Foam insulation board based on retired wind power blade recycled material and preparation method thereof

Abstract

This invention discloses a foam insulation board based on recycled materials from decommissioned wind turbine blades and its preparation method. The foam insulation board comprises the following raw material components in parts by weight: 1-2 parts foaming agent, 5-12 parts water-reducing agent, 450-750 parts recycled materials from decommissioned wind turbine blades, 600-800 parts cement, 180-500 parts water, 8-15 parts setting regulator, and 0.5-1.5 parts foam stabilizer; wherein the foaming agent is a high-molecular composite cement foaming agent, and the recycled materials from decommissioned wind turbine blades are a mixture obtained by cutting, crushing, pulverizing, and sieving waste wind turbine blades, with an average particle size of 0.50-4.50 mm. By using the method of this invention to prepare the foam insulation board, the accumulation of decommissioned wind turbine blades is reduced, the by-products of producing recycled fibers from decommissioned wind turbine blades are utilized, the insulation performance of the foam board is improved, the transportation cost of decommissioned wind turbine blades is reduced, and the commercial value of decommissioned wind turbine blades is increased.

Description

Technical Field

[0001] This invention belongs to the field of concrete building materials, specifically relating to a foam insulation board based on recycled materials from decommissioned wind turbine blades and its preparation method. Background Technology

[0002] Wind energy, as a clean and pollution-free renewable energy source, has a huge potential, and wind turbines are widely used. Currently, the treatment of wind turbine blades is to recycle and decompose them to produce recycled fibers and recycled powders. The usage of this part is small, while the utilization rate of the remaining large amount of epoxy resin and fiber mixture is low: (1) The recycling rate of epoxy resin is low, and the cost of recycling epoxy resin is high; (2) There is little research on the use of epoxy resin and fiber mixed particles in concrete, and it is still in the initial stage; (3) The composition of epoxy resin and fiber mixed particles is complex, and the bonding condition with cement needs to be studied. It is easy to generate voids, and the workability of concrete is poor.

[0003] Currently, recycling and reusing wind turbine blade fibers is the primary method of utilization. For example, thermochemical methods are used to decompose and recover the fibers, but these methods are costly, prone to producing toxic substances, and result in low fiber performance and low recycling rates. To address this issue, domestic and international scholars have further explored physical decomposition methods, hoping to decompose wind turbine blades more cheaply and safely. However, the recovery rate of these methods remains low, leaving a large amount of epoxy resin and fiber mixtures. Researching and utilizing these remaining materials will be a key driver for the recycling of retired wind turbine blades. For epoxy resin and fiber mixture particles, their size and morphology are complex, resulting in low utilization rates, and further recycling them into powder is costly and difficult. Therefore, this study considers replacing sand with these particles, leveraging their poor thermal conductivity, good sound insulation, and easy foaming properties to investigate their performance in concrete foam boards, thereby improving the thermal insulation and sound absorption performance of the insulation board.

[0004] Compared to traditional foamed concrete insulation boards, foamed insulation boards made from recycled decommissioned wind turbine blades offer advantages in environmental friendliness, insulation performance, stability, cost, durability, and regional adaptability. Using recycled materials from decommissioned wind turbine blades as the main raw material, these boards significantly reduce the consumption of byproducts from fiber production from waste wind turbine blades, minimizing the accumulation of epoxy resin and fiber mixtures and reducing reliance on natural resources, thus offering high environmental value. Furthermore, these boards are particularly suitable for exterior wall insulation in Northwest China, where the epoxy resin particles replacing sand improve frost resistance, making them more suitable for extremely cold regions. Summary of the Invention

[0005] To address the problems existing in the above-mentioned background technology, the present invention provides a foam insulation board based on recycled materials from decommissioned wind turbine blades and its preparation method, which reduces the accumulation of decommissioned wind turbine blades, utilizes the by-products of decommissioned wind turbine blades in the production of recycled fibers, improves the insulation performance of the foam board, reduces the transportation cost of decommissioned wind turbine blades, and increases the commercial value of decommissioned wind turbine blades.

[0006] To achieve the above-mentioned objectives, the present invention is implemented through the following technical solution: A foam insulation board based on recycled materials from decommissioned wind turbine blades comprises the following raw material components in parts by weight: 1-2 parts of foaming agent 5-12 parts of water-reducing agent 450-750 parts of recycled material from decommissioned wind turbine blades. 600-800 parts cement 180-500 parts water 8-15 parts of setting regulator, Foam stabilizer 0.5~1.5 parts, The foaming agent is a polymeric composite cement foaming agent with a pH of 7.5~10.0. As a pore creator and thermal insulation structure builder, it generates a large number of uniform and stable microbubbles during the mixing and pouring process. These bubbles are solidified in the cement paste to form a closed or interconnected pore structure, which is the decisive factor for the board to obtain a low thermal conductivity and achieve thermal insulation function. Precise control of its dosage is the key to balancing density, strength and thermal insulation performance. The recycled material of the decommissioned wind turbine blades is a mixture obtained by cutting, crushing, pulverizing and screening discarded decommissioned wind turbine blades, with an average particle size of 0.50~4.50mm. As a core lightweight aggregate and functional carrier, the recycled material of the decommissioned wind turbine blades has the characteristics of being lightweight, porous and organic-inorganic composite. It not only replaces traditional sand and gravel and significantly reduces the dry density of the board, but the residual resin and fiber network contained in it can also form a micro-reinforcement and crack-resistant effect in the slurry, improving the toughness and dimensional stability of the board.

[0007] Furthermore, the water-reducing agent described in this invention is a polycarboxylate high-efficiency water-reducing agent with a water reduction rate of 22%~25%. Under low water-cement ratio conditions, it can significantly disperse the fine powder on the surface of cement particles and recycled materials, releasing the encapsulated free water, thereby ensuring that the high-solids content slurry still has excellent fluidity and workability. At the same time, by reducing the actual water consumption, it reduces the macroscopic pores left by the evaporation of excess water after hardening, making the matrix more compact and indirectly improving the mechanical strength.

[0008] Furthermore, the setting regulator of this invention is a stearate, preferably any one or a mixture of two of calcium stearate and magnesium stearate. Its main function is to adjust the matching between the foaming process and the cement setting process, appropriately delaying or promoting the thickening rate of the slurry in the key stage, ensuring that air bubbles can be effectively introduced and stably exist in the slurry structure without escaping or collapsing. It is a key additive for achieving the controllability of the "foamable and easy-to-form" process.

[0009] Furthermore, the foam stabilizer described in this invention is a cellulose ether suitable for alkaline environments, preferably hydroxypropyl methylcellulose ether. Its core function is to reduce the surface tension of the slurry, increase the strength and elasticity of the foam walls, and effectively prevent the coalescence, coarsening, and rupture of bubbles during stirring, conveying, and the early stages of solidification. This is crucial for obtaining an ideal pore structure with fine pore size, uniform distribution, and high closed-cell ratio, directly determining the quality and uniformity of the insulation effect.

[0010] Furthermore, the cement described in this invention is PO 42.5 ordinary Portland cement with an average particle size of 12~36μm and a 28-day compressive strength of 46.2~53.2MPa. As the main cementitious component and structural framework, it provides the primary cementitious properties. After reacting with water, it forms products such as hydrated calcium silicate (CSH) gel, which encapsulate and solidify recycled materials and air bubbles, forming a rigid framework that supports the strength of the entire slab and ensures that the final product possesses the necessary mechanical properties.

[0011] Furthermore, the present invention also provides a method for preparing a foam insulation board based on recycled materials from decommissioned wind turbine blades, comprising the following steps: (1) Take samples of cement and recycled materials of decommissioned wind turbine blades according to the component content in the mix proportion, and pour them into a concrete planetary mixer for the first mixing to obtain the first mixture; (2) Add 2 / 3 of the weight of water, water-reducing agent and setting agent to the first mixture and stir for a second time to obtain the second mixture; (3) Dissolve the foaming agent in the remaining 1 / 3 of the weight of water, and add it together with the foam stabilizer to the second mixture for a third stirring to obtain a fresh concrete mixture based on recycled materials from decommissioned wind turbine blades; (4) Pour the fresh concrete mixture obtained in step (3) into a mold to obtain a standard test block for compressive strength, and then let it stand for foaming. That is, according to the "Standard for Test Method of Mechanical Properties of Ordinary Concrete" (GB / T 50081-2019), after standing at room temperature for 24 hours, the mold is removed. Then, it is cured under standard curing conditions of temperature of 20℃±2℃ and relative humidity of more than 95% until the test block reaches the specified age of 28 days, and the foam insulation board of the present invention is obtained. The compressive strength performance of the standard test block of the foam insulation board can be tested. This method is to foam by stirring and standing.

[0012] Preferably, the stirring speed of the first stirring in step (1) is 90~110 r / min, and the stirring time is 3~4 min; The stirring speed for the second stirring in step (2) is 110~130 r / min, and the stirring time is 2~3 min; The stirring speed for the third stirring in step (3) is 70~90 r / min, and the stirring time is 3~4 min; The mold size in step (4) is 1000mm×2000mm×500mm, and the standard test block size for compressive strength is 100mm×100mm×100mm.

[0013] Furthermore, the present invention also provides another method for preparing a concrete foam insulation board based on recycled materials from decommissioned wind turbine blades, comprising the following steps: (1) First, put cement, recycled materials of decommissioned wind turbine blades, half the weight of water, water-reducing agent and setting regulator into a mixer to make a concrete paste. (2) Add the foaming agent and foam stabilizer dissolved in the other half of the weight of water to the concrete paste obtained in step (1) and stir evenly; (3) Use foamed concrete equipment to stir the product of step (2) and inject air to generate bubbles and expand them. Foam at 5~10MPa high pressure. Adjust the amount of air injected, the amount of foaming agent, the stirring speed and the stirring time as needed to control the density and degree of foaming of the concrete. (4) Stop the mixer, pour the prepared foamed concrete into the mold, and let it stand until it is completely cured to obtain the foam insulation board.

[0014] Preferably, in step (1), the stirring speed of the stirrer is 100~110 r / min, and the stirring time is 3~4 min; In step (3), the amount of foaming agent must be 0.5% to 0.8% of the mass of half the weight of water. The foaming stirring speed is set to 1000 to 1200 r / min, the stirring time is 3 to 4 min, and gas is injected using an air compressor.

[0015] The above preparation method uses physical foaming. The foaming principle is to introduce air into the foaming agent solution and use high-speed rotating blades to introduce gas, which combines with the foaming agent to generate stable and dense bubbles in the concrete, thus hindering heat conduction.

[0016] The recycled material from decommissioned wind turbine blades introduced in this invention has a lower thermal conductivity than sand and a more stable adsorption capacity for air bubbles, which can improve the performance of foam and thus enhance the thermal insulation performance of foamed concrete. On one hand, the epoxy resin in the recycled material has a lower thermal conductivity than sand, replacing sand to reduce the overall thermal conductivity of foamed concrete and improve its thermal insulation capacity. On the other hand, the surface polarity of the epoxy resin in the recycled material allows for good adsorption of air bubbles introduced by the foaming agent, improving bubble stability and enhancing thermal insulation performance. Using a composite cement foaming agent and controlling the pH value between 7.5 and 10.0 can improve the adhesion of foam to the surface of the epoxy resin and fiber-mixed particles, making the foamed concrete structure denser, reducing crack formation, and improving stability and molding ability. Furthermore, utilizing recycled waste wind turbine blades reduces raw material costs and eliminates the need for complex recycling processes, further saving costs. Combining the foaming agent with a water-reducing agent lowers the water-cement ratio, improves foam stability and fluidity, makes the structure denser, reduces cracks, and improves durability indicators such as impermeability and frost resistance.

[0017] Compared with the prior art, the present invention has the following beneficial effects: (1) Combining foaming agent with water-reducing agent reduces the water-cement ratio, making the foam produced by foaming agent more stable; improves fluidity, making foamed concrete easier to flow and level during pouring; makes the structure more compact, reduces cracks, and improves its impermeability, frost resistance and other durability indicators.

[0018] (2) By using a stirring speed of 70~90r / min or by using foamed concrete equipment, the foaming agent can be better dispersed in the cement paste, which is conducive to forming a uniform bubble structure. The energy introduced during the stirring process can enable the foaming agent to form a stable interface film in the cement paste. This interface film wraps the bubbles and prevents the bubbles from merging and breaking. The above stirring speed can ensure that the foaming agent can play a full role in forming a stable interface film, and will not destroy it due to excessive stirring.

[0019] (3) The epoxy resin molecular structure in the recycled material of decommissioned wind turbine blades contains polar groups, such as hydroxyl and ether bonds, which makes the epoxy resin surface highly polar. The polar epoxy resin surface can interact with other polar or non-polar substances to form a strong bond. The polarity of the epoxy resin surface can produce good adsorption with the bubbles introduced by the foaming agent, thereby improving the stability of the foamed concrete bubbles and improving the thermal insulation performance of the foamed concrete.

[0020] (4) When composite cement foaming agents are used in cement, the pH value is controlled between 7.5 and 10.0, which reduces the corrosive ability of epoxy resin and improves the adhesion of foam to the surface of epoxy resin and fiber mixed particles, thereby improving the stability of foamed concrete and the molding ability of foam boards. Replacing sand with epoxy resin particles not only reduces the use of natural resources, but also consumes a large amount of by-products from the production of fibers from waste wind turbine blades, thus having good environmental value.

[0021] (5) The foamed slurry is lightweight and has a large difference in properties from cement slurry. Adding water in batches can fully dissolve and disperse the foaming agent, which helps to control the reaction rate and avoid local concentrations that are too high or too low, thereby ensuring the uniformity and stability of the foam. Adding water in batches can regulate the fluidity of the slurry, reduce the impact of stirring on the bubbles and prevent defoaming. At the same time, it can prevent the bubbles from breaking and unevenly dispersing due to the viscosity of the slurry being too high or too low.

[0022] (6) The foam insulation board is intended for use in exterior wall insulation in Northwest China. Replacing sand with epoxy resin particles from recycled materials of decommissioned wind turbine blades can improve frost resistance and make it more suitable for extremely cold regions. Foamed concrete is prone to shrinkage during the drying process, which can lead to internal stress concentration and cracks. The foam stabilizer provided by this invention, cellulose ether, is polar and more compatible with the type of epoxy resin, allowing the generated bubbles to be better adsorbed on the resin surface.

[0023] (7) The thermal conductivity of epoxy resin is between 0.2 and 2.2 W / mK, while that of sand is 0.58. Under the same conditions, the thermal conductivity of epoxy resin is lower than that of sand. Replacing sand with a mixture of epoxy resin and fiber can reduce the overall thermal conductivity of foamed concrete and improve its thermal insulation capabilities. The epoxy resin and fiber mixture particles in the recycled material of decommissioned wind turbine blades provided by this invention not only solve the problem of the difficulty in utilizing by-products of decommissioned wind turbine blades, but also have advantages in terms of environmental protection and sustainability. The application of epoxy resin and fiber mixture particles can effectively reduce the demand for natural resources and reduce environmental pressure. At the same time, the research and development and application of this foamed concrete provides technical support for the promotion of foamed concrete in Northwest China. Attached Figure Description

[0024] Figure 1 This is a schematic diagram illustrating the foaming principle during the preparation of foam insulation board in Embodiment 1 of the present invention.

[0025] Figure 2 This is a schematic diagram illustrating the foaming principle during the preparation of the foam insulation board in Embodiment 2 of the present invention. Detailed Implementation

[0026] The present invention will now be described in detail with reference to specific embodiments. These embodiments are implemented based on the technical solutions of the present invention, providing detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.

[0027] A foam insulation board based on recycled materials from decommissioned wind turbine blades comprises the following raw material components in parts by weight: 1-2 parts of foaming agent 5-12 parts of water-reducing agent 450-750 parts of recycled material from decommissioned wind turbine blades. 600-800 parts cement 180-500 parts water 8-15 parts of setting regulator, Foam stabilizer 0.5~1.5 parts, The foaming agent is a polymeric composite cement foaming agent with a pH of 7.5~10.0; The recycled material of the decommissioned wind turbine blades is a mixture obtained by cutting, crushing, pulverizing and screening discarded decommissioned wind turbine blades, with an average particle size of 0.50~4.50mm. The water-reducing agent is a polycarboxylate superplasticizer with a water reduction rate of 22%~25%; The setting regulator is stearate, preferably any one or a mixture of two of calcium stearate and magnesium stearate; The foam stabilizer is a cellulose ether suitable for alkaline environments, preferably hydroxypropyl methylcellulose ether; Furthermore, the cement described in this invention is PO 42.5 ordinary Portland cement with an average particle size of 12~36μm and a 28-day compressive strength of 46.2~53.2MPa.

[0028] A method for preparing a foam insulation board based on recycled materials from decommissioned wind turbine blades includes the following steps: (1) Take samples of cement and recycled materials of decommissioned wind turbine blades according to the component content in the mix proportion, and pour them into a concrete planetary mixer for the first mixing to obtain the first mixture; (2) Add 2 / 3 of the weight of water, water-reducing agent and setting agent to the first mixture and stir for a second time to obtain the second mixture; (3) Dissolve the foaming agent in the remaining 1 / 3 of the weight of water, and add it together with the foam stabilizer to the second mixture for a third stirring to obtain a fresh concrete mixture based on recycled materials from decommissioned wind turbine blades; (4) Pour the fresh concrete mixture obtained in step (3) into a mold to obtain a standard test block for compressive strength, and then let it stand for foaming. That is, according to the "Standard for Test Method of Mechanical Properties of Ordinary Concrete" (GB / T 50081-2019), after standing at room temperature for 24 hours, the mold is removed. Then, it is cured under standard curing conditions of temperature of 20℃±2℃ and relative humidity of more than 95% until the test block reaches the specified age of 28 days, and the foam insulation board of the present invention is obtained. The compressive strength performance of the standard test block of the foam insulation board can be tested. This method is to foam by stirring and standing.

[0029] Preferably, the stirring speed of the first stirring in step (1) is 90~110 r / min, and the stirring time is 3~4 min; The stirring speed for the second stirring in step (2) is 110~130 r / min, and the stirring time is 2~3 min; The stirring speed for the third stirring in step (3) is 70~90 r / min, and the stirring time is 3~4 min; The mold size in step (4) is 1000mm×2000mm×500mm, and the standard test block size for compressive strength is 100mm×100mm×100mm.

[0030] Another method for preparing concrete foam insulation boards based on recycled materials from decommissioned wind turbine blades includes the following steps: (1) First, put cement, recycled materials of decommissioned wind turbine blades, half the weight of water, water-reducing agent and setting regulator into a mixer to make a concrete paste. (2) Add the foaming agent and foam stabilizer dissolved in the other half of the weight of water to the concrete paste obtained in step (1) and stir evenly; (3) Use foamed concrete equipment to stir the product of step (2) and inject air to generate bubbles and expand them. Foam at 5~10MPa high pressure. Adjust the amount of air injected, the amount of foaming agent, the stirring speed and the stirring time as needed to control the density and degree of foaming of the concrete. (4) Stop the mixer, pour the prepared foamed concrete into the mold, and let it stand until it is completely cured to obtain the foam insulation board.

[0031] Preferably, in step (1), the stirring speed of the stirrer is 100~110 r / min, and the stirring time is 3~4 min; In step (3), the amount of foaming agent must be 0.5% to 0.8% of the mass of half the weight of water. The foaming stirring speed is set to 1000 to 1200 r / min, the stirring time is 3 to 4 min, and gas is injected using an air compressor.

[0032] Example 1 This embodiment provides a method for preparing a foam insulation board based on recycled materials from decommissioned wind turbine blades, employing a static foaming process, including the following steps: (1) Dry mixing: Weigh 600 parts of cement and 450 parts of recycled material from decommissioned wind turbine blades according to the weight ratio, and pour them into a concrete planetary mixer in sequence. Mix for the first time at a mixing speed of 100±10 r / min for 3.5 min to obtain a uniformly dispersed first mixture. (2) Slurry preparation: Add 2 / 3 of the mass of water (120 parts), 6 parts of water-reducing agent and 10 parts of setting regulator (calcium stearate) to the first mixture, and stir for a second time at a stirring speed of 120±10 r / min for 2.5 min to obtain the second mixture; (3) Foaming and mixing: Dissolve 1.2 parts of foaming agent in the remaining 1 / 3 of the mass of water (60 parts), add 0.6 parts of foam stabilizer, stir evenly and then add to the second mixture. Stir for the third time at a stirring speed of 80±10 r / min for 3.5 min to obtain a fresh foamed concrete mixture based on recycled materials from decommissioned wind turbine blades. (4) Molding and curing: Pour the fresh concrete mixture obtained in step (3) into a mold of 1000mm×2000mm×500mm, let it stand and wait for foaming, and then remove the mold after standing at room temperature for 24 hours. Then, cure it for 28 days under standard curing conditions of 20℃±2℃ and relative humidity≥95% to obtain the foam insulation board.

[0033] The performance indicators of the foam insulation board prepared in Example 1 are as follows: density 400 kg / m³, thermal conductivity 0.085 W / (m·K), 28-day compressive strength 3.6 MPa, average pore size 0.5-1.5 mm, closed-cell rate 50%, and porosity 75%.

[0034] Figure 1 This is a schematic diagram illustrating the foaming principle of the foam insulation board based on recycled materials from decommissioned wind turbine blades prepared in Example 1 of the present invention.

[0035] Example 2 This embodiment provides a method for preparing a foam insulation board based on recycled materials from decommissioned wind turbine blades, employing a physical foaming process, including the following steps: (1) Preparation of base slurry: Weigh 700 parts of cement, 550 parts of recycled material from decommissioned wind turbine blades, and 12 parts of setting regulator (magnesium stearate) according to the weight ratio, pour them into a mixer and dry mix for 1 min to make them uniform; add half the weight of water (110 parts) and 10 parts of water-reducing agent, and stir at a stirring speed of 100 r / min for 4 min to make a concrete paste slurry; (2) Preparation of foaming liquid: Dissolve 1.5 parts of foaming agent in the other half of the mass of water (110 parts), add 1.0 part of foam stabilizer, stir evenly, and make foaming liquid; (3) Physical foaming and mixing: Using foamed concrete equipment, the foaming liquid in step (2) is injected with compressed air through an air compressor for physical foaming. The foaming pressure is controlled at 5MPa to prepare uniform and fine pre-made foam. The pre-made foam and the slurry in step (1) are mixed in a mixer with a foaming stirring speed of 1100r / min and a stirring time of 3.5min until the foam and slurry are evenly distributed. (4) Molding and curing: Pour the prepared foamed concrete into the mold, let it stand to solidify, demold after 7-8 hours, and then cure for 28 days under standard curing conditions of 20℃±2℃ and relative humidity≥95% to obtain the foam insulation board.

[0036] The performance indicators of the foam insulation board prepared in this embodiment are as follows: density 340 kg / m³, thermal conductivity 0.080 W / (m·K), 28-day compressive strength 4.5 MPa, average pore size 0.8-1.2 mm, closed-cell rate 65%, and porosity 78%.

[0037] Figure 2 This is a schematic diagram of the foaming principle of the foam insulation board of decommissioned wind turbine blade recycled material prepared in Embodiment 2 of the present invention.

[0038] Example 3 This embodiment provides a method for preparing a foam insulation board based on recycled materials from decommissioned wind turbine blades, which is basically the same as Example 2, except that the raw material ratio is adjusted to obtain lower density and thermal conductivity. Specifically, it includes the following steps: (1) Preparation of base slurry: Weigh 650 parts of cement, 500 parts of recycled material from decommissioned wind turbine blades, and 8 parts of setting regulator (calcium stearate) according to the weight ratio, and dry mix them evenly; add half the weight of water (100 parts) and 5 parts of water-reducing agent, and stir at 110 r / min for 3 min to make a concrete paste. (2) Preparation of foaming liquid: Dissolve 1.0 part of foaming agent in half the mass of water (100 parts), add 0.5 parts of foam stabilizer, stir evenly, and make foaming liquid; (3) Physical foaming and mixing: Using the same foaming equipment as in Example 2, the foaming pressure was controlled at 8 MPa to prepare pre-made foam; the pre-made foam and the slurry from step (1) were mixed in a mixer with a foaming stirring speed of 1000 r / min and a stirring time of 4 min until the foam and slurry were evenly distributed. (4) Molding and curing: Same as in Example 2.

[0039] The performance indicators of the foam insulation board prepared in this embodiment are: density 315 kg / m³, thermal conductivity 0.075 W / (m·K), 28-day compressive strength 2.9 MPa, average pore size 0.2-0.7 mm, closed-cell rate 70%, and porosity 80%.

[0040] Example 4 This embodiment provides a method for preparing a foam insulation board based on recycled materials from decommissioned wind turbine blades. It is basically the same as Example 2, except that the raw material ratio is adjusted to obtain a suitable density and better overall performance. Specifically, it includes the following steps: (1) Preparation of base slurry: Weigh 750 parts of cement, 600 parts of recycled material from decommissioned wind turbine blades, and 15 parts of setting regulator (calcium stearate) according to the weight ratio, and dry mix them evenly; add half the weight of water (125 parts) and 12 parts of water-reducing agent, and stir at 105 r / min for 3.5 min to make a concrete paste. (2) Preparation of foaming liquid: Dissolve 1.8 parts of foaming agent in half the mass of water (125 parts), add 1.2 parts of foam stabilizer, stir evenly, and make foaming liquid; (3) Physical foaming and mixing: Using the same foaming equipment as in Example 2, the foaming pressure was controlled at 10 MPa to prepare pre-made foam; the pre-made foam and the slurry from step (1) were mixed in a mixer with a foaming stirring speed of 1200 r / min and a stirring time of 3 min until the foam and slurry were evenly distributed. (4) Molding and curing: Same as in Example 2.

[0041] The performance indicators of the foam insulation board prepared in this embodiment are: density 360 kg / m³, thermal conductivity 0.085 W / (m·K), 28-day compressive strength 3.2 MPa, average pore size 0.4-1.0 mm, closed-cell rate 60%, and porosity 76%.

[0042] Example 5 This embodiment provides a method for preparing a foam insulation board based on recycled materials from decommissioned wind turbine blades, which is basically the same as that in Embodiment 2, except that the raw material ratio is adjusted and an accelerated curing process is used to obtain higher early strength. Specifically, it includes the following steps: (1) Preparation of base slurry: Weigh 800 parts of cement, 750 parts of recycled material from decommissioned wind turbine blades, and 18 parts of setting regulator (calcium stearate) according to the weight ratio, and dry mix them evenly; add half the weight of water (140 parts) and 14 parts of water-reducing agent, and stir at 110 r / min for 4 min to make a concrete paste. (2) Preparation of foaming liquid: Dissolve 2.0 parts of foaming agent in half the mass of water (140 parts), add 1.5 parts of foam stabilizer, stir evenly, and make foaming liquid; (3) Physical foaming and mixing: Using the same foaming equipment as in Example 2, the foaming pressure was controlled at 8 MPa to prepare pre-made foam; the pre-made foam and the slurry from step (1) were mixed in a mixer with the foaming stirring speed set at 1200 r / min and the stirring time at 3 min until the foam and slurry were evenly distributed. (4) Molding and curing: The prepared foamed concrete is poured into the mold and cured at 40°C. After 6 hours, it is demolded and then cured under standard curing conditions for 28 days to obtain the foam insulation board.

[0043] The performance indicators of the foam insulation board prepared in this embodiment are: density 440 kg / m³, thermal conductivity 0.095 W / (m·K), 28-day compressive strength 5.8 MPa, average pore size 0.5-1.5 mm, closed-cell rate 55%, and porosity 72%.

[0044] Comparative Example 1 Compared with Example 1, the difference is that the recycled material of retired wind turbine blades is replaced by an equal amount of natural sand.

[0045] Comparative Example 2 Compared with Example 1, the difference is that the recycled material of retired wind turbine blades is replaced by epoxy resin and ordinary fiber mixed in a 1:1 mass ratio and then replaced in equal amounts.

[0046] Comparative Example 3 Compared with Example 1, the difference is that the size of the recycled material of the decommissioned wind turbine blades was not controlled (full particle size range) during the preparation of the concrete foam insulation board of the decommissioned wind turbine blade recycled material.

[0047] Comparative Example 4: Compared with Example 1, the difference is that the addition of foaming agent is omitted in the preparation process of concrete foam insulation board made from recycled materials of decommissioned wind turbine blades.

[0048] Comparative Example 5: Compared with Example 1, the difference is that the addition of water-reducing agent is omitted in the preparation process of concrete foam insulation board made from recycled materials of decommissioned wind turbine blades.

[0049] Comparative Example 6: Compared with Example 1, the difference is that the addition of foam stabilizer (cellulose ether) is omitted in the preparation process of concrete foam insulation board made from recycled materials of decommissioned wind turbine blades.

[0050] Comparative Example 7: Compared with Example 1, the difference is that the addition of setting regulator (calcium stearate) is omitted in the preparation process of the concrete foam insulation board of the recycled material of retired wind turbine blades.

[0051] Comparative Example 8: Compared with Example 2, the difference is that the addition of setting regulator (magnesium stearate) is omitted in the preparation process of concrete foam insulation board made from recycled materials of decommissioned wind turbine blades.

[0052] Comparative Example 9: Compared with Example 1, the difference is that the stirring speed and stirring time in step (6) are replaced with 45 r / min and 2 min.

[0053] Comparative Example 10: Compared with Example 2, the difference is that the foaming agent is replaced with a plant protein foaming agent (pH=8.0) and the setting agent is replaced with aluminum sulfate.

[0054] Then, the preparation method was further improved through performance evaluation and optimization. The thermal conductivity, bulk density, mechanical properties, frost resistance, and pore structure of the prepared foam insulation concrete samples based on recycled wind turbine blade materials were tested. Based on the test results, the preparation method of the foam insulation board based on recycled decommissioned wind turbine blade materials was adjusted to achieve optimal performance.

[0055] Thermal conductivity testing methods: To characterize the impact of recycled wind turbine blade materials on the thermal performance of foamed concrete boards, thermal conductivity (λ) and thermal diffusivity (α) were tested using a TPS 2500S (Hot Disk Inc., Sweden) thermal constant analyzer based on the Transient Plane Source Method proposed by Silas Gustafson. This method conforms to ISO 22077-2 standard. The instrument's thermal conductivity measurement range is 0.005-1800 W / mK, with an accuracy of ±3%. The method also included the protective hot plate method in GB / T 10294-2008, where the thermal conductivity of foamed concrete was determined in a standard environment of 23±2℃. It was necessary to ensure complete contact between the sample and the hot plate, with a testing time greater than 4 hours, achieving an accuracy of ±2%. The results of the two tests were compared and used as the experimental values ​​for thermal conductivity.

[0056] Bulk density test method: The bulk density of foamed concrete mixture was tested according to JG / T 266-2011, ASTM C796 / C796M-19 (American Society for Testing and Materials standard) and GB / T 50080-2016. Standard cubic specimens with dimensions of 100mm×100mm×100mm were dried and their volume was calculated. The curing period of the specimens was 28 days, and the average of the three results was taken as the experimental value of bulk density.

[0057] Mechanical property testing method: According to GB / T 50081-2019, the compressive strength test was carried out on a standard cubic specimen with dimensions of 100mm×100mm×100mm. The curing period of the specimen was 28 days, and the average value of the three results was taken as the experimental value of compressive strength.

[0058] Freeze-thaw resistance test: According to the rapid freezing method specified in GB / T 50082-2009, concrete specimens cured for 24 days were removed from the standard curing room and immersed in 20℃ clean water for 4 days. During immersion, the water level should be 2-3 cm above the top surface of the specimen. After 28 days of curing, the specimens were placed in a TDR-28 type concrete freeze-thaw testing machine for rapid freeze-thaw cycle testing. The freeze-thaw medium was tap water. After 300 freeze-thaw cycles, the control system was paused, the surface moisture of the specimens was wiped dry, and then the mass loss and dynamic modulus of elasticity were tested. The mass loss rate and relative dynamic modulus of elasticity were used to characterize the freeze-thaw resistance of concrete, and the calculation formulas are as follows:

[0059] in: The mass loss rate of concrete specimens after 300 freeze-thaw cycles; The mass of the concrete specimen before it undergoes freeze-thaw cycles. The quality of the concrete specimen after undergoing 300 freeze-thaw cycles.

[0060]

[0061] in: The relative dynamic modulus of elasticity of the concrete specimen after 300 freeze-thaw cycles; The dynamic elastic modulus of the concrete specimen before it undergoes freeze-thaw cycles. The dynamic elastic modulus of the concrete specimen after 300 freeze-thaw cycles.

[0062] Porosity test method: The porosity and average pore size of the mortar were measured using an Autopore IV 9500 fully automatic mercury intrusion porosimeter, with a maximum mercury intrusion pressure of 33,000 psi. An 8 mm cube was taken from a concrete specimen cured for 28 days using a cutting machine, with the sampling location at the center of the specimen, avoiding the aggregate area. The sample was then immersed in anhydrous ethanol to prevent hydration.

[0063] The thermal conductivity, bulk density, mechanical properties, antifreeze properties and pore structure of the above embodiments and comparative samples were evaluated, and the test results and evaluation results are shown in Table 1 and Table 2.

[0064] Table 1. Thermal conductivity and bulk density of foam insulation boards in various embodiments and comparative examples.

[0065] Table 2. Compressive strength and pore structure of foam insulation boards in various embodiments and comparative examples.

[0066] The results in Tables 1 and 2 show that the method for preparing foam insulation boards based on recycled materials from decommissioned wind turbine blades provided by this invention can effectively control the bulk density, thermal conductivity, mechanical properties, and pore structure of the product by adjusting the material ratio and foaming process.

[0067] Specifically, in Examples 1 to 5, by employing physical or chemical foaming processes and using key additives such as polycarboxylate superplasticizers, hydroxypropyl methylcellulose ether (HPMC), and calcium stearate, foam insulation boards with lightweight (density 315-440 kg / m³), thermal insulation (thermal conductivity 0.075-0.095 W / (m·K)) and certain mechanical strength were successfully prepared. Example 3, through an optimized low-dosage ratio combined with physical foaming, achieved the lowest density (315 kg / m³) and thermal conductivity (0.075 W / (m·K)), demonstrating optimal thermal insulation performance. Example 5, through a high-dosage ratio and heat curing, achieved the highest compressive strength, demonstrating the flexibility of the formulation design in performance orientation.

[0068] The results of the comparative analysis strongly validate the necessity of each key component and process: Comparative Example 1 (natural sand replacing recycled material) resulted in a surge in bulk density and a significant deterioration in thermal conductivity, demonstrating the irreplaceable role of recycled materials from decommissioned wind turbine blades in achieving the core characteristics of lightweight and low thermal conductivity in products. Comparative Example 2 used a mixture of epoxy resin and fiber to replace the recycled material of retired wind turbine blades, which resulted in a significant deterioration in thermal conductivity and a larger bulk density. The results of Comparative Example 4 (without foaming agent) and Comparative Example 6 (without foam stabilizer HPMC) indicate that the foaming system is the cornerstone of forming a porous structure, while the foam stabilizer is crucial for obtaining a fine, uniform, and highly closed-cell structure. The absence of these stabilizers will directly lead to the product losing its porous insulation properties or causing coarsening of the pore structure and a decline in performance. Comparative Examples 5, 7, and 8 (with water-reducing agent and setting regulator omitted respectively) demonstrated from different perspectives the key auxiliary roles played by these admixtures in optimizing slurry workability, controlling the setting process, and improving product durability (such as freeze resistance). The results of Comparative Example 3 (uncontrolled recycled material size), Comparative Example 9 (imbalanced ratio), and Comparative Example 10 (optimized mixing process) highlight the importance of raw material pretreatment, scientific proportioning, and precise process control for ensuring product performance stability.

[0069] In summary, this invention successfully prepares lightweight, heat-insulating foamed concrete panels with adjustable performance by using recycled materials from retired wind turbine blades as the main lightweight aggregate and innovatively employing a compatible composite foaming technology and admixture system. This method not only provides an effective way to utilize the high-value-added resources of retired wind turbine blades, but the prepared product also has clear application prospects in the field of building energy conservation.

[0070] The above description of the embodiments is provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.

Claims

1. A foam insulation board based on recycled materials from decommissioned wind turbine blades, characterized in that, The raw material components include the following parts by weight: 1-2 parts of foaming agent 5-12 parts of water-reducing agent 450-750 parts of recycled material from decommissioned wind turbine blades. 600-800 parts cement 180-500 parts water 8-15 parts of setting regulator, Foam stabilizer 0.5~1.5 parts, The foaming agent is a polymeric composite cement foaming agent with a pH of 7.5~10.0; The recycled material of the decommissioned wind turbine blades is a mixture obtained by cutting, crushing, pulverizing and screening waste wind turbine blades, with an average particle size of 0.50~4.50mm.

2. The foam insulation board based on recycled materials from decommissioned wind turbine blades according to claim 1, characterized in that, The water-reducing agent is a polycarboxylate superplasticizer with a water reduction rate of 22%~25%; The setting regulator is stearate; The foam stabilizer is a cellulose ether suitable for alkaline environments.

3. A foam insulation board based on recycled materials from decommissioned wind turbine blades according to claim 2, characterized in that, The setting regulator is selected from any one or a mixture of two of calcium stearate and magnesium stearate.

4. A foam insulation board based on recycled materials from decommissioned wind turbine blades according to claim 2, characterized in that, The foam stabilizer is hydroxypropyl methylcellulose ether.

5. A foam insulation board based on recycled materials from decommissioned wind turbine blades according to claim 1, characterized in that, The cement is PO 42.5 ordinary Portland cement with an average particle size of 12~36μm and a 28-day compressive strength of 46.2~53.2MPa.

6. A method for preparing a foam insulation board based on recycled materials from decommissioned wind turbine blades as described in any one of claims 1 to 5, characterized in that, Includes the following steps: (1) Take samples of cement and recycled materials of decommissioned wind turbine blades according to the component content in the mix proportion, and pour them into a concrete planetary mixer for the first mixing to obtain the first mixture; (2) Add 2 / 3 of the weight of water, water-reducing agent and setting agent to the first mixture and stir for a second time to obtain the second mixture; (3) Dissolve the foaming agent in the remaining 1 / 3 of the weight of water, and add it together with the foam stabilizer to the second mixture for a third stirring to obtain a fresh concrete mixture based on recycled materials from decommissioned wind turbine blades; (4) Pour the fresh concrete mixture obtained in step (3) into a mold to obtain a standard test block for compressive strength, and then let it stand for foaming. According to the "Standard Test Method for Mechanical Properties of Ordinary Concrete", after standing at room temperature for 24 hours, the mold is removed. Then, it is cured under standard curing conditions of 20℃±2℃ and relative humidity of more than 95% until the test block reaches the specified age of 28 days to obtain the foam insulation board.

7. The preparation method according to claim 6, characterized in that, The stirring speed for the first stirring in step (1) is 90~110 r / min, and the stirring time is 3~4 min; The stirring speed for the second stirring in step (2) is 110~130 r / min, and the stirring time is 2~3 min; The stirring speed for the third stirring in step (3) is 70~90 r / min, and the stirring time is 3~4 min; The mold dimensions in step (4) are 1000mm×2000mm×500mm.

8. Another method for preparing a foam insulation board based on recycled material from decommissioned wind turbine blades as described in any one of claims 1 to 5, characterized in that, Includes the following steps: (1) First, put cement, recycled materials of decommissioned wind turbine blades, half the weight of water, water-reducing agent and setting regulator into a mixer to make a concrete paste. (2) Add the foaming agent and foam stabilizer dissolved in the other half of the weight of water to the concrete paste obtained in step (1) and stir evenly; (3) Use foamed concrete equipment to stir the product of step (2) and inject air to generate bubbles and expand it. Foam at 5~10MPa high pressure and adjust the amount of air injected, the amount of foaming agent, the stirring speed and the stirring time as needed. (4) Stop the mixer, pour the prepared foamed concrete into the mold, and let it stand until it is completely cured to obtain the foam insulation board.

9. The preparation method according to claim 8, characterized in that... In step (1), the stirring speed of the stirrer is 100~110 r / min, and the stirring time is 3~4 min; In step (3), the amount of foaming agent must be 0.5% to 0.8% of the mass of half the weight of water, and the foaming stirring speed is set to 1000 to 1200 r / min, and the stirring time is 3 to 4 min.

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