High-performance repairing material as well as preparation method and application thereof

Abstract

The invention discloses a high-performance repairing material and a preparation method and application thereof, and belongs to the technical field of building materials and structural durability repairing, the high-performance repairing material comprises a component A and a component B, the component A comprises high belite sulphoaluminate cement, nano silicon dioxide, a polycarboxylic acid anti-freezing water reducing agent, a nano self-repairing component, a polycarboxylic acid sodium salt dispersing agent and quartz sand; the component B comprises an anti-freezing agent, water and a functional anti-erosion agent. The repairing material prepared by the invention forms compact C-(A)-S-H gel in situ in an interface area and constructs multiple barriers of hydrophobic, compact and barrier, and has good construction adaptability, early mechanical property and durability at the temperature of-20 DEG C or above under the action of salinized environment and freeze-thaw cycle; and the concrete has excellent freeze-thaw cycle resistance, and is suitable for durability repair of cold-region infrastructures such as ultrahigh-voltage power transmission tower footing and expressway roadbed.

Description

Technical Field

[0001] This invention belongs to the field of building materials and structural durability repair technology, and particularly relates to a high-performance repair material, its preparation method and application. Background Technology

[0002] In saline and permafrost regions, concrete infrastructure is subjected to the coupled erosive effects of multiple environmental factors, including low temperatures, freeze-thaw cycles, and salt ion infiltration, making it highly susceptible to severe durability degradation. Frequent freeze-thaw cycles in winter cause pore water within the concrete to freeze and expand, generating internal stress, triggering microcracks that gradually propagate. Simultaneously, corrosive media such as chloride and sulfate ions in the environment penetrate the material through capillary action and diffusion, not only disrupting the stability of cement hydration products but also inducing steel corrosion, further exacerbating structural cracking and spalling. Conventional cement-based repair materials face severe challenges under these extreme service environments. First, low temperatures significantly inhibit the hydration kinetics of cement, resulting in extremely slow early strength development, making rapid repair and reopening to traffic in cold regions difficult and posing significant structural safety risks. Second, due to insufficient hydration and shrinkage mismatch at the interface between new and old concrete, the bond strength between conventional repair materials and the matrix is ​​generally low, making them highly susceptible to forming weak interfaces under the combined effects of freeze-thaw stress and salt corrosion expansion, becoming the starting point for structural failure. Furthermore, traditional materials rapidly lose their load-bearing capacity due to the deterioration of their pore structure during repeated freeze-thaw cycles, exhibiting poor freeze-thaw resistance and a significantly shortened service life. More seriously, ordinary silicate cement systems have limited ability to solidify harmful ions such as chloride ions, and continuous salt penetration will lead to corrosion of the reinforcing steel inside the repair layer and decomposition of the cement paste, ultimately causing irreversible deterioration of the overall material performance.

[0003] To address the aforementioned issues, existing technologies attempt to improve the low-temperature performance or salt resistance of repair materials by optimizing the cementitious system or adding functional admixtures. However, these improvements are often limited to enhancing a single property and lack a systematic strategy to address the coupled environment of "full negative temperature-salt corrosion," resulting in significant problems such as incomplete protective functions and insufficient long-term durability in practical applications. For example, European patent EP 3908561A1 discloses a two-component system containing Portland cement, calcium aluminate cement, and carbonate powder. While this system possesses certain early-strength characteristics, it reveals significant shortcomings in long-term saline environments: on the one hand, the density of its interfacial hydration products is insufficient, failing to effectively block chloride ion penetration, leading to a rapid decline in corrosion resistance over time; on the other hand, this material is prone to microcracks under repeated freeze-thaw conditions and lacks a self-healing mechanism. Once formed, the cracks continue to expand, severely affecting the structural integrity and service life, making it difficult to meet the long-term stable operation requirements of cold-region infrastructure. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention proposes a high-performance repair material, its preparation method, and its application.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] A high-performance repair material, the raw materials of which include component A and component B;

[0007] According to the weight parts, component A includes: 80-92 parts of high belite sulfoaluminate cement, 3-8 parts of nano silica, 0.1-0.3 parts of polycarboxylate antifreeze water-reducing agent, 1-6 parts of nano self-healing component, 0.05-0.50 parts of sodium polycarboxylate dispersant, and 100-160 parts of quartz sand;

[0008] Component B comprises: 15-50 parts of antifreeze, 85-100 parts of water, and 0.5-2.0 parts of functionalized anti-corrosion agent.

[0009] Beneficial effects: This invention discloses a high-performance repair material suitable for coupled environments of full negative temperature and salt corrosion. Based on a full negative temperature-salt corrosion synergistic protection system, the material forms multiple protective barriers through the synergistic compounding of sodium polycarboxylate dispersant, nano-inorganic particles and functionalized anti-corrosion agents, thereby significantly improving the material's durability, interfacial adhesion performance and self-healing ability in extreme low temperature and high salt environments.

[0010] The repair material of this invention forms a dense C-(A)-SH gel in situ at the interface and constructs a multi-barrier structure of "hydrophobic-dense-barrier". It can have good construction adaptability, early mechanical and durability properties under conditions of -20℃ and above, saline environment and freeze-thaw cycle, and has excellent freeze-thaw cycle resistance. It is suitable for the durability repair of cold-region infrastructure such as ultra-high voltage transmission tower bases and highway subgrades.

[0011] Optionally, the nano-self-healing component is selected from at least one of nano-calcium carbonate, nano-polyvinyl alcohol, or epoxy microcapsules.

[0012] Furthermore, according to the weight parts, component A includes: 88 parts of high belite sulfoaluminate cement, 6 parts of nano silica, 120 parts of quartz sand, 0.1 parts of polycarboxylate antifreeze water-reducing agent, 2 parts of nano PVA (nano polyvinyl alcohol), 2 parts of nano CaCO3 (nano calcium carbonate), and 0.2 parts of sodium polycarboxylate dispersant.

[0013] Furthermore, the quartz sand includes 40-80 mesh quartz sand, 80-120 mesh quartz sand and 120-200 mesh quartz sand, with the three in a mass ratio of 20-30:50-70:30-40 respectively.

[0014] Optionally, the antifreeze includes inorganic or organic antifreeze.

[0015] Furthermore, the inorganic antifreeze is selected from at least one of calcium chloride, sodium nitrite, or sodium chloride.

[0016] Furthermore, the organic antifreeze is selected from at least one of glycerol or ethylene glycol, and when the antifreeze is an organic antifreeze, component A further includes 0.5-1.5 parts of lithium carbonate.

[0017] Furthermore, the functionalized anti-corrosion agent includes quaternary ammonium salts or silane coupling agents.

[0018] Furthermore, by weight, component B comprises: 19 parts calcium chloride antifreeze, 1 part quaternary ammonium salt, and 100 parts water.

[0019] A method for preparing a high-performance repair material includes the following steps:

[0020] The raw materials are mixed evenly to obtain component A and component B respectively; then the two components are stirred for 2-5 minutes to prepare the high-performance repair material.

[0021] Optionally, the mass ratio of component A to component B is (1.5~2.2):1.

[0022] The above-mentioned high-performance repair materials are used in repairing cracks in power transmission line foundations, and in reinforcing the interfaces of highway subgrades and railway sleepers.

[0023] Compared with the prior art, the present invention has the following advantages and technical effects:

[0024] This invention proposes a high-performance repair material and its preparation method specifically designed for a fully negative temperature-salt erosion coupled environment, fundamentally overcoming the limitations of existing technologies. Based on the concept of "synergistic protection," this invention constructs a multi-scale composite system composed of high-belite sulfoaluminate cement, nano-silica, sodium polycarboxylate dispersant, nano-self-healing components, polycarboxylate antifreeze and water-reducing agent, and functionalized antifreeze. This material can still achieve rapid hydration at -20℃, and its compressive strength reaches 24.4 MPa after 12 hours, significantly superior to traditional materials. Its unique "hydrophobic-dense-barrier" multi-protection mechanism, through hydrophobic modification of the sodium polycarboxylate dispersant, nanoparticle filling, and in-situ densification of C-(A)-SH gel, significantly improves the material's resistance to chloride ion penetration and interfacial bonding strength. Simultaneously, the synergistic effect of nano-PVA and nano-CaCO3 endows the material with excellent self-healing capabilities, effectively inhibiting microcrack propagation.

[0025] Furthermore, as can be seen from the experiments and data described in this invention, the high-performance repair material prepared by this invention exhibits a strength loss rate of only 4.5% after 150 freeze-thaw cycles and a corrosion resistance coefficient as high as 0.99, demonstrating excellent overall durability. Therefore, this invention not only solves the problem of performance degradation of traditional repair materials in extreme environments, but also provides an innovative solution for the long-term and efficient repair of infrastructure in cold regions.

[0026] The mechanism of action involved in this invention is as follows: Based on the concept of "synergistic protection against salt erosion at full negative temperatures," this invention systematically designs the synergistic relationship between each component from four levels: cementation system, pore structure regulation, interfacial reaction, and self-healing mechanism, forming a composite protection system with low-temperature early strength, resistance to salt erosion, and crack self-healing. The specific mechanism is as follows:

[0027] In component A, high-Belit sulfoaluminate cement (HBAC) contains a large amount of easily activated C2S and C4A3S mineral phases. Even at low temperatures, these phases can release heat and promote the formation of hydration products through reactions with antifreeze agents such as CaCl2 and NaNO2. This process forms a C2AH8 and AFt crystal framework, providing structural support for early strength development. Polycarboxylate antifreeze water-reducing agents are adsorbed onto the particle surface through carboxyl and ethoxy side chains, inhibiting free water freezing and lowering the freezing point, thereby maintaining the system's fluidity and early hydration kinetics balance. Nano-silica plays a dual role in the system, acting as both a "nucleation inducer" and a "pore filler," with its surface hydroxyl groups reacting with CaCl2 and NaNO2. 2+ The reaction generates a high-density C-(A)-SH gel layer, significantly improving interfacial compactness. Sodium polycarboxylate dispersant, under alkaline conditions, directionally adsorbs to form a hydrophobic layer, transforming the interface from hydrophilic to hydrophobic, constructing a "hydrophobic-dense-barrier" composite structure that effectively prevents chloride ion penetration and freeze-thaw water migration. Nano-CaCO3 acts as a rehydration nucleus, promoting CSH gel regeneration; nano-PVA possesses excellent film-forming properties and a reversible hydrogen-bonded structure, enabling the in-situ formation of flexible films at microcracks. The synergistic effect of both allows for rapid crack closure under freeze-thaw and salt corrosion stress, achieving "self-healing after cracking."

[0028] In component B, the quaternary ammonium salt or silane coupling agent forms a positively charged organic-inorganic composite film at the hydration interface, which has adsorption and repulsion effects on corrosive ions such as chloride ions and sulfate ions, and forms a composite hydrophobic layer with the sodium polycarboxylate dispersant, achieving dual protection of ion barrier and chemical passivation.

[0029] In summary, this invention systematically solves the problems of early hydration obstruction, weak interfacial adhesion, and severe salt-freezing damage in repair materials under cold environments through multi-scale coupling and interface synergy, significantly improving the service durability of materials under -20℃ and salt-corrosion coupled environments. Attached Figure Description

[0030] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0031] Figure 1 The images shown are SEM images of the interfaces of the high-performance repair materials prepared in Examples 1-5 of this invention, where (a) is Example 1, (b) is Example 2, (c) is Example 3, (d) is Example 4, and (e) is Example 5. Detailed Implementation

[0032] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0033] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Every smaller range between any stated value or intermediate value within a stated range, and any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0034] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0035] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be apparent to those skilled in the art. This specification and embodiments are merely exemplary.

[0036] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0037] This invention proposes a "full negative temperature-salt erosion synergistic protection system", which discloses a high-performance repair material based on the full negative temperature-salt erosion protection system and its preparation method. Through the synergistic effect of sodium polycarboxylate dispersant, nano-inorganic particles and functionalized anti-erosion agent, multiple protective barriers are formed, thereby significantly improving the material's construction adaptability and long-term durability in extreme environments.

[0038] This invention discloses a high-performance repair material based on a full negative temperature-salt erosion synergistic protection system, wherein the raw materials include component A and component B by weight.

[0039] Component A includes: 80-92 parts of high-belite sulfoaluminate cement, 3-8 parts of nano-silica (Suzhou Ya Nano Technology Co., Ltd., average particle size 50 nm), 0.1-0.3 parts of polycarboxylate antifreeze water-reducing agent (Hunan Zhongyan Building Materials Technology Co., Ltd.), 1-6 parts of nano self-healing component, 0.05-0.50 parts of sodium polycarboxylate dispersant (Yuanfeng imported additive), and 100-160 parts of quartz sand;

[0040] Component B is an antifreeze solution, comprising 15-50 parts of (inorganic or organic) antifreeze, 85-100 parts of water, and 0.5-2.0 parts of functionalized anti-corrosion agent (chitosan quaternary ammonium salt, Shanghai Maclean Chemical Reagent, analytical grade, degree of substitution 98%; or, KH-550 silane coupling agent, Shanghai Maclean Chemical Reagent, analytical grade).

[0041] The inorganic antifreeze is selected from at least one of calcium chloride, sodium nitrite, or sodium chloride.

[0042] The organic antifreeze is selected from at least one of glycerol or ethylene glycol.

[0043] In some alternative embodiments, when component B is an organic antifreeze, component A is further doped with 0.5 to 1.5 parts of lithium carbonate (Shanghai Maclean Chemical Reagent, analytical grade) to enhance the hardening ability at low temperatures.

[0044] In some optional embodiments, the nano-self-healing component is selected from nano-calcium carbonate (Shanghai Maclean Chemical Reagent, analytical grade, particle size 50 nm) and nano-polyvinyl alcohol (P816863, M...). w 205000, Shanghai Maclean Chemical Reagent) or at least one of epoxy microcapsules (35° PU microcapsules, core material is n-dodecane, particle size 50 μm, phase change material experimental reagent); it can generate a dense C-(A)-SH gel layer in situ during the hardening process, thereby sealing microcracks and improving interface durability.

[0045] This invention discloses a high-performance repair material based on a synergistic protection system against full negative temperature and salt erosion. The added antifreeze significantly improves the antifreeze effect of the repair mortar, enabling it to maintain good workability in salt-freezing environments above -20°C and to harden rapidly. It can be applied at extreme negative temperatures, achieving structural strength in 12 hours; after 150 freeze-thaw cycles, the performance degradation rate is less than 15%, and the interfacial bond strength is ≥1.0 MPa; upon the formation of microcracks, it automatically releases repair components, forming a dense C-(A)-SH gel layer at the interface.

[0046] Unless otherwise specified, the term "parts" in this invention refers to parts by weight.

[0047] All raw materials used in this invention were purchased commercially. The polycarboxylate antifreeze and water-reducing agent used in the following examples was purchased from Hunan Zhongyan Building Materials Technology Co., Ltd., model ZY-FD; the sodium polycarboxylate dispersant was purchased from Guangdong Yuanfeng New Materials Co., Ltd., model SN-5040.

[0048] The technical solution of the present invention will be further illustrated by the following embodiments.

[0049] Example 1 (Inorganic antifreeze-calcium chloride system)

[0050] A high-performance repair material based on a synergistic protection system against full negative temperature and salt corrosion, comprising the following raw materials by weight:

[0051] Component A: 88 parts of high-belite sulfoaluminate cement, 6 parts of nano silica, 120 parts of quartz sand, 0.1 parts of polycarboxylate antifreeze water-reducing agent, 2 parts of nano PVA, 2 parts of nano CaCO3, and 0.2 parts of sodium polycarboxylate dispersant;

[0052] Among them, 120 parts of quartz sand consisted of 20 parts of 40-80 mesh quartz sand, 60 parts of 80-120 mesh quartz sand, and 40 parts of 120-200 mesh quartz sand;

[0053] Component B: 19 parts calcium chloride antifreeze, 1 part quaternary ammonium salt, and 100 parts water.

[0054] The mass ratio of component A to component B is 217.3:120.

[0055] The preparation method of the above-mentioned high-performance repair material based on the full negative temperature-salt erosion synergistic protection system includes the following steps:

[0056] The raw materials of component A are uniformly mixed to obtain solid component A;

[0057] Component B is obtained by mixing antifreeze, functionalized anti-corrosion agent and water;

[0058] When using it, components A and B are mixed in a certain proportion to prepare repair mortar, which is a high-performance repair material.

[0059] The performance of the high-performance repair material based on the full negative temperature-salt erosion synergistic protection system prepared in this embodiment is as follows: after curing at -20℃ for 12 h, the flexural strength of the repair mortar was measured to be 4.9 MPa, the compressive strength to be 24.4 MPa, and the interfacial bond strength to be 1.5 MPa. The 28-day compressive strength was 62.1 MPa, the strength loss rate after 150 freeze-thaw cycles was 4.5%, and the corrosion resistance coefficient was 0.99.

[0060] The interface SEM image of the calcium chloride solution mixed with cement mortar (high-performance repair material) prepared in Example 1 of this invention after 1 day is shown below. Figure 1 As shown in Figure (a), the cement mortar interface mixed with calcium chloride solution forms a dense C-(A)-SH gel layer, which demonstrates the excellent self-repairing ability and interface density of the repair material under negative temperature conditions. In particular, the inorganic antifreeze system exhibits a denser microstructure, which is significantly better than traditional materials without added nano self-healing components.

[0061] Example 2 (Inorganic antifreeze-sodium chloride system)

[0062] Component A: Same as in Example 1.

[0063] Component B: 36.9 parts sodium chloride antifreeze, 1 part quaternary ammonium salt, and 95 parts water.

[0064] The mass ratio of component A to component B is 217.3:132.9.

[0065] Preparation steps of a high-performance repair material based on a full negative temperature-salt erosion synergistic protection system: same as in Example 1.

[0066] The performance of the high-performance repair material based on the full negative temperature-salt erosion synergistic protection system prepared in this embodiment is as follows: after curing at -20℃ for 12 h, the flexural strength of the repair mortar was measured to be 3.8 MPa, the compressive strength to be 18.4 MPa, and the interfacial bond strength to be 1.2 MPa. The compressive strength after 28 days was 50.2 MPa, the strength loss rate after 150 freeze-thaw cycles was 5.8%, and the corrosion resistance coefficient was 0.96.

[0067] The interface SEM image of the sodium chloride solution mixed with cement mortar prepared in this embodiment after 1 day is shown below. Figure 1 As shown in Figure (b), it can be seen from the figure that a dense C-(A)-SH gel layer is formed at the interface of the cement mortar mixed with sodium chloride solution.

[0068] Example 3 (Inorganic antifreeze-sodium nitrite system)

[0069] Component A: Same as in Example 1.

[0070] Component B: 25 parts sodium nitrite antifreeze, 1 part silane, and 100 parts water.

[0071] The mass ratio of component A to component B is 217.3:126.

[0072] Preparation steps of a high-performance repair material based on a full negative temperature-salt erosion synergistic protection system: same as in Example 1.

[0073] The performance of the high-performance repair material based on the full negative temperature-salt erosion synergistic protection system prepared in this embodiment is as follows: after curing at -20℃ for 12 h, the flexural strength of the repair mortar was measured to be 3.1 MPa, the compressive strength to be 17.4 MPa, and the interfacial bond strength to be 1.1 MPa. The compressive strength after 28 days was 55.5 MPa, the strength loss rate after 150 freeze-thaw cycles was 6.0%, and the corrosion resistance coefficient was 0.96.

[0074] The interface SEM image of the sodium nitrite solution mixed with cement mortar prepared in this embodiment after 1 day is shown below. Figure 1 As shown in (c), a dense C-(A)-SH gel layer is formed at the interface of cement mortar mixed with sodium nitrite solution.

[0075] Example 4 (Organic antifreeze - glycerol system)

[0076] Component A: Same as in Example 1, except that 1 part of lithium carbonate is added.

[0077] Component B: 38.6 parts glycerol antifreeze, 1 part silane, and 85 parts water.

[0078] The mass ratio of component A to component B is 217.3:124.6.

[0079] Preparation steps of a high-performance repair material based on a full negative temperature-salt erosion synergistic protection system: same as in Example 1.

[0080] The performance of the high-performance repair material based on the full negative temperature-salt erosion synergistic protection system prepared in this embodiment is as follows: after curing at -20℃ for 12 h, the flexural strength of the repair mortar was measured to be 2.4 MPa, the compressive strength to be 14.4 MPa, and the interfacial bond strength to be 1.0 MPa. The compressive strength after 28 days was 44.1 MPa, the strength loss rate after 150 freeze-thaw cycles was 8.5%, and the corrosion resistance coefficient was 0.94.

[0081] The interface SEM image of the cement mortar mixed with the glycerol solution prepared in this embodiment after 1 day is shown below. Figure 1As shown in (d), a dense C-(A)-SH gel layer is formed at the interface of the cement mortar mixed with glycerol solution.

[0082] Example 5 (Organic Antifreeze - Ethylene Glycol System)

[0083] Component A: Same as in Example 1, except that 1 part of lithium carbonate is added.

[0084] Component B: 42.5 parts ethylene glycol antifreeze, 1 part silane, and 85 parts water.

[0085] The mass ratio of component A to component B is 217.3:128.5.

[0086] Preparation steps of a high-performance repair material based on a full negative temperature-salt erosion synergistic protection system: same as in Example 1.

[0087] The performance of the high-performance repair material based on the full negative temperature-salt erosion synergistic protection system prepared in this embodiment is as follows: after curing at -20℃ for 12 h, the flexural strength of the repair mortar was measured to be 1.9 MPa, the compressive strength to be 8.7 MPa, and the interfacial bond strength to be 1.0 MPa. The compressive strength after 28 days was 28.1 MPa, the strength loss rate after 150 freeze-thaw cycles was 13.5%, and the corrosion resistance coefficient was 0.90.

[0088] The interface SEM image of the cement mortar mixed with the ethylene glycol solution prepared in this embodiment after 1 day is shown below. Figure 1 As shown in (e), a dense C-(A)-SH gel layer is formed at the interface of the cement mortar mixed with ethylene glycol solution.

[0089] Comparative Example 1

[0090] The preparation method of this comparative repair material is the same as that of Example 1, except that calcium chloride antifreeze is not added to the raw materials, only water and quaternary ammonium salt are used.

[0091] The performance of the repair material prepared in Comparative Example 1 is as follows: after curing at -20℃ for 12 h, the flexural strength of the repair mortar was measured to be 1.5 MPa, the compressive strength to be 5.1 MPa, and the interfacial bond strength to be 0.5 MPa. The 28-day compressive strength was 25.0 MPa, the strength loss rate after 150 freeze-thaw cycles was 19.0%, and the corrosion resistance coefficient was 0.82. Detailed performance data are shown in Table 1.

[0092] Comparative Example 2

[0093] The preparation method of this comparative repair material is the same as that of Example 1, except that the nano self-healing components "2 parts nano PVA and 2 parts nano CaCO3" are replaced with "4 parts nano silica".

[0094] The performance of the repair material prepared in Comparative Example 2 was as follows: after curing at -20℃ for 12 h, the flexural strength of the repair mortar was measured to be 4.2 MPa, the compressive strength to be 20.9 MPa, and the interfacial bond strength to be 1.4 MPa. Specific performance data are shown in Table 1. From the above data, it can be seen that the repair material prepared in this comparative example has a 28-day compressive strength of 54.0 MPa, a strength loss rate of 16.1% after 150 freeze-thaw cycles, and a corrosion resistance coefficient of 0.87.

[0095] Comparative Example 3

[0096] The preparation method of this comparative repair material is the same as that of Example 1, except that nano-SiO2 is not added to the raw materials.

[0097] The performance of the repair material prepared in Comparative Example 3 is as follows: After curing at -20℃ for 12 h, the flexural strength of the repair mortar was measured to be 3.7 MPa, the compressive strength to be 20.0 MPa, and the interfacial bond strength to be 1.3 MPa. The 28-day compressive strength was 54.5 MPa, the strength loss rate after 150 freeze-thaw cycles was 11.0%, and the corrosion resistance coefficient was 0.93. Specific performance data are shown in Table 1. From the above data, it can be seen that the repair material prepared in this comparative example exhibits a decrease in strength after 12 h, a decrease in the density of the interfacial C-(A)-SH gel layer, a decrease in chloride ion curing rate, and a decrease in corrosion resistance coefficient.

[0098] Comparative Example 4

[0099] The preparation method of this comparative repair material is the same as that of Example 1, except that polycarboxylate antifreeze and water-reducing agent is not added to the raw materials.

[0100] The performance of the repair material prepared in Comparative Example 4 is as follows: After curing at -20℃ for 12 h, the flexural strength of the repair mortar was measured to be 3.2 MPa, the compressive strength to be 18.0 MPa, and the interfacial bond strength to be 1.1 MPa. The 28-day compressive strength was 48.2 MPa, the strength loss rate after 150 freeze-thaw cycles was 12.6%, and the corrosion resistance coefficient was 0.94. Specific performance data are shown in Table 1. From the above performance data, it can be seen that the repair material prepared in this comparative example exhibits decreased strength, decreased workability at negative temperatures, increased water requirement for mixing, or an increased probability of "dry lumps / segregation," with both early strength and interfacial bond strength declining simultaneously.

[0101] Comparative Example 5

[0102] The preparation method of the comparative repair material is the same as that in Example 1, except that sodium polycarboxylate dispersant is not added to the raw materials.

[0103] The performance of the repair material prepared in Comparative Example 5 is as follows: After curing at -20℃ for 12 h, the flexural strength of the repair mortar was measured to be 3.9 MPa, the compressive strength to be 21.0 MPa, and the interfacial bond strength to be 1.3 MPa. The 28-day compressive strength was 50.3 MPa, the strength loss rate after 150 freeze-thaw cycles was 14.8%, and the corrosion resistance coefficient was 0.92. Specific performance data are shown in Table 1. From the above data, it can be seen that the hydrophobic-dense-barrier composite effect is weakened, the corrosion resistance coefficient is reduced, and the strength loss after freeze-thaw cycles is increased.

[0104] Performance testing

[0105] The repair materials prepared in Examples 1-5 and Comparative Examples 1-5 were subjected to performance tests, and the specific test results are shown in Table 1. The performance test standards are as follows:

[0106] The compressive strength of high-performance repair materials was tested according to GB / T 17671-2021 "Test Method for Strength of Cement Mortar (ISO Method)";

[0107] The bonding strength of high-performance repair materials was tested according to JC / T 2381-2016 "Repair Mortar";

[0108] The frost resistance of high-performance repair materials was tested according to JC / T 70-2009 "Standard for Test Methods of Basic Performance of Building Mortar";

[0109] The corrosion resistance of high-performance repair materials was tested in accordance with JC / T 1011-2021 "Concrete Anti-sulfate Corrosion Inhibitor".

[0110] Table 1. Performance test results of repair materials in Examples 1-5 and Comparative Examples 1-5

[0111] Ambient temperature / °C 12-hour flexural strength / MPa 12 h interfacial bond strength / MPa 12-hour compressive strength / MPa 28-day compressive strength / MPa Strength loss after 150 freeze-thaw cycles / % Corrosion resistance coefficient Example 1 -20 4.9 1.5 24.4 62.1 4.5 0.99 Example 2 -20 3.8 1.2 18.4 50.2 5.8 0.96 Example 3 -20 3.1 1.1 17.4 55.5 6.0 0.96 Example 4 -20 2.4 1.0 14.4 44.1 8.5 0.94 Example 5 -20 1.9 1.0 8.7 28.1 13.5 0.90 Comparative Example 1 -20 1.5 0.5 5.1 25.0 19.0 0.82 Comparative Example 2 -20 4.2 1.4 20.9 54.0 16.1 0.87 Comparative Example 3 -20 3.7 1.3 20.0 54.5 11.0 0.93 Comparative Example 4 -20 3.2 1.1 18.0 48.2 12.6 0.94 Comparative Example 5 -20 3.9 1.3 21.0 50.3 14.8 0.92

[0112] As can be seen from the data in Table 1, this invention significantly improves the early and late mechanical properties of the repair material through the synergistic design of high-belite sulfoaluminate cement, nano-silica, sodium polycarboxylate dispersant, polycarboxylate antifreeze and water-reducing agent, nano-self-healing components, and functionalized antifreeze. Experimental results show that after curing at an extreme low temperature of -20℃ for 12 hours, the repair mortar of Example 1 achieves a compressive strength of 24.4 MPa, a flexural strength of 4.9 MPa, an interfacial bond strength of 1.5 MPa, and a 28-day compressive strength as high as 62.1 MPa, far superior to the comparative example without the addition of key components. Simultaneously, after 150 freeze-thaw cycles, the material exhibits a strength loss rate of only 4.5% and a corrosion resistance coefficient of 0.99, demonstrating excellent freeze-thaw resistance and salt corrosion resistance. The improved performance is attributed to the in-situ formation of a dense C-(A)-SH gel in the interfacial region, constructing a multi-layered protective system of "hydrophobic-dense-barrier," effectively inhibiting chloride ion penetration and microcrack propagation. Therefore, the formulation of this invention not only significantly enhances the mechanical strength and durability of the repair material, but also ensures its good construction adaptability in the coupled environment of full negative temperature and salt erosion. It successfully solves the technical problems of slow early strength development, weak interfacial bonding, easy cracking and peeling, and sharp decline in durability of traditional repair materials in extreme cold environments, and provides reliable technical support for efficient and durable repair of infrastructure in high-altitude and saline areas.

[0113] In summary, the high-performance repair material prepared by the method of this invention has excellent mechanical properties (such as compressive and flexural strength), and also ensures excellent construction applicability in low-temperature salt corrosion environment, thus solving the problem of performance degradation of traditional materials in extreme environments.

[0114] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A high-performance repair material, characterized in that, The raw materials include component A and component B. According to the weight parts, component A includes: 80-92 parts of high belite sulfoaluminate cement, 3-8 parts of nano silica, 0.1-0.3 parts of polycarboxylate antifreeze water-reducing agent, 1-6 parts of nano self-healing component, 0.05-0.50 parts of sodium polycarboxylate dispersant, and 100-160 parts of quartz sand; Component B comprises: 15-50 parts of antifreeze, 85-100 parts of water, and 0.5-2.0 parts of functionalized anti-corrosion agent.

2. The high-performance repair material according to claim 1, characterized in that, The nano-self-healing component is selected from at least one of nano-calcium carbonate, nano-polyvinyl alcohol, and epoxy microcapsules.

3. The high-performance repair material according to claim 2, characterized in that, By weight, component A comprises: 88 parts of high belite sulfoaluminate cement, 6 parts of nano silica, 120 parts of quartz sand, 0.1 parts of polycarboxylate antifreeze and water-reducing agent, 2 parts of nano polyvinyl alcohol, 2 parts of nano calcium carbonate, and 0.2 parts of sodium polycarboxylate dispersant.

4. The high-performance repair material according to claim 1, characterized in that, The antifreeze includes inorganic or organic antifreeze.

5. The high-performance repair material according to claim 4, characterized in that, The inorganic antifreeze is selected from at least one of calcium chloride, sodium nitrite, and sodium chloride.

6. The high-performance repair material according to claim 4, characterized in that, The organic antifreeze is selected from at least one of glycerol and ethylene glycol.

7. The high-performance repair material according to claim 1, characterized in that, The functionalized anti-corrosion agents include quaternary ammonium salts or silane coupling agents.

8. The high-performance repair material according to claim 7, characterized in that, By weight, component B comprises: 19 parts antifreeze, 1 part quaternary ammonium salt, and 100 parts water.

9. A method for preparing a high-performance repair material as described in any one of claims 1-8, characterized in that, Includes the following steps: The raw materials are mixed evenly to obtain component A and component B respectively; then the two components are stirred evenly at a mass ratio of (1.5~2.2):1 to prepare the high-performance repair material.

10. The application of the high-performance repair material as described in any one of claims 1-8 in repairing cracks in the foundation of power transmission lines, and in reinforcing the interface of highway subgrades and railway sleepers.

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