Method for rapid repair of concrete tower sections using light-cured fiber reinforced composites

Abstract

The application discloses a method for repairing a concrete tower in a quick manner by using a photocured fiber reinforced composite material and belongs to the technical field of wind power structure reinforcement. First, a reinforcement scheme is determined according to the area, depth and hollow range of the concrete tower skin peeling, then the peeling area is pretreated, the failed concrete is removed and a clean active base surface is formed; an interface sealing layer is formed on the pretreated base surface; a smooth stress transition layer is formed on the interface sealing layer; an outer constraint layer is formed by alternately laying photocured circumferential fiber cloth and photocured longitudinal prestressed fiber cloth to form a main reinforcement layer in the form of a quadrilateral grid, and the circumferential fiber cloth is prestressed; a strain sensor is embedded in the reinforcement layer, and a photocured polyurea elastomer protective layer is sprayed on the outermost layer. According to the scheme, the solidification time of the reinforcement layer is shortened to the minute level, the reinforcement efficiency and durability are significantly improved, and the scheme is especially suitable for the quick reinforcement of the concrete tower skin peeling in a severe environment such as high humidity and low temperature, and has the advantages of high construction efficiency and intelligent management.

Description

Technical Field

[0001] This invention belongs to the field of rapid repair technology for wind turbine tower structures, specifically relating to a method for rapidly repairing concrete towers using photocured fiber-reinforced composite materials. Background Technology

[0002] Hybrid-tower wind turbines combine concrete towers with steel or other material towers. Concrete towers, as the primary load-bearing components, offer advantages such as good compressive strength, relatively low cost, and high rigidity, leading to their widespread use in modern wind power. However, concrete towers are constantly exposed to complex and harsh natural environments, enduring the combined effects of wind loads, turbine vibrations, temperature changes, freeze-thaw cycles, and high humidity and salt spray. Consequently, their outer concrete walls are prone to surface peeling, hollowing, micro-crack expansion, and material powdering – all known as "skin peeling" defects.

[0003] Although surface peeling does not directly affect the overall load-bearing capacity of the structure in the early stages, its harm is gradual and insidious. First, the peeling of the surface concrete directly weakens the thickness of the concrete cover, accelerating the corrosion process of the internal steel reinforcement. Second, the peeling area forms a stress concentration point, which is prone to crack propagation under cyclic loading. Third, surface damage reduces the aerodynamic integrity of the tower, affecting structural durability. Ultimately, it may lead to a decrease in tower stiffness and insufficient local load-bearing capacity, affecting the safe operation and design life of the wind turbine, and even causing safety accidents.

[0004] To address the issue of concrete tower surface peeling, commonly used repair methods mainly include the following categories: First, manual application of polymer repair mortar. This method is simple to construct but has a long curing period (usually 24-72 hours), low bonding strength between the old and new concrete surfaces (generally ≤1.5MPa), and is prone to shrinkage cracking and re-peeling. Second, reinforcement with traditional thermosetting carbon fiber cloth. This method requires on-site mixing of epoxy resin adhesive, with a curing time ranging from several hours to tens of hours. The curing process is significantly affected by ambient temperature and humidity, making it difficult to construct under low temperature or humid conditions. Third, partial removal followed by pouring high-performance concrete. This method involves complex construction procedures, requires formwork and curing, involves long downtime, and has a weak layer at the interface between the old and new concrete.

[0005] The existing technologies described above suffer from the following technical bottlenecks in practical applications: First, the long curing time of the repair materials leads to prolonged wind turbine shutdowns, resulting in power generation losses and increased risks associated with high-altitude operations. Second, the bonding strength at the repair interface is insufficient, making it difficult to withstand long-term wind loads and temperature stresses, and prone to secondary detachment. Third, traditional repair methods lack real-time monitoring of the repair effect, making it impossible to assess the changes in the repair layer's condition during long-term service. Fourth, in existing carbon fiber reinforcement processes, prestressing requires a complex anchoring system, making rapid construction on curved tower surfaces difficult. Therefore, there is an urgent need for a rapid repair method for concrete tower skin detachment that features fast curing speed, reliable interface bonding, strong construction adaptability, and monitoring capabilities. Summary of the Invention

[0006] Based on the above technical problems, this invention proposes a method for rapid repair of concrete towers using photocurable fiber-reinforced composite materials. By using photocuring technology, the method enables rapid molding of each functional layer, significantly shortens construction time, improves interfacial bonding performance, and integrates intelligent monitoring functions, providing an efficient, reliable, and measurable repair solution for wind power hybrid towers.

[0007] To achieve the above-mentioned technical objectives, the technical solution adopted by the present invention is as follows:

[0008] A method for rapid repair of concrete towers using photocured fiber-reinforced composite materials includes the following steps:

[0009] Step 1: Based on the area, depth, and extent of voids in the concrete tower skin of the hybrid tower wind turbine, assess the severity of the damage and select the corresponding photocured fiber reinforced composite repair solution according to the severity of the damage.

[0010] Step 2: Pre-treat the detached area by removing the failed concrete layer down to a solid substrate to form a clean and active substrate.

[0011] Step 3: Apply a light-curing penetrating interface sealant to the pretreated substrate and cure it with ultraviolet irradiation to form an interface sealing layer;

[0012] Step 4: Lay a light-cured fiber-reinforced leveling material on the interface sealing layer, and cure it with ultraviolet irradiation to form a leveling layer;

[0013] Step 5: Alternately lay photocured longitudinal fiber cloth and photocured circumferential prestressed fiber cloth on the leveling layer to form an orthogonal grid-shaped main reinforcement layer; apply photosensitive resin adhesive to the fiber cloth bonding area; install wedge-shaped anchors on the concrete surface of the tower according to the repair plan; tension the circumferential carbon fiber cloth; and use a mobile ultraviolet lamp array to perform in-situ irradiation curing to form a composite main reinforcement layer.

[0014] Step 6: Embed a miniature fiber optic strain sensor in the main reinforcement layer. The miniature fiber optic strain sensor is connected to the wireless acquisition module to monitor the strain state of the reinforcement layer in real time.

[0015] Step 7: Spray a UV-cured polyurea elastomer coating onto the outermost layer of the main reinforcement layer, and cure it with ultraviolet radiation to form a durable protective layer.

[0016] To optimize the above technical solution, the specific measures also include:

[0017] In step 1, a combination of infrared thermal imaging and tapping method is used to assess the severity of the damage. The specific repair scheme for photocured fiber reinforced composite repair is as follows: For mild detachment (area ≤ 0.5 m², depth ≤ 5 mm), a single layer of circumferential prestressed photocured fiber cloth is used for reinforcement; for moderate detachment (area 0.5-2.0 m², depth 5-15 mm), a combination of longitudinal and circumferential prestressed photocured fiber cloth is used for reinforcement; for severe detachment (area ≥ 2.0 m², depth ≥ 15 mm), a composite of circumferential, longitudinal, and circumferential repair methods is used. The structural reinforcement, specifically the "longitudinal + circumferential prestressed light-cured fiber cloth" combined reinforcement, involves first laying and tensioning prestressed light-cured fiber cloth circumferentially along the tower, and then laying longitudinal light-cured fiber cloth axially along the tower, forming an orthogonal grid-like main reinforcement layer. The "circumferential + longitudinal + circumferential" composite structural reinforcement involves laying the first layer of circumferential prestressed light-cured fiber cloth, the second layer of longitudinal light-cured fiber cloth, and the third layer of circumferential prestressed light-cured fiber cloth sequentially from the inside out, forming a three-layer orthogonal composite main reinforcement layer.

[0018] Step 2 specifically involves: using an infrared thermal imager to locate the boundary of the hollow area, using a tapping method to further confirm the detached and hollow areas, removing the failed concrete layer down to a solid base surface, and then performing high-pressure water jet treatment on the base surface to form a clean and active base surface with a roughness Ra≥80μm, thus creating the repair work area.

[0019] In step 3, the photocurable penetrating interface sealant is a modified epoxy acrylate system or a polyurethane acrylate system, with a viscosity ≤500mPa·s, a penetration depth ≥5mm, a bond strength to concrete ≥3.0MPa after curing, an ultraviolet irradiation wavelength of 365-405nm, an irradiation intensity ≥50mW / cm², and an interface sealing layer thickness of 0.2-0.5mm after curing.

[0020] In step 4, the leveling material is composed of photosensitive resin and chopped carbon fibers, and is formed by scraping. After curing by ultraviolet irradiation, a smooth stress transition layer is formed. The chopped carbon fibers in the photocurable fiber-reinforced leveling material have a length of 6-12 mm and a volume content of 1.0%-2.0%. The photosensitive resin matrix is ​​epoxy acrylate or polyurethane acrylate. After curing, the compressive strength is ≥80MPa, the flexural strength is ≥40MPa, and the bonding strength with the interface sealing layer is ≥2.5MPa. The thickness of a single layer of leveling layer does not exceed 10 mm. When laying multiple layers, the next layer can only be constructed after each layer has been cured.

[0021] In step 5, the photocurable fiber cloth is a carbon fiber cloth pre-impregnated with photosensitive resin, with a single-layer thickness of 0.2-0.3 mm, tensile strength ≥3400 MPa, elastic modulus ≥240 GPa, resin content of 35%-45%, and a storage period of ≥6 months under light-proof conditions and at a temperature ≤25℃; after curing, the fiber volume content is ≥55%, and the interlaminar shear strength is ≥50 MPa; the circumferential fiber cloth is continuously laid along the circumference of the tower, with an overlap length ≥150 mm, and prestress is applied; the longitudinal fiber cloth is laid along the axial direction of the tower, with a spacing of 20 mm. The length of the wedge-shaped anchor is ≥300mm beyond the boundary of the detachment area. The anchor structure includes an anchor ring and a wedge-shaped wedge. The anchor ring wall thickness is ≥8mm, the clamping force is ≥30kN, and the slippage is ≤0.05mm. The length of the wedge-shaped wedge is the width of the fiber cloth + 20mm, the width is 40mm, and the wedge angle is 10°-15°. The contact surface between the anchor and the fiber cloth is coated with a light-curing adhesive and simultaneously light-cured to form an integral anchor structure. The outside of the anchor is covered with a weather-resistant stainless steel protective cover.

[0022] In step 6, the outer diameter of the miniature fiber optic strain sensor is ≤0.5mm, the center wavelength is 1525-1565nm, the strain measurement accuracy is ±1με, and the temperature compensation sensor is deployed simultaneously. The sensor is arranged at the intersection of the circumferential fiber cloth and the longitudinal fiber cloth, and at the mid-span of the longitudinal fiber cloth. It is fixed with light-curing adhesive, and the curing time is ≤2 minutes. The sensor is connected to the wireless acquisition module at the bottom of the tower through an optical cable. The acquisition module has the function of remote data transmission.

[0023] In step 7, the photocurable polyurea elastomer coating is a two-component photocurable polyurea system with tensile strength ≥20MPa, elongation at break ≥300%, tear strength ≥50kN / m, salt spray resistance ≥2000h, no powdering or cracking after ≥1500h of accelerated aging, water absorption ≤5%, and UV curing depth ≥2mm. The coating is applied using an airless spraying device, with a single layer thickness of 0.5-1.0mm and multiple layers applied to the designed thickness. Each layer is immediately cured by UV irradiation after spraying.

[0024] Ultraviolet irradiation is carried out using an ultraviolet lamp array. The ultraviolet lamp array uses LED light source with a power density of ≥100mW / cm², a lamp array width of 300-600mm, and a lamp array shape adapted to the curvature of the tower surface. The lamp array moving speed is ≤0.5m / min, and the distance between the lamp array and the construction surface is 50-150mm. The lamp array integrates a temperature sensor, which automatically reduces the power or stops irradiation when the surface temperature exceeds 60℃.

[0025] After step 7 is completed, the repair quality is inspected: infrared thermal imaging is used to detect the adhesion between the coating and the base layer, and the debonded area does not exceed 2% of the total repair area; a pull-out tester is used to detect the coating adhesion, and the adhesion is ≥2.5MPa; the strain data of the repair layer is continuously monitored through a wireless acquisition module, and the initial strain value is used as the baseline value. Subsequent monitoring data are compared with the baseline value to evaluate the long-term condition of the repaired structure.

[0026] The present invention has the following beneficial effects:

[0027] 1. Rapid curing, significantly shortening construction time: This invention uses light curing technology to replace the traditional thermosetting resin system. The curing time of each functional layer is only 2-10 minutes, which is more than 90% shorter than the several hours to tens of hours of traditional thermosetting resin. This greatly reduces the power generation loss caused by wind turbine shutdown, while also reducing the time spent working at heights and improving construction safety.

[0028] 2. On-site instant curing, overcoming environmental limitations: The UV curing process relies on ultraviolet radiation rather than ambient temperature, allowing operation under harsh conditions where traditional thermosetting resins are difficult to apply, such as -10℃ low temperatures, high humidity, and high wind speeds. This effectively extends the construction window for wind turbine tower repairs. It is especially suitable for emergency repair operations in special environments such as offshore wind power and northern winters.

[0029] 3. Excellent interfacial adhesion and strong durability: This invention uses a penetrating, light-cured interfacial sealant. Its low viscosity allows it to penetrate deep into the microporous structure of concrete (penetration depth ≥ 5mm). After curing, it forms a dual bonding mechanism of mechanical interlocking and chemical bonding, achieving a bonding strength of over 3.0 MPa, which is more than 100% higher than traditional repair mortar (1.0-1.5 MPa). Combined with a multi-layer fiber-reinforced structure and a light-cured polyurea protective layer, the repair layer's resistance to peeling, impact, and fatigue is significantly improved, effectively resisting long-term effects such as wind loads, temperature stress, and unit vibration.

[0030] 4. Prestressed active constraint to suppress interface peeling: This invention applies prestress of 15%-25% of the ultimate tensile strength to the circumferential fiber cloth, and achieves rapid anchoring through light-cured wedge anchors. It applies active constraint force to the repair area, improves the stress distribution of the repair layer, reduces the risk of peeling between the new and old interfaces, and improves the crack resistance and fatigue life of the repaired structure.

[0031] 5. No heat damage, safe and environmentally friendly: The UV curing process is low-temperature curing (material temperature rise ≤10℃ during curing), with no open flame, no high temperature, and no large release of volatile organic compounds. This avoids the risk of heat damage to concrete and existing structures that may be caused by traditional thermosetting processes, making it especially suitable for heat-sensitive wind turbine tower structures and outdoor work scenarios with high fire prevention requirements. The UV-cured material is a 100% solids content system with no solvent evaporation, meeting green construction requirements.

[0032] In summary, this invention breaks through the technical bottlenecks of traditional concrete tower skin peeling repair methods in terms of curing time, interface bonding, environmental adaptability, and monitoring methods, significantly improving repair efficiency and quality. It provides a fast, reliable, and intelligent repair solution for concrete towers of mixed-tower wind turbine units, and has significant engineering application value and economic benefits. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the method for reinforcing the concrete tower skin of the hybrid tower wind turbine of the present invention.

[0034] Figure 2 This is a schematic diagram showing the peeling off of the outer skin of a mixed concrete tower.

[0035] Figure 3 A schematic diagram of the carbon fiber cloth application scheme;

[0036] Figure 4 A schematic diagram showing the attachment of a fiber Bragg grating sensor in the middle region of a carbon fiber cloth;

[0037] Figure 5 This is a schematic diagram of the installation of a photocurable anchor.

[0038] Figure 6 Diagram showing the arrangement of a UV-curing lamp array;

[0039] Figure 7 This is a cross-sectional view of the reinforced area where the outer skin of the mixed concrete tower has detached. Detailed Implementation

[0040] To make the objectives, technical solutions, and advantages of this application clearer, the application is described and illustrated below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application. All other embodiments obtained by those skilled in the art based on the embodiments provided in this application without inventive effort are within the scope of protection of this application.

[0041] Obviously, the accompanying drawings described below are merely some examples or embodiments of this application. Those skilled in the art can apply this application to other similar scenarios based on these drawings without any inventive effort. Furthermore, it is understood that although the efforts made in this development process may be complex and lengthy, for those skilled in the art related to the content disclosed in this application, any changes to design, manufacturing, or production based on the technical content disclosed in this application are merely conventional technical means and should not be construed as insufficient disclosure of the content of this application.

[0042] In this application, the reference to "embodiment" means that a specific feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment that is mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described in this application may be combined with other embodiments without conflict.

[0043] Unless otherwise defined, the technical or scientific terms used in this application shall have the ordinary meaning understood by one of ordinary skill in the art to which this application pertains. The terms “a,” “an,” “an,” “the,” and similar words used in this application do not indicate quantity limitation and may indicate singular or plural. The terms “comprising,” “including,” “having,” and any variations thereof used in this application are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or device that includes a series of steps or units (elements) is not limited to the listed steps or units, but may also include steps or units not listed, or may include other steps or units inherent to these processes, methods, products, or devices. The terms “connected,” “linked,” “coupled,” and similar words used in this application are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. The terms “multiple” / “several” used in this application refer to two or more. “And / or” describes the relationship between related objects, indicating that three relationships may exist; for example, “A and / or B” can indicate: A alone, A and B simultaneously, or B alone. The character " / " generally indicates that the preceding and following objects are in an "or" relationship. The terms "first," "second," and "third" used in this application are merely to distinguish similar objects and do not represent a specific ordering of the objects.

[0044] This invention provides a rapid repair method for the peeling of the concrete tower skin of a hybrid wind turbine based on photocured fiber-reinforced composite materials, such as... Figure 1As shown, the repair method includes determining the repair level and reinforcement plan based on the area, depth, and hollow area of ​​the epidermis; diagnosis and pretreatment of the diseased area; construction of the light-cured interface sealing layer; construction of the light-cured fiber-reinforced leveling layer; construction of the light-cured fiber-reinforced reinforcement layer, including longitudinal fiber cloth laying and circumferential prestressed fiber cloth tensioning and anchoring; embedding of the intelligent monitoring layer; construction of the light-cured durable protective layer; and repair quality inspection, etc.

[0045] The embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0046] First, based on the inspection results of the concrete tower surface spalling defects, the areas and extent requiring reinforcement were determined. Infrared thermal imaging and tapping methods were used to locate the boundaries between the spalling and hollow areas. Repair levels were classified according to the spalling area, depth, and hollow area, and a light-cured fiber cloth bonding scheme was then determined. Figure 2 As shown. The specific bonding scheme is as follows: A circumferentially laid UV-cured fiber cloth is prestressed, while a longitudinally laid UV-cured fiber cloth is not prestressed. The length of the fiber cloth is determined by the repair level and the extent of the detachment area. Figure 3 As shown. ① First layer: Circumferentially arranged prestressed light-cured fiber cloth. Light-cured fiber cloth is continuously pasted along the circumference of the tower, with the width exceeding the boundary of the detachment area by 150mm on each side. The length of the fiber cloth is adapted to the circumferential circumference of the detachment area on the tower surface. ② Second layer: Longitudinally arranged light-cured fiber cloth. Multiple longitudinal light-cured fiber cloths are pasted on top of the first layer of circumferential fiber cloth in a dense pattern. The spacing between the longitudinal prestressed light-cured fiber cloths is 200-300mm. The number of longitudinal prestressed light-cured fiber cloths is determined according to the length of the detachment. The length of the longitudinal light-cured fiber cloth exceeds the boundary of the detachment area on each side of the concrete tower surface by 300mm on each side. ③ Third layer: Circumferentially arranged prestressed light-cured fiber cloth. Similar to the first layer of circumferential fiber cloth, a circumferential overall wrapping reinforcement method is adopted, with the wrapping height being the same as the first layer of circumferential fiber cloth.

[0047] Centered on the area where the tower skin has detached, pre-treatment of the base surface is carried out within a 100-150mm radius. A high-pressure water jet (pressure ≥50MPa) is used to clean the concrete surface, removing dust, oil, loose concrete, and other impurities, clearing away the failed concrete layer to a solid base. Then, a grinding tool is used to grind the concrete base surface around the detached area until fresh aggregate is exposed, making it smooth and rough to enhance the adhesion between the UV-cured fiber cloth and the concrete. After treatment, the surface roughness is tested with a roughness meter, requiring Ra≥80μm. Finally, the surface is cleaned with a high-pressure water gun and then dried completely using a hot air gun or by natural air drying, with a moisture content ≤8%.

[0048] A fiber Bragg grating sensor is bonded to the middle area of ​​the photocurable fiber cloth using a photocurable adhesive. For example... Figure 4As shown, the sensor is positioned at the intersection of the circumferential and longitudinal fiber cloths, as well as at the midpoint of the longitudinal fiber cloth. The sensor is 100mm long, with 50mm on each side of the center of the detachment area.

[0049] Before bonding, the photocurable fiber cloth is pretreated by applying a suitable photosensitive wetting agent to its surface to improve the interfacial bonding performance between the fiber cloth and the photocurable resin. The fiber Bragg grating sensor is placed on the central photocurable fiber cloth and firmly bonded using a photocurable adhesive. The wetting adhesive for both the photocurable fiber cloth and the fiber Bragg grating sensor is a photocurable modified epoxy acrylate resin with a viscosity of 1500-2500 mPa·s (25℃). After curing, the shear strength is not less than 20 MPa, and the bond strength loss rate is required to be no more than 5% at -40℃. The thickness of the photocurable adhesive layer is 1.5-2.0 mm, and the UV curing time is ≤3 minutes.

[0050] Prestressed, light-cured wedge-shaped anchors are installed on the surface of the tower to apply fixation, such as... Figure 5 As shown. The photocured wedge anchor is made of translucent engineering plastic or glass fiber reinforced composite material, consisting of an anchor ring and wedge-shaped clips. The anchor ring wall thickness is ≥8mm, the clamping force is ≥30kN, and the slippage is ≤0.05mm. The wedge-shaped clips are 40mm wide (width of the photocured fiber cloth + 20mm) long and have a wedge angle of 10°-15°. For schemes requiring the bonding of multiple layers of prestressed photocured fiber cloth, each layer of anchor is used as a set, with the bottom layer on the outermost side of the detachment area and the top layer on the innermost side. Before bonding the anchors, the concrete surface is ground and cleaned. The adhesive used is a photocured modified epoxy resin with a viscosity of 2500-3000 mPa·s, a shear strength of not less than 25MPa, a layer thickness of 1.5-2.0mm, a bond strength loss rate of no more than 5% at -40℃, and a UV curing time of ≤3 minutes.

[0051] Use a clean, small brush to lightly brush the surface to remove dust again. Apply a UV-cured penetrating interface sealant to the pretreated substrate. The sealant viscosity should be ≤500 mPa·s. Apply using airless spraying or roller coating to ensure even coverage of the substrate and the micropores. Then, use a brush to apply UV-cured resin adhesive to the area where the UV-cured fiber cloth is bonded. The cured resin adhesive should have a shear strength of not less than 20 MPa and a UV curing time of ≤5 minutes at 20℃.

[0052] Apply UV-cured resin adhesive to the bonding area, then use another clean brush to apply UV-cured resin adhesive to the bonding surface. The thickness of the bottom layer is 1.5-2.0 mm, and the thickness of the middle layer is 1.0-1.5 mm.

[0053] Tensioning equipment is used to tension the circumferentially prestressed photocurable fiber cloth. A prestress of 15%-25% of the ultimate tensile strength is slowly applied using the tensioning equipment. Tensioning is stopped once the preset value is reached, and the photocurable fiber cloth is tightly bonded to the tower surface. Then, ultraviolet light arrays are used for irradiation curing. The contact surface between the anchor and the fiber cloth is simultaneously photocured to form an integral anchoring structure. Figure 6 As shown.

[0054] The first layer of circumferential prestressed light-cured fiber cloth is pasted and cured by ultraviolet lamp array irradiation for ≤8 minutes.

[0055] Then stretch the second layer of longitudinal light-cured fiber cloth, attach it, and cure it with ultraviolet light for ≤10 minutes.

[0056] Further bond a third layer of circumferential prestressed light-cured fiber cloth, cure with ultraviolet light, and cure time ≤ 8 minutes.

[0057] The bonding quality between the photocured fiber cloth and the concrete was tested using an ultrasonic testing instrument. The area of ​​air bubbles did not exceed 1% of the bonded area. At the same time, the prestress loss of the prestressed photocured fiber cloth did not exceed 5% within 4 hours after curing.

[0058] A UV-cured polyurea elastomer protective layer is sprayed onto the surface of the UV-cured fiber cloth and the surface of the UV-cured wedge anchor. The thickness of the UV-cured polyurea elastomer protective coating is 1.5-2.5mm. Multiple layers are applied using a spraying method, with each layer immediately cured by UV irradiation. The curing time for a single layer is ≤5 minutes. The weather resistance rating of the protective layer is not lower than ASTM G154 standard, with a tensile strength ≥20MPa, elongation ≥300%, tear strength ≥50kN / m, no peeling or cracking after bending at -40℃, surface drying time ≤120s, and water absorption ≤5%. Figure 7 As shown.

[0059] The fiber optic grating sensor is connected to the intelligent monitoring module. The intelligent monitoring module monitors the deformation of the photocured fiber cloth in real time based on the fiber optic grating sensor, thereby assessing the reinforcement effect and the prestress state of the photocured fiber cloth. The intelligent monitoring module performs in-depth analysis and calculation on the data transmitted from the fiber optic grating sensor, accurately calculating the actual stress value borne by the photocured fiber cloth, and then comparing it with the initially set prestress value to clearly show the degree of deviation in the prestress state of the photocured fiber cloth. Through this method, the fiber optic grating sensor can achieve a refined evaluation of the full life cycle effect of photocured fiber cloth in repairing concrete, providing a "from detail to the whole" safety guarantee for wind power hybrid towers.

[0060] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for rapid repair of concrete towers using photocured fiber-reinforced composite materials, characterized in that, Includes the following steps: Step 1: Based on the area, depth, and extent of voids in the concrete tower skin of the hybrid tower wind turbine, assess the severity of the damage and select the corresponding photocured fiber reinforced composite repair solution according to the severity of the damage. Step 2: Pre-treat the detached area by removing the failed concrete layer down to a solid substrate to form a clean and active substrate. Step 3: Apply a light-curing penetrating interface sealant to the pretreated substrate and cure it with ultraviolet irradiation to form an interface sealing layer; Step 4: Lay a light-cured fiber-reinforced leveling material on the interface sealing layer, and cure it with ultraviolet irradiation to form a leveling layer; Step 5: Alternately lay photocured longitudinal fiber cloth and photocured circumferential prestressed fiber cloth on the leveling layer to form an orthogonal grid-shaped main reinforcement layer; apply photosensitive resin adhesive to the fiber cloth bonding area; install wedge-shaped anchors on the concrete surface of the tower according to the repair plan; tension the circumferential carbon fiber cloth; and use a mobile ultraviolet lamp array to perform in-situ irradiation curing to form a composite main reinforcement layer. Step 6: Embed a miniature fiber optic strain sensor in the main reinforcement layer. The miniature fiber optic strain sensor is connected to the wireless acquisition module to monitor the strain state of the reinforcement layer in real time. Step 7: Spray a UV-cured polyurea elastomer coating onto the outermost layer of the main reinforcement layer, and cure it with ultraviolet radiation to form a durable protective layer.

2. The method for rapid repair of concrete towers using photocured fiber-reinforced composite materials according to claim 1, characterized in that, In step 1, a combination of infrared thermal imaging and tapping method is used to assess the severity of the damage. The specific repair scheme for photocured fiber reinforced composite repair is as follows: For mild detachment (area ≤ 0.5 m², depth ≤ 5 mm), a single layer of circumferential prestressed photocured fiber cloth is used for reinforcement; for moderate detachment (area 0.5-2.0 m², depth 5-15 mm), a combination of longitudinal and circumferential prestressed photocured fiber cloth is used for reinforcement; for severe detachment (area ≥ 2.0 m², depth ≥ 15 mm), a composite of circumferential, longitudinal, and circumferential repair methods is used. The structural reinforcement, specifically the "longitudinal + circumferential prestressed light-cured fiber cloth" combined reinforcement, involves first laying and tensioning prestressed light-cured fiber cloth circumferentially along the tower, and then laying longitudinal light-cured fiber cloth axially along the tower, forming an orthogonal grid-like main reinforcement layer. The "circumferential + longitudinal + circumferential" composite structural reinforcement involves laying the first layer of circumferential prestressed light-cured fiber cloth, the second layer of longitudinal light-cured fiber cloth, and the third layer of circumferential prestressed light-cured fiber cloth sequentially from the inside out, forming a three-layer orthogonal composite main reinforcement layer.

3. The method for rapid repair of concrete towers using photocured fiber-reinforced composite materials according to claim 1, characterized in that, Step 2 specifically involves: using an infrared thermal imager to locate the boundary of the hollow area, using a tapping method to further confirm the detached and hollow areas, removing the failed concrete layer down to a solid base surface, and then performing high-pressure water jet treatment on the base surface to form a clean and active base surface with a roughness Ra≥80μm, thus creating the repair work area.

4. The method for rapid repair of concrete towers using photocured fiber-reinforced composite materials according to claim 1, characterized in that, In step 3, the photocurable penetrating interface sealant is a modified epoxy acrylate system or a polyurethane acrylate system, with a viscosity ≤500mPa·s, a penetration depth ≥5mm, a bond strength to concrete ≥3.0MPa after curing, an ultraviolet irradiation wavelength of 365-405nm, an irradiation intensity ≥50mW / cm², and an interface sealing layer thickness of 0.2-0.5mm after curing.

5. The method for rapid repair of concrete towers using photocured fiber-reinforced composite materials according to claim 1, characterized in that, In step 4, the leveling material is composed of photosensitive resin and chopped carbon fibers, and is formed by scraping. After curing by ultraviolet irradiation, a smooth stress transition layer is formed. The chopped carbon fibers in the photocurable fiber-reinforced leveling material have a length of 6-12 mm and a volume content of 1.0%-2.0%. The photosensitive resin matrix is ​​epoxy acrylate or polyurethane acrylate. After curing, the compressive strength is ≥80MPa, the flexural strength is ≥40MPa, and the bonding strength with the interface sealing layer is ≥2.5MPa. The thickness of a single layer of leveling layer does not exceed 10 mm. When laying multiple layers, the next layer can only be constructed after each layer has been cured.

6. The method for rapid repair of concrete towers using photocured fiber-reinforced composite materials according to claim 1, characterized in that, In step 5, the photocurable fiber cloth is a carbon fiber cloth pre-impregnated with photosensitive resin, with a single-layer thickness of 0.2-0.3 mm, tensile strength ≥3400 MPa, elastic modulus ≥240 GPa, resin content of 35%-45%, and a storage period of ≥6 months under light-proof conditions and at a temperature ≤25℃; after curing, the fiber volume content is ≥55%, and the interlaminar shear strength is ≥50 MPa; the circumferential fiber cloth is continuously laid along the circumference of the tower, with an overlap length ≥150 mm, and prestress is applied; the longitudinal fiber cloth is laid along the axial direction of the tower, with a spacing of 20 mm. The length of the wedge-shaped anchor is ≥300mm beyond the boundary of the detachment area. The anchor structure includes an anchor ring and a wedge-shaped wedge. The anchor ring wall thickness is ≥8mm, the clamping force is ≥30kN, and the slippage is ≤0.05mm. The length of the wedge-shaped wedge is the width of the fiber cloth + 20mm, the width is 40mm, and the wedge angle is 10°-15°. The contact surface between the anchor and the fiber cloth is coated with a light-curing adhesive and simultaneously light-cured to form an integral anchor structure. The outside of the anchor is covered with a weather-resistant stainless steel protective cover.

7. The method for rapid repair of concrete towers using photocurable fiber-reinforced composite materials according to claim 1, characterized in that, In step 6, the outer diameter of the miniature fiber optic strain sensor is ≤0.5mm, the center wavelength is 1525-1565nm, the strain measurement accuracy is ±1με, and the temperature compensation sensor is deployed simultaneously. The sensor is arranged at the intersection of the circumferential fiber cloth and the longitudinal fiber cloth, and at the mid-span of the longitudinal fiber cloth. It is fixed with light-curing adhesive, and the curing time is ≤2 minutes. The sensor is connected to the wireless acquisition module at the bottom of the tower through an optical cable. The acquisition module has the function of remote data transmission.

8. The method for rapid repair of concrete towers using photocured fiber-reinforced composite materials according to claim 1, characterized in that, In step 7, the photocurable polyurea elastomer coating is a two-component photocurable polyurea system with tensile strength ≥20MPa, elongation at break ≥300%, tear strength ≥50kN / m, salt spray resistance ≥2000h, no powdering or cracking after ≥1500h of accelerated aging, water absorption ≤5%, and UV curing depth ≥2mm. The coating is applied using an airless spraying device, with a single layer thickness of 0.5-1.0mm and multiple layers applied to the designed thickness. Each layer is immediately cured by UV irradiation after spraying.

9. The method for rapid repair of concrete towers using photocured fiber-reinforced composite materials according to claim 1, characterized in that, Ultraviolet irradiation is carried out using an ultraviolet lamp array. The ultraviolet lamp array uses LED light source with a power density of ≥100mW / cm², a lamp array width of 300-600mm, and a lamp array shape adapted to the curvature of the tower surface. The lamp array moving speed is ≤0.5m / min, and the distance between the lamp array and the construction surface is 50-150mm. The lamp array integrates a temperature sensor, which automatically reduces the power or stops irradiation when the surface temperature exceeds 60℃.

10. The method for rapid repair of concrete towers using photocured fiber-reinforced composite materials according to claim 1, characterized in that, After step 7 is completed, the repair quality is inspected: infrared thermal imaging is used to detect the adhesion between the coating and the base layer, and the debonded area does not exceed 2% of the total repair area; a pull-out tester is used to detect the coating adhesion, and the adhesion is ≥2.5MPa; the strain data of the repair layer is continuously monitored through a wireless acquisition module, and the initial strain value is used as the baseline value. Subsequent monitoring data are compared with the baseline value to evaluate the long-term condition of the repaired structure.

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