Performance enhancement, design, and preparation methods of FRP aggregate concrete from decommissioned wind turbine blades

Abstract

This invention belongs to the field of concrete aggregate technology, specifically involving the performance improvement, design, and preparation method of FRP aggregate concrete using recycled FRP from decompressed wind turbine blades. Firstly, this invention uses formulas (1) to (6) to determine the replacement rate of modified FRP aggregate and the amount of epoxy mortar coating during the concrete preparation process based on the preset compressive strength and mix proportion of the concrete. Then, based on the amount of epoxy mortar coating, the modified recycled FRP aggregate is prepared; finally, the modified recycled FRP aggregate is used to prepare the concrete containing the modified recycled FRP aggregate. Therefore, the preparation method provided by this invention can determine the parameters of the preparation process based on the preset compressive strength of the concrete, thereby achieving the preparation of concrete containing modified recycled FRP aggregate with a target compressive strength. Simultaneously, it solves the problems of difficult FRP waste treatment and low resource utilization rate in the prior art, effectively reducing environmental pollution and promoting the recycling of decompressed wind turbine blades.

Description

Technical Field

[0001] This invention belongs to the field of concrete aggregate technology, specifically relating to the performance improvement, design, and preparation methods of FRP aggregate concrete recycled from decommissioned wind turbine blades. Background Technology

[0002] With the rapid development of the construction industry, the use of traditional building materials has placed enormous pressure on the environment. The excessive consumption of resources such as cement, river sand, and natural coarse aggregates has not only led to resource depletion but also increased carbon emissions. Fiber-reinforced polymer (FRP) composites, due to their high strength, lightweight, corrosion resistance, and fatigue resistance, are used in the manufacture of wind turbine blades. As wind power is an important component of new clean energy, the amount of FRP waste generated from retired wind turbine blades is increasing with equipment upgrades and the expiration of the service life of early units. However, traditional landfilling and incineration methods for treating FRP waste from retired wind turbine blades are not only costly but also cause serious environmental pollution. Recycling and utilizing FRP waste from retired wind turbine blades and applying it to concrete preparation can not only reduce the significant environmental harm caused by improper disposal of waste FRP from retired wind turbine blades but also reduce the over-exploitation of resources such as sand and gravel. Therefore, to promote the green recycling and treatment of FRP waste from retired wind turbine blades, it is crucial to continue researching and utilizing FRP aggregate concrete from retired wind turbine blades.

[0003] However, in existing methods for preparing FRP aggregate concrete from decommissioned wind turbine blades, directly adding untreated FRP aggregate from the decommissioned wind turbine blades leads to a decrease in concrete strength and elastic modulus. This results in unstable mechanical properties of the prepared FRP aggregate concrete from decommissioned wind turbine blades, failing to meet the application standards of practical engineering projects. Therefore, surface modification treatment of the FRP waste from decommissioned wind turbine blades is necessary to improve the mechanical properties of FRP aggregate concrete from decommissioned wind turbine blades.

[0004] Modified FRP aggregate concrete for decommissioned wind turbine blades, prepared by wrapping recycled FRP waste with epoxy mortar, exhibits improved strength compared to unmodified FRP aggregate concrete. However, in the current design process of modified FRP aggregate concrete for decommissioned wind turbine blades, the replacement rate of recycled FRP aggregate and the amount of epoxy mortar wrapping cannot be directly determined from the compressive strength index and mix proportions of the modified FRP aggregate concrete. Therefore, it is impossible to prepare concrete materials with predetermined compressive strength indexes. Summary of the Invention

[0005] The purpose of this invention is to provide a method for improving the performance, designing, and preparing FRP aggregate concrete from decommissioned wind turbine blades. The preparation method provided by this invention can determine the parameters of the preparation process based on the preset compressive strength of the concrete, thereby achieving the preparation of concrete containing modified recycled FRP aggregate with the target compressive strength, and promoting the recycling of decommissioned wind turbine blades.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] This invention provides a method for preparing concrete containing modified recycled FRP aggregate, comprising the following steps:

[0008] According to formulas (1) to (6), based on the preset compressive strength and mix proportion of the concrete containing modified recycled FRP aggregate, the substitution rate and coating amount of the concrete containing modified recycled FRP aggregate are obtained; the substitution rate is the volume percentage of modified recycled FRP aggregate in the coarse aggregate of the concrete containing modified recycled FRP aggregate, the modified recycled FRP aggregate is epoxy mortar modified recycled FRP aggregate, and the coating amount is the mass ratio of epoxy mortar to recycled FRP aggregate;

[0009]

[0010] k s1 =1+0.449s 2 +0.928rs-0.699s(3);

[0011]

[0012] k s2 = -78.696s 2 -1.326rs+47.359s-5.921(5);

[0013]

[0014] In formulas (1) to (6): f c 'F represents the compressive strength of concrete containing modified recycled FRP aggregate.' co ε is the compressive strength of concrete with natural aggregate. c ' is the peak strain of concrete containing modified recycled FRP aggregate, r is the replacement rate, and k is the peak strain. s1 k is the elastic modulus coefficient of concrete related to the amount of wrapping. s2 The peak strain coefficient of concrete related to the amount of encapsulation, where s is the amount of encapsulation and E is the peak strain coefficient. c k represents the elastic modulus of concrete containing modified recycled FRP aggregate. e The elastic modulus of concrete is related to the replacement rate.

[0015] Based on the stated amount of encapsulation, epoxy mortar is used to encapsulate and modify the recycled FRP material to obtain the modified recycled FRP aggregate.

[0016] Based on the replacement rate and mix proportion, the modified recycled FRP aggregate is used to prepare the concrete containing the modified recycled FRP aggregate, and the compressive strength of the concrete containing the modified recycled FRP aggregate is ≥ the preset compressive strength.

[0017] Preferably, the method for determining the substitution rate and package quantity includes the following steps:

[0018] The compressive strength of the concrete containing modified recycled FRP aggregate is preset, and the preset compressive strength of the concrete containing modified recycled FRP aggregate is obtained. The mix proportion of the concrete containing modified recycled FRP aggregate is determined. The compressive strength of the concrete containing natural aggregate is obtained from the mix proportion. The range of two parameters, substitution rate and wrapping amount, is obtained by formula (1) to (6). The range is the range when the compressive strength of the concrete containing modified recycled FRP aggregate is ≥ the preset compressive strength under the condition that the mix proportion is determined. Then the substitution rate and wrapping amount of the concrete containing modified recycled FRP aggregate are determined by the range of the two parameters, substitution rate and wrapping amount.

[0019] Preferably, the package weight is 0.1 to 0.5.

[0020] Preferably, the substitution rate is ≥30%.

[0021] Preferably, the epoxy mortar includes epoxy resin, curing agent, and additives; the additives include cement and quartz sand.

[0022] Preferably, the mass ratio of the epoxy resin, curing agent and additives is (1-2):(1-5):(12-20).

[0023] Preferably, the mass ratio of cement to quartz sand in the additive is 1:(1-3).

[0024] Preferably, the particle size range of the recycled FRP material is 5-25 mm; the aspect ratio is <1.6.

[0025] Preferably, the package modification includes the following steps:

[0026] The recycled FRP material and additives are premixed to obtain a premixed material;

[0027] The epoxy resin and curing agent are mixed and then mixed with the premix to obtain the initial modified product;

[0028] The initial modified product is cured to obtain the modified recycled FRP aggregate.

[0029] Preferably, the water-cement ratio in the mix proportion is 0.45.

[0030] Preferably, the curing conditions for preparing the concrete containing modified recycled FRP aggregate include: a curing temperature of 20±2℃, a relative humidity of 95%, and a curing time of 28 days.

[0031] This invention provides a method for preparing concrete containing modified recycled FRP aggregate. First, the invention uses formulas (1) to (6) to determine two key parameters in the concrete preparation process: the substitution rate and the amount of coating. Then, based on the amount of coating, epoxy mortar is used to coat and modify the recycled FRP material, resulting in the modified recycled FRP aggregate. Finally, based on the substitution rate and the mix proportion, the modified recycled FRP aggregate is used to prepare the concrete containing the modified recycled FRP aggregate, and the compressive strength of the resulting concrete containing the modified recycled FRP aggregate is greater than or equal to the preset compressive strength. Therefore, the preparation method provided by this invention enables the determination of the parameters of the preparation process based on the preset compressive strength of the concrete, thereby achieving the preparation of concrete containing modified recycled FRP aggregate with a target compressive strength. Furthermore, the preparation method provided by this invention is simple, using recycled FRP waste modified as aggregate in the preparation of concrete, significantly improving the mechanical properties (including strength and modulus of elasticity) of the recycled FRP-concrete, and meeting the requirements of high-performance building materials. It also solves the problems of difficult FRP waste disposal and low resource utilization in existing technologies, effectively reduces environmental pollution, and promotes the recycling of retired wind turbine blades. Attached Figure Description

[0032] Figure 1 Grading curves for recycled GFRP aggregate and natural coarse aggregate;

[0033] Figure 2 This example illustrates the relationship between the replacement rate of recycled FRP aggregate concrete and its compressive strength under different replacement rates.

[0034] Figure 3 Comparison of experimental and predicted stress-strain curves for concrete containing recycled GFRP aggregate;

[0035] Figure 4 This example compares the compressive strength of the core of modified recycled GFRP aggregate concrete.

[0036] Figure 5 Comparison of experimental and predicted stress-strain curves for concrete containing modified recycled GFRP aggregate;

[0037] Figure 6This diagram illustrates the relationship between the replacement rate of recycled GFRP aggregate from modified decommissioned wind turbine blades, the amount of epoxy mortar coating, and the compressive strength of concrete containing recycled GFRP aggregate from modified decommissioned wind turbine blades when the compressive strength of ordinary concrete (i.e., concrete with natural aggregates) is 35 MPa, according to a preferred embodiment of the method for determining the compressive bearing capacity of concrete containing recycled GFRP aggregate from modified decommissioned wind turbine blades. Detailed Implementation

[0038] This invention provides a method for preparing concrete containing modified recycled FRP aggregate, comprising the following steps:

[0039] According to formulas (1) to (6), based on the preset compressive strength and mix proportion of the concrete containing modified recycled FRP aggregate, the substitution rate and coating amount of the concrete containing modified recycled FRP aggregate are obtained; the substitution rate is the volume percentage of modified recycled FRP aggregate in the coarse aggregate of the concrete containing modified recycled FRP aggregate, the modified recycled FRP aggregate is epoxy mortar modified recycled FRP aggregate, and the coating amount is the mass ratio of epoxy mortar to recycled FRP aggregate;

[0040]

[0041] k s1 =1+0.449s 2 +0.928rs-0.699s(3);

[0042]

[0043] k s2 = -78.696s 2 -1.326rs+47.359s-5.921(5);

[0044]

[0045] In formulas (1) to (6): f c 'F represents the compressive strength of concrete containing modified recycled FRP aggregate.' co ε is the compressive strength of concrete with natural aggregate. c ' is the peak strain of concrete containing modified recycled FRP aggregate, r is the replacement rate, and k is the peak strain. s1 k is the elastic modulus coefficient of concrete related to the amount of wrapping. s2 The peak strain coefficient of concrete related to the amount of encapsulation, where s is the amount of encapsulation and E is the peak strain coefficient. c k represents the elastic modulus of concrete containing modified recycled FRP aggregate. e The elastic modulus of concrete is related to the replacement rate.

[0046] Based on the stated amount of encapsulation, epoxy mortar is used to encapsulate and modify the recycled FRP material to obtain the modified recycled FRP aggregate.

[0047] Based on the replacement rate and mix proportion, the modified recycled FRP aggregate is used to prepare the concrete containing the modified recycled FRP aggregate, and the compressive strength of the concrete containing the modified recycled FRP aggregate is ≥ the preset compressive strength.

[0048] In this invention, unless otherwise specified, all raw materials / components used in the preparation are commercially available products well known to those skilled in the art.

[0049] In this invention, the raw materials for preparing concrete include coarse aggregate, fine aggregate, cement, and water. In the concrete prepared with natural aggregate, all coarse aggregate is natural coarse aggregate. In the concrete prepared with recycled FRP aggregate, the coarse aggregate is either recycled FRP aggregate or a combination of recycled FRP aggregate and natural coarse aggregate. In the concrete prepared with modified recycled FRP aggregate, the coarse aggregate is either modified recycled FRP aggregate or a combination of modified recycled FRP aggregate and natural coarse aggregate.

[0050] In this invention, the replacement rate is the replacement rate of modified recycled FRP aggregate. The coating amount is the coating amount of epoxy mortar.

[0051] In this invention, the raw materials for preparing the concrete containing modified recycled FRP aggregate include cement, water, coarse aggregate and natural fine aggregate. The coarse aggregate in the concrete containing modified recycled FRP aggregate is modified recycled FRP aggregate, or it is a mixture of modified recycled FRP aggregate and natural coarse aggregate.

[0052] In this invention, the raw materials for preparing the concrete with natural aggregates include cement, water, natural coarse aggregates, and natural fine aggregates.

[0053] In this invention, the mix proportion of the concrete with natural aggregate is the mass ratio of cement, water, natural coarse aggregate, and natural fine aggregate. The one-to-one correspondence between the mix proportion of the concrete with natural aggregate and the compressive strength of the concrete with natural aggregate can be determined from literature data.

[0054] In this invention, the substitution rate is the substitution rate of modified FRP aggregate, and the coating amount is the coating amount of epoxy mortar.

[0055] According to formulas (1) to (6), the present invention obtains the substitution rate and coating amount of the concrete containing modified recycled FRP aggregate based on the preset compressive strength and mix proportion of the concrete containing modified recycled FRP aggregate; the substitution rate is the volume percentage of modified recycled FRP aggregate in the coarse aggregate of the concrete containing modified recycled FRP aggregate, the modified recycled FRP aggregate is epoxy mortar modified recycled FRP aggregate, and the coating amount is the mass ratio of epoxy mortar to recycled FRP aggregate.

[0056] In this invention, the method for constructing formulas (1) to (6) includes the following steps:

[0057] Provide concrete specimens, including concrete specimens with natural aggregates, concrete specimens containing recycled FRP aggregates, and concrete specimens containing modified recycled FRP aggregates;

[0058] The concrete specimens were subjected to compressive strength tests to obtain the initial compressive strength information of the concrete specimens with natural aggregates, the alternative compressive strength information of the concrete specimens containing recycled FRP aggregates, and the modified compressive strength information of the concrete specimens containing modified recycled FRP aggregates.

[0059] Based on the initial compressive strength information and the alternative compressive strength information, an initial formula is constructed for the compressive strength of concrete with natural aggregate, the compressive strength of concrete containing recycled FRP aggregate, and the recycled FRP aggregate replacement rate, wherein the recycled FRP aggregate replacement rate is the volume percentage of recycled FRP aggregate in the coarse aggregate of the concrete specimen containing recycled FRP aggregate.

[0060] Based on the initial compressive strength information and the modified compressive strength information, formulas (2) to (6) are constructed;

[0061] The initial formulas are modified using formulas (2) to (6) to obtain formulas (1) to (6).

[0062] This invention provides concrete specimens, including concrete specimens with natural aggregates, concrete specimens containing recycled FRP aggregates, and concrete specimens containing modified recycled FRP aggregates. In this invention, the raw materials for preparing the concrete specimens include coarse aggregates, fine aggregates, cement, and water. The mix proportions of the concrete specimens with natural aggregates, those containing recycled FRP aggregates, and those containing modified recycled FRP aggregates are the same. The coarse aggregate in the concrete specimens with natural aggregates is natural coarse aggregate; the coarse aggregate in the concrete specimens containing recycled FRP aggregates is recycled FRP aggregate, or a mixture of recycled FRP aggregate and natural coarse aggregate; the coarse aggregate in the concrete specimens containing modified recycled FRP aggregates is modified recycled FRP aggregate, or a mixture of modified recycled FRP aggregate and natural coarse aggregate. This invention, based on the "Standard for Test Methods of Physical and Mechanical Properties of Concrete" GB / T50081-2019, "Construction Gravel and Crushed Stone" GB / T14685-2011, and "Construction Sand" GB / T 14684-2011, selects and prepares the natural coarse aggregate, natural fine aggregate, and recycled FRP aggregate required for the above-mentioned concrete specimens, determines the mix proportion of the concrete specimens, and ensures that the gradation of FRP aggregate and gravel (natural coarse aggregate) is consistent during the experimental process. In this invention, the above-mentioned concrete specimens (ordinary concrete specimens with the same mix proportion (i.e., concrete specimens with natural aggregate), ordinary recycled FRP aggregate concrete specimens (i.e., concrete specimens containing recycled FRP aggregate), and modified recycled FRP concrete specimens (i.e., concrete specimens containing modified recycled FRP aggregate)) can be prepared in advance or provided beforehand.

[0063] In preparing the above-mentioned concrete specimens according to the present invention, cement, sand (natural fine aggregate), gravel (natural coarse aggregate), water, and recycled FRP aggregate are prepared separately according to the determined mix proportions. The quality of each material is ensured to meet the standard requirements. Cement, sand, gravel, water, and recycled FRP aggregate are added to a mixer in sequence. The mixer is started and uniformly mixed until all materials are fully mixed to form a homogeneous concrete mixture. The mixing time and speed are adjusted according to the specific requirements of the concrete to ensure the uniformity and fluidity of the mixture. The mixed concrete is poured into a mold and compacted by vibration. Vibration can be performed using mechanical vibration to expel air bubbles from the concrete, improving its density and strength. The concrete specimens are obtained by curing under standard curing conditions for twenty-eight days.

[0064] In this invention, the mix proportions of cementitious material (cement), coarse aggregate, and fine aggregate are the same for the above-mentioned ordinary concrete specimen, ordinary recycled FRP aggregate concrete specimen with a recycled FRP aggregate replacement rate, and epoxy mortar-coated modified recycled FRP aggregate concrete specimen with the specified replacement rate. That is, determining the mix proportion of the ordinary concrete specimen involves selecting fine aggregate (sand), coarse aggregate (gravel), and cementitious material (cement) with a certain aggregate gradation. The proportion of fine aggregate (sand) in the ordinary recycled FRP aggregate concrete specimen and the modified recycled FRP aggregate concrete specimen is consistent with that in the ordinary concrete. In the ordinary recycled FRP aggregate concrete specimen and the modified recycled FRP aggregate concrete specimen, the coarse aggregate replaces part or all of the coarse aggregate according to the corresponding replacement rate.

[0065] After obtaining the concrete specimens, the present invention conducts compressive strength tests on the concrete specimens to obtain the initial compressive strength information of the concrete specimens with natural aggregates, the alternative compressive strength information of the concrete specimens containing recycled FRP aggregates, and the modified compressive strength information of the concrete specimens containing modified recycled FRP aggregates.

[0066] This invention conducts compressive strength tests on ordinary concrete specimens (i.e., concrete specimens with natural aggregate) to obtain the initial compressive strength information of the natural aggregate concrete specimens. This invention also conducts compressive strength tests on various ordinary recycled FRP aggregate concrete specimens (i.e., concrete specimens containing recycled FRP aggregate) under different recycled FRP replacement rates to obtain the corresponding replacement compressive strength information for each specimen. Furthermore, it obtains the epoxy mortar coating amount for various recycled FRP aggregate concretes under different recycled FRP aggregate replacement rates; based on the epoxy mortar coating amount, it conducts compressive strength tests on modified recycled FRP aggregate concrete (i.e., concrete specimens containing modified recycled FRP aggregate) under corresponding modified recycled FRP aggregate replacement rates to obtain the corresponding modified compressive strength information for each type of modified recycled FRP aggregate concrete.

[0067] This invention involves conducting uniaxial compression tests on ordinary concrete, various types of ordinary recycled FRP aggregate concrete, and various types of modified recycled FRP aggregate concrete. The initial strength of the ordinary concrete (which can be the average of multiple groups, as shown in Table 2), the recycled FRP aggregate replacement rate and replacement strength of each type of ordinary recycled FRP aggregate concrete (which can be the average of multiple groups at that replacement rate, as shown in Table 2), and the epoxy mortar dosage and modified strength of each type of modified recycled FRP aggregate concrete (which can be the average of multiple groups at that dosage, as shown in Table 3) are obtained respectively.

[0068] In this invention, after obtaining the modified recycled FRP aggregate concrete specimen, a uniaxial compression test is also required to obtain the stress-strain curve, compressive strength, elastic modulus, etc. of the modified recycled FRP-concrete, and to evaluate the mechanical properties of the modified recycled FRP aggregate concrete over time.

[0069] After obtaining the initial compressive strength information, the alternative compressive strength information, and the modified compressive strength information, this invention constructs an initial formula for the compressive strength of concrete with natural aggregate, the compressive strength of concrete containing recycled FRP aggregate, and the recycled FRP aggregate replacement rate based on the initial compressive strength information and the alternative compressive strength information. The recycled FRP aggregate replacement rate is the volume percentage of recycled FRP aggregate in the coarse aggregate of the concrete specimen containing recycled FRP aggregate. Based on the initial compressive strength information and the modified compressive strength information, formulas (2) to (6) are constructed. Formulas (2) to (6) are used to modify the initial formulas to obtain formulas (1) to (6).

[0070] This invention first obtains the initial compressive strength information of ordinary concrete specimens, the corresponding alternative compressive strength information of ordinary recycled FRP aggregate concrete specimens under the recycled FRP replacement rate, and the modified compressive strength information of modified recycled FRP aggregate concrete specimens under the corresponding recycled FRP aggregate replacement rate; based on the initial compressive strength information and the alternative compressive strength information, an initial formula is constructed between the strength of ordinary concrete and the strength of ordinary recycled FRP aggregate concrete under any corresponding recycled FRP aggregate replacement rate; based on the modified compressive strength information and the initial equation, target formulas are constructed for the initial compressive strength of ordinary concrete, the compressive strength of modified recycled FRP aggregate concrete, the recycled FRP aggregate replacement rate, and the amount of epoxy mortar coating (Formulas (1) to (6)).

[0071] In this invention, based on initial compressive strength information and alternative compressive strength information, an initial formula is constructed between the initial compressive strength of ordinary concrete and the alternative compressive strength of ordinary recycled FRP aggregate concrete under any corresponding recycled FRP aggregate substitution rate, specifically including:

[0072] The initial compressive strength information and various alternative compressive strength information under different recycled FRP aggregate replacement rates are analyzed to obtain the first coefficient of the recycled FRP aggregate replacement rate. Based on the first coefficient, an initial formula is generated between the initial compressive strength of ordinary concrete and the compressive strength of ordinary recycled FRP aggregate concrete under any corresponding recycled FRP aggregate replacement rate.

[0073] The initial compressive strength of ordinary concrete and the corresponding modified compressive strength of recycled FRP aggregate concrete at specific replacement rates under different epoxy mortar coating amounts were obtained. Based on the initial compressive strength of ordinary concrete and the modified compressive strength of recycled FRP aggregate concrete at various specific replacement rates, a quadratic function relationship between the initial compressive strength of ordinary concrete and the modified compressive strength of recycled FRP aggregate concrete at specific replacement rates was obtained.

[0074] Obtain the modified compressive strength information of modified recycled FRP aggregate concrete under the modified recycled FRP aggregate replacement rate, specifically including:

[0075] Obtain the epoxy mortar coating amount of various recycled FRP aggregate concretes under different recycled FRP replacement rates; based on the epoxy mortar coating amount, conduct compressive strength tests on the modified recycled FRP aggregate concretes under the corresponding modified recycled FRP replacement rates to obtain the corresponding modified strength information of various modified recycled FRP aggregate concretes.

[0076] Based on the modified strength information and the initial equation, the target equations for the initial strength of ordinary concrete, the compressive strength of modified recycled FRP aggregate concrete, the recycled FRP replacement rate, and the epoxy mortar coating amount are constructed. Specifically, based on the quadratic function relationship (Formulas 2 to 6), the target formulas for the initial strength of ordinary concrete, the compressive strength of modified recycled FRP aggregate concrete, the modified recycled FRP replacement rate, and the epoxy mortar coating amount are obtained (Formula 1).

[0077] This invention analyzes the relationship between three types of concrete: unmodified ordinary concrete without recycled FRP aggregate replacement, ordinary recycled FRP aggregate concrete with a certain recycled FRP aggregate replacement rate, and modified recycled FRP aggregate concrete with epoxy mortar coating modified under the same recycled FRP aggregate replacement rate. It determines the mathematical relationship between the strength of modified recycled FRP aggregate concrete, the initial strength of ordinary concrete, and the amount of epoxy mortar coating under a certain recycled FRP aggregate replacement rate. Given the initial strength of ordinary concrete and the recycled FRP aggregate replacement rate, the invention can accurately calculate the strength of ordinary recycled FRP aggregate concrete and accurately calculate the required amount of epoxy mortar coating based on the target strength of modified recycled FRP aggregate concrete and the target bearing capacity of the concrete beam prepared from it.

[0078] In a specific embodiment of the present invention, the method for determining the substitution rate and the amount of packages includes the following steps:

[0079] The compressive strength of the concrete containing modified recycled FRP aggregate is preset (i.e., preset compressive strength), and the mix proportion of the concrete containing modified recycled FRP aggregate is determined. The compressive strength of the concrete containing natural aggregate is obtained from the mix proportion. The range of two parameters, substitution rate and wrapping amount, is obtained by formula (1) to (6). The range is the range where the compressive strength of the concrete containing modified recycled FRP aggregate is ≥ preset compressive strength under the condition that the mix proportion is determined. Then the substitution rate and wrapping amount of the concrete containing modified recycled FRP aggregate are determined by the range of the two parameters, substitution rate and wrapping amount.

[0080] In this invention, the package weight is preferably 0.1 to 0.5, and most preferably 0.3.

[0081] In this invention, the substitution rate is ≥30%.

[0082] After obtaining the stated amount of encapsulation, the present invention modifies the recycled FRP material by encapsulating it with epoxy mortar based on the stated amount of encapsulation, thereby obtaining the modified recycled FRP aggregate.

[0083] In this invention, the method for preparing the modified recycled FRP material preferably includes the following steps:

[0084] The recycled FRP material is mixed with epoxy mortar and then coated and modified to obtain the modified recycled FRP material; the epoxy mortar includes epoxy resin, curing agent and additives.

[0085] This invention does not have special requirements regarding the source of the recycled FRP material; it can be obtained using methods well-known in the art. In a specific embodiment of this invention, the recycled FRP material is specifically recycled FRP waste from decommissioned wind turbine blades. This invention preferably pre-treats the recycled FRP material, and the pre-treatment preferably includes sequential crushing, screening, washing, and drying. This invention does not have special requirements regarding the specific implementation of the crushing, screening, washing, and drying processes. This invention removes resin and filler dust from the surface of the recycled FRP material through washing. In this invention, the particle size range of the recycled FRP material is preferably 5–25 mm; the aspect ratio is preferably <1.6. In a specific embodiment of this invention, the recycled FRP material is specifically recycled GFRP material.

[0086] In this invention, the curing agent is preferably an epoxy resin curing agent. The additives preferably include cement and quartz sand; the mass ratio of cement to quartz sand is preferably 1:(1-3), specifically 1:2 in the examples. The mass ratio of epoxy resin, curing agent and additives is preferably (1-2):(1-5):(12-20), specifically 1:3:16 in the examples.

[0087] In a specific embodiment of the present invention, the package ratio is specifically 0.25:1, 0.3:1, or 0.35:1.

[0088] In this invention, the package modification preferably includes the following steps:

[0089] The recycled FRP material and additives are premixed to obtain a premixed material;

[0090] The epoxy resin and curing agent are mixed and then mixed with the premix to obtain the initial modified product;

[0091] The initial modified product is cured to obtain the modified recycled FRP material.

[0092] This invention involves premixing the recycled FRP material and additives to obtain a premix. The premixing is preferably carried out in a mixer, and the mixing time is preferably 1-2 minutes. Preferably, the additives are coated onto the surface of the recycled FRP material during premixing.

[0093] In this invention, the epoxy resin and curing agent are first stirred and mixed to obtain an epoxy resin mixture; the epoxy resin mixture and the premix are then second stirred and mixed to obtain an initial modified product. In this invention, the second stirring and mixing time is preferably 3–5 minutes.

[0094] After obtaining the initial modified product, the present invention cures the initial modified product to obtain the modified recycled FRP material. In the present invention, the curing preferably includes a first-stage curing and a second-stage curing. The temperature of the first-stage curing is preferably room temperature, and the time is preferably 48 hours. Between the first-stage and second-stage curing, the present invention preferably stirs the product obtained after the first-stage curing, and the stirring time is preferably 1 minute. The present invention preferably separates some materials that are bonded together due to a small amount of epoxy mortar between particles through the stirring treatment between the first-stage and second-stage curing. The temperature of the second-stage curing is preferably room temperature, and the time is preferably 7 days.

[0095] After obtaining the modified recycled FRP aggregate, the present invention uses the modified recycled FRP aggregate to prepare the concrete containing the modified recycled FRP aggregate according to the replacement rate and mix proportion, wherein the compressive strength of the concrete containing the modified recycled FRP aggregate is ≥ the preset compressive strength.

[0096] In this invention, the raw materials for preparing the concrete containing modified recycled FRP aggregate preferably include coarse aggregate, fine aggregate, cement, and water. In the embodiments, the cement used is specifically OPC. The fine aggregate is specifically river sand.

[0097] In this invention, the water-cement ratio in the mix proportion is 0.45. The mix proportion is the mass ratio of water, cement, coarse aggregate, and fine aggregate in the raw materials. In a specific embodiment of this invention, the mix proportion of the concrete containing modified recycled FRP aggregate is 190:422:950:683.

[0098] In specific embodiments of the present invention, the substitution rate is preferably 30% to 100%, specifically 30%, 50%, 70%, or 100% in the embodiments. In the present invention, when the volume of the modified recycled FRP material accounts for less than 100% of the total volume of coarse aggregate in the concrete containing modified recycled FRP aggregate, the coarse aggregate of the concrete containing modified recycled FRP aggregate preferably includes the modified recycled FRP material and natural coarse aggregate. The natural coarse aggregate is preferably gravel.

[0099] In this invention, the selection of the gradation of the modified recycled FRP material in the concrete mix proportion has a significant impact on the concrete performance. This invention preferably follows the standards GB / T50081-2019 "Standard for Test Methods of Physical and Mechanical Properties of Concrete", GB / T 14685-2011 "Construction Gravel and Crushed Stone", and GB / T14684-2011 "Construction Sand". Natural coarse aggregate, natural fine aggregate, and recycled FRP aggregate required for concrete are selected and prepared, and the concrete mix proportion is determined. During the experimental process, the gradation of the recycled FRP aggregate is ensured to be consistent with that of the natural coarse aggregate. This invention preferably involves crushing the recycled FRP waste to obtain recycled FRP aggregates of different particle sizes, preferably in the range of 5–25 mm. This minimizes the impact of different aggregate gradations on the concrete strength after the recycled FRP particles replace natural aggregates. Furthermore, the aspect ratio of the recycled FRP particles is preferably controlled to be low (<1.6) to avoid the adverse effects of excessively elongated recycled FRP aggregate particles. The crushed FRP aggregate was subjected to particle size distribution testing to ensure that the particle size distribution met the design requirements. Aggregates with uniform particle size distribution can improve the density and strength of concrete. It is important to note that the crushing of recycled FRP differs from that of ordinary natural aggregates; it requires the use of an electric saw to cut it into appropriate sizes. Furthermore, since the crushed recycled FRP reinforcement produces a large amount of resin and other filler dust, and the surface of the natural coarse aggregate is also covered with dirt, both are rinsed with clean water. Afterward, the natural coarse aggregate is dried in a drying oven, while the recycled FRP aggregate is placed outdoors to air dry. In this invention, the recycled FRP material, after the above-mentioned coating modification, becomes modified recycled FRP material, which is then used as all or part of the coarse aggregate in the raw materials for the preparation of the concrete.

[0100] In this invention, the preferred method for preparing the concrete is as follows: mixing the raw materials for concrete preparation to obtain a slurry; pouring the slurry into a mold for a first curing, and demolding to obtain a molded body; subjecting the molded body to a second curing to obtain the concrete product. The first curing temperature is preferably room temperature (25°C), and the curing time is preferably 24 hours. The second curing is preferably carried out in a standard curing room, with a preferred temperature of 20±2°C, a preferred curing time of 28 days, and a preferred relative humidity of 95%.

[0101] To further illustrate the present invention, the technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0102] Example 1

[0103] This embodiment designed 15 standard cylindrical compressive strength specimens (ф150mm×300mm). This embodiment mainly considers the volume replacement rate (r) of natural coarse aggregate with recycled GFRP aggregate from decommissioned wind turbine blades (used in this embodiment): 0%, 30%, 50%, 70%, and 100%. The volume replacement rate r = recycled GFRP aggregate from decommissioned wind turbine blades / (recycled GFRP aggregate from decommissioned wind turbine blades + natural coarse aggregate); each volume replacement rate r has 3 replicate specimens to minimize experimental error. The specific designations of each group of specimens are shown in Table 1. For example, FRP30 indicates that the volume replacement rate r of recycled GFRP aggregate from decommissioned wind turbine blades to natural coarse aggregate is 30%, and so on. The concrete mix proportions of this embodiment (kg / m³) are... 3 As shown in Table 1, this mix design has a water-cement ratio of 0.45, which allows the target cube (150mm×150mm×150mm cube) to achieve a compressive strength of approximately 40MPa. All specimens were stored at approximately 25℃ after casting and demolded after 24 hours. The specimens were then placed in a standard curing room for 28 days at a temperature of 20±2℃ and a relative humidity of 95%.

[0104] Table 1. Concrete mix proportions (kg / m³) 3 )

[0105]

[0106] The compressive strength test was conducted using a 3000KNMTS servo hydraulic press with a displacement control rate of 0.3 mm / min. Force sensors were used to measure the force, and four longitudinal LVDTs were used to monitor the longitudinal displacement. Data was acquired on a computer using a Dewesoft dynamic acquisition box. The test results are summarized in Table 2. The results show that as the volume replacement rate (r) of recycled GFRP aggregate from decommissioned wind turbine blades to natural coarse aggregate increases, the compressive strength gradually decreases, and the decrease is significant: when the volume replacement rate (r) is 50%, the compressive strength decreases by 63.76%, and when the recycled GFRP aggregate from decommissioned wind turbine blades completely replaces the natural coarse aggregate, the compressive strength is approximately one-seventh of the control group (FRP0). The elastic modulus of RFAC (recycled GFRP aggregate concrete) from decommissioned wind turbine blades gradually decreases with increasing volume replacement rate (r) of the recycled GFRP aggregate. For peak strain, within the volume replacement rate (r) range of 0% to 50%, the peak strain first decreases and then increases with increasing r; the same trend is observed when the volume replacement rate (r) exceeds 50%. Furthermore, Figure 2 The relationship between the replacement rate of recycled FRP aggregate concrete and its compressive strength under different replacement rates is shown. Figure 3 The test results and predicted results of the stress-strain curves of axial compression tests on decommissioned wind turbine blades using recycled GFRP aggregate concrete under a replacement rate r = 100% are also presented. Figure 3 The replacement rate r = 100%, and the horizontal axis represents strain. The results show that although the experimental and predicted results of the volume replacement rate r of recycled GFRP aggregate for different decommissioned wind turbine blades are slightly different, they generally provide a good estimate of the stress and strain changes of the concrete made from recycled GFRP aggregate for decommissioned wind turbine blades under compression.

[0107] Table 2. Axial compression test results of FRP aggregate concrete specimens for decommissioned wind turbine blades.

[0108]

[0109] Example 2

[0110] Epoxy mortar wrapping treatment:

[0111] ① Prepare recycled GFRP aggregate and epoxy mortar for retired wind turbine blades. The epoxy mortar includes epoxy resin (A material, Lica-131 carbon fiber adhesive (Nanjing Haituo Composite Materials Co., Ltd.)), curing agent (B material), cement and quartz sand (C material, the mass ratio of cement and quartz sand is 1:2), several pallets, and an electronic scale.

[0112] ② Weigh out m mass of recycled GFRP aggregate from decommissioned wind turbine blades, and simultaneously weigh out materials A, B and C in a mass ratio of 1:3:16; Epoxy mortar coating amount s = mass of epoxy mortar / mass of recycled GFRP aggregate from decommissioned wind turbine blades;

[0113] ③ Pour the recycled GFRP aggregate from the decommissioned wind turbine blades into a small mixer, and pour in the weighed C material together. Then mix for 1 to 2 minutes to ensure that the C material fully covers the surface of the recycled GFRP aggregate from the decommissioned wind turbine blades.

[0114] ④ Mix the weighed A and B materials evenly in a container, then start the mixer and slowly and evenly pour the mixture into the mixing drum;

[0115] ⑤ After the mixture is poured in, let the mixer continue to mix for 3-5 minutes. Then, take out the wrapped retired wind turbine blades, recycle the GFRP aggregate, place it on a tray, and put it in the curing room for curing.

[0116] ⑥ After curing for 48 hours, take out the wrapped GFRP aggregate from the decommissioned wind turbine blades and pour it back into the mixer for 1 minute. The purpose is to separate the aggregates that are stuck together due to a small amount of epoxy mortar between the particles. Finally, pour out the GFRP aggregate from the decommissioned wind turbine blades and put it into the curing room for 7 days.

[0117] In this embodiment, three modified recycled FRP aggregates from decommissioned wind turbine blades were prepared with epoxy mortar and recycled GFRP aggregates from decommissioned wind turbine blades at mass ratios (coating amount s) of 0.25, 0.3, and 0.35, for use in subsequent concrete pouring.

[0118] This embodiment designed 6 groups of modified GFRP aggregate concrete (MRFAC) for decommissioned wind turbine blades, with 3 replicate specimens in each group, for a total of 18 standard cylindrical compressive strength specimens (ф150mm×300mm). The entire experiment involved two independent variables: epoxy mortar coating amount s and the volume replacement rate r of the decommissioned wind turbine blade recycled GFRP aggregate to natural coarse aggregate. On the one hand, modified decommissioned wind turbine blade recycled GFRP aggregate was prepared with an epoxy mortar coating amount s of 0.25, and 4 groups of MRFAC specimens with different volume replacement rates r (30%, 50%, 70%, 100%) were designed to study the improvement of mechanical properties after modification. On the other hand, with a volume replacement rate r of 100%, the epoxy mortar coating amount s was changed to 0.3 and 0.35 respectively as another 2 groups to analyze the effect of different epoxy mortar coating amounts on compressive strength. The specific labels of each specimen are shown in Table 3. For example, FRP30-S0.25 indicates that the ratio of the epoxy mortar coating amount of the modified decommissioned wind turbine blade recycled GFRP aggregate to the mass of the decommissioned wind turbine blade recycled GFRP aggregate (epoxy mortar coating amount s) is 0.25, and the volume replacement rate r of the decommissioned wind turbine blade recycled GFRP aggregate to natural coarse aggregate is 30%, and so on.

[0119] Table 3 Design of GFRP aggregate concrete specimens for modified decommissioned wind turbine blades

[0120] Specimen GFRP aggregate replacement rate r Epoxy mortar coating amount s FRP30 30％ 0 FRP50 50％ 0 FRP70 70％ 0 FRP100 100％ 0 FRP30-S0.25 30％ 0.25 FRP50-S0.25 50％ 0.25 FRP70-S0.25 70％ 0.25 FRP100-S0.25 100％ 0.25 FRP100-S0.3 100％ 0.30 FRP100-S0.35 100％ 0.35

[0121] Table 4 shows the peak stress, corresponding peak strain, and elastic modulus of modified concrete specimens made from recycled GFRP aggregate from decommissioned wind turbine blades with different GFRP replacement rates (r). After being coated with epoxy mortar, the overall compressive strength of the recycled GFRP aggregate from decommissioned wind turbine blades showed a significant increase compared to the unmodified specimens, ranging from approximately 18% to 86%. When the coating amount (s = 0.25) was constant, the increase in compressive strength first decreased and then increased with increasing replacement rate. When the replacement rate (r) was 30%, the modified axial compressive strength increased by 21.4% compared to the unmodified specimens. At a replacement rate (r) of 50%, the increase slightly decreased to 18.6%. Further increases in replacement rate (r) to 70% and 100% resulted in increases of 29.4% and 72.2%, respectively. This indicates that the epoxy mortar coating modification method can better improve the compressive strength of concrete with more modified recycled GFRP aggregate from decommissioned wind turbine blades, especially in cases with initial defects (initial defects refer to poor bonding between the recycled GFRP aggregate and the concrete matrix in decommissioned wind turbine blades that are not coated with epoxy mortar, resulting in voids and lower strength and modulus of elasticity). In specimens with the same replacement rate r (100%), different coating amounts s showed similar increases in compressive strength, approximately 70%–86%, but the group with the best effect was the FRP100-S0.30 group.

[0122] Figure 4 A comparison of the core compressive strength of modified recycled GFRP aggregate concrete is presented.

[0123] Figure 5 A comparison of experimental and predicted results for the axial compressive stress-strain curves of GFRP aggregate concrete in modified decommissioned wind turbine blades is presented. Overall, the model proposed in this invention performs well at various substitution rates, especially when the amount of epoxy mortar coating increases, the model curves show a higher degree of agreement with the experimental curves. Figure 5 When the substitution is r = 100%, the amount of wrapping is s = 0.25, the horizontal axis represents strain, and the vertical axis represents stress.

[0124] Table 4. Axial compression test results of modified recycled GFRP aggregate concrete specimens.

[0125]

[0126]

[0127] The above allows us to obtain the initial strength of ordinary concrete, the replacement strength of ordinary recycled FRP aggregate concrete under a certain FRP replacement rate for decommissioned wind turbine blades, and the modified strength and epoxy mortar dosage of modified decommissioned wind turbine blade recycled FRP aggregate concrete under the same FRP replacement rate. It is worth noting that the FRP replacement rate for decommissioned wind turbine blades mentioned in this embodiment includes 30%, 50%, 70%, and 100%, but is not limited to these. It may include only a few of these rates, or it may include multiple other replacement rates. Furthermore, the FRP replacement rate may be a non-integer value, such as 9% or 17%.

[0128] Then, by comparing the stress-strain curves (strain on the horizontal axis and stress on the vertical axis), peak stress (concrete strength), initial slope (i.e. elastic modulus), and elastic modulus change characteristics before and after modification under different FRP replacement rates for decommissioned wind turbine blades, constitutive equations were established for the peak stress of modified decommissioned wind turbine blade recycled FRP aggregate concrete, the FRP aggregate replacement rate of decommissioned wind turbine blades, and the change in epoxy mortar coating amount.

[0129] Based on initial strength information and replacement strength information, this invention constructs an initial equation relating the initial strength of ordinary concrete to the strength of ordinary recycled FRP aggregate concrete under any corresponding recycled FRP aggregate replacement rate, as shown in equation (1).

[0130] Based on the modified strength information and initial equations, this invention constructs target equations relating the initial strength of ordinary concrete, the compressive strength of modified decommissioned wind turbine blade recycled FRP aggregate concrete, the replacement rate of decommissioned wind turbine blade recycled FRP aggregate, and the amount of epoxy mortar coating. As shown in equations (2)-(6).

[0131] Finally, this invention obtains the target parameters of the modified decommissioned wind turbine blade recycled FRP aggregate concrete, and inputs the target parameter data into the target equation, which outputs the current compressive strength of the modified decommissioned wind turbine blade recycled FRP aggregate concrete. The target parameters include the FRP replacement rate of the decommissioned wind turbine blade, the amount of epoxy mortar coating, and the initial strength of ordinary concrete.

[0132] This invention utilizes constitutive equations to determine the compressive strength of modified concrete using recycled FRP aggregate from decommissioned wind turbine blades, under specific conditions of FRP aggregate replacement rate and epoxy mortar coating amount. Figure 3 , Figure 5 ).

[0133] Understandably, existing technologies cannot, based on the preset target strength and mix proportion of the modified decommissioned wind turbine blade recycled FRP aggregate concrete, select other data (replacement rate of decommissioned wind turbine blade recycled FRP aggregate, amount of epoxy mortar coating) to ensure that the compressive strength of the obtained modified decommissioned wind turbine blade recycled FRP aggregate concrete is greater than or equal to the preset target strength of the modified decommissioned wind turbine blade recycled FRP aggregate concrete.

[0134] In this invention, the mix proportion of concrete and the preset target strength of the modified decommissioned wind turbine blade recycled FRP aggregate concrete are obtained. The preset target strength is used as the compressive strength of the modified decommissioned wind turbine blade recycled FRP aggregate concrete in the target formula, and the mix proportion is input into the target equation. The target equation outputs the data range of parameters to be confirmed (replacement rate and wrapping amount), and the target data of the parameters to be confirmed are determined according to the data range. The determined data and target data are input into the target equation, and the target equation outputs the current compressive strength of the modified decommissioned wind turbine blade recycled FRP aggregate concrete, so that the current compressive strength is above the preset target strength.

[0135] In the first implementation of the present invention Figure 6This diagram illustrates the relationship between the FRP aggregate replacement rate (r), epoxy mortar coating amount (s), and compressive strength of the modified decommissioned wind turbine blade FRP aggregate concrete when the ordinary concrete strength is 35 MPa. The target strength and concrete mix proportion of the modified decommissioned wind turbine blade FRP aggregate concrete are determined; that is, the target parameter is the initial strength of the ordinary concrete (natural aggregate concrete). Obtain the current initial strength of ordinary concrete and the preset target compressive strength of modified FRP aggregate concrete for decommissioned wind turbine blades. Input the preset target strength as the compressive strength and the current initial strength into the target equation. The target equation outputs the data ranges corresponding to the current replacement rate r and the current epoxy mortar coating amount s of the modified FRP aggregate concrete for decommissioned wind turbine blades. Based on the data ranges corresponding to the current replacement rate and the current epoxy mortar coating amount of the modified FRP aggregate concrete for decommissioned wind turbine blades, determine the target replacement rate and the target epoxy mortar coating amount (i.e., the area above the design target plane). Input the initial strength, target replacement rate, and target epoxy mortar coating amount into the target equation. The target equation outputs the current compressive strength of the modified FRP aggregate concrete for decommissioned wind turbine blades, so that the current compressive strength is above the preset target strength.

[0136] This invention involves setting the same mix proportion for concrete, adding a certain amount of recycled FRP aggregate from decommissioned wind turbine blades, and varying the replacement rate of the recycled FRP aggregate within a certain range. By using different amounts of epoxy mortar to coat the aggregate, the concrete is modified to achieve the target strength.

[0137] As can be seen from the above embodiments, this invention uses modified and recycled waste FRP to replace natural stones (natural coarse aggregate) in concrete as coarse aggregate, solving the problems of difficult FRP waste treatment and low resource utilization in the prior art, effectively reducing environmental pollution, and has significant environmental protection significance. Furthermore, this invention significantly improves the compressive strength and elastic modulus of recycled FRP aggregate concrete by modifying the surface of the recycled FRP aggregate by coating it with epoxy mortar, meeting the requirements of high-performance building materials.

[0138] Although the above embodiments have provided a detailed description of the present invention, they are only some embodiments of the present invention, and not all embodiments. Other embodiments can be obtained based on these embodiments without creative effort, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A method for preparing concrete containing modified recycled FRP aggregate, characterized in that, Includes the following steps: The compressive strength of the concrete containing modified recycled FRP aggregate is preset, and the mix proportion of the concrete containing modified recycled FRP aggregate is determined. The compressive strength of the concrete containing natural aggregate is obtained from the mix proportion. The range of two parameters, substitution rate and wrapping amount, is obtained by formula (1)~(6). The range is the range where the compressive strength of the concrete containing modified recycled FRP aggregate is ≥ the preset compressive strength under the condition that the mix proportion is determined. Then, the substitution rate and wrapping amount of the concrete containing modified recycled FRP aggregate are determined by the range of two parameters, substitution rate and wrapping amount. The substitution rate is the volume percentage of modified recycled FRP aggregate in the coarse aggregate of the concrete containing modified recycled FRP aggregate. The modified recycled FRP aggregate is epoxy mortar modified recycled FRP aggregate. The wrapping amount is the mass ratio of epoxy mortar to recycled FRP aggregate. （1）； （2）； （3）； （4）； （5）； （6）； In formulas (1)~(6): f c ’ The compressive strength of concrete containing modified recycled FRP aggregate. f co ’ The compressive strength of concrete with natural aggregates. ε c ’ The peak strain of the concrete containing modified recycled FRP aggregate is given by r, where r is the replacement rate. k s1 The elastic modulus of concrete is related to the amount of wrapping. k s2 The peak strain coefficient of concrete is related to the amount of encapsulation. s For package volume, E c The elastic modulus of concrete containing modified recycled FRP aggregate. k e The elastic modulus of concrete is related to the replacement rate. Based on the stated amount of encapsulation, epoxy mortar is used to encapsulate and modify the recycled FRP material to obtain the modified recycled FRP aggregate. Based on the substitution rate and mix proportion, the modified recycled FRP aggregate is used to prepare the concrete containing the modified recycled FRP aggregate, and the compressive strength of the concrete containing the modified recycled FRP aggregate is ≥ the preset compressive strength.

2. The preparation method according to claim 1, characterized in that, The package quantity is 0.1~0.5; the replacement rate is ≥30%.

3. The preparation method according to claim 1, characterized in that, The epoxy mortar includes epoxy resin, curing agent, and additives; the additives include cement and quartz sand.

4. The preparation method according to claim 3, characterized in that, The mass ratio of the epoxy resin, curing agent and additives is (1~2):(1~5):(12~20).

5. The preparation method according to claim 4, characterized in that, The mass ratio of cement to quartz sand in the additive is 1:(1~3).

6. The preparation method according to claim 1, characterized in that, The particle size range of the recycled FRP material is 5~25mm; the aspect ratio is <1.

6.

7. The preparation method according to claim 3, characterized in that, The package modification includes the following steps: The recycled FRP material and additives are premixed to obtain a premixed material; The epoxy resin and curing agent are mixed and then mixed with the premix to obtain the initial modified product; The initial modified product is cured to obtain the modified recycled FRP aggregate.

8. The preparation method according to claim 1, characterized in that, The water-cement ratio in the specified mix proportion is 0.

45.

9. The preparation method according to claim 1, characterized in that, The curing conditions for preparing the concrete containing modified recycled FRP aggregate include: a curing temperature of 20±2℃, a relative humidity of 95%, and a curing time of 28 days.

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