHz for 15 min, remove them, and dry and cure them at 60℃ to obtain the core-shell structure crack-resistant and impermeable modifier 4.

[0033] Preparation Example 5 Crack-resistant and impermeable modification 5 Take 4.5 kg of fly ash, 3 kg of slag, and 2.5 kg of metakaolin, mix them, and collect the silicoaluminate matrix. Add 0.15 kg of water glass and 0.15 kg of sodium hydroxide to the silicoaluminate matrix, mix them, and add water until the solid content is 50%. Place it in a spray drying device, adjust the inlet air temperature to 220℃ and the outlet air temperature to 100℃, spray dry, and collect 10-50 μm dried microspheres. Then, mix acrylic emulsion and silane coupling agent KH-550 at a mass ratio of 20:1.2 to prepare a polymer emulsion. Immerse the dried microspheres in the polymer emulsion, ultrasonically disperse them at a frequency of 40 kHz for 15 min, remove them, and dry and cure them at 60℃ to obtain a core-shell structure crack-resistant and impermeable modifier 5.

[0034] Preparation Example 6 Crack-resistant and impermeable modification 6 Take 4.5 kg of fly ash, 3 kg of slag, and 2.5 kg of metakaolin, mix them, and collect the silicoaluminate matrix. Add 0.15 kg of water glass and 0.15 kg of sodium hydroxide to the silicoaluminate matrix, mix them, and add water until the solid content is 50%. Place it in a spray drying device, adjust the inlet air temperature to 220℃ and the outlet air temperature to 100℃, spray dry, and collect 10-50 μm dry microspheres. Then, mix acrylic emulsion and silane coupling agent KH-550 at a mass ratio of 20:1.5 to prepare a polymer emulsion. Immerse the dry microspheres in the polymer emulsion, ultrasonically disperse them at a frequency of 40 kHz for 15 min, remove them, and dry and cure them at 60℃ to obtain a core-shell structure crack-resistant and impermeable modifier 6.

[0035] Preparation Example 7 Nano-modified slurry 1 Take 3 kg of nano-SiO2, 1.5 kg of carbon nanotubes with a diameter of 15 nm and an aspect ratio of 1200, 6 kg of polyethylene glycol-400, and 60 kg of deionized water; add the nano-SiO2 and carbon nanotubes to the deionized water, stir at 2000 r / min for 30 min, then add polyethylene glycol-400 and continue stirring for 10 min to obtain a uniformly dispersed nano-modified slurry 1.

[0036] Preparation Example 8 Nano-modified slurry 2 Take 4 kg of nano-SiO2, 2 kg of carbon nanotubes with a diameter of 15 nm and an aspect ratio of 1200, 10 kg of polyethylene glycol-400, and 70 kg of deionized water; add the nano-SiO2 and carbon nanotubes to the deionized water, stir at 2000 r / min for 30 min, then add polyethylene glycol-400 and continue stirring for 10 min to obtain a uniformly dispersed nano-modified slurry 2.

[0037] Preparation Example 9 Nano-modified slurry 3 Take 6 kg of nano-SiO2, 2.5 kg of carbon nanotubes with a diameter of 15 nm and an aspect ratio of 1200, 15 kg of polyethylene glycol-400, and 80 kg of deionized water; add the nano-SiO2 and carbon nanotubes to the deionized water, stir at 2000 r / min for 30 min, then add polyethylene glycol-400 and continue stirring for 10 min to obtain a uniformly dispersed nano-modified slurry 3.

[0038] Preparation Example 10 Toughening fiber 1 Basalt fibers with a length of 10-20 mm and a diameter of 12 μm were mixed with steel fibers with a diameter of 0.3-0.5 mm and a length of 15-20 mm at a ratio of 2:1. The mixture was ultrasonically cleaned with anhydrous ethanol at a frequency of 40 kHz for 10 min to remove surface impurities. After drying, toughened fiber 1 was prepared.

[0039] Preparation Example 11 Toughening fiber 2 Basalt fibers with a length of 10-20 mm and a diameter of 12 μm were mixed with steel fibers with a diameter of 0.3-0.5 mm and a length of 15-20 mm at a ratio of 3:1. The mixture was ultrasonically cleaned with anhydrous ethanol at a frequency of 40 kHz for 10 min to remove surface impurities. After drying, toughened fiber 2 was prepared.

[0040] Example 1 A high-performance crack-resistant and impermeable concrete for hydraulic structures, comprising the following materials: 25kg cement, 80kg coarse aggregate, 70kg fine aggregate, 10kg water and 3kg crack-resistant and impermeable modifier 1.

[0041] A method for preparing high-performance crack-resistant and impermeable concrete for hydraulic structures includes the following steps: Coarse and fine aggregates were added to the cement and stirred for 2 minutes. Then, crack-resistant and impermeable modifier 1 was added and stirred at a medium speed of 120 r / min for 8 minutes to fill the gaps between the aggregates with microspheres, thus obtaining a mixture. The mixture was poured into a 100 mm × 100 mm × 100 mm mold and compacted on a vibrating table at a frequency of 50 Hz for 2 minutes. After curing with a film for 24 hours, the mixture was demolded and naturally cured at an ambient temperature of 25 ℃ and a humidity of ≥90% for 28 days to obtain high-performance crack-resistant and impermeable concrete for hydraulic structures.

[0042] Example 2 A high-performance crack-resistant and impermeable concrete for hydraulic structures, comprising the following materials: 27kg cement, 90kg coarse aggregate, 75kg fine aggregate, 13kg water and 4kg crack-resistant and impermeable modifier 2.

[0043] A method for preparing high-performance crack-resistant and impermeable concrete for hydraulic structures includes the following steps: Coarse and fine aggregates were added to the cement and stirred for 2 minutes. Then, crack-resistant and impermeable modifier 2 was added and stirred at a medium speed of 120 r / min for 8 minutes to fill the gaps between the aggregates with microspheres, thus obtaining a mixture. The mixture was poured into a 100 mm × 100 mm × 100 mm mold and compacted on a vibrating table at a frequency of 50 Hz for 2 minutes. After curing with a film for 24 hours, the mixture was demolded and naturally cured at an ambient temperature of 25 ℃ and a humidity of ≥90% for 28 days to obtain high-performance crack-resistant and impermeable concrete for hydraulic structures.

[0044] Example 3 A high-performance crack-resistant and impermeable concrete for hydraulic structures, comprising the following materials: 30kg cement, 100kg coarse aggregate, 80kg fine aggregate, 15kg water and 5kg crack-resistant and impermeable modifier 3.

[0045] A method for preparing high-performance crack-resistant and impermeable concrete for hydraulic structures includes the following steps: Coarse and fine aggregates were added to the cement and stirred for 2 minutes. Then, crack-resistant and impermeable modifier 3 was added and stirred at a medium speed of 120 r / min for 8 minutes to fill the gaps between the aggregates with microspheres, thus obtaining a mixture. The mixture was poured into a 100 mm × 100 mm × 100 mm mold and compacted on a vibrating table at a frequency of 50 Hz for 2 minutes. After curing with a film for 24 hours, the mixture was demolded and naturally cured at an ambient temperature of 25 ℃ and a humidity of ≥90% for 28 days to obtain high-performance crack-resistant and impermeable concrete for hydraulic structures.

[0046] Example 4 A high-performance crack-resistant and impermeable concrete for hydraulic structures, comprising the following materials: 27kg cement, 90kg coarse aggregate, 75kg fine aggregate, 13kg water and 4kg crack-resistant and impermeable modifier.

[0047] A method for preparing high-performance crack-resistant and impermeable concrete for hydraulic structures includes the following steps: Coarse and fine aggregates were added to the cement and stirred for 2 minutes. Then, crack-resistant and impermeable modifier 4 was added and stirred at a medium speed of 120 r / min for 8 minutes to fill the gaps between the aggregates with microspheres, thus obtaining a mixture. The mixture was poured into a 100 mm × 100 mm × 100 mm mold and compacted on a vibrating table at a frequency of 50 Hz for 2 minutes. After curing with a film for 24 hours, the mixture was demolded and naturally cured at an ambient temperature of 25 ℃ and a humidity of ≥90% for 28 days to obtain high-performance crack-resistant and impermeable concrete for hydraulic structures.

[0048] Example 5 A high-performance crack-resistant and impermeable concrete for hydraulic structures, comprising the following materials: 27kg cement, 90kg coarse aggregate, 75kg fine aggregate, 13kg water and 4kg crack-resistant and impermeable modifier.

[0049] A method for preparing high-performance crack-resistant and impermeable concrete for hydraulic structures includes the following steps: Coarse and fine aggregates were added to the cement and stirred for 2 minutes. Then, crack-resistant and impermeable modifier 5 was added and stirred at a medium speed of 120 r / min for 8 minutes to fill the gaps between the aggregates with microspheres, thus obtaining a mixture. The mixture was poured into a 100 mm × 100 mm × 100 mm mold and compacted on a vibrating table at a frequency of 50 Hz for 2 minutes. After curing with a film for 24 hours, the mixture was demolded and naturally cured at an ambient temperature of 25 ℃ and a humidity of ≥90% for 28 days to obtain high-performance crack-resistant and impermeable concrete for hydraulic structures.

[0050] Example 6 A high-performance crack-resistant and impermeable concrete for hydraulic structures, comprising the following materials: 27kg cement, 90kg coarse aggregate, 75kg fine aggregate, 13kg water and 4kg crack-resistant and impermeable modifier 6.

[0051] A method for preparing high-performance crack-resistant and impermeable concrete for hydraulic structures includes the following steps: Coarse and fine aggregates were added to the cement and stirred for 2 minutes. Then, crack-resistant and impermeable modifier 6 was added and stirred at a medium speed of 120 r / min for 8 minutes to fill the gaps between the aggregates with microspheres, thus obtaining a mixture. The mixture was poured into a 100 mm × 100 mm × 100 mm mold and compacted on a 50 Hz vibrating table for 2 minutes. After curing with a film for 24 hours, the mixture was demolded and naturally cured at an ambient temperature of 25℃ and a humidity of ≥90% for 28 days to obtain high-performance crack-resistant and impermeable concrete for hydraulic structures.

[0052] Example 7 A high-performance crack-resistant and impermeable concrete for hydraulic structures, comprising the following materials: 27kg cement, 90kg coarse aggregate, 75kg fine aggregate, 13kg water, 10kg nano-modified grout, and 4kg crack-resistant and impermeable modifier.

[0053] A method for preparing high-performance crack-resistant and impermeable concrete for hydraulic structures includes the following steps: Cement and nano-modified slurry 2 were added to a mixer and stirred at a low speed of 60 r / min for 5 min to ensure that the nano-slurry uniformly coated the cement particles, resulting in mixture 1. Coarse aggregate and fine aggregate were added to mixture 1 and stirred for 2 min. Then, crack-resistant and impermeable modifier 5 was added and stirred at a medium speed of 120 r / min for 8 min to fill the gaps between the aggregates with microspheres, resulting in a mixture. The mixture was poured into a 100 mm × 100 mm × 100 mm mold and compacted on a vibrating table at a frequency of 50 Hz for 2 min. After curing with a film for 24 h, the mixture was demolded and naturally cured at an ambient temperature of 25℃ and a humidity of ≥90% for 28 days to obtain high-performance crack-resistant and impermeable concrete for hydraulic structures.

[0054] Example 8 A high-performance crack-resistant and impermeable concrete for hydraulic structures, comprising the following materials: 27kg cement, 90kg coarse aggregate, 75kg fine aggregate, 13kg water, 12kg nano-modified slurry, and 4kg crack-resistant and impermeable modifier.

[0055] A method for preparing high-performance crack-resistant and impermeable concrete for hydraulic structures includes the following steps: Cement and nano-modified slurry 2 were added to a mixer and stirred at a low speed of 60 r / min for 5 min to ensure that the nano-slurry uniformly coated the cement particles, resulting in mixture 1. Coarse aggregate and fine aggregate were added to mixture 1 and stirred for 2 min. Then, crack-resistant and impermeable modifier 5 was added and stirred at a medium speed of 120 r / min for 8 min to fill the gaps between the aggregates with microspheres, resulting in a mixture. The mixture was poured into a 100 mm × 100 mm × 100 mm mold and compacted on a vibrating table at a frequency of 50 Hz for 2 min. After curing with a film for 24 h, the mixture was demolded and naturally cured at an ambient temperature of 25℃ and a humidity of ≥90% for 28 days to obtain high-performance crack-resistant and impermeable concrete for hydraulic structures.

[0056] Example 9 A high-performance crack-resistant and impermeable concrete for hydraulic structures, comprising the following materials: 27kg cement, 90kg coarse aggregate, 75kg fine aggregate, 13kg water, 15kg nano-modified grout, and 4kg crack-resistant and impermeable modifier.

[0057] A method for preparing high-performance crack-resistant and impermeable concrete for hydraulic structures includes the following steps: Cement and nano-modified slurry 3 were added to a mixer and stirred at a low speed of 60 r / min for 5 min to ensure that the nano-slurry uniformly coated the cement particles, resulting in mixture 1. Coarse aggregate and fine aggregate were added to mixture 1 and stirred for 2 min. Then, crack-resistant and impermeable modifier 5 was added and stirred at a medium speed of 120 r / min for 8 min to ensure that the microspheres filled the gaps between the aggregates, resulting in a mixture. The mixture was poured into a 100 mm × 100 mm × 100 mm mold and compacted on a vibrating table at a frequency of 50 Hz for 2 min. After curing with a film for 24 h, the mixture was demolded and naturally cured at an ambient temperature of 25 ℃ and a humidity of ≥90% for 28 days to obtain high-performance crack-resistant and impermeable concrete for hydraulic structures.

[0058] Example 10 A high-performance crack-resistant and impermeable concrete for hydraulic structures, comprising the following materials: 27kg cement, 90kg coarse aggregate, 75kg fine aggregate, 13kg water, 15kg nano-modified slurry, 3kg toughening fiber, and 4kg crack-resistant and impermeable modifier.

[0059] A method for preparing high-performance crack-resistant and impermeable concrete for hydraulic structures includes the following steps: Cement and nano-modified slurry 3 are added to a mixer and stirred at a low speed of 60 r / min for 5 min to make the nano-slurry uniformly coat the cement particles, thus obtaining mixture 1. Coarse aggregate and fine aggregate are added to mixture 1 and stirred for 2 min. Then, crack-resistant and impermeable modifier 5 is added and stirred at a medium speed of 120 r / min for 8 min to make the microspheres fill the gaps between the aggregates, thus obtaining mixture 2. Add toughening fiber 1 to mixture 2 and stir at high speed of 220 r / min for 10 min to obtain mixture 3.

[0060] Mixture 3 was poured into a 100mm×100mm×100mm mold, vibrated at a frequency of 50Hz for 2 minutes to compact, cured with a film for 24 hours, demolded, and naturally cured at an ambient temperature of 25℃ and humidity ≥90% for 28 days to obtain high-performance crack-resistant and impermeable concrete for hydraulic structures.

[0061] Example 11 A high-performance crack-resistant and impermeable concrete for hydraulic structures, comprising the following materials: 27kg cement, 90kg coarse aggregate, 75kg fine aggregate, 13kg water, 15kg nano-modified slurry, 8kg toughening fiber, and 4kg crack-resistant and impermeable modifier.

[0062] A method for preparing high-performance crack-resistant and impermeable concrete for hydraulic structures includes the following steps: Cement and nano-modified slurry 3 are added to a mixer and stirred at a low speed of 60 r / min for 5 min to make the nano-slurry uniformly coat the cement particles, thus obtaining mixture 1. Coarse aggregate and fine aggregate are added to mixture 1 and stirred for 2 min. Then, crack-resistant and impermeable modifier 5 is added and stirred at a medium speed of 120 r / min for 8 min to make the microspheres fill the gaps between the aggregates, thus obtaining mixture 2. Add toughening fiber 2 to mixture 2 and stir at high speed of 220r / min for 10min to obtain mixture 3.

[0063] Mixture 3 was poured into a 100mm×100mm×100mm mold, vibrated at a frequency of 50Hz for 2 minutes to compact, cured with a film for 24 hours, demolded, and naturally cured at an ambient temperature of 25℃ and humidity ≥90% for 28 days to obtain high-performance crack-resistant and impermeable concrete for hydraulic structures.

[0064] Example 12 A high-performance crack-resistant and impermeable concrete for hydraulic structures, comprising the following materials: 27kg cement, 90kg coarse aggregate, 75kg fine aggregate, 13kg water, 15kg nano-modified slurry, 8kg toughening fiber, and 4kg crack-resistant and impermeable modifier.

[0065] A method for preparing high-performance crack-resistant and impermeable concrete for hydraulic structures includes the following steps: Cement and nano-modified slurry 3 are added to a mixer and stirred at a low speed of 60 r / min for 5 min to make the nano-slurry uniformly coat the cement particles, thus obtaining mixture 1. Coarse aggregate and fine aggregate are added to mixture 1 and stirred for 2 min. Then, crack-resistant and impermeable modifier 5 is added and stirred at a medium speed of 120 r / min for 8 min to make the microspheres fill the gaps between the aggregates, thus obtaining mixture 2. Add toughening fiber 2 to mixture 2 and stir at high speed of 220r / min for 10min to obtain mixture 3.

[0066] Pour mixture 3 into a 100mm×100mm×100mm mold, vibrate at 50Hz for 2 minutes to compact, and apply at a spraying rate of 0.2kg / m². 2 The surface is sprayed with fluorocarbon resin emulsion with a solid content of 40%, and after curing in a film for 24 hours, it is demolded and naturally cured at an ambient temperature of 25℃ and a humidity of ≥90% for 28 days to obtain high-performance crack-resistant and impermeable concrete for hydraulic structures.

[0067] Comparative Example 1 Compared with Example 1, Comparative Example 1 uses basalt fiber of equal mass to replace crack-resistant and impermeable modifier 1.

[0068] Comparative Example 2 Compared with Example 1, Comparative Example 2 uses steel fibers of equal mass instead of crack-resistant and impermeable modifier 1.

[0069] Compressive strength: tested according to GB / T 50081-2019 "Standard for Test Methods of Physical and Mechanical Properties of Concrete"; Impermeability: Tested according to GB / T 50082-2009 "Standard for Test Methods of Long-Term Performance and Durability of Ordinary Concrete"; Fracture resistance: Tested according to GB / T 50081-2019 "Standard for Test Methods of Physical and Mechanical Properties of Concrete"; the results are shown in Table 1 below: Table 1 Performance Test Table sample Compressive strength (MPa) Seepage height (mm) <![CDATA[Fracture energy (J / m 2 )]]> Example 1 42 46 110 Example 2 45 44 130 Example 3 47 42 145 Example 4 50 38 160 Example 5 53 32 185 Example 6 51 35 170 Example 7 55 28 200 Example 8 58 22 240 Example 9 60 18 280 Example 10 62 15 310 Example 11 65 12 350 Example 12 68 8 400 Comparative Example 1 38 65 90 Comparative Example 2 35 70 80 By comparing the test results of Examples 1-12 and Comparative Examples 1-2 with those in Table 1, it can be found that: Comparing Examples 1-3 with Comparative Examples 1-2 further illustrates how this application achieves a synergistic improvement in crack resistance and impermeability through a silica-alumina matrix composite modifier. The particle size distribution of the three materials forms a complementary gradation, further optimizing the pore structure. In terms of effect, compared to single mineral admixtures, this composite system can more efficiently refine the pore size distribution, reduce the permeability coefficient of concrete, reduce interfacial stress concentration caused by directional crystal growth, and fundamentally inhibit the initiation of microcracks, achieving a "dual improvement" in both crack resistance and impermeability.

[0070] By comparing Examples 4-6 with Examples 1-3, it can be seen that the technical solution of this application optimizes the preparation process of the "core-shell microspheres" of the crack-resistant and impermeable modifier. The structure of the active core and the functional shell is achieved by spray drying and emulsion coating, and finally the impermeability performance is stably improved.

[0071] By comparing Examples 7-9 with Examples 4-6, it can be seen that the technical solution of this application significantly reduces the nanoporosity of concrete by introducing nano-modified slurry, while improving the fracture energy of the gel phase, effectively suppressing nanoscale microcracks caused by shrinkage or load, and providing a microscopic-level basic guarantee for the crack resistance and impermeability of concrete.

[0072] By comparing Examples 10-11 with Examples 7-9, it can be seen that the technical solution of this application forms a gradient reinforcement network of "microfiber crack resistance + coarse fiber load bearing" through the composite toughening body of basalt fiber and steel fiber. This composite fiber system covers the full-scale control from microcracks to macrocracks, and avoids the limitations of single fibers, significantly improving the crack resistance and toughness of concrete.

[0073] By comparing Examples 12 and 10-11, it is demonstrated that this application constructs a long-lasting and stable hydrophobic barrier on the surface of hydraulic concrete through fluorocarbon resin emulsion surface protection. This not only directly improves the impermeability and corrosion resistance of the concrete, but also indirectly assists the crack resistance effect of the internal modified system by delaying the intrusion of external corrosive media.

[0074] The present invention has been described in detail above with reference to specific embodiments and exemplary examples; however, these descriptions should not be construed as limiting the present invention. Those skilled in the art will understand that various equivalent substitutions, modifications, or improvements can be made to the technical solutions and embodiments of the present invention without departing from the spirit and scope of the invention, and all such modifications and improvements fall within the scope of the present invention. The scope of protection of the present invention is defined by the appended claims.

[0075] All publications, patent applications, patents, and other references mentioned in this specification are incorporated herein by reference. Unless otherwise defined, all technical and scientific terms used in this specification have the meanings commonly understood by those skilled in the art. In case of conflict, the definitions in this specification shall prevail.

[0076] When this specification uses prefixes such as "known to those skilled in the art," "prior art," or similar terms to derive materials, substances, methods, steps, apparatus, or components, the objects derived from such prefixes cover those commonly used in the art at the time of this application, but also include those that are not currently commonly used but will become generally recognized in the art as suitable for similar purposes.

[0077] In the context of this specification, except where expressly stated otherwise, any matters or issues not mentioned shall apply directly to those known in the art without any modification.

Claims

1. A high-performance crack-resistant and impermeable concrete for hydraulic structures, characterized in that, Includes the following substances in parts by weight: 25-30 parts cement; 80-100 parts coarse aggregate; 70-80 parts fine aggregate; 10-15 parts water; 3-5 parts of crack-resistant and seepage-resistant modifier; The crack-resistant and impermeable modifier includes a silica-alumina matrix, which comprises fly ash, slag and metakaolin mixed in a mass ratio of (4-5):(2.5-3.5):(2-3).

2. The high-performance crack-resistant and impermeable concrete for hydraulic structures according to claim 1, characterized in that, The crack-resistant and seepage-resistant modifier also includes an interface coating layer, which is formed by coating and curing a polymer emulsion. The polymer emulsion is prepared by mixing an acrylic emulsion and a silane coupling agent at a mass ratio of (20:1-1.5).

3. The high-performance crack-resistant and impermeable concrete for hydraulic structures according to claim 1, characterized in that, The crack-resistant and impermeable modifier is prepared using the following technical solution: Fly ash, slag, and metakaolin were mixed with an activator, stirred, and collected to obtain a mixed slurry. The mixed slurry was taken and spray-dried to obtain dried microspheres; The crack-resistant and impermeable modifier can be prepared by taking dried microspheres, immersing them in a polymer emulsion, ultrasonically dispersing them, and then drying and curing them.

4. The high-performance crack-resistant and impermeable concrete for hydraulic structures according to claim 1, characterized in that, The high-performance crack-resistant and impermeable concrete for hydraulic structures further includes 10-15 parts by weight of nano-modified grout, wherein the nano-modified grout comprises the following substances in parts by weight: 3-6 parts of nano-silica; 1.5-2.5 parts of carbon nanotubes; Polyethylene glycol-400 6-15 parts; 60-80 parts deionized water.

5. A high-performance crack-resistant and impermeable concrete for hydraulic structures according to claim 1, characterized in that, The high-performance crack-resistant and impermeable concrete for hydraulic structures also includes 3-8 parts by weight of toughening fibers, which are basalt fibers and steel fibers mixed in a mass ratio of 2-3:

1.

6. A high-performance crack-resistant and impermeable concrete for hydraulic structures according to claim 4, characterized in that, The toughening fibers consist of basalt fibers with a diameter of 10-20 mm and steel fibers with a diameter of 0.3-0.5 mm and a length of 15-20 mm.

7. A method for preparing high-performance crack-resistant and impermeable concrete for hydraulic structures according to any one of claims 1-5, characterized in that, The preparation steps include the following: Take cement and nano-modified slurry, mix them at low speed and collect the mixture; After adding coarse and fine aggregates to the mixture, add crack-resistant and impermeable modifier, stir at medium speed, and collect the mixture liquid; After taking the mixed liquid and adding toughening fibers, it is stirred at high speed and poured into a mold. It is then vibrated to compact the mixture and sprayed with a protective emulsion layer. After curing for 24 weeks, the film is removed and allowed to cure naturally, thus producing high-performance crack-resistant and impermeable concrete for hydraulic structures.

8. The method for preparing high-performance crack-resistant and impermeable concrete for hydraulic structures according to claim 7, characterized in that, The low-speed stirring rate is 50-70 r / min; the medium-speed stirring rate is 90-150 r / min; and the high-speed stirring rate is 180-250 r / min.

9. A method for preparing high-performance crack-resistant and impermeable concrete for hydraulic structures according to claim 7, characterized in that, The protective emulsion layer is a fluorocarbon resin emulsion, and the spraying amount of the fluorocarbon resin emulsion is 0.15-0.25 kg / m². 2 .