Repair method and system for freeze-thaw damage of power plant concrete

Abstract

The invention discloses a method and a system for repairing freeze-thaw damage of power plant concrete. According to the invention, the combination of Portland cement and nano-silica in the repairing material enhances the compactness of concrete and reduces the number of capillary pores, and the silane coupling agent significantly improves the bonding strength between the repairing material and original concrete and ensures the long-term stability of a repairing layer; the alkali activator sodium hydroxide accelerates the hydration reaction of the cement, and improves the early strength and durability of the repair material; the antibacterial agent benzalkonium bromide effectively inhibits the growth of bacteria, prevents microorganisms from eroding the concrete, and prolongs the service life of the repair structure; the defoaming agent alkyl sulfate reduces bubbles in the repairing material and improves the compactness and impermeability of the concrete; tiny air bubbles are introduced into the air entraining agent polyethylene wax, so that the freezing resistance and the crack resistance of the concrete are enhanced, and the high efficiency and the reliability of a repair project in a complex environment are also ensured.

Description

Technical Field

[0001] The invention belongs to the technical field of concrete freeze-thaw repair, and specifically relates to a method and system for repairing freeze-thaw damaged concrete in a power plant. Background Art

[0002] In the existing concrete structures of power plants, due to long-term exposure to harsh environmental conditions, such as freeze-thaw cycles, temperature changes, chemical erosion, etc., there are often different degrees of damage, such as cracks, spalling, honeycomb damage, etc. These damages not only affect the appearance of the concrete structure, but more importantly, reduce the durability and safety of the structure, thereby threatening the stable operation of the power plant and the safety of equipment. At present, the commonly used repair methods for freeze-thaw damage to concrete structures mainly include surface coating, grouting repair, shotcrete, etc.

[0003] However, these traditional methods have certain limitations, such as insufficient bonding strength between the repair material and the original concrete, no obvious improvement in durability, high construction complexity, poor environmental adaptability, etc. At the same time, traditional repair materials often lack the necessary freeze-thaw resistance, resulting in a difficult to last long repair effect, requiring frequent maintenance and repair. Summary of the invention

[0004] The purpose of the present invention is to provide a method and system for repairing freeze-thaw damaged concrete in a power plant in order to solve the above-mentioned problems.

[0005] The technical solution adopted by the present invention is as follows: a method for repairing freeze-thaw damaged concrete in a power plant, the method comprising the following steps:

[0006] S1: Investigation and evaluation: Conduct a detailed investigation of concrete damaged by freeze-thaw to assess the extent, scope and cause of damage and provide a basis for subsequent repair plans;

[0007] S2: Clean the damaged part, use high-pressure water gun and shovel tools to clean the dirt, loose materials and residues on the damaged concrete surface to ensure the cleanliness of the repair surface;

[0008] S3: Drilling drainage: Drill holes on the damaged concrete surface to set drainage holes to remove internal water and reduce the internal humidity of the concrete;

[0009] S4: Break loose concrete, use pneumatic picks and hydraulic breaker tools to remove loose and broken concrete until a solid base surface is exposed;

[0010] S5: Concrete interface treatment, grinding and cleaning the cleaned concrete interface to improve the interface bonding performance;

[0011] S6: Apply an interface agent on the treated concrete interface to enhance the bonding strength between new and old concrete;

[0012] S7: preparing repair materials, according to the performance requirements of the damaged concrete, preparing concrete repair materials with anti-freeze-thaw properties, such as polymer cement mortar;

[0013] S8: Repair construction, apply or pour the prepared repair material to the damaged part for repair; during the construction process, ensure that the material is fully filled and dense;

[0014] S9: Curing and solidification. After the construction of the repair materials is completed, cover and spray water to ensure that the materials are fully solidified. During the curing period, pay attention to controlling the ambient temperature to prevent the newly repaired concrete from being damaged by freezing and thawing again. After the curing period, the repair effect will be inspected and accepted.

[0015] In a preferred embodiment, in step S1, ultrasonic testing, core sampling, and microscopic observation are used to determine the extent of damage; the assessment report should record in detail the scope, depth, type, and possible number of freeze-thaw cycles of the damage; at the same time, it is also necessary to analyze environmental conditions, concrete composition, and construction history factors to determine the cause of freeze-thaw damage and provide a scientific basis for formulating a repair plan.

[0016] In a preferred embodiment, in step S2, a high-pressure water gun is used to thoroughly rinse the damaged concrete surface to remove salt, dirt and moss; then, loose concrete fragments are manually removed using a shovel or scraper tool, and the cleaning area is at least 10 cm beyond the visible damaged area; ensure that the base surface after cleaning is dust-free and the exposed concrete surface roughness Ra is above 12.5 μm.

[0017] In a preferred embodiment, in step S3, holes are drilled on the damaged concrete surface at intervals of 25 cm, with a hole diameter of 16 mm and a hole depth of at least 15 cm to ensure penetration of the freeze-thaw damage layer; a drain pipe with a filter screen is installed with an inclination angle of not less than 5 degrees to allow the accumulated water to be discharged smoothly; a water collection well is set near each drainage hole, and the drainage condition is checked regularly.

[0018] In a preferred embodiment, in step S4, a pneumatic pick or a hydraulic breaker is used to remove the loose and broken concrete until a solid base surface is exposed; during the crushing process, the crushing depth is controlled not to exceed 5 cm to avoid damage to the intact concrete.

[0019] In a preferred embodiment, in step S5, the concrete interface is grinded using an angle grinder equipped with a diamond grinding head to increase the roughness to Ra 50 μm or more; after grinding, the interface is rinsed with clean water to ensure that there is no oil, dust or impurities; after rinsing, the interface should remain moist but without water accumulation.

[0020] In a preferred embodiment, in step S6, an epoxy resin interface agent is selected and applied with a brush or roller to ensure uniform application with a thickness of 0.15 mm. After application, it is necessary to wait for at least 2 hours until the interface agent is completely dry.

[0021] In a preferred embodiment, in step S7, the repair material formula includes: 450 parts by weight of ordinary Portland cement, 20 parts by weight of nano-silicon dioxide, 10 parts by weight of polypropylene fiber, 50 parts by weight of water-based polyurethane emulsion, 30 parts by weight of metakaolin, 750 parts by weight of high-quality river sand, 8 parts by weight of high-efficiency water reducer, 10 parts by weight of antifreeze agent, 5-10 parts by weight of multifunctional additive, and 130 parts by weight of water;

[0022] The multifunctional auxiliary agent consists of 1 part by weight of a silane coupling agent, 1 part by weight of an alkali activator sodium hydroxide, 1 part by weight of an antibacterial agent benzalkonium bromide, 1 part by weight of a defoaming agent alkyl sulfate and 1 part by weight of an air entraining agent polyethylene wax.

[0023] In a preferred embodiment, in step S8, during construction, the repair layer is constructed in layers, and the thickness of each layer is controlled to be 15 mm, and a flat vibrator is used to vibrate and compact the layer; for larger defects, a template is used to ensure that the repair layer is tightly bonded to the original structure without hollows;

[0024] In step S9, during the curing period, the ambient temperature is maintained between 10 and 20 degrees Celsius to prevent the newly repaired concrete from being damaged by freeze-thaw again; the curing time is at least 7 days, and for special climatic conditions or materials, the curing time can be extended to 14 days; after the curing period, a rebound tester is used to perform strength testing on the repaired area to ensure that the strength meets the design requirements; at the same time, the appearance and bonding condition of the repaired area are checked to ensure that there are no cracks or peeling defects.

[0025] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0026] 1. In the present invention, the combination of silicate cement and nano-silicon dioxide in the repair material enhances the compactness of the concrete and reduces the number of capillaries. The silane coupling agent significantly improves the bonding strength between the repair material and the original concrete, ensuring the long-term stability of the repair layer. The alkali activator sodium hydroxide accelerates the hydration reaction of cement and improves the early strength and durability of the repair material. The antibacterial agent benzalkonium bromide effectively inhibits bacterial growth, prevents microbial erosion of concrete, and prolongs the service life of the repair structure. The defoaming agent alkyl sulfate reduces the bubbles in the repair material and improves the compactness and impermeability of the concrete. The air entraining agent polyethylene wax enhances the frost resistance and crack resistance of the concrete by introducing tiny air bubbles. The synergistic effect of these multifunctional additives not only improves the overall performance of the repair material, but also ensures the efficiency and reliability of the repair project in a complex environment.

[0027] 2. In the present invention, the introduction of silane coupling agent significantly improves the bonding strength between the repair material and the original concrete, ensuring that the repair layer and the original structure can form a solid whole. The application of high-efficiency water reducer and antifreeze agent ensures that the repair material still has good workability and hydration reaction under low temperature conditions, thereby improving the early strength and bonding performance of the repair material. These measures help to ensure that the repair material can be firmly attached to the damaged concrete surface and effectively prevent further damage to the concrete structure due to freeze-thaw cycles. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a schematic diagram of the process principle of the present invention. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0030] Embodiment one:

[0031] Reference Figure 1 ,

[0032] The repair method of freeze-thaw damage to concrete in power plants includes the following steps:

[0033] S1: Investigation and evaluation: Conduct a detailed investigation of concrete damaged by freeze-thaw damage to assess the extent, scope and cause of the damage, and provide a basis for subsequent repair plans.

[0034] S2: Clean the damaged area and use high-pressure water guns, shovels and other tools to clean the dirt, loose materials and residues on the damaged concrete surface to ensure the cleanliness of the repair surface.

[0035] S3: Drilling drainage: Drill holes on the damaged concrete surface to set drainage holes to remove internal water and reduce the internal humidity of the concrete.

[0036] S4: Break loose concrete and use pneumatic picks, hydraulic breakers and other tools to remove the loose and broken concrete until a solid base surface is exposed.

[0037] S5: Concrete interface treatment, grinding and cleaning the cleaned concrete interface to improve the interface bonding performance.

[0038] S6: Apply interface agent. Apply a layer of interface agent on the treated concrete interface to enhance the bonding strength between new and old concrete.

[0039] S7: Prepare repair materials. According to the performance requirements of the damaged concrete, prepare concrete repair materials with anti-freeze-thaw properties, such as polymer cement mortar, etc.

[0040] S8: Repair construction, apply or pour the prepared repair material to the damaged part for repair. During the construction process, ensure that the material is fully filled and dense.

[0041] S9: Curing and curing. After the repair material is constructed, cover and spray water to ensure that the material is fully cured. During the curing period, pay attention to controlling the ambient temperature to prevent the newly repaired concrete from being damaged by freezing and thawing again. After the curing period, the repair effect is inspected and accepted.

[0042] In step S1, ultrasonic testing, core sampling, microscopic observation and other methods are used to determine the extent of damage. The assessment report should record in detail the scope, depth, type (such as cracks, spalling, honeycomb, etc.) of the damage and the number of possible freeze-thaw cycles. At the same time, factors such as environmental conditions, concrete composition, and construction history need to be analyzed to determine the cause of freeze-thaw damage and provide a scientific basis for formulating a repair plan.

[0043] In step S2, a high-pressure water gun (pressure set at 150 bar) is used to thoroughly rinse the damaged concrete surface to remove salt, dirt and moss. Subsequently, loose concrete fragments are manually removed using tools such as shovels and scrapers, and the cleaning area is at least 10 cm beyond the visible damaged area. Ensure that the base surface after cleaning is dust-free and the exposed concrete surface roughness Ra is above 12.5 μm.

[0044] In step S3, holes are drilled on the damaged concrete surface at intervals of 25 cm, with a hole diameter of 16 mm and a hole depth of at least 15 cm to ensure penetration of the freeze-thaw damage layer. A drainage pipe with a filter screen is installed with an inclination angle of not less than 5 degrees to allow the accumulated water to be discharged smoothly. A water collection well is set near each drainage hole to regularly check the drainage situation.

[0045] In step S4, a pneumatic pick (hammering frequency is not less than 1000 times / minute) or a hydraulic breaker is used to remove the loose and broken concrete until a solid base surface is exposed. During the crushing process, the crushing depth is controlled to be no more than 5 cm to avoid damage to the intact concrete.

[0046] In step S5, an angle grinder (speed not less than 3000 rpm) equipped with a diamond grinding head is used to grind the concrete interface to increase the roughness to Ra 50 μm or more. After grinding, the interface is rinsed with clean water to ensure that there is no impurities such as oil, dust, etc. After rinsing, the interface should remain moist but without stagnant water.

[0047] In step S6, an epoxy resin interface agent is selected and applied with a brush or roller to ensure uniform application with a thickness of 0.15 mm. After application, it is necessary to wait for at least 2 hours until the interface agent is completely dry.

[0048] In step S7, the repair material formula includes: 450 parts by weight of ordinary Portland cement, 20 parts by weight of nano silicon dioxide, 10 parts by weight of polypropylene fiber, 50 parts by weight of waterborne polyurethane emulsion, 30 parts by weight of metakaolin, 750 parts by weight of high-quality river sand, 8 parts by weight of high-efficiency water reducing agent, 10 parts by weight of antifreeze agent, 5 parts by weight of multifunctional additive, and 130 parts by weight of water;

[0049] The multifunctional auxiliary agent consists of 1 part by weight of a silane coupling agent, 1 part by weight of an alkali activator sodium hydroxide, 1 part by weight of an antibacterial agent benzalkonium bromide, 1 part by weight of a defoaming agent alkyl sulfate and 1 part by weight of an air entraining agent polyethylene wax.

[0050] In step S8, during construction, the repair layer is carried out in layers, and the thickness of each layer is controlled to be 15 mm, and a flat vibrator (frequency 50 Hz) is used for vibration compaction. For larger defects, a template is used for construction to ensure that the repair layer is tightly bonded to the original structure without hollows.

[0051] In step S9, during the curing period, the ambient temperature is maintained between 10 and 20 degrees Celsius to prevent the newly repaired concrete from being damaged by freeze-thaw again. The curing time is at least 7 days. For special climatic conditions or materials, the curing time can be extended to 14 days. After the curing period, the strength of the repaired area is tested using a rebound tester to ensure that the strength meets the design requirements. At the same time, the appearance and bonding of the repaired area are checked to ensure that there are no defects such as cracks and peeling.

[0052] A repair system for power plant concrete damaged by freeze-thaw, the system runs the repair method for power plant concrete damaged by freeze-thaw of the above embodiment.

[0053] From the above we can know:

[0054] In the present invention, the combination of silicate cement and nano-silicon dioxide in the repair material enhances the compactness of the concrete and reduces the number of capillaries. The silane coupling agent significantly improves the bonding strength between the repair material and the original concrete, ensuring the long-term stability of the repair layer; the alkali activator sodium hydroxide accelerates the hydration reaction of the cement, improving the early strength and durability of the repair material; the antibacterial agent benzalkonium bromide effectively inhibits bacterial growth, prevents microbial erosion of concrete, and prolongs the service life of the repair structure; the defoaming agent alkyl sulfate reduces the bubbles in the repair material and improves the compactness and impermeability of the concrete; the air entraining agent polyethylene wax enhances the frost resistance and crack resistance of the concrete by introducing tiny air bubbles. The synergistic effect of these multifunctional additives not only improves the overall performance of the repair material, but also ensures the efficiency and reliability of the repair project in a complex environment.

[0055] In the present invention, the introduction of silane coupling agent significantly improves the bonding strength between the repair material and the original concrete, ensuring that the repair layer and the original structure can form a solid whole. The application of high-efficiency water reducer and antifreeze agent ensures that the repair material still has good workability and hydration reaction under low temperature conditions, thereby improving the early strength and bonding performance of the repair material. These measures help to ensure that the repair material can be firmly attached to the damaged concrete surface and effectively prevent further damage to the concrete structure by freeze-thaw cycles.

[0056] Embodiment 2:

[0057] Reference Figure 1 , the repair method of freeze-thaw damage to concrete in power plants, the repair method includes the following steps:

[0058] S1: Investigation and evaluation: Conduct a detailed investigation of concrete damaged by freeze-thaw damage to assess the extent, scope and cause of the damage, and provide a basis for subsequent repair plans.

[0059] S2: Clean the damaged area and use high-pressure water guns, shovels and other tools to clean the dirt, loose materials and residues on the damaged concrete surface to ensure the cleanliness of the repair surface.

[0060] S3: Drilling drainage: Drill holes on the damaged concrete surface to set drainage holes to remove internal water and reduce the internal humidity of the concrete.

[0061] S4: Break loose concrete and use pneumatic picks, hydraulic breakers and other tools to remove the loose and broken concrete until a solid base surface is exposed.

[0062] S5: Concrete interface treatment, grinding and cleaning the cleaned concrete interface to improve the interface bonding performance.

[0063] S6: Apply interface agent. Apply a layer of interface agent on the treated concrete interface to enhance the bonding strength between new and old concrete.

[0064] S7: Prepare repair materials. According to the performance requirements of the damaged concrete, prepare concrete repair materials with anti-freeze-thaw properties, such as polymer cement mortar, etc.

[0065] S8: Repair construction, apply or pour the prepared repair material to the damaged part for repair. During the construction process, ensure that the material is fully filled and dense.

[0066] S9: Curing and curing. After the repair material is constructed, cover and spray water to ensure that the material is fully cured. During the curing period, pay attention to controlling the ambient temperature to prevent the newly repaired concrete from being damaged by freezing and thawing again. After the curing period, the repair effect is inspected and accepted.

[0067] In step S1, ultrasonic testing, core sampling, microscopic observation and other methods are used to determine the extent of damage. The assessment report should record in detail the scope, depth, type (such as cracks, spalling, honeycomb, etc.) of the damage and the number of possible freeze-thaw cycles. At the same time, factors such as environmental conditions, concrete composition, and construction history need to be analyzed to determine the cause of freeze-thaw damage and provide a scientific basis for formulating a repair plan.

[0068] In step S2, a high-pressure water gun (pressure set at 150 bar) is used to thoroughly rinse the damaged concrete surface to remove salt, dirt and moss. Subsequently, loose concrete fragments are manually removed using tools such as shovels and scrapers, and the cleaning area is at least 10 cm beyond the visible damaged area. Ensure that the base surface after cleaning is dust-free and the exposed concrete surface roughness Ra is above 12.5 μm.

[0069] In step S3, holes are drilled on the damaged concrete surface at intervals of 25 cm, with a hole diameter of 16 mm and a hole depth of at least 15 cm to ensure penetration of the freeze-thaw damage layer. A drainage pipe with a filter screen is installed with an inclination angle of not less than 5 degrees to allow the accumulated water to be discharged smoothly. A water collection well is set near each drainage hole to regularly check the drainage situation.

[0070] In step S4, a pneumatic pick (hammering frequency is not less than 1000 times / minute) or a hydraulic breaker is used to remove the loose and broken concrete until a solid base surface is exposed. During the crushing process, the crushing depth is controlled to be no more than 5 cm to avoid damage to the intact concrete.

[0071] In step S5, an angle grinder (speed not less than 3000 rpm) equipped with a diamond grinding head is used to grind the concrete interface to increase the roughness to Ra 50 μm or more. After grinding, the interface is rinsed with clean water to ensure that there is no impurities such as oil, dust, etc. After rinsing, the interface should remain moist but without stagnant water.

[0072] In step S6, an epoxy resin interface agent is selected and applied with a brush or roller to ensure uniform application with a thickness of 0.15 mm. After application, it is necessary to wait for at least 2 hours until the interface agent is completely dry.

[0073] In step S7, the repair material formula includes: 450 parts by weight of ordinary Portland cement, 20 parts by weight of nano silicon dioxide, 10 parts by weight of polypropylene fiber, 50 parts by weight of waterborne polyurethane emulsion, 30 parts by weight of metakaolin, 750 parts by weight of high-quality river sand, 8 parts by weight of high-efficiency water reducing agent, 10 parts by weight of antifreeze agent, 10 parts by weight of multifunctional additive, and 130 parts by weight of water;

[0074] The multifunctional auxiliary agent consists of 1 part by weight of a silane coupling agent, 1 part by weight of an alkali activator sodium hydroxide, 1 part by weight of an antibacterial agent benzalkonium bromide, 1 part by weight of a defoaming agent alkyl sulfate and 1 part by weight of an air entraining agent polyethylene wax.

[0075] In step S8, during construction, the repair layer is carried out in layers, and the thickness of each layer is controlled to be 15 mm, and a flat vibrator (frequency 50 Hz) is used for vibration compaction. For larger defects, a template is used for construction to ensure that the repair layer is tightly bonded to the original structure without hollows.

[0076] In step S9, during the curing period, the ambient temperature is maintained between 10 and 20 degrees Celsius to prevent the newly repaired concrete from being damaged by freeze-thaw again. The curing time is at least 7 days. For special climatic conditions or materials, the curing time can be extended to 14 days. After the curing period, the strength of the repaired area is tested using a rebound tester to ensure that the strength meets the design requirements. At the same time, the appearance and bonding of the repaired area are checked to ensure that there are no defects such as cracks and peeling.

[0077] A repair system for power plant concrete damaged by freeze-thaw, the system runs the repair method for power plant concrete damaged by freeze-thaw of the above embodiment.

[0078] From the above we can know:

[0079] In the present invention, the combination of silicate cement and nano-silicon dioxide in the repair material enhances the compactness of the concrete and reduces the number of capillaries. The silane coupling agent significantly improves the bonding strength between the repair material and the original concrete, ensuring the long-term stability of the repair layer; the alkali activator sodium hydroxide accelerates the hydration reaction of the cement, improving the early strength and durability of the repair material; the antibacterial agent benzalkonium bromide effectively inhibits bacterial growth, prevents microbial erosion of concrete, and prolongs the service life of the repair structure; the defoaming agent alkyl sulfate reduces the bubbles in the repair material and improves the compactness and impermeability of the concrete; the air entraining agent polyethylene wax enhances the frost resistance and crack resistance of the concrete by introducing tiny air bubbles. The synergistic effect of these multifunctional additives not only improves the overall performance of the repair material, but also ensures the efficiency and reliability of the repair project in a complex environment.

[0080] In the present invention, the introduction of silane coupling agent significantly improves the bonding strength between the repair material and the original concrete, ensuring that the repair layer and the original structure can form a solid whole. The application of high-efficiency water reducer and antifreeze agent ensures that the repair material still has good workability and hydration reaction under low temperature conditions, thereby improving the early strength and bonding performance of the repair material. These measures help to ensure that the repair material can be firmly attached to the damaged concrete surface and effectively prevent further damage to the concrete structure by freeze-thaw cycles.

[0081] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the term "comprises" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprises a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0082] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for repairing freeze-thaw damaged concrete in a power plant, characterized in that: The repair method comprises the following steps: S1: Investigation and evaluation: Conduct a detailed investigation of concrete damaged by freeze-thaw to assess the extent, scope and cause of damage and provide a basis for subsequent repair plans; S2: Clean the damaged part, use high-pressure water gun and shovel tools to clean the dirt, loose materials and residues on the damaged concrete surface to ensure the cleanliness of the repair surface; S3: Drilling drainage: Drill holes on the damaged concrete surface to set drainage holes to remove internal water and reduce the internal humidity of the concrete; S4: Break loose concrete, use pneumatic picks and hydraulic breaker tools to remove loose and broken concrete until a solid base surface is exposed; S5: Concrete interface treatment, grinding and cleaning the cleaned concrete interface to improve the interface bonding performance; S6: Apply an interface agent on the treated concrete interface to enhance the bonding strength between new and old concrete; S7: Prepare repair materials. According to the performance requirements of the damaged concrete, prepare concrete repair materials with anti-freezing and thawing properties, such as polymer cement mortar; S8: Repair construction, apply or pour the prepared repair materials to the damaged parts for repair; during the construction process, ensure that the materials are fully filled and dense; S9: Curing and solidification. After the construction of the repair materials is completed, cover and spray water to ensure that the materials are fully solidified. During the curing period, pay attention to controlling the ambient temperature to prevent the newly repaired concrete from being damaged by freezing and thawing again. After the curing period, the repair effect will be inspected and accepted.

2. The method for repairing freeze-thaw damaged concrete in a power plant according to claim 1, characterized in that: In step S1, ultrasonic testing, core sampling, and microscopic observation are used to determine the extent of damage; the assessment report should record in detail the scope, depth, type, and possible number of freeze-thaw cycles of the damage; at the same time, it is also necessary to analyze environmental conditions, concrete composition, and construction history factors to determine the cause of freeze-thaw damage and provide a scientific basis for formulating a repair plan.

3. The method for repairing freeze-thaw damaged concrete in a power plant according to claim 1, characterized in that: In step S2, a high-pressure water gun is used to thoroughly rinse the damaged concrete surface to remove salt, dirt and moss; then, loose concrete fragments are manually removed using a shovel or scraper tool, and the cleaning area is at least 10 cm beyond the visible damaged area; ensure that the base surface after cleaning is dust-free and the exposed concrete surface roughness Ra is above 12.5 μm.

4. The method for repairing freeze-thaw damaged concrete in a power plant according to claim 1, characterized in that: In step S3, holes are drilled on the damaged concrete surface at intervals of 25 cm, with a hole diameter of 16 mm and a hole depth of at least 15 cm to ensure penetration of the freeze-thaw damage layer; a drain pipe with a filter screen is installed with an inclination angle of not less than 5 degrees to allow the accumulated water to be discharged smoothly; a water collection well is set near each drainage hole, and the drainage condition is checked regularly.

5. The method for repairing freeze-thaw damaged concrete in a power plant according to claim 1, characterized in that: In step S4, a pneumatic pick or a hydraulic breaker is used to remove the loose and broken concrete until a solid base surface is exposed; during the crushing process, the crushing depth is controlled not to exceed 5 cm to avoid damage to the intact concrete.

6. The method for repairing freeze-thaw damaged concrete in a power plant according to claim 1, characterized in that: In step S5, the concrete interface is grinded with an angle grinder equipped with a diamond grinding head to increase the roughness to Ra 50 μm or more; after grinding, the interface is rinsed with clean water to ensure that there is no oil, dust or impurities; after rinsing, the interface should remain moist but without water accumulation.

7. The method for repairing freeze-thaw damaged concrete in a power plant according to claim 1, characterized in that: In the step S6, an epoxy resin interface agent is selected and applied with a brush or roller to ensure uniform application with a thickness of 0.15 mm. After application, it is necessary to wait for at least 2 hours until the interface agent is completely dry.

8. The method for repairing freeze-thaw damaged concrete in a power plant according to claim 1, characterized in that: In step S7, the repair material formula includes: 450 parts by weight of ordinary Portland cement, 20 parts by weight of nano silicon dioxide, 10 parts by weight of polypropylene fiber, 50 parts by weight of waterborne polyurethane emulsion, 30 parts by weight of metakaolin, 750 parts by weight of high-quality river sand, 8 parts by weight of high-efficiency water reducing agent, 10 parts by weight of antifreeze agent, 5-10 parts by weight of multifunctional additive, and 130 parts by weight of water; The multifunctional auxiliary agent consists of 1 part by weight of a silane coupling agent, 1 part by weight of an alkali activator sodium hydroxide, 1 part by weight of an antibacterial agent benzalkonium bromide, 1 part by weight of a defoaming agent alkyl sulfate and 1 part by weight of an air entraining agent polyethylene wax.

9. The method for repairing freeze-thaw damaged concrete in a power plant according to claim 1, characterized in that: In step S8, during construction, the repair layer is carried out in layers, and the thickness of each layer is controlled to be 15 mm, and a flat vibrator is used to vibrate and compact the layer; for larger defects, a template is used to ensure that the repair layer is tightly bonded to the original structure without hollows; In step S9, during the curing period, the ambient temperature is maintained between 10 and 20 degrees Celsius to prevent the newly repaired concrete from being damaged by freeze-thaw again; the curing time is at least 7 days, and for special climatic conditions or materials, the curing time can be extended to 14 days; after the curing period, a rebound tester is used to perform strength testing on the repaired area to ensure that the strength meets the design requirements; at the same time, the appearance and bonding condition of the repaired area are checked to ensure that there are no cracks or peeling defects.

10. A repair system for freeze-thaw damaged concrete in a power plant, characterized by: The system operates the method for repairing freeze-thaw damage to concrete in a power plant as described in any one of claims 1 to 9.

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