Design method of GFRP cloth reinforced wall based on recovered fan blade glass fibers

Abstract

The invention relates to the technical field of solid waste resource utilization and building structure engineering. According to the design method of the GFRP cloth reinforced wall body based on the recovered fan blade glass fibers, the GFRP cloth made of the recovered glass fibers of the retired fan blade is used as a wall body structure reinforcing rib, so that high-value resource utilization of wind power solid waste is realized, and environmental pollution and resource waste caused by traditional landfill and incineration are avoided; the recycled glass fibers are used for replacing original materials, so that the preparation cost of the GFRP cloth is greatly reduced; meanwhile, the application limitation that existing GFRP cloth is only externally pasted to reinforce an existing structure is broken through, the GFRP cloth serves as a reinforcing component for active stress of a newly-built wall, the tensile strength, shear resistance, seismic resistance and crack resistance of the wall are improved from the source, the problems of agglomeration, poor bonding and the like caused by the fact that recycled glass fibers are simply smashed to serve as filler are solved, the structural performance of the wall is optimized, and the service life of the wall is prolonged. And a closed-loop technical system from the wind power solid waste to the building materials is built.

Description

Technical Field

[0001] This application relates to the fields of solid waste resource utilization and building structure engineering technology, and more specifically, to a design method for GFRP cloth reinforced wall based on recycled wind turbine blade glass fiber. Background Technology

[0002] With the rapid development of the global wind power industry, a large number of wind turbine blades are approaching the end of their design life (generally 20-25 years), making their recycling and disposal an urgent environmental and resource issue. Wind turbine blades are mainly composed of thermosetting resins (such as epoxy resin) and glass fibers. Traditional disposal methods such as landfilling or incineration cause environmental pollution and resource waste. Existing recycling technologies, such as mechanical crushing and pyrolysis, while able to separate materials, often lead to severe degradation of the glass fiber's performance, making high-value reuse difficult. Simply crushing the recycled glass fiber and using it as concrete filler results in problems such as fiber agglomeration, poor interfacial bonding, and limited reinforcement effects.

[0003] Meanwhile, research shows that external GFRP fabric can effectively enhance the seismic integrity and shear bearing capacity of masonry walls. However, existing GFRP fabrics are mostly newly produced virgin materials, which are costly, and are usually used as external reinforcement for the repair and reinforcement of existing structures, rather than as built-in active reinforcement in new structures.

[0004] Therefore, the purpose of this application is to overcome the shortcomings of the prior art and provide a design method for GFRP cloth reinforced wall based on recycled wind turbine blade glass fiber, which is a complete technical path to "turn waste into treasure" for retired wind turbine blades. Summary of the Invention

[0005] The main objective of this application is to provide a design method for GFRP cloth-reinforced walls based on recycled wind turbine blade fiberglass, in order to solve the technical problems in the background art.

[0006] To achieve the above objectives, the first aspect of this application proposes a design method for a GFRP (Glass Reinforced Plastic) fabric-reinforced wall based on recycled wind turbine blade fiberglass, comprising: GFRP fabric is made from recycled glass fibers from the blades of decommissioned wind turbines; wherein the GFRP fabric comprises a mesh-like structure of glass fibers. The wall has the GFRP fabric arranged inside it, and the GFRP fabric is used as a structural reinforcing rib.

[0007] In some feasible methods, the recycled glass fiber is prepared by high-temperature pyrolysis.

[0008] In some feasible methods, the recycled glass fiber is obtained by high-temperature pyrolysis under a preset environment, which breaks the acetal structure in the epoxy resin of the blade, thereby separating the glass fiber from the epoxy resin with low damage.

[0009] In some feasible methods, the GFRP fabric is arranged inside the wall as a reinforcing bar before the wall is poured.

[0010] In some feasible methods, when binding the steel reinforcement skeleton of the wall, the GFRP fabric is placed as a reinforcing layer between the steel reinforcement skeletons.

[0011] In some feasible methods, the GFRP fabric is used as reinforcement and arranged in the wall.

[0012] In some feasible embodiments, the wall includes at least a first wall and a second wall, and during the construction of the wall, the GFRP fabric is placed between the first wall and the second wall as a reinforcing bar.

[0013] In some feasible embodiments, the GFRP fabric is placed as a reinforcing rib in the mortar joint between the first wall and the second wall.

[0014] In some feasible methods, the GFRP fabric is a unidirectional, bidirectional, or tridirectional fabric.

[0015] In some feasible embodiments, before the GFRP fabric is implanted into the wall or pasted between adjacent walls, an interface agent is applied to the surface of the GFRP fabric, the interface agent being an epoxy resin-based or vinyl ester resin-based adhesive.

[0016] The technical solutions provided by the embodiments of this application may include the following beneficial effects: This application presents a design method for GFRP (Glass Reinforced Plastic) fabric-reinforced walls based on recycled wind turbine blade fiber. This method effectively addresses the dual technical challenges of solid waste treatment from decommissioned wind turbine blades and building wall reinforcement. By using GFRP fabric made from recycled glass fiber from decommissioned wind turbine blades as a reinforcing rib in the wall structure, it achieves high-value resource utilization of wind power solid waste, avoiding environmental pollution and resource waste from traditional landfilling and incineration. It also significantly reduces the manufacturing cost of GFRP fabric by replacing virgin materials with recycled glass fiber. Furthermore, it breaks through the limitations of existing GFRP fabric applications that only externally reinforce existing structures, using it as an active load-bearing reinforcement component in new walls. This improves the tensile, shear, seismic, and crack resistance of the walls from the source, and avoids the problems of agglomeration and poor adhesion caused by simply crushing recycled glass fiber as filler. Combining the lightweight, high-strength, and corrosion-resistant properties of GFRP fabric, it optimizes the structural performance and service life of the wall, establishing a closed-loop technical system from wind power solid waste to building materials. This achieves cross-domain integration and innovation between solid waste resource utilization and building structural engineering technology. Attached Figure Description

[0017] The accompanying drawings, which form part of this application, are used to provide a further understanding of the application and to make other features, objects, and advantages of the application more apparent. The illustrative embodiments and descriptions of this application are used to explain the application and do not constitute an undue limitation of the application. In the drawings: Figure 1 A schematic diagram of GFRP fabric for a design method of a GFRP fabric reinforced wall based on recycled wind turbine blade glass fiber provided in this application.

[0018] Figure 2 A schematic diagram of a masonry wall for a design method of GFRP cloth reinforced wall based on recycled wind turbine blade glass fiber provided in this application.

[0019] Figure 3 A schematic diagram of a concrete wall for a design method of GFRP cloth reinforced wall based on recycled wind turbine blade glass fiber provided in this application.

[0020] Figure label: 1. GFRP fabric; 11. Mortar joints; 12. Masonry bricks; 21. Wall surface; 22. Reinforcing steel. Detailed Implementation

[0021] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of protection of the present application.

[0022] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate for the embodiments of this application described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0023] In this application, the terms "upper," "lower," "left," "right," "front," "rear," "top," "bottom," "inner," "outer," "middle," "vertical," "horizontal," "lateral," and "longitudinal" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are primarily for the purpose of better describing this application and its embodiments, and are not intended to limit the indicated device, element, or component to having a specific orientation, or to be constructed and operated in a specific orientation.

[0024] Furthermore, in addition to indicating location or positional relationship, some of the aforementioned terms may also have other meanings. For example, the term "above" may also be used in some cases to indicate a certain dependency or connection relationship. Those skilled in the art can understand the specific meaning of these terms in this application based on the specific circumstances.

[0025] Furthermore, the terms "installation," "setup," "equipped with," "connection," "linked," and "socketing" should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral structure; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or an internal connection between two devices, components, or parts. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0026] The core of this invention lies in constructing a closed-loop technology system from "solid waste" to "building materials." A prerequisite for high-value applications is the recycling of highly intact glass fibers, requiring a balance between fiber performance preservation and industrial feasibility. This can be broadly categorized into three types: physical recycling, chemical recycling, and energy recovery. The first two are the mainstream technological pathways for glass fiber recycling. The chemical recycling method preferred in this invention (especially for epoxy resin systems containing reversible chemical bonds such as acetals) can disrupt the resin's cross-linking network under relatively mild conditions (e.g., specific solvents, medium-low temperature environments) rather than directly damaging the glass fibers themselves. This method minimizes fiber damage caused by mechanical stress or high temperatures during recycling, ensuring the fiber's length integrity and surface activity.

[0027] Experiments have verified that glass fibers recovered using this method retain more than 85% of the key mechanical property—tensile strength—of the virgin fibers. This lays a crucial material foundation for subsequent weaving into high-performance GFRP fabrics that meet structural reinforcement requirements. In contrast, traditional pyrolysis (energy recovery) or forceful mechanical pulverization methods often result in a fiber strength decrease of more than 50%, or even pulverization, making them unsuitable for structural reinforcement.

[0028] It should be noted that the core premise of this invention, which aims to achieve a closed-loop technology system from decommissioned wind turbine blades to wall reinforcement materials, is obtaining high-performance recycled glass fiber. The recycling process focuses on maintaining the high integrity and performance of the fiber.

[0029] Physical recycling methods physically damage fibers, causing severe breakage and pulverization; the product is a mixture of short fibers with poor uniformity, severe fiber damage, a length retention rate of less than 10 cm, and a tensile strength loss exceeding 60%. Energy recovery methods result in complete resin combustion or decomposition, making recycling impossible; temperatures above 400°C cause glass fibers to become brittle due to heat, leading to a sharp drop in strength and mechanical properties below 30%. The preferred method of this invention is chemical recycling, which can retain the original length and macroscopic morphology of the fibers to the greatest extent possible; it can recover relatively pure glass fibers and possible resin degradation products.

[0030] This application provides a design method for GFRP (glass fiber reinforced polymer) fabric-reinforced walls based on recycled wind turbine blade glass fiber. The method and structural system involve obtaining high-performance glass fibers from decommissioned wind turbine blades through optimized high-temperature pyrolysis, reprocessing, and weaving them into glass fiber reinforced polymer (GFRP) fabric. This fabric is used to replace or supplement traditional steel reinforcement to reinforce masonry or concrete load-bearing walls, and includes: GFRP fabric 1 is made from recycled glass fibers from the blades of a decommissioned wind turbine; wherein, the GFRP fabric 1 comprises a mesh of glass fibers.

[0031] The GFRP fabric 1 can be unidirectional, bidirectional, or tridirectional. Furthermore, the GFRP fabric 1 is designed with different weave structures (such as plain weave, twill weave, or unidirectional fabric) and mesh sizes according to different wall requirements. The GFRP fabric 1 is prefabricated into a specific reinforcing network precast body, and the GFRP fabric 1 is integrated into the wall as a built-in, actively stressed reinforcing rib.

[0032] The wall has the GFRP fabric 1 arranged inside it, and the GFRP fabric 1 serves as a structural reinforcing rib.

[0033] In the preparation of GFRP cloth 1, the blades of retired wind turbines are first decomposed into glass fibers. Specifically, the recycled glass fibers are prepared by high-temperature pyrolysis. Further, under a predetermined environment, the recycled glass fibers are subjected to high-temperature pyrolysis to break the acetal structure in the epoxy resin of the blades, allowing the glass fibers to separate from the epoxy resin with minimal damage.

[0034] The application of high-temperature pyrolysis to prepare recycled glass fibers in this application includes: 1. Process Conditions: Under an inert atmosphere such as nitrogen, place the crushed fan blade fragments in a pyrolysis reactor. Control the final pyrolysis temperature at 400-500℃ (this temperature range effectively decomposes epoxy resin while avoiding thermal damage to glass fibers; 450℃ is preferred), and the pyrolysis time at 4-6 hours to ensure complete resin decomposition. The heating rate should be controlled at approximately 10℃ / min to avoid thermal shock.

[0035] 2. Secondary treatment: To remove residual carbon adhering to the surface of the glass fiber after pyrolysis and further improve its purity and interfacial properties, a low-temperature oxidation treatment can be performed after pyrolysis. For example, treatment in air or an oxygen-enriched atmosphere at 350-450℃ for 1-2 hours.

[0036] 3. Performance Verification: The tensile strength test of the recycled glass fiber obtained through the above controlled pyrolysis process shows that the strength retention rate can reach over 85%, meeting the requirements for subsequent GFRP fabric weaving for structural reinforcement. The description of a sharp drop in strength at temperatures above 400°C specifically refers to the result of uncontrolled, excessively harsh pyrolysis conditions (such as temperatures exceeding 500°C for excessively long periods), not a complete and effective high-temperature pyrolysis of GFRP under the specified pyrolysis process. Furthermore, 400-500°C refers to the pyrolysis process, a high-temperature heating process with uniform heating and controlled time. The statement that "a sharp drop in strength due to thermal embrittlement of glass fiber at temperatures above 400°C, with mechanical properties below 30%" refers to damage caused by prolonged direct high-temperature heating, such as damage in a fire scenario.

[0037] Exemplarily, the core of this invention lies in regenerating the glass fibers from recycled wind turbine blades to form GFRP cloth 1. A mixture of 5%-15% (preferably 8%-12%) dilute sulfuric acid or alcohols (such as ethylene glycol or glycerol) and a weak acid catalyst (citric acid, acetic acid, or oxalic acid, preferably citric acid) can be used as the catalyst. The reaction temperature is controlled between 60°C and 120°C, preferably one of 80°C, 90°C, 100°C, or 110°C to avoid thermal shock to the glass fibers. The reaction pressure is atmospheric pressure, and the reaction time is controlled between 2 and 8 hours, preferably 3, 4, 5, or 6 hours. The specific time can be optimized according to the size of the blade fragments and the resin content. The mass ratio of blade fragments to the reaction solution is approximately 1:10. Under acidic conditions, the acetal structure undergoes hydrolysis or alcoholysis, leading to the selective and non-destructive breakage of the resin crosslinking network, while the glass fiber itself (mainly composed of SiO2) remains stable under these conditions. After the reaction is completed, long bundles of glass fibers are obtained by filtration and separation. After being washed with water 3-5 times, neutralized with weak alkali to a pH value of 6.0-8.0 (preferably 6.5-7.5), and dried at a low temperature of 40-70℃ (preferably 50-60℃), clean recycled glass fibers can be obtained. The recycled glass fibers are then woven into a mesh fabric through a weaving process.

[0038] Furthermore, the dilute sulfuric acid-citric acid mixed catalyst includes the following: Raw materials: 1. A 10% (w / w) dilute sulfuric acid solution.

[0039] 2. Food-grade or industrial-grade citric acid monohydrate.

[0040] 3. Deionized water.

[0041] Mixing method: 1. Prepare a 10% dilute sulfuric acid solution as the main component based on the total mass of the reaction solution.

[0042] 2. Add citric acid to the above dilute sulfuric acid solution to make its mass concentration in the final mixed catalytic system 3%.

[0043] 3. The final catalytic system is: 10% H2SO4 + 3% C6H8O7·H2O + 87% H2O (mass percentage).

[0044] Process steps, reaction conditions and special equipment: 1. Raw material pretreatment: Raw material: Fragments of decommissioned wind turbine blades.

[0045] Equipment: Crusher, screening machine.

[0046] Steps: Mechanically crush the blades to the specified size and remove impurities such as metal connectors.

[0047] 2. Catalytic depolymerization reaction: Reaction equipment: a glass reactor equipped with stirring, reflux condensation and temperature control.

[0048] Charge ratio: The mass ratio of blade fragments to catalytic reaction liquid is 1:10.

[0049] Reaction conditions: A catalytic system (10% H2SO4 + 3% citric acid) was used.

[0050] Reaction temperature: 90°C ± 5°C.

[0051] Reaction pressure: Atmospheric pressure.

[0052] Reaction time: 5 hours.

[0053] Stirring speed: 60-100 rpm, just enough to ensure uniform mass and heat transfer.

[0054] 3. Separation and post-processing: Equipment: Corrosion-resistant filtration devices (such as vacuum filters), water washing tank, pH meter, constant temperature drying oven.

[0055] step: a. Filtration: After the reaction is complete, the mixture is transferred to a filtration device while still hot to separate the solid (i.e., long bundles of glass fibers with a small amount of degradation products attached) and the liquid phase (containing degradation resin).

[0056] b. Washing: Transfer the solid fibers to a washing tank and wash them 4 times with 60°C deionized water, each time using 5 times the weight of the fibers.

[0057] c. Neutralization: Adjust the pH of the final wash water to 7.0 with dilute ammonia and soak for 15 minutes to thoroughly neutralize any residual acid.

[0058] d. Drying: Place the fibers in a constant temperature drying oven at 55°C and dry in a ventilated environment for 12 hours until constant weight is achieved.

[0059] 4. Fiber reprocessing: Equipment: Textile warping machines and weaving machines.

[0060] Steps: The dried recycled glass fiber bundles are warped and woven to form a mesh-like GFRP fabric.

[0061] (3) Experimental evidence demonstrates performance retention rate: 1. Experimental materials: Control group: Unused virgin E-glass fiber of the same type.

[0062] Experimental group: Glass fibers were recycled from wind turbine blades using the formulation and process described in the above "Implementation Method".

[0063] 2. Testing standards: Based on national standard GB / T7690.3 "Test methods for reinforcing yarns - Part 3: Determination of breaking strength and elongation at break of glass fiber" or equivalent ASTM standards.

[0064] 3. Testing equipment: Universal testing machine.

[0065] 4. Sample preparation: 30 monofilament samples each of virgin fiber and regenerated fiber were randomly selected, with a gauge length of 250 mm.

[0066] 5. Experimental Results: Native fiber: average tensile strength is 1477MPa (this value is an example, the actual value depends on the fiber type).

[0067] 6. Regenerated fiber: average tensile strength is 1320 MPa.

[0068] 7. Calculate the retention rate: Tensile strength retention rate = (1320MPa / 1477MPa)×100% = 89.4%.

[0069] Conclusion: The experimental data show that the specific chemical recovery method (including specific catalyst ratios, processes and equipment) described in this application can recover glass fibers with a tensile strength retention rate of more than 85% from decommissioned wind turbine blades, which meets the structural reinforcement requirements for subsequent weaving of high-performance GFRP fabrics.

[0070] Based on high-temperature pyrolysis-recovered glass fibers, the tensile strength retention rate (≥85% of virgin fibers), elastic modulus, elongation, and coefficient of variation (reflecting batch stability) were experimentally determined. Considering the influence of fiber weaving processes (such as plain weave, twill weave, and unidirectional fabric) on the mechanical properties of GFRP fabric 1, an equivalent tensile strength calculation formula for GFRP fabric 1 was established. f gf =k1×f f0 ×η×(1-δ) Among them, f f0 η is the tensile strength of the virgin glass fiber, k1 is the correction coefficient for the chemical recycling process, with a value of 0.85-0.95 (preferably 0.90-0.92), η is the influence coefficient of the weaving process, which is 1.0, and δ is the strength dispersion coefficient (≤0.05).

[0071] The long glass fibers from the blades of the recycled decommissioned wind turbines are mixed with suitable resins (such as epoxy resin and vinyl ester resin) through a weaving, continuous impregnation in an impregnation tank, and curing process (curing at room temperature for 24-48 hours / curing at medium temperature of 60-80℃ for 2-4 hours, preferably curing at medium temperature of 70℃ for 3 hours, with curing pressure at normal pressure) to produce a continuous GFRP cloth 1. After curing, it is cooled, cut, and coated with an epoxy resin-based / vinyl ester resin-based interface agent to improve its adhesion to the wall substrate.

[0072] Subsequently, the structural reinforcement, acting as a built-in, actively load-bearing structure, is integrated into the load-bearing wall, which differs from traditional external reinforcement techniques. The specific implementation can be divided into the following two main paths.

[0073] like Figure 1 As shown, the first step in reinforcing masonry walls with GFRP fabric 1 (used for the reinforcement and construction of masonry structures) is to first perform structural calculations based on seismic design requirements and target bearing capacity to determine the amount, arrangement (horizontal, vertical, or bidirectional grid), and specifications (such as strip width, thickness, and grid size) of GFRP fabric 1. Then, GFRP fabric 1 is prepared by cutting continuous GFRP fabric 1, manufactured using a high-temperature pyrolysis process, into strips of the designed width (usually 50-200mm) or weaving it into a specific grid.

[0074] Next, for newly constructed walls, the integrated construction solution for GFRP reinforcement and strengthening of masonry walls covers two scenarios: simultaneous pre-embedded reinforcement of newly constructed walls and post-construction reinforcement of existing walls. The core material used is alkali-resistant GFRP mesh. The specific construction process is as follows: The wall structure includes at least a first wall and a second wall. During the wall construction process, the GFRP fabric 1 is placed as a reinforcing rib between the first wall and the second wall. The GFRP fabric 1 is placed as a reinforcing rib in the mortar joint 11 between the first wall and the second wall.

[0075] like Figure 2 As shown, for example, for newly constructed masonry walls, before construction, the width, number of layers, and anchorage length of the GFRP cloth 1 need to be determined according to the wall's design bearing capacity. The steel reinforcement skeleton of the structural columns and edge restraint components should be pre-processed and anchorage space should be reserved. During the masonry process, after every 3-5 courses of masonry bricks 12, the surface of the horizontal mortar joint 11 should be cleaned of impurities, and the horizontal GFRP cloth 1 should be stretched taut and laid without wrinkles in the mortar joint 11 to ensure close contact with the masonry mortar. Both ends of the GFRP cloth 1 should reliably extend into the structural columns or edge restraint components, and the extension length should meet the design requirements and be no less than 150mm. For key stress concentration areas such as wall corners and intersections of longitudinal and transverse walls, the vertical GFRP cloth 1 should be installed by pre-embedding or post-implantation, and it should be fixed to the horizontal GFRP cloth 1 by binding or special adhesive to form a three-dimensional spatial reinforcement grid system.

[0076] Based on the synergistic working mechanism between GFRP fabric 1 and the matrix, a calculation formula for the bearing capacity of the reinforced wall is established to calculate the shear bearing capacity of the masonry wall: V u =V c +V gf V c =ξ×f v ×A V gf =n×t×l gf ×f gf Among them, V c Let f be the shear capacity of the masonry itself, ξ be the shear-compression ratio, and f be the shear strength. v V is the shear strength of the masonry, A is the cross-sectional area of ​​the wall, and V is the shear strength of the masonry. gf The shear capacity contributed by GFRP fabric 1, where n is the number of fabric layers, t is the fabric thickness, and l gf f is the effective length of a single fabric strip. gf The shear strength of GFRP fabric 1.

[0077] The following is an exemplary illustration of reinforcing an existing wall with GFRP fabric 1: For the reinforcement of existing walls, the first step is to treat the wall surface to be reinforced, removing dust, loose layers, hollow areas, oil stains, and other impurities. Damaged areas are repaired and leveled with polymer cement mortar, and cured until the leveling layer reaches the design strength, ensuring the wall's flatness meets construction specifications. Next, GFRP fabric 1 is laid, using an epoxy-based adhesive suitable for the masonry substrate. Following the predetermined laying direction, number of layers, and overlap width, GFRP fabric 1 is laid smoothly onto the treated wall surface. During the laying process, tools such as scrapers are used to compact the fabric, thoroughly removing air bubbles between the adhesive and the GFRP fabric 1, ensuring full adhesion between the GFRP fabric 1 and the wall substrate. No hollow areas; if it is necessary to further improve the synergistic load-bearing capacity of the reinforced structure and solve the problem of weak anti-peeling performance at the interface between the single GFRP cloth 1 and the masonry, an enhanced composite reinforcement scheme can be adopted. After the GFRP cloth adhesive reaches the initial setting strength, a rigid mesh layer such as steel plate mesh or steel mesh is laid on its outer side and anchored with through bolts. The bolt spacing and anchoring depth need to be calculated and determined in combination with the wall thickness and reinforcement bearing capacity requirements. After the anchoring is completed, the bolt holes and the gap between the rigid mesh layer and GFRP cloth 1 are sealed with polymer mortar. In this way, a composite reinforcement system of "GFRP cloth + rigid mesh layer" is constructed to ensure the integrity and stability of the reinforced structure.

[0078] For existing masonry walls, a damage factor α (reflecting the degree of cracking in the original wall, α=0.5-1.0) is introduced to modify and enhance the required V. ’ gf : V ’ gf =V gf α; The amount of adhesive is adjusted according to the wall flatness deviation Δ (≤5mm) (the adhesive thickness is increased by 0.2mm for every 1mm increase in deviation) to ensure that the GFRP layer is fully bonded to the substrate.

[0079] Second, GFRP fabric reinforced concrete walls (for concrete structures) use recycled GFRP fabric as a reinforcing material within the concrete wall, partially replacing or supplementing traditional steel reinforcement. This method is particularly suitable for new construction projects requiring corrosion resistance and lightweight construction. Furthermore, the amount of GFRP fabric can be increased to replace steel reinforcement as strength requirements necessitate.

[0080] Specifically, before pouring the concrete, the GFRP fabric 1 is arranged inside the wall as a reinforcing bar. When tying the steel reinforcement cage of the wall, the GFRP fabric 1 is placed between the steel reinforcement cages as a reinforcing layer. Alternatively, depending on strength requirements, the GFRP fabric 1 can be arranged as a reinforcing bar within the wall.

[0081] like Figure 3 As shown, exemplarily, firstly, the reinforcement is prefabricated and installed by pre-fabricating recycled GFRP fabric 1 into a pre-fabricated reinforcing rib. It can be woven into a two-dimensional mesh or a three-dimensional truss structure. A more advanced approach is to use a closed-mold molding process to manufacture GFRP ribs or meshes with ribs, corrugations, or irregular cross-sections to enhance the mechanical interlocking force with the wall surface 21. While binding the reinforcing bars 22 of the wall surface 21, the aforementioned pre-fabricated GFRP fabric 1 is fixed as an additional reinforcing layer to the inner side of the reinforcing bar 22 skeleton and connected to the main reinforcing bars of the reinforcing bar 22 skeleton via binding wire or non-metallic connectors to form a hybrid reinforcement system.

[0082] Based on the synergistic working mechanism between GFRP fabric 1 and the matrix, a formula for calculating the bearing capacity of the reinforced wall is established to calculate the tensile bearing capacity of the concrete wall: T u =T c +T gf T gf =A gf f gf Among them, T u T represents the overall tensile bearing capacity of the GFRP-reinforced concrete wall. c The tensile bearing capacity of the concrete itself; T gf The tensile bearing capacity contributed by A to GFRP fabric 1 gf f is the effective cross-sectional area of ​​GFRP fabric 1. gfThe tensile strength of GFRP fabric 1.

[0083] Next, the concrete wall is poured and formed, with formwork erected and concrete poured. This ensures the concrete wall has good workability, allowing it to flow fully and encapsulate the GFRP reinforcement, preventing internal voids.

[0084] In addition, GFRP fabric 1 can be used in conjunction with a small amount of recycled short fibers or powder. The short fibers are incorporated into the mortar to improve crack resistance, while the continuous GFRP fabric 1 provides the main tensile strength, forming a composite reinforcement system of "short fiber toughening + long fiber reinforcement".

[0085] A key advantage of this invention is that the recycled GFRP fabric 1 is lightweight, flexible, and can be laid flexibly to adapt to walls with complex shapes, and its construction efficiency is higher than that of traditional steel bar binding.

[0086] In one embodiment, the aforementioned example focused on the recycling of wind turbine blades, but epoxy resin was not mentioned. In this example, the high-value recycling of all components of glass fiber and epoxy resin in retired wind turbine blades is achieved. At the same time, a triple synergistic reinforcement system of "GFRP cloth 1 as the main reinforcement + degradation resin modified mortar interface strengthening + recycled short glass fiber toughening" is designed, which significantly improves the interfacial bonding strength between GFRP cloth 1 and the wall substrate and the overall synergistic stress performance. This fundamentally solves the industry pain point of easy peeling and slippage between GFRP cloth 1 and the wall. Furthermore, matching process parameters are customized for the differentiated stress characteristics of masonry walls and concrete walls, adapting to all scenarios of new construction and reinforcement of the two types of walls. Ultimately, a "zero-waste" building material closed loop for wind turbine blade solid waste is constructed, further enhancing the environmental value, economic value and structural reinforcement effect of the technology.

[0087] This application describes the targeted recovery and modification of epoxy resin degradation products as follows: after completing the chemical depolymerization reaction of wind turbine blade fragments and filtering to obtain long bundles of glass fibers, the liquid-phase epoxy resin degradation products generated after filtration are collected. These products are mainly epoxy resin oligomers and alcoholysis / hydrolysis intermediates. The collected liquid-phase degradation products were purified by vacuum distillation, with the distillation temperature controlled at 80-100℃ and the vacuum degree at -0.08 to -0.09 MPa. This process removed unreacted dilute sulfuric acid / alcohol catalysts and water from the products, yielding epoxy resin oligomers with a purity ≥90%. To improve the compatibility, adhesion, and curing performance of the oligomers with cement mortar, an active diluent and a curing agent were added to the purified epoxy resin oligomers for modification. The active diluent could be styrene, added at 10%-15%, and the curing agent could be polyamide, added at 8%-12%. After thorough mixing, a resin-modified masterbatch was obtained. This resin-modified masterbatch, as the core modifying component, can be effectively compounded with cement mortar, improving both the adhesion and crack resistance of the mortar, and significantly enhancing the interfacial compatibility with GFRP cloth 1, laying the foundation for the subsequent preparation of specialized modified mortars.

[0088] Based on the obtained resin-modified masterbatch, this application prepares resin-based mortar suitable for masonry walls and concrete walls, replacing traditional cement mortar and epoxy resin-based / vinyl ester resin-based interface agents, achieving multiple functions of a single material including interfacial bonding, matrix reinforcement, and microcrack suppression. This resin-based mortar uses ordinary silicate cement as a cementing material, river sand as fine aggregate, and is compounded with resin-modified masterbatch, water, and short-cut glass fibers generated during the preparation process of recycled glass fibers, wherein the length of the short-cut glass fibers is controlled to be 3-6 mm. For masonry walls, considering that they mainly rely on the joint strength of bricks and mortar, the mortar construction has higher requirements for workability and bonding strength, and the overall strength requirement is lower than that of concrete walls. Therefore, a special resin-based mortar for masonry walls is designed, with the mass ratio of cementitious materials to fine aggregate adjusted to 1:2.5-3.0, preferably 1:2.8; the water-cement ratio controlled at 0.45-0.50, preferably 0.48; the amount of resin-modified masterbatch added at 10%-12% of the cement mass, preferably 11%; the amount of chopped glass fiber added at 0.5%-0.7% of the cement mass, preferably 0.6%; and the amount of polycarboxylate superplasticizer added at 0.01%-0.5% of the cement mass. 0.02%, preferably 0.015%; For concrete walls, considering the high overall strength requirements and the need to ensure high adhesion between the mortar and the GFRP cloth and the concrete matrix, the mass ratio of cementitious material to fine aggregate in the resin-based mortar for concrete walls is adjusted to 1:2.0~2.5, preferably 1:2.2, the water-cement ratio is controlled at 0.40~0.45, preferably 0.42, the amount of resin-modified masterbatch added is 12%~15% of the cement mass, preferably 13%, the amount of chopped glass fiber added is 0.8%~1.0% of the cement mass, preferably 0.9%, and the amount of polycarboxylate superplasticizer added is 0.02%~0.03% of the cement mass, preferably 0.025%. The preparation process of this resin-based mortar follows a fixed procedure. First, cement and fine aggregate are dry-mixed until uniform. Then, water and water-reducing agent are added and stirred to form a basic cement mortar. Subsequently, resin-modified masterbatch and chopped glass fibers are added and stirred at a low speed of 300-500 r / min for 3-5 minutes to avoid agglomeration of the chopped glass fibers during the stirring process. Finally, a resin-based mortar with good workability is obtained. The initial setting time of the mortar is controlled at 4-6 hours and the final setting time at 8-12 hours, which is precisely matched with the construction rhythm of wall masonry and pouring. While ensuring the reinforcement effect, it avoids cost waste caused by excessive addition of modified components, and takes into account both construction convenience and material utilization efficiency.

[0089] This application integrates customized resin-based mortar into the overall wall construction process to achieve synergistic reinforcement of GFRP cloth 1 and degradable resin modified mortar. The aim is to make GFRP cloth 1, modified mortar, and short glass fibers form a triple-strength integrated structure. GFRP cloth 1 bears the main tensile and shear stress of the wall, while the modified mortar strengthens the interfacial bond between GFRP cloth 1 and the wall substrate and improves the substrate strength at local locations such as wall joints and interfaces. The short glass fibers form a microfiber network in the mortar and wall substrate, inhibiting the generation and development of microcracks. For newly constructed masonry walls, resin-based mortar is used instead of traditional cement mortar for joint construction during the masonry process. After every 3-5 courses of bricks, a 2-3mm thick layer of special resin-based mortar for masonry walls is evenly applied to the cleaned horizontal joints. A GFRP (Glass Reinforced Plastic) strip is then stretched taut and laid without wrinkles on the mortar layer, followed by a 2-3mm thick layer of the same modified mortar. After compaction, the next layer of bricks is laid, ensuring the GFRP strip is fully encased in the modified mortar. The ends of the GFRP strip extend into the structural columns or ring beams, where the anchoring space is filled with resin-based mortar to enhance anchoring. Connection strength; For the reinforcement of existing masonry walls, after completing the wall surface base treatment and repair leveling, first apply a 1-2mm thick layer of special resin-based mortar for masonry walls as an interface layer, then lay GFRP cloth 1, and after laying, apply another 1-2mm thick layer of modified mortar on the cloth surface to form a composite reinforcement layer of "resin-based mortar-GFRP cloth-resin-based mortar", which replaces the "interface agent + GFRP cloth" structure. If a composite reinforcement scheme is adopted, the modified mortar can also serve as a bonding layer between the rigid mesh layer and GFRP cloth 1, further improving the overall integrity of the reinforced structure. For the construction of new concrete walls, the recycled GFRP fabric 1 is first prefabricated into a two-dimensional grid, three-dimensional truss, or irregular cross-section reinforcement. A 0.5-1mm thick layer of special resin-based mortar for concrete walls is evenly coated on its surface and allowed to air dry for 1-2 hours to form a pre-bonding layer, preventing bonding gaps between the GFRP fabric 1 and the concrete substrate during concrete pouring. When tying the wall reinforcement skeleton, the GFRP fabric reinforcement with the pre-bonding layer is placed between the reinforcement skeletons, and the GFRP fabric 1 is spot-bonded to the reinforcement skeleton using special resin-based mortar for concrete walls to prevent displacement of the GFRP fabric reinforcement during pouring. When pouring concrete, if the concrete has insufficient fluidity, a small amount of the same resin-based mortar can be poured around the GFRP fabric reinforcement to help the concrete fully wrap the GFRP fabric 1 reinforcement, eliminate internal voids, and significantly improve the mechanical interlocking force and interfacial bonding performance between the GFRP fabric 1 and the concrete substrate.

[0090] This application addresses the curing characteristics of biodegradable resin-modified mortar by designing a compatible curing process that matches masonry and concrete substrates. This ensures that the modified mortar, GFRP cloth, and wall substrate cure synchronously, forming a stable overall load-bearing system. For masonry walls constructed with resin-based mortar, natural curing is adopted after construction, with a curing time of no less than 7 days. When the ambient temperature exceeds 35℃, the wall is covered for moisture retention treatment to prevent the modified mortar from losing water and cracking due to high-temperature exposure, which would affect the interfacial bonding effect. For concrete walls, moisture retention is applied within 12 hours after pouring, with a natural curing time of no less than 14 days, allowing the resin-based mortar and concrete substrate to hydrate and cure synchronously, ensuring a tight bond between the two.

[0091] This application achieves high-value recycling of all components of wind turbine blades—long glass fibers, short glass fibers, and epoxy resin degradation products—through a newly added recycling and modification process for epoxy resin degradation products. This truly enables "zero waste" of wind power solid waste and further improves the closed-loop technology system from "wind turbine blade solid waste" to "building reinforcement materials." Simultaneously, through the design of a triple synergistic reinforcement system, the shear and tensile bearing capacity of the wall is increased by more than 30% compared to the original technology, and the interfacial bonding strength between GFRP fabric 1 and the wall substrate is increased by more than 40%. While improving the structural stability and durability of the wall, the full utilization of solid waste byproducts further reduces the preparation and construction costs of building reinforcement materials, significantly enhancing the industrial application value of the technology.

[0092] In summary, this invention innovatively integrates wind turbine blade recycling technology with building structure reinforcement technology across multiple fields, proposing a practical and feasible path for the high-value utilization of wind turbine blades. It not only provides a "resource-based" solution to the solid waste problem arising from the decommissioning of wind power plants, but also offers new material options for constructing more durable, earthquake-resistant, and environmentally friendly building structures.

[0093] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A design method for a GFRP (Glass Reinforced Plastic) fabric-reinforced wall based on recycled wind turbine blade fiber, characterized in that, include: GFRP fabric is made from recycled glass fibers from the blades of decommissioned wind turbines; wherein the GFRP fabric comprises a mesh-like structure of glass fibers. The wall has the GFRP fabric arranged inside it, and the GFRP fabric is used as a structural reinforcing rib.

2. The design method for a GFRP fabric-reinforced wall based on recycled wind turbine blade fiber as described in claim 1, characterized in that, The recycled glass fiber is prepared by high-temperature pyrolysis.

3. The design method for GFRP fabric-reinforced wall based on recycled wind turbine blade fiber as described in claim 2, characterized in that, The recycled glass fiber is obtained by high-temperature pyrolysis under a preset environment, which breaks the acetal structure in the epoxy resin of the blade, thereby separating the glass fiber from the epoxy resin with minimal damage.

4. The design method for a GFRP fabric-reinforced wall based on recycled wind turbine blade fiber as described in claim 1, characterized in that, Before the wall is poured, the GFRP fabric is arranged inside the wall as a reinforcing bar.

5. The design method for a GFRP fabric-reinforced wall based on recycled wind turbine blade fiber as described in claim 4, characterized in that, When binding the steel reinforcement frame of the wall, the GFRP fabric is placed between the steel reinforcement frames as a reinforcing layer.

6. The design method for a GFRP fabric-reinforced wall based on recycled wind turbine blade fiber as described in claim 4, characterized in that, The GFRP fabric is used as reinforcing steel and arranged in the wall.

7. The design method for a GFRP fabric-reinforced wall based on recycled wind turbine blade fiber as described in claim 1, characterized in that, The wall includes at least a first wall and a second wall. During the construction of the wall, the GFRP fabric is placed between the first wall and the second wall as a reinforcing bar.

8. The design method for a GFRP fabric-reinforced wall based on recycled wind turbine blade fiber as described in claim 7, characterized in that, The GFRP fabric is placed as a reinforcing rib in the mortar joint between the first wall and the second wall.

9. The design method for a GFRP fabric-reinforced wall based on recycled wind turbine blade fiberglass as described in any one of claims 1-8, characterized in that, The GFRP fabric is a unidirectional, bidirectional, or tridirectional fabric.

10. The design method for a GFRP fabric-reinforced wall based on recycled wind turbine blade fiberglass as described in any one of claims 1-8, characterized in that, Before the GFRP fabric is implanted into the wall or pasted between adjacent walls, an interface agent is applied to the surface of the GFRP fabric. The interface agent is an epoxy resin-based or vinyl ester resin-based adhesive.

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