Low-temperature fast-permeable quick-setting self-repairing concrete material and preparation method thereof

Abstract

The application relates to a low-temperature fast-permeation rapid-setting self-repairing concrete material and a preparation method thereof. A composite low-temperature cementing base material, superfine active admixture and fine aggregate are put into a closed dry powder mixer, and are uniformly mixed at low speed to obtain a basic dry powder mixture; low-temperature anti-freezing permeation components, micro-expansion anti-shrinkage stable components and composite additives are sequentially added into the basic dry powder mixture, and are uniformly stirred and blended; low-temperature low-speed self-repairing components are put in, and are sealed and moisture-proof packaged after stirring, so that the self-repairing concrete material is obtained. The application can realize heating-free, heat preservation-free and moisture-free construction in the whole negative temperature range of-25 DEG C to 5 DEG C, and can realize multiple performances of high capillary permeation, super-early strength rapid setting, low-temperature self-repairing of cracks, high frost resistance and high impermeability, and can meet the use requirements of winter emergency repair and long-term repair engineering in cold regions; through step-by-step and graded feeding and low-speed functional mixing, the complete structure of microcapsules is protected to the maximum extent, and the self-repairing performance is ensured, and the process is simple and suitable for industrialized batch production.

Description

Technical Field

[0001] This invention belongs to the field of building materials technology, and relates to concrete repair materials, particularly a low-temperature fast-penetrating and quick-setting self-healing concrete material and its preparation method. Background Technology

[0002] High-altitude permafrost regions and frigid areas account for over 50% of my country's land area. Infrastructure in these regions operates under extreme conditions of prolonged sub-zero temperatures (-25℃ to 5℃), severe freeze-thaw cycles, large temperature differences, and low humidity. Freeze-thaw damage to concrete structures is irreversible and progressively deteriorating. Concrete defects specific to cold regions are highly insidious and persistent. Initially, micro-cracks are difficult to detect with the naked eye but become the core channels for corrosive media penetration, accelerating concrete carbonation, sulfate attack, and internal steel reinforcement corrosion. This results in a reduction in the effective load-bearing cross-section, a decline in mechanical properties, and a significant decrease in overall durability. A more prominent engineering challenge is the long winters in high-altitude regions with no effective construction window. Most defects cannot be addressed in winter and must be postponed until the following spring and summer. Over the course of the winter, accumulated freeze-thaw damage can transform minor defects into large-scale structural failures, significantly increasing later maintenance costs and severely impacting traffic safety, structural stability, and hindering the long-term safe operation and economic development of infrastructure in high-altitude regions.

[0003] Currently, the low-temperature concrete repair materials, early-strength repair mortars, and antifreeze concrete systems developed in the industry can only be adapted to construction scenarios with conventional low temperatures above 0°C or weak negative temperatures below -5°C, and cannot meet the engineering needs of extremely cold and low-temperature conditions.

[0004] To address the aforementioned issues, developing a specialized concrete repair material and preparation method that is adaptable to extreme low-temperature conditions, exhibits synergistic infiltration and coagulation, and possesses low-temperature intelligent self-healing properties is an urgent need and a key technological challenge in the field of durability repair of infrastructure in cold regions. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings and deficiencies of existing technologies by providing a low-temperature, fast-penetrating, self-healing concrete material and its preparation method. This material enables construction without heating, insulation, or wet curing within a full negative temperature range of -25℃ to 5℃, while also exhibiting multiple properties such as high capillary permeability, ultra-early strength and rapid setting, low-temperature self-repairing of cracks, and high frost and impermeability resistance. It is suitable for emergency repair and long-term repair projects in cold regions during winter.

[0006] The technical problem solved by this invention is achieved through the following technical solution: A low-temperature, fast-penetrating, quick-setting, self-healing concrete material, wherein the material comprises the following components by weight: 55-65 parts of composite low-temperature cementitious substrate; 12-18 parts of ultrafine active admixture; 6-10 parts of low-temperature antifreeze penetrating component; 8-12 parts of low-temperature triggered self-healing component; 3-6 parts of micro-expansion anti-shrinkage stabilizing component; 1.5 to 3.5 parts of compound additives; 18-25 parts of fine aggregate.

[0007] Moreover, the composite low-temperature cementitious substrate is composed of rapid-hardening sulfoaluminate cement, high-alumina cement and ultrafine silicate cement in a mass ratio of 5:3:2.

[0008] Moreover, the ultrafine active admixture has a specific surface area ≥500m². 2 It is a mixture of ultrafine slag powder, nano silica fume and metakaolin in a mass ratio of 4:2:1.

[0009] Moreover, the low-temperature antifreeze penetrating component is composed of modified polycarboxylate low-temperature water-reducing agent, composite organic antifreeze agent and capillary penetrating wetting agent in a mass ratio of 2:3:1.

[0010] Moreover, the low-temperature triggered self-healing component is a core-shell structured low-temperature responsive microcapsule, the capsule wall of which is a low-temperature water-resistant modified sodium alginate shell, and the core of which is a Bacillus pasteurellii bacterial solution, low-temperature slow-release urease, and a calcium source saturated solution.

[0011] Moreover, the micro-expansion anti-shrinkage stabilizing component is composed of ettringite-type micro-expansion agent, polypropylene short fibers and nano-magnesium oxide.

[0012] Moreover, the composite additive is composed of low-temperature rapid-setting seed crystals, defoamer, and water-retaining and slurry-stabilizing agent.

[0013] Moreover, the fine aggregate is continuously graded quartz sand with a particle size of 0.1 to 1.0 mm and a mud content of ≤0.3%.

[0014] A method for preparing a low-temperature, fast-penetrating, quick-setting, self-healing concrete material, comprising the following steps: S1. Premixed base material: The composite low-temperature cementitious base material, ultrafine active admixture, and fine aggregate are put into a closed dry powder mixer and stirred at low speed for 3-5 minutes to obtain a basic dry powder mixture. S2, Functional compounding: Add low-temperature antifreeze penetrating component, micro-expansion anti-shrinkage stabilizing component and composite additive to the basic dry powder mixture in sequence, and stir for 4-6 minutes to mix evenly. S3. Low-temperature encapsulation: Add the low-temperature triggered self-healing component at a low temperature and low speed, stir for 1-2 minutes, and then seal and moisture-proof to obtain self-healing concrete material.

[0015] The advantages and beneficial effects of this invention are as follows: Compared with existing technologies, it has four disruptive innovative advantages, precisely solving the core problem of winter repair of concrete in cold regions: 1. Extremely low temperature construction window, suitable for severe cold and extreme working conditions: It can achieve open-air construction at extremely low temperatures of -25℃ without heating, heating, or insulation curing. The slurry will not freeze, hydration will not stop, and the molding will not turn into powder. It is suitable for year-round emergency repair operations in high-altitude and cold regions of my country during winter.

[0016] 2. Relying on the low-tension capillary permeation system, the slurry can autonomously penetrate 0.05mm ultra-fine freeze-thaw cracks; at the same time, relying on the low-temperature seed crystal rapid setting technology, it can achieve minute-level setting and hour-level hardening, taking into account the dual needs of deep penetration to eradicate diseases and rapid opening of traffic.

[0017] 3. Unique low-temperature self-sustaining and self-repairing performance: The self-repairing microcapsules of this invention can be autonomously activated in negative temperature and humid environment without the need for temperature and humidity maintenance. At low temperature, they continuously generate calcium carbonate crystals to seal newly formed frost heave microcracks. The self-repair closure rate of low-temperature cracks is ≥55% after 28 days, which can block the freeze-thaw damage cycle for a long time and greatly extend the service life of the repaired structure.

[0018] 4. Stable volume, durable and freeze-resistant, with high overall cost performance: The micro-expansion component accurately compensates for low-temperature hardening shrinkage, without secondary cracking; the bonding strength between the repair layer and the old concrete interface is high, and there is no peeling, hollowing, or water seepage after hundreds of freeze-thaw cycles; no high-salt antifreeze agent is added, eliminating problems such as steel corrosion and surface efflorescence, and is low-carbon, environmentally friendly, and has extremely low operation and maintenance costs. Detailed Implementation

[0019] The present invention will be further described in detail below through specific embodiments. The following embodiments are merely descriptive and not limiting, and should not be used to limit the scope of protection of the present invention.

[0020] Example 1 Material proportions (parts by weight): 60 parts of composite low-temperature cementitious substrate, 15 parts of ultrafine active admixture, 8 parts of low-temperature antifreeze penetrating component, 10 parts of low-temperature triggered self-healing component, 4 parts of micro-expansion anti-shrinkage stabilizing component, 2.5 parts of composite additive, 22 parts of fine aggregate, water-powder ratio 0.26, which is the ratio of water to all powder materials except fine aggregate.

[0021] The triple cementitious system of rapid-hardening sulfoaluminate cement, high-alumina cement and ultrafine silicate cement complement each other and can stably start the hydration reaction in an extremely low negative temperature environment, providing a core foundation for the rapid setting and early strength performance of the material. The ultrafine particles of the ultrafine active admixture can effectively fill the micropores of the slurry, optimize the powder gradation, improve the matrix density and the interlocking performance of the new and old interfaces, and at the same time, it can undergo continuous secondary hydration reaction, steadily improving the material's later strength and impermeability durability. The low-temperature antifreeze penetrating component can lower the freezing point of the liquid phase of the slurry to below -30℃, ensuring that the slurry mixed at an extremely low temperature of -25℃ does not freeze and has stable fluidity. At the same time, it significantly reduces the surface tension of the slurry, giving the material excellent capillary penetration ability, and can autonomously penetrate into the interior of ultra-fine freeze-thaw cracks at the 0.05mm level. The microcapsules of the low-temperature triggered self-healing component can be autonomously broken and activated in a low-temperature and humid environment of -25℃ to 5℃, without the need for high-temperature and high-humidity maintenance conditions. They can continuously generate calcium carbonate precipitate to seal microcracks and achieve long-term self-healing at low temperatures. The micro-expansion shrinkage-resistant and stabilizing component can accurately compensate for the shrinkage deformation during the low-temperature hardening process of the material and inhibit the generation of temperature shrinkage cracks. At the same time, the fiber can synergistically toughen the material, greatly improving its crack resistance, freeze resistance and fatigue resistance.

[0022] The low-temperature rapid-setting seed crystals of the composite additives can provide a large number of active nucleation sites for the negative temperature hydration reaction, significantly shortening the setting time and achieving a minute-level rapid setting effect; the water-retaining and slurry-stabilizing agent can effectively prevent the slurry from rapidly losing water and turning into powder under negative temperature conditions, ensuring the molding quality; Fine aggregates ensure that the repair layer is dense, wear-resistant, and dimensionally stable, avoiding performance defects caused by impurities in the aggregates.

[0023] Preparation method: (1) Raw material pretreatment: Weigh each component raw material and mixing water according to the above proportions. Screen the fine aggregate to remove impurities and oversized particles to ensure that the aggregate particle size is uniform, clean and dry. Place all powder raw materials in a dry and sealed environment for pretreatment to avoid moisture absorption and clumping, and ensure the activity of raw materials and the accuracy of proportions.

[0024] (2) Dry powder premixing treatment: The weighed composite low-temperature cementitious substrate, ultrafine active admixture, micro-expansion anti-shrinkage stabilizing component, and composite additive are sequentially added to the dry powder mixing equipment. First, low-speed dry mixing is carried out, with the mixing speed controlled at 300-400 r / min and the dry mixing time at 3-5 min, so that the various base powders, additives and expansion components are fully and evenly mixed. Then, the low-temperature antifreeze penetration component and the low-temperature triggered self-healing component are added, and dry mixing is continued for 2-3 min to achieve uniform integration of functional components and base powders, avoid local enrichment of functional components, and ensure the overall uniformity of the mixture.

[0025] (3) Wet mixing and shaping: The pretreated fine aggregate is added to the mixed dry powder material and stirred continuously for 2 minutes to ensure that the aggregate and powder mixture are fully combined. Then, the weighed mixing water is slowly added to the mixing equipment in batches. During the water addition process, the stirring speed is increased to 500-600 r / min and stirred continuously for 5-8 minutes until the material forms a uniform, lump-free, and stable slurry. This ensures that the slurry has uniform viscosity and that all components are completely dispersed, so as to give full play to the synergistic properties of low temperature antifreeze, self-healing, and micro-expansion anti-shrinkage.

[0026] (4) Vibration compaction and static defoaming: The mixed cementitious slurry is quickly poured into the pre-set mold and compacted using a vibrating table. The vibration frequency is controlled at 50Hz and the vibration time is 1-2 minutes to fully remove air bubbles inside the slurry, eliminate defects such as honeycomb and voids, and ensure the density of the material. After vibration, the surface of the sample is smoothed and placed in a clean environment at room temperature for 30-60 minutes for preliminary defoaming and slurry settling.

[0027] (5) Curing and molding: After static curing, the sample is covered with a film and sealed for curing to prevent the rapid evaporation of moisture and shrinkage cracks. First, it is statically cured at room temperature for 24 hours. After the sample has initially set and hardened, it is demolded. After demolding, it continues to be cured with standard wet curing for no less than 7 days to allow the composite low-temperature cementitious system to fully hydrate and stabilize, and finally obtain a low-temperature fast-penetrating self-healing concrete material with low-temperature freeze resistance, penetration and density, self-healing, and shrinkage resistance.

[0028] Performance testing: During open-air construction at -22℃ without insulation, the slurry does not freeze, exhibits excellent fluidity, and can completely penetrate 0.05mm micro-cracks; initial setting time is 22 minutes, final setting time is 45 minutes; 3-hour compressive strength is ≥22MPa, meeting the requirements for opening to traffic; after 28 days of curing at negative temperatures, the compressive strength is ≥40MPa, the self-healing closure rate of low-temperature cracks is 56%, and the strength loss after 150 freeze-thaw cycles is ≤4%.

[0029] Example 2 Material proportions (parts by weight): 58 parts of composite low-temperature cementitious substrate, 16 parts of ultrafine active admixture, 7 parts of low-temperature antifreeze penetrating component, 11 parts of low-temperature triggered self-healing component, 3.5 parts of micro-expansion anti-shrinkage stabilizing component, 2 parts of composite additive, 20 parts of fine aggregate, and water-powder ratio of 0.25.

[0030] Preparation method: (1) Raw material pretreatment: Weigh each component raw material and mixing water accurately according to the above proportions. Screen the fine aggregate to remove impurities and oversized particles to ensure that the aggregate particle size is uniform, clean and dry; place all powder raw materials in a dry and sealed environment for pretreatment to avoid moisture absorption and clumping, and ensure the activity of raw materials and the accuracy of proportions.

[0031] (2) Dry powder premixing treatment: The weighed composite low-temperature cementitious substrate, ultrafine active admixture, micro-expansion anti-shrinkage stabilizing component, and composite additive are sequentially added to the dry powder mixing equipment. First, low-speed dry mixing is carried out, with the mixing speed controlled at 300-400 r / min and the dry mixing time at 3-5 min, so that the various base powders, additives and expansion components are fully and evenly mixed. Then, the low-temperature antifreeze penetration component and the low-temperature triggered self-healing component are added, and dry mixing is continued for 2-3 min to achieve uniform integration of functional components and base powders, avoid local enrichment of functional components, and ensure the overall uniformity of the mixture.

[0032] (3) Wet mixing and shaping: The pretreated fine aggregate is added to the mixed dry powder material and stirred continuously for 2 minutes to ensure that the aggregate and powder mixture are fully combined. Then, the weighed mixing water is slowly added to the mixing equipment in batches. During the water addition process, the stirring speed is increased to 500-600 r / min and stirred continuously for 5-8 minutes until the material forms a uniform, lump-free, and stable slurry. This ensures that the slurry has uniform viscosity and that all components are completely dispersed, so as to give full play to the synergistic properties of low temperature antifreeze, self-healing, and micro-expansion anti-shrinkage.

[0033] (4) Vibration compaction and static defoaming: The mixed cementitious slurry is quickly poured into the pre-set mold and compacted using a vibrating table. The vibration frequency is controlled at 50Hz and the vibration time is 1-2 minutes to fully remove air bubbles inside the slurry, eliminate defects such as honeycomb and voids, and ensure the density of the material. After vibration, the surface of the sample is smoothed and placed in a clean environment at room temperature for 30-60 minutes for preliminary defoaming and slurry settling.

[0034] (5) Curing and molding: After standing, the sample is covered with a film and sealed for curing to prevent the rapid evaporation of moisture and shrinkage cracks. First, it is placed at room temperature for 24 hours for initial curing. After the sample has initially hardened, it is demolded. After demolding, it continues to be treated with standard wet curing for no less than 7 days to allow the composite low-temperature gelling system to fully hydrate and stabilize, and finally obtain a gelling composite material with low-temperature freeze resistance, penetration and density, self-healing and shrinkage resistance.

[0035] Performance testing: -5℃ outdoor construction, traffic can be opened in 1.5 hours; 28d compressive strength ≥43MPa, interfacial bond strength ≥2.6MPa, crack self-healing closure rate 58%, impermeability grade ≥P12, no shrinkage cracking, no efflorescence or rust.

[0036] Example 3 Material proportions (parts by weight): 56 parts of composite low-temperature cementitious substrate, 13 parts of ultrafine active admixture, 6.5 parts of low-temperature antifreeze penetrating component, 9 parts of low-temperature triggered self-healing component, 5 parts of micro-expansion anti-shrinkage stabilizing component, 2 parts of composite additive, 24 parts of fine aggregate, and water-powder ratio of 0.24.

[0037] Preparation method: (1) Raw material pretreatment: Weigh each component raw material and mixing water accurately according to the above proportions. Screen the fine aggregate to remove impurities and oversized particles to ensure that the aggregate particle size is uniform, clean and dry; place all powder raw materials in a dry and sealed environment for pretreatment to avoid moisture absorption and clumping, and ensure the activity of raw materials and the accuracy of proportions.

[0038] (2) Dry powder premixing treatment: The weighed composite low-temperature cementitious substrate, ultrafine active admixture, micro-expansion anti-shrinkage stabilizing component, and composite additive are sequentially added to the dry powder mixing equipment. First, low-speed dry mixing is carried out, with the mixing speed controlled at 300-400 r / min and the dry mixing time at 3-5 min, so that the various base powders, additives and expansion components are fully and evenly mixed. Then, the low-temperature antifreeze penetration component and the low-temperature triggered self-healing component are added, and dry mixing is continued for 2-3 min to achieve uniform integration of functional components and base powders, avoid local enrichment of functional components, and ensure the overall uniformity of the mixture.

[0039] (3) Wet mixing and shaping: The pretreated fine aggregate is added to the mixed dry powder material and stirred continuously for 2 minutes to ensure that the aggregate and powder mixture are fully combined. Then, the weighed mixing water is slowly added to the mixing equipment in batches. During the water addition process, the stirring speed is increased to 500-600 r / min and stirred continuously for 5-8 minutes until the material forms a uniform, lump-free, and stable slurry. This ensures that the slurry has uniform viscosity and that all components are completely dispersed, so as to give full play to the synergistic properties of low temperature antifreeze, self-healing, and micro-expansion anti-shrinkage.

[0040] (4) Vibration compaction and static defoaming: The mixed cementitious slurry is quickly poured into the pre-set mold and compacted using a vibrating table. The vibration frequency is controlled at 50Hz and the vibration time is 1-2 minutes to fully remove air bubbles inside the slurry, eliminate defects such as honeycomb and voids, and ensure the density of the material. After vibration, the surface of the sample is smoothed and placed in a clean environment at room temperature for 30-60 minutes for preliminary defoaming and slurry settling.

[0041] (5) Curing and molding: After standing, the sample is covered with a film and sealed for curing to prevent the rapid evaporation of moisture and shrinkage cracks. First, it is placed at room temperature for 24 hours for initial curing. After the sample has initially hardened, it is demolded. After demolding, it continues to be treated with standard wet curing for no less than 7 days to allow the composite low-temperature gelling system to fully hydrate and stabilize, and finally obtain a gelling composite material with low-temperature freeze resistance, penetration and density, self-healing and shrinkage resistance.

[0042] Performance testing: During open-air construction at an ambient temperature of 3℃, the grout exhibits excellent capillary penetration, rapidly filling various micro-cracks; initial setting time is 18 minutes, final setting time is 36 minutes; it reaches the strength required for road use after 1 hour of curing; after 28 days of curing from negative to normal temperature, the compressive strength is ≥45MPa, the bond strength between new and old interfaces is ≥2.7MPa, and the crack self-healing closure rate is 61%; after 150 freeze-thaw cycles, the strength loss is ≤3.2%, with no volume shrinkage, no hollowing or peeling, demonstrating optimal overall durability.

[0043] Comparative Example 1 Comparative Example 1 uses commercially available fast-hardening and early-strength repair mortar, which is suitable for environments with slightly negative temperatures above -5℃.

[0044] Performance testing: During open-air construction at -22℃, the grout had high viscosity and surface tension, allowing it to adhere only to the concrete surface and preventing penetration into micro-cracks; initial setting time was 75 minutes, and final setting time was 162 minutes; the 3-hour compressive strength was only 10.5 MPa, which could not meet the requirements for opening to traffic; the 28-day compressive strength was 26.8 MPa, and the interfacial bond strength was only 1.3 MPa; after 80 freeze-thaw cycles, the repair layer delaminated and peeled off; it did not have low-temperature self-healing capabilities, and new cracks continued to expand.

[0045] Comparative Example 2 Comparative Example 2 uses industry-standard high chloride salt antifreeze concrete, with ordinary Portland cement as the main cementitious material, compounded with sodium chloride and calcium nitrite antifreeze agents, and conventional sand and gravel aggregates, prepared according to the commonly used mix proportions in cold regions.

[0046] Performance testing: After mixing at -22℃, the surface of the slurry freezes rapidly, and internal hydration basically stops; the initial setting time is >180min, the final setting time cannot be determined, and there is no effective strength after 3 hours; the 28-day compressive strength is only 11.2MPa, and the surface of the material powders, loosens and falls off; it cannot penetrate 0.05mm micro-cracks, and only simple surface sealing is achieved; it has no self-healing function, and large-area cracking and efflorescence occur after 30 freeze-thaw cycles, posing a significant risk of steel reinforcement corrosion.

[0047] This invention constructs a synergistic mechanism of a dual-function system: an ultra-low temperature non-freezing hydration system, a capillary penetration modification system, and a low-temperature triggered self-healing system. A composite low-temperature cementitious system replaces the single cement system, coupled with a low-freezing-point composite antifreeze and early-strength component to lower the freezing point of the mixing liquid phase, ensuring no freezing and continuous hydration at -25℃. Through ultra-fine particle gradation and penetration-modifying additives, the capillary penetration capacity of the slurry is significantly improved, achieving deep filling of micro-cracks. It incorporates low-temperature activatable microbial repair capsules and nano-active seeds, eliminating the need for room temperature curing. Under low-temperature conditions, it can autonomously trigger calcium carbonate deposition and cementation repair, achieving crack closure and self-healing. Simultaneously, a micro-expansion anti-shrinkage component is added to counteract low-temperature hardening shrinkage, ensuring interfacial adhesion and volume stability.

[0048] Although embodiments of the invention have been disclosed for illustrative purposes, those skilled in the art will understand that various substitutions, variations, and modifications are possible without departing from the spirit and scope of the invention and the appended claims. Therefore, the scope of the invention is not limited to the contents disclosed in the embodiments.

Claims

1. A low-temperature, fast-penetrating, quick-setting, self-healing concrete material, characterized in that: The material comprises the following components in parts by weight: 55-65 parts of composite low-temperature cementitious substrate; 12-18 parts of ultrafine active admixture; 6-10 parts of low-temperature antifreeze penetrating component; 8-12 parts of low-temperature triggered self-healing component; 3-6 parts of micro-expansion anti-shrinkage stabilizing component; 1.5 to 3.5 parts of compound additives; 18-25 parts fine aggregate; The low-temperature triggered self-healing component is a core-shell structured low-temperature responsive microcapsule. The capsule wall of the microcapsule is a low-temperature water-resistant modified sodium alginate shell, and the core of the microcapsule is a Bacillus pasteurellii bacterial solution, a low-temperature slow-release urease, and a calcium source saturated solution. The micro-expansion anti-shrinkage stabilizing component is composed of ettringite-type micro-expansion agent, polypropylene short fibers, and nano-magnesium oxide.

2. The low-temperature rapid-penetration, quick-setting, self-healing concrete material according to claim 1, characterized in that: The composite low-temperature cementitious substrate is composed of rapid-hardening sulfoaluminate cement, high-alumina cement and ultrafine silicate cement in a mass ratio of 5:3:

2.

3. The low-temperature rapid-penetration, quick-setting, self-healing concrete material according to claim 1, characterized in that: The ultrafine active admixture has a specific surface area ≥ 500 m². 2 It is a mixture of ultrafine slag powder, nano silica fume and metakaolin in a mass ratio of 4:2:

1.

4. The low-temperature rapid-penetration, quick-setting, self-healing concrete material according to claim 1, characterized in that: The low-temperature antifreeze penetrating component is composed of modified polycarboxylate low-temperature water-reducing agent, composite organic antifreeze agent and capillary penetrating wetting agent in a mass ratio of 2:3:

1.

5. The low-temperature rapid-penetration, quick-setting, self-healing concrete material according to claim 1, characterized in that: The composite additive consists of low-temperature rapid-setting seed crystals, defoamer, and water-retaining and slurry-stabilizing agent.

6. The low-temperature rapid-penetration, quick-setting, self-healing concrete material according to claim 1, characterized in that: The fine aggregate is continuously graded quartz sand with a particle size of 0.1–1.0 mm and a mud content of ≤0.3%.

7. A method for preparing a low-temperature, fast-penetrating, quick-setting, self-healing concrete material, characterized in that: The method for preparing the concrete material according to any one of claims 1 to 6 comprises the following steps: S1. Premixed base material: The composite low-temperature cementitious base material, ultrafine active admixture, and fine aggregate are put into a closed dry powder mixer and stirred at low speed for 3-5 minutes to obtain a basic dry powder mixture. S2, Functional compounding: Add low-temperature antifreeze penetrating component, micro-expansion anti-shrinkage stabilizing component and composite additive to the basic dry powder mixture in sequence, and stir for 4-6 minutes to mix evenly. S3. Low-temperature encapsulation: Add the low-temperature triggered self-healing component at a low temperature and low speed, stir for 1-2 minutes, and then seal and moisture-proof to obtain self-healing concrete material.