Method for modifying FRP (Fiber Reinforced Plastic) aggregate recycled from retired fan blade, concrete material of FRP aggregate and structural design method of FRP aggregate

Abstract

The invention belongs to the technical field of FRP aggregate concrete recycled from modified retired fan blades, and particularly relates to FRP aggregate modification recycled from retired fan blades and a concrete material and structure design method thereof. The structural parameters of the concrete containing the modified recycled FRP aggregate comprise the compressive strength and the mix proportion of the concrete containing the modified retired fan blade recycled FRP aggregate, the substitution rate of the modified recycled FRP aggregate and the wrapping amount of epoxy mortar. According to the method provided by the invention, the determination of the structural parameters of the concrete containing the modified retired fan blade recycled FRP aggregate and the steel bar-modified retired fan blade recycled FRP aggregate concrete beam component can be accurately realized; therefore, the comprehensive design of the compressive strength of the concrete containing the modified retired fan blade recycled FRP aggregate and the bending moment bearing capacity of the steel bar-modified retired fan blade recycled FRP aggregate concrete beam component is realized.

Description

Technical Field

[0001] The invention belongs to the technical field of modified FRP aggregate concrete recycled from retired fan blades, and in particular relates to the modification of FRP aggregate recycled from retired fan blades and a concrete material and structure design method thereof. Background Art

[0002] With the rapid development of the construction industry, the use of traditional building materials has put tremendous pressure on the environment. The excessive consumption of resources such as cement, river sand, and natural coarse aggregate has not only led to resource depletion, but also increased carbon emissions. Fiber reinforced plastics (FRP) are used to manufacture wind turbine blades due to their advantages such as high strength, light weight, corrosion resistance, and fatigue resistance. As wind power is an important component of new clean energy, with the replacement of equipment and the expiration of the service life of early units, the FRP waste generated by retired wind turbine blades is increasing. However, for the FRP waste in retired wind turbine blades, the traditional landfill and incineration treatment methods are not only costly, but also cause serious pollution to the environment. If the FRP waste in retired wind turbine blades is recycled and used in the preparation of concrete, it can not only reduce the huge harm to the environment caused by improper treatment of waste FRP in retired wind turbine blades, but also reduce the over-exploitation of resources such as sand and gravel. Therefore, in order to promote the green recycling of FRP waste in retired wind turbine blades, it is very important to continue to promote the research and utilization of FRP aggregate concrete recycled from retired wind turbine blades.

[0003] However, in the existing preparation scheme of FRP aggregate concrete recycled from retired wind turbine blades, directly adding untreated FRP aggregate recycled from retired wind turbine blades will cause the strength and elastic modulus of concrete to decrease, resulting in unstable mechanical properties of the prepared FRP aggregate concrete recycled from retired wind turbine blades, which cannot meet the application standards of actual projects. Therefore, it is necessary to perform surface modification treatment on FRP waste recycled from retired wind turbine blades to improve the mechanical properties of FRP aggregate concrete recycled from retired wind turbine blades. Summary of the invention

[0004] The purpose of the present invention is to provide a modified FRP aggregate recycled from retired wind turbine blades and a concrete material and structure design method thereof. The method provided by the present invention can accurately determine the structural parameters of the concrete containing the modified FRP aggregate recycled from retired wind turbine blades and the steel bar-modified FRP aggregate concrete beam component, thereby realizing the comprehensive design of the compressive strength of the concrete containing the modified FRP aggregate recycled from retired wind turbine blades and the bending moment bearing capacity of the steel bar-modified FRP aggregate concrete beam component.

[0005] In order to achieve the above object, the present invention provides the following technical solutions:

[0006] The present invention provides a method for determining structural parameters of concrete containing modified recycled FRP aggregates, wherein the structural parameters include compressive strength, mix ratio, substitution rate and encapsulation amount, wherein the substitution rate is the volume percentage of the modified recycled FRP aggregate in the coarse aggregate of the concrete containing the modified recycled FRP aggregates, the modified recycled FRP aggregates are epoxy mortar modified recycled FRP aggregates, and the encapsulation amount is the mass ratio of the epoxy mortar to the recycled FRP aggregates;

[0007] The determination method comprises the following steps: obtaining three structural parameters including the mix ratio, obtaining the compressive strength of the concrete with natural aggregate from the mix ratio, and determining the remaining structural parameters using formulas (1) to (6);

[0008] Alternatively, the determination method comprises the following steps: obtaining the compressive strength, replacement rate and encapsulation amount, using formulas (1) to (6) to obtain the compressive strength of the concrete with natural aggregate, and determining the mix ratio according to the compressive strength of the concrete with natural aggregate;

[0009] Alternatively, the determination method comprises the following steps: presetting the compressive strength, obtaining any one of the mix ratio, the substitution rate and the amount of coating, when the obtained structural parameter is the mix ratio, obtaining the compressive strength of the concrete with natural aggregate from the mix ratio, using formulas (1) to (6) to obtain the range of the remaining two structural parameters of the mix ratio, the substitution rate and the amount of coating, the range being the range when the compressive strength of the concrete containing modified recycled FRP aggregate is ≥ the preset compressive strength under the condition that any one of the mix ratio, the substitution rate and the amount of coating is determined; determining the remaining two structural parameters from the range of the remaining two structural parameters, and determining the compressive strength from the mix ratio, the substitution rate and the amount of coating using formulas (1) to (6);

[0010]

[0011] k s1 =1+0.449s 2 +0.928rs-0.699s (3);

[0012]

[0013] k s2 =-78.696s 2 -1.326rs+47.359s-5.921 (5);

[0014]

[0015] In formulas (1) to (6): f c ' is the compressive strength of concrete containing modified recycled FRP aggregate, f co ' is the compressive strength of concrete with natural aggregate, εc ' is the peak strain of concrete containing modified recycled FRP aggregate, r is the substitution rate, k s1 k is the elastic modulus of concrete related to the amount of wrapping, s2 is the peak strain coefficient of concrete related to the encapsulation amount, s is the encapsulation amount, E c is the elastic modulus of concrete containing modified recycled FRP aggregate, k e is the elastic modulus coefficient of concrete related to the replacement rate.

[0016] Preferably, the method for constructing formulas (1) to (6) comprises the following steps:

[0017] Providing concrete specimens, the concrete specimens comprising concrete specimens of natural aggregates, concrete specimens containing recycled FRP aggregates, and concrete specimens containing modified recycled FRP aggregates;

[0018] The concrete specimens are subjected to a compression test to obtain initial compressive strength information of the concrete specimens containing natural aggregates, alternative compressive strength information of the concrete specimens containing recycled FRP aggregates, and modified compressive strength information of the concrete specimens containing modified recycled FRP aggregates;

[0019] According to the initial compressive strength information and the replacement compressive strength information, construct an initial formula correlating the compressive strength of concrete with natural aggregates, the compressive strength of concrete containing recycled FRP aggregates, and the replacement rate of recycled FRP aggregates, wherein the replacement rate of recycled FRP aggregates is the volume percentage of recycled FRP aggregates in the coarse aggregates of the concrete specimen containing recycled FRP aggregates;

[0020] According to the initial compressive strength information and the modified compressive strength information, formulas (2) to (6) are constructed;

[0021] Formulas (2) to (6) are used to correct the initial formula to obtain formulas (1) to (6).

[0022] Preferably, the method for preparing the modified recycled FRP aggregate comprises the following steps:

[0023] The recycled FRP aggregate and epoxy mortar are mixed and packaged and modified to obtain the modified recycled FRP aggregate; the epoxy mortar includes epoxy resin, curing agent and auxiliary agent.

[0024] Preferably, the mass ratio of the epoxy resin, the curing agent and the auxiliary agent is (1-2): (1-5): (12-20).

[0025] Preferably, the particle size of the recycled FRP aggregate is in the range of 5 to 25 mm, and the aspect ratio is less than 1.6.

[0026] The present invention provides a system for determining structural parameters of concrete containing modified recycled FRP aggregate, comprising a data acquisition module, an initial formula building module, a target formula determination module and an output module;

[0027] The data acquisition module is used to collect compressive strength information obtained by performing compression tests on concrete specimens, wherein the concrete specimens include concrete specimens with natural aggregates, concrete specimens containing recycled FRP aggregates, and concrete specimens containing modified recycled FRP aggregates; the compressive strength information includes initial compressive strength information of concrete specimens with natural aggregates, alternative compressive strength information of concrete specimens containing recycled FRP aggregates, and modified compressive strength information of concrete specimens containing modified recycled FRP aggregates;

[0028] The initial formula construction module obtains the initial compressive strength information and the replacement compressive strength information transmitted by the data acquisition module, and is used to construct an initial formula for the compressive strength of concrete associated with natural aggregates, the compressive strength of concrete containing recycled FRP aggregates, and the replacement rate of recycled FRP aggregates, wherein the replacement rate of recycled FRP aggregates is the volume percentage of recycled FRP aggregates in the coarse aggregates of the concrete specimen containing recycled FRP aggregates;

[0029] The target formula determination module is used to construct formulas (1) to (6);

[0030]

[0031] k s1 =1+0.449s 2 +0.928rs-0.699s (3);

[0032]

[0033] k s2 =-78.696s 2 -1.326rs+47.359s-5.921 (5);

[0034]

[0035] In formulas (1) to (6): f c ' is the compressive strength of concrete containing modified recycled FRP aggregate, f co ' is the compressive strength of concrete with natural aggregate, ε c ' is the peak strain of concrete containing modified recycled FRP aggregate, r is the substitution rate, k s1 k is the elastic modulus of concrete related to the amount of wrapping, s2 is the peak strain coefficient of concrete related to the encapsulation amount, s is the encapsulation amount, E cis the elastic modulus of concrete containing modified recycled FRP aggregate, k e is the elastic modulus coefficient of concrete related to the replacement rate;

[0036] The output module is used to output the remaining structural parameters.

[0037] The present invention provides a method for determining structural parameters of a steel bar-modified recycled FRP aggregate concrete beam component, wherein the structural parameters include the moment bearing capacity of the steel bar-modified recycled FRP aggregate concrete beam component and structural parameters of concrete containing modified recycled FRP aggregate;

[0038] The structural parameters of the concrete containing modified recycled FRP aggregate are determined by the method described in the above technical solution;

[0039] The acquisition of the moment bearing capacity of the steel bar-modified recycled FRP aggregate concrete beam component includes: converting the actual stress-strain curve of the concrete containing modified recycled FRP aggregate in the compression zone of the steel bar-modified recycled FRP aggregate concrete beam component into an equivalent rectangular stress-strain curve according to an equivalent condition, wherein the equivalent condition is that the resultant forces of the actual stress-strain curve and the equivalent rectangular stress-strain curve are equal and the positions of the action points coincide; determining dimensionless parameters k1 and k2 from the actual stress-strain curve of the concrete containing modified recycled FRP aggregate and the equivalent rectangular stress-strain curve according to the equivalent condition; k1 is determined by formula (7), and k2 is determined by formula (8);

[0040]

[0041] In formula (7) and formula (8), k1 is the ratio of the area of ​​the actual stress-strain curve of concrete containing modified recycled FRP aggregate to the area of ​​the equivalent rectangular stress-strain curve, k2 is the ratio of the distance from the resultant point to the compressive edge of the actual stress-strain curve of concrete containing modified recycled FRP aggregate to the strain of the compressive edge, and ε m is the compressive edge strain of the concrete containing modified recycled FRP aggregate in the beam section of the reinforced steel-modified recycled FRP aggregate concrete beam component; σ is the stress of the concrete containing modified recycled FRP aggregate, ε is the strain of the concrete containing modified recycled FRP aggregate, f c ' is the compressive strength of concrete containing modified recycled FRP aggregate;

[0042] Set the height of the compression zone of the equivalent rectangular stress-strain curve to βx, and the uniformly distributed equivalent stress in the equivalent rectangular stress-strain curve to αf c', the coefficients of the equivalent rectangular stress-strain curve are β and α, where β = 2k2, α = k1 / 2k2; the height of the compressive zone of the beam section of the reinforced-modified recycled FRP aggregate concrete beam component is determined by formula (9):

[0043]

[0044] In formula (9), x is the actual compressive zone height of the beam section of the reinforced concrete beam with modified recycled FRP aggregate, β is the height coefficient of the equivalent rectangular stress-strain curve, α is the strength coefficient of the equivalent rectangular stress-strain curve, and A s is the tensile reinforcement area, f y is the tensile strength of the reinforcement, f c ' is the compressive strength of concrete containing modified recycled FRP aggregate, b is the beam width of the reinforced steel-modified recycled FRP aggregate concrete beam component;

[0045] The moment bearing capacity of the steel bar-modified recycled FRP aggregate concrete beam member is determined by formula (10):

[0046] M=αf c 'bx(h0-x / 2) Formula (10);

[0047] In formula (10), M is the moment bearing capacity of the reinforced concrete beam with modified recycled FRP aggregate, α is the strength coefficient of the equivalent rectangular stress-strain curve, and f c ' is the compressive strength of concrete containing modified recycled FRP aggregate, x is the actual compression zone height of the beam section of the steel bar-modified recycled FRP aggregate concrete beam component, b is the beam width of the steel bar-modified recycled FRP aggregate concrete beam component; h0 is the effective height of the beam section of the steel bar-modified recycled FRP aggregate concrete beam component;

[0048] The actual stress-strain curve of the concrete containing modified recycled FRP aggregate in the actual compression zone of the steel bar-modified recycled FRP aggregate concrete beam component is shown in formula (11):

[0049]

[0050] In formula (11), parameter a and parameter b1 are determined by formula (12) and formula (13), respectively:

[0051] a=1.927+0.489r+1.23r 2 -1.333r 3 Formula (12);

[0052] b1=0.129(r+0.011) -0.571 +57.371(1+rs)-39.124 s Formula (13);

[0053] In formulas (11) to (13), f c ' is the compressive strength of concrete containing modified recycled FRP aggregate, ε c ' is the peak strain of concrete containing modified recycled FRP aggregate; σ is the stress of concrete containing modified recycled FRP aggregate; ε is the strain of concrete containing modified recycled FRP aggregate; a is the shape coefficient of the rising section of the actual stress-strain curve of concrete containing modified recycled FRP aggregate; b1 is the shape coefficient of the rising and falling sections of the actual stress-strain curve of concrete containing modified recycled FRP aggregate; r is the substitution rate; s is the encapsulation amount.

[0054] The present invention provides a method for determining structural parameters of concrete containing modified recycled FRP aggregates, wherein the structural parameters include compressive strength, mix ratio, substitution rate and encapsulation amount, wherein the substitution rate is the volume percentage of the modified recycled FRP aggregate in the coarse aggregate of the concrete containing the modified recycled FRP aggregates, wherein the modified recycled FRP aggregates are epoxy mortar modified recycled FRP aggregates, and the encapsulation amount is the mass ratio of the epoxy mortar to the recycled FRP aggregates. The present invention adopts formulas (1) to (6) to accurately complete the comprehensive design of the mix ratio (corresponding to the compressive strength of natural aggregate concrete), the substitution rate (i.e., the substitution rate of the modified recycled FRP aggregates), the encapsulation amount (i.e., the encapsulation amount of the epoxy mortar) and the compressive strength of the concrete containing the modified recycled FRP aggregates.

[0055] The present invention provides a system for determining the structural parameters of concrete containing modified recycled FRP aggregates, including a data acquisition module, an initial formula construction module, a target formula determination module and an output module. The design system provided by the present invention can realize the integrated design of the output of the structural parameters (compressive strength, mix ratio, replacement rate and packaging amount) of concrete containing modified recycled FRP aggregates from the collection of original data, the construction of equations and the results, and can more efficiently realize the integrated design of the structural parameters of concrete containing modified recycled FRP aggregates.

[0056] The present invention provides a method for determining the structural parameters of a steel bar-modified recycled FRP aggregate concrete beam component, wherein the structural parameters include the moment bearing capacity of the steel bar-modified recycled FRP aggregate concrete beam component and the structural parameters of concrete containing modified recycled FRP aggregate. The present invention converts the actual stress-strain curve of the concrete containing modified recycled FRP aggregate in the compression zone of the steel bar-modified recycled FRP aggregate concrete beam component to obtain formulas (7) to (13), and introduces the associated formulas (1) to (6) of the structural parameters of the concrete containing modified recycled FRP aggregate, and combines the result parameters of the equivalent condition conversion with the compressive strength of the concrete containing modified recycled FRP aggregate, so as to accurately complete the comprehensive design of the moment bearing capacity of the steel bar-modified recycled FRP aggregate concrete beam component, the compressive strength of the concrete containing modified recycled FRP aggregate, the mix ratio, the replacement rate of the modified recycled FRP aggregate, and the epoxy mortar wrapping amount. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] Figure 1 is the gradation curve of recycled GFRP aggregate and natural coarse aggregate;

[0058] Figure 2 Comparison between the experimental and predicted stress-strain curves of concrete containing recycled GFRP aggregates;

[0059] Figure 3 Comparison between the experimental and predicted stress-strain curves of concrete containing modified recycled GFRP aggregates;

[0060] Figure 4 A schematic diagram of the relationship between the replacement rate of modified recycled GFRP aggregate, the epoxy mortar coating amount and the compressive strength of the concrete containing modified recycled GFRP aggregate when the compressive strength of ordinary concrete (i.e., concrete with natural aggregate) is 35 MPa in a preferred embodiment of the method for determining the compressive bearing capacity of concrete containing modified recycled GFRP aggregate of the present invention;

[0061] Figure 5 This is a schematic diagram of the relationship between the replacement rate of modified recycled FRP aggregate, the epoxy mortar wrapping amount and the moment bearing capacity of the steel bar-modified recycled FRP aggregate concrete beam component when the compressive strength of ordinary concrete (i.e., concrete with natural aggregate) is 35MPa in a preferred embodiment of the method for determining the design moment bearing capacity of the steel bar-modified recycled FRP aggregate concrete beam component of the present invention. DETAILED DESCRIPTION

[0062] The present invention provides a method for determining structural parameters of concrete containing modified recycled FRP aggregates, wherein the structural parameters include compressive strength, mix ratio, substitution rate and encapsulation amount, wherein the substitution rate is the volume percentage of the modified recycled FRP aggregate in the coarse aggregate of the concrete containing the modified recycled FRP aggregates, the modified recycled FRP aggregates are epoxy mortar modified recycled FRP aggregates, and the encapsulation amount is the mass ratio of the epoxy mortar to the recycled FRP aggregates;

[0063] The determination method comprises the following steps: obtaining three structural parameters including the mix ratio, obtaining the compressive strength of the concrete with natural aggregate from the mix ratio, and determining the remaining structural parameters using formulas (1) to (6);

[0064] Alternatively, the determination method comprises the following steps: obtaining the compressive strength, replacement rate and encapsulation amount, using formulas (1) to (6) to obtain the compressive strength of the concrete with natural aggregate, and determining the mix ratio according to the compressive strength of the concrete with natural aggregate;

[0065] Alternatively, the determination method comprises the following steps: presetting the compressive strength, obtaining any one of the mix ratio, the substitution rate and the amount of coating, when the obtained structural parameter is the mix ratio, obtaining the compressive strength of the concrete with natural aggregate from the mix ratio, using formulas (1) to (6) to obtain the range of the remaining two structural parameters of the mix ratio, the substitution rate and the amount of coating, the range being the range when the compressive strength of the concrete containing modified recycled FRP aggregate is ≥ the preset compressive strength under the condition that any one of the mix ratio, the substitution rate and the amount of coating is determined; determining the remaining two structural parameters from the range of the remaining two structural parameters, and determining the compressive strength from the mix ratio, the substitution rate and the amount of coating using formulas (1) to (6);

[0066]

[0067]

[0068] k s1 =1+0.449s 2 +0.928rs-0.699s (3);

[0069]

[0070] k s2 =-78.696s 2 -1.326rs+47.359s-5.921 (5);

[0071]

[0072] In formulas (1) to (6): f c' is the compressive strength of concrete containing modified recycled FRP aggregate, f co ' is the compressive strength of concrete with natural aggregate, ε c ' is the peak strain of concrete containing modified recycled FRP aggregate, r is the substitution rate, k s1 k is the elastic modulus of concrete related to the amount of wrapping, s2 is the peak strain coefficient of concrete related to the encapsulation amount, s is the encapsulation amount, E c is the elastic modulus of concrete containing modified recycled FRP aggregate, k e is the elastic modulus coefficient of concrete related to the replacement rate.

[0073] In the present invention, unless otherwise specified, all preparation raw materials / components are commercially available products well known to those skilled in the art.

[0074] In the present invention, the raw materials for preparing the concrete include coarse aggregate, fine aggregate, cement and water. The raw materials for preparing the concrete with natural aggregate are all natural coarse aggregate. The raw materials for preparing the concrete containing recycled FRP aggregate are recycled FRP aggregate or recycled FRP aggregate and natural coarse aggregate. The raw materials for preparing the concrete containing modified recycled FRP aggregate are modified recycled FRP aggregate or modified recycled FRP aggregate and natural coarse aggregate.

[0075] In the present invention, the replacement rate is the replacement rate of modified recycled FRP aggregate. The wrapping amount is the epoxy mortar wrapping amount.

[0076] In the present 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 is modified recycled FRP aggregate and natural coarse aggregate.

[0077] In the present invention, the raw materials for preparing the natural aggregate concrete include cement, water, natural coarse aggregate and natural fine aggregate.

[0078] In the present invention, the mix ratio 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 ratio of the concrete with natural aggregate and the compressive strength of the concrete with natural aggregate can be determined by literature data.

[0079] In the present invention, the preparation method of the modified recycled FRP aggregate preferably includes the following steps: recycled FRP aggregate, epoxy resin, curing agent and auxiliary agent are mixed and packaged for modification to obtain the modified recycled FRP aggregate; the mass ratio of the epoxy resin, curing agent and auxiliary agent is (1-2): (1-5): (12-20).

[0080] The present invention has no special requirements on the source of the recycled FRP material, and it can be obtained by methods well known in the art. In a specific embodiment of the present invention, the recycled FRP material is specifically recycled FRP waste from retired wind turbine blades.

[0081] The particle size range of the recycled FRP aggregate is preferably 5 to 25 mm; the aspect ratio is preferably <1.6. In a specific embodiment of the present invention, the present invention crushes the FRP waste to obtain recycled FRP aggregates of different particle sizes, usually in the range of 5 mm to 25 mm. This can minimize the impact of different aggregate gradings on the strength of concrete after FRP particles replace natural aggregates, and the cutting method with a particle size range of 5 mm to 25 mm considers the better continuity of FRP particle grading on the one hand, and the limited FRP size types in actual recycling situations on the other hand, and the aspect ratio of the particles is controlled to a lower state (<1.6) as much as possible, so as to avoid the FRP aggregate particles being too narrow and long and causing bad effects. The particle size distribution test is performed on the crushed FRP aggregate to ensure that the particle size distribution of the aggregate meets the design requirements. Aggregates with uniform particle size distribution can improve the density and strength of concrete. It should be noted that the crushing of FRP is different from the crushing of ordinary natural aggregates, and it is necessary to use an electric saw cutting method to divide it into suitable sizes. In addition, since there is a large amount of dust from resin and other fillers after FRP is crushed, and there is also mud on the surface of natural coarse aggregate, both are rinsed with clean water, and then the natural coarse aggregate is placed in a drying box to dry, while the recycled FRP aggregate is placed outdoors to dry.

[0082] In the present invention, the auxiliary agent is specifically cement and quartz sand, and the mass ratio of the cement to quartz sand is 1:2. The mass ratio of the epoxy resin, the curing agent and the auxiliary agent is preferably (1-2): (1-5): (12-20), specifically 1:3:16. The mixing preferably includes the following steps: premixing the recycled FRP aggregate and the auxiliary agent to obtain a premix; mixing the epoxy resin and the curing agent, and then mixing with the premix. The mixing is carried out under stirring. In the present invention, the time for the encapsulation modification after the above-mentioned raw materials are mixed is preferably 3-5 minutes. After the encapsulation modification, initial modified particles are obtained. In the present invention, the initial modified particles are preferably cured to obtain the modified recycled FRP aggregate. The curing includes a first stage curing and a second stage curing, and the time of the first stage curing is preferably 48 hours. Between the first stage curing and the second stage curing, the present invention preferably stirs the material in order to separate some aggregates that are bonded together due to a small amount of epoxy mortar between the particles. The second stage curing time is preferably 7 days. The curing is preferably carried out in a curing room.

[0083] In the present invention, the gradation of the natural coarse aggregate in the natural aggregate concrete is consistent with that of the coarse aggregate in the modified recycled FRP aggregate concrete.

[0084] In the present invention, the mix ratio of the natural aggregate concrete and the modified recycled FRP aggregate concrete is the same. The raw materials for preparing the concrete include cement, fine aggregate, water and coarse aggregate. The mix ratio of concrete includes the mass ratio of cement, fine aggregate, water and coarse aggregate. In the present invention, the coarse aggregate includes natural coarse aggregate and recycled FRP aggregate (or modified recycled FRP aggregate). According to the specific engineering requirements, the proportion of each component can be appropriately adjusted to meet different mechanical property requirements.

[0085] In a specific embodiment of the present invention: the determination method specifically includes the following steps: obtaining the mix ratio, replacement rate and encapsulation amount, obtaining the compressive strength of the concrete containing natural aggregate from the mix ratio, and using formulas (1) to (6) to determine the compressive strength of the concrete containing modified recycled FRP aggregate.

[0086] In a specific embodiment of the present invention, the method for determining the parameters specifically includes the following steps: determining a preset compressive strength of concrete containing modified recycled FRP aggregate, obtaining a mix ratio, obtaining the compressive strength of concrete containing natural aggregate from the mix ratio, and using formulas (1) to (6) to obtain a range of a replacement rate and an encapsulation amount, wherein the range is a range in which, under the condition that the mix ratio is determined, the compressive strength of concrete containing modified recycled FRP aggregate is greater than or equal to the preset compressive strength; determining a remaining replacement rate and an encapsulation amount from the range of the replacement rate and the encapsulation amount, and using formulas (1) to (6) to determine the compressive strength of concrete containing modified recycled FRP aggregate from the mix ratio, the replacement rate and the encapsulation amount.

[0087] In the present invention, the method for constructing formulas (1) to (6) includes the following steps:

[0088] Providing concrete specimens, the concrete specimens comprising concrete specimens of natural aggregates, concrete specimens containing recycled FRP aggregates, and concrete specimens containing modified recycled FRP aggregates;

[0089] The concrete specimens are subjected to a compression test to obtain initial compressive strength information of the concrete specimens containing natural aggregates, alternative compressive strength information of the concrete specimens containing recycled FRP aggregates, and modified compressive strength information of the concrete specimens containing modified recycled FRP aggregates;

[0090] According to the initial compressive strength information and the replacement compressive strength information, construct an initial formula correlating the compressive strength of concrete with natural aggregates, the compressive strength of concrete containing recycled FRP aggregates, and the replacement rate of recycled FRP aggregates, wherein the replacement rate of recycled FRP aggregates is the volume percentage of recycled FRP aggregates in the coarse aggregates of the concrete specimen containing recycled FRP aggregates;

[0091] According to the initial compressive strength information and the modified compressive strength information, formulas (2) to (6) are constructed;

[0092] The initial formula is modified using formulas (2) to (6) to obtain formulas (1) to (6).

[0093] The present invention provides concrete specimens, which include concrete specimens of natural aggregates, concrete specimens containing recycled FRP aggregates, and concrete specimens containing modified recycled FRP aggregates. In the present invention, the raw materials for preparing the concrete specimens include coarse aggregates, fine aggregates, cement, and water, and the mix ratios of the concrete specimens of natural aggregates, the concrete specimens containing recycled FRP aggregates, and the concrete specimens containing modified recycled FRP aggregates are the same; the coarse aggregates of the concrete specimens of natural aggregates are natural coarse aggregates, the coarse aggregates of the concrete specimens containing recycled FRP aggregates are recycled FRP aggregates, or a mixture of recycled FRP aggregates and natural coarse aggregates, and the coarse aggregates of the concrete specimens containing modified recycled FRP aggregates are modified recycled FRP aggregates, or a mixture of modified recycled FRP aggregates and natural coarse aggregates. According to the "Concrete Physical and Mechanical Properties Test Method Standard" GB / T50081-2019, "Construction Pebbles and Crushed Stones" GB / T 14685-2011, and "Construction Sand" GB / T 14684-2011, the present invention selects and prepares the natural coarse aggregate, natural fine aggregate and recycled FRP aggregate required for the above-mentioned concrete specimens, determines the concrete specimen mix ratio, and the experimental process ensures that the gradation of FRP aggregate and gravel (natural coarse aggregate) is consistent. In the present invention, the above-mentioned concrete specimens (ordinary concrete specimens with the same mix ratio (i.e., concrete specimens of natural aggregates), ordinary recycled FRP aggregate concrete specimens (i.e., concrete specimens containing recycled FRP aggregates), and modified recycled FRP concrete specimens (i.e., concrete specimens containing modified recycled FRP aggregates)) can be prepared, or can be provided in advance.

[0094] When 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 ratio. Ensure that the quality of each material meets the standard requirements. Add cement, sand, gravel, water and recycled FRP aggregates to the mixer in sequence. Start the mixer and stir evenly until all materials are fully mixed to form a uniform concrete mixture. The stirring time and speed are adjusted according to the specific requirements of the concrete to ensure the uniformity and fluidity of the mixture. Pour the mixed concrete into a mold and vibrate it to make it dense. Vibration can be carried out by mechanical vibration to discharge the bubbles inside the concrete and improve the density and strength of the concrete. After curing for twenty-eight days under standard curing conditions, the above-mentioned concrete specimens are obtained.

[0095] In the present invention, the mix ratios of cementitious materials (cement), coarse aggregates and fine aggregates among the above-mentioned ordinary concrete specimens, ordinary recycled FRP aggregate concrete specimens at the recycled FRP aggregate replacement rate, and epoxy mortar-wrapped modified recycled FRP aggregate concrete specimens at the replacement rate are the same. In other words, the mix ratio of ordinary concrete specimens is determined, that is, fine aggregates (sand), coarse aggregates (stones) and cementitious materials (cement) of a certain aggregate gradation are selected, the proportion of fine aggregates (sand) in ordinary recycled FRP aggregate concrete specimens and modified recycled FRP aggregate concrete specimens is consistent with that of ordinary concrete, and the coarse aggregates in ordinary recycled FRP aggregate concrete specimens and modified recycled FRP aggregate concrete specimens replace part or all of the coarse aggregates according to the corresponding replacement rate.

[0096] After obtaining the concrete specimens, the present invention performs a compressive test on the concrete specimens to obtain initial compressive strength information of the concrete specimens containing natural aggregates, alternative compressive strength information of the concrete specimens containing recycled FRP aggregates, and modified compressive strength information of the concrete specimens containing modified recycled FRP aggregates.

[0097] The present invention conducts a compression test on ordinary concrete specimens (i.e., concrete specimens with natural aggregates) to obtain the initial compressive strength information of the concrete specimens with natural aggregates. The present invention conducts compression tests on various ordinary recycled FRP aggregate concrete specimens (i.e., concrete specimens containing recycled FRP aggregates) at different recycled FRP substitution rates to obtain the corresponding replacement compressive strength information of the concrete specimens containing recycled FRP aggregates. The epoxy mortar coating amount of each of the various recycled FRP aggregate concretes at different recycled FRP aggregate substitution rates is obtained; according to the epoxy mortar coating amount, a compression test is conducted on the modified recycled FRP aggregate concrete (i.e., concrete specimens containing modified recycled FRP aggregates) at the corresponding modified recycled FRP aggregate substitution rate to obtain the corresponding modified compressive strength information of each of the various modified recycled FRP aggregate concretes.

[0098] The present invention conducts uniaxial compression tests on ordinary concrete, corresponding ordinary recycled FRP aggregate concretes, and corresponding modified recycled FRP aggregate concretes, thereby obtaining the initial strength of ordinary concrete (which may be the average value of multiple groups as shown in Table 2), the recycled FRP aggregate replacement rate and replacement strength of each ordinary recycled FRP aggregate concrete (which may be the average value of multiple groups at the replacement rate as shown in Table 2), and the epoxy mortar dosage and modified strength of each modified recycled FRP aggregate concrete (which may be the average value of multiple groups at the dosage as shown in Table 3).

[0099] In the present invention, after obtaining the modified recycled FRP aggregate concrete specimen, the present invention further needs to conduct a uniaxial compression test to obtain the stress-strain curve, compressive strength, elastic modulus, etc. of the modified recycled FRP-concrete time, and evaluate the mechanical properties of the modified recycled FRP aggregate concrete time.

[0100] After obtaining the initial compressive strength information, the alternative compressive strength information and the modified compressive strength information, the present invention constructs an initial formula for the compressive strength of concrete associated with natural aggregates, the compressive strength of concrete containing recycled FRP aggregates and the replacement rate of recycled FRP aggregates according to the initial compressive strength information and the alternative compressive strength information, wherein the replacement rate of recycled FRP aggregates is the volume percentage of recycled FRP aggregates in the coarse aggregates of the concrete specimen containing recycled FRP aggregates; constructs formulas (2) to (6) according to the initial compressive strength information and the modified compressive strength information; and uses formulas (2) to (6) to correct the initial formulas to obtain formulas (1) to (6).

[0101] The present invention first obtains the initial compressive strength information of ordinary concrete specimens, the corresponding replacement 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; according to the initial compressive strength information and the replacement compressive strength information, an initial formula between the strength of ordinary concrete and the corresponding strength of ordinary recycled FRP aggregate concrete under any recycled FRP aggregate replacement rate is constructed; according to the modified compressive strength information and the initial equation, a target formula (formula (1) to (6)) 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 epoxy mortar coating amount is constructed.

[0102] In the present invention, based on the initial compressive strength information and the replacement compressive strength information, an initial formula between the initial compressive strength of ordinary concrete and the replacement compressive strength of ordinary recycled FRP aggregate concrete at any corresponding replacement rate of recycled FRP aggregate is constructed, specifically including:

[0103] 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 between the initial compressive strength of ordinary concrete and the corresponding alternative compressive strength of ordinary recycled FRP aggregate concrete under any recycled FRP aggregate replacement rate is generated.

[0104] The initial compressive strength of ordinary concrete and the corresponding modified compressive strength of modified recycled FRP aggregate concrete at a specific substitution rate under different epoxy mortar coating amounts are obtained; based on the initial compressive strength of ordinary concrete and the modified compressive strength of modified recycled FRP aggregate concrete at multiple specific substitution rates, the quadratic function relationship between the initial compressive strength of ordinary concrete and the modified compressive strength of modified recycled FRP aggregate concrete at a specific substitution rate is obtained.

[0105] Obtain the modified compressive strength information of modified recycled FRP aggregate concrete under the modified recycled FRP aggregate replacement rate, including:

[0106] The epoxy mortar coating amounts of various recycled FRP aggregate concretes under different recycled FRP replacement rates were obtained; according to the epoxy mortar coating amounts, the modified recycled FRP aggregate concretes under the corresponding modified recycled FRP replacement rates were subjected to compressive tests to obtain the corresponding modified strength information of various modified recycled FRP aggregate concretes.

[0107] According to the modified strength information and the initial equation, a target equation between the initial strength of the ordinary concrete, the compressive strength of the modified recycled FRP aggregate concrete, the replacement rate of the recycled FRP and the epoxy mortar coating amount is constructed, specifically including: according to the quadratic function relationship (Formulas 2 to 6), a target formula (Formula 1) for the initial strength of the ordinary concrete, the compressive strength of the modified recycled FRP aggregate concrete, the replacement rate of the modified recycled FRP and the epoxy mortar coating amount is obtained.

[0108] The present invention analyzes the relationship among unmodified ordinary concrete without recycled FRP aggregate substitution, ordinary recycled FRP aggregate concrete with a certain recycled FRP aggregate substitution rate, and modified recycled FRP aggregate concrete wrapped with epoxy mortar at the same recycled FRP aggregate substitution rate, and determines the mathematical relationship among the strength of modified recycled FRP aggregate concrete, the initial strength of ordinary concrete, and the epoxy mortar wrapping amount at a certain recycled FRP aggregate substitution rate. Under the conditions of given initial strength of ordinary concrete and recycled FRP aggregate substitution rate, the strength of ordinary recycled FRP aggregate concrete can be accurately calculated, and the required epoxy mortar wrapping amount can be accurately calculated according to the target strength of the modified recycled FRP aggregate concrete and the target bearing capacity of the concrete beam prepared therefrom.

[0109] The present invention provides a system for determining structural parameters of concrete containing modified recycled FRP aggregate, comprising a data acquisition module, an initial formula building module, a target formula determination module and an output module;

[0110] The data acquisition module is used to collect compressive strength information obtained by performing compression tests on concrete specimens, wherein the concrete specimens include concrete specimens with natural aggregates, concrete specimens containing recycled FRP aggregates, and concrete specimens containing modified recycled FRP aggregates; the compressive strength information includes initial compressive strength information of concrete specimens with natural aggregates, alternative compressive strength information of concrete specimens containing recycled FRP aggregates, and modified compressive strength information of concrete specimens containing modified recycled FRP aggregates;

[0111] The initial formula construction module obtains the initial compressive strength information and the replacement compressive strength information transmitted by the data acquisition module, and is used to construct an initial formula for the compressive strength of concrete associated with natural aggregates, the compressive strength of concrete containing recycled FRP aggregates, and the replacement rate of recycled FRP aggregates, wherein the replacement rate of recycled FRP aggregates is the volume percentage of recycled FRP aggregates in the coarse aggregates of the concrete specimen containing recycled FRP aggregates;

[0112] The target formula determination module is used to construct formulas (1) to (6);

[0113]

[0114] k s1 =1+0.449s 2 +0.928rs-0.699s (3);

[0115]

[0116] k s2 =-78.696s 2 -1.326rs+47.359s-5.921 (5);

[0117]

[0118] In formulas (1) to (6): f c ' is the compressive strength of concrete containing modified recycled FRP aggregate, f co ' is the compressive strength of concrete with natural aggregate, ε c ' is the peak strain of concrete containing modified recycled FRP aggregate, r is the substitution rate, k s1 k is the elastic modulus of concrete related to the amount of wrapping, s2 is the peak strain coefficient of concrete related to the encapsulation amount, s is the encapsulation amount, E cis the elastic modulus of concrete containing modified recycled FRP aggregate, k e is the elastic modulus coefficient of concrete related to the replacement rate;

[0119] The output module is used to output the remaining structural parameters.

[0120] In the present invention, the data acquisition module acquires compressive strength information obtained by performing a compressive test on a concrete specimen, wherein the concrete specimen includes a concrete specimen with natural aggregate, a concrete specimen containing recycled FRP aggregate, and a concrete specimen containing modified recycled FRP aggregate; the raw materials for preparing the concrete specimen include coarse aggregate, fine aggregate, cement, and water; the mix ratios of the concrete specimen with natural aggregate, the concrete specimen containing recycled FRP aggregate, and the concrete specimen containing modified recycled FRP aggregate are the same; the coarse aggregate of the concrete specimen with natural aggregate is natural coarse aggregate, and the coarse aggregate of the concrete specimen containing recycled FRP aggregate is recycled FRP aggregate. P aggregate, or a mixture of recycled FRP aggregate and natural coarse aggregate, the coarse aggregate of the concrete specimen containing modified recycled FRP aggregate is modified recycled FRP aggregate, or a mixture of modified recycled FRP aggregate and natural coarse aggregate, the modified recycled FRP aggregate is a material modified by wrapping recycled FRP aggregate with epoxy mortar, and the epoxy mortar includes epoxy resin, curing agent and additives; the compressive strength information includes initial compressive strength information of concrete specimens with natural aggregate, alternative compressive strength information of concrete specimens containing recycled FRP aggregate and modified compressive strength information of concrete specimens containing modified recycled FRP aggregate.

[0121] The present invention transmits the initial compressive strength information and the replacement compressive strength information collected by the data collection module to an initial formula construction module, and the initial formula construction module constructs an initial formula that associates the compressive strength of concrete containing natural aggregates, the compressive strength of concrete containing recycled FRP aggregates, and the replacement rate of recycled FRP aggregates. The replacement rate of recycled FRP aggregates is the volume percentage of recycled FRP aggregates in the coarse aggregates of the recycled FRP aggregate concrete specimen.

[0122] The present invention transmits the initial compressive strength information and the modified compressive strength information collected by the data collection module and the initial formula constructed by the initial formula construction module to the target formula determination module, and the target formula determination module obtains formulas (1) to (6).

[0123] In the present invention, the output module is used to output the remaining structural parameters.

[0124] In the present invention, the mix ratio, replacement rate and packaging amount, as well as formulas (1) to (6) are sent to the output module, in which the compressive strength of the concrete containing the natural aggregate is obtained from the mix ratio, and the compressive strength of the concrete containing the modified recycled FRP aggregate is output from the output module.

[0125] In the present invention, the preset compressive strength of concrete containing modified recycled FRP aggregate, the mix ratio and formulas (1) to (6) are sent to an output module, and the compressive strength of concrete containing natural aggregate is obtained from the mix ratio in the output module. The range of substitution rate and encapsulation amount is obtained from formulas (1) to (6) in the output module, and the range is obtained when the compressive strength of concrete containing modified recycled FRP aggregate is greater than or equal to the preset compressive strength under the condition of the determined mix ratio; the remaining substitution rate and encapsulation amount are determined from the range of substitution rate and encapsulation amount, and the compressive strength of concrete containing modified recycled FRP aggregate is determined from the mix ratio, substitution rate and encapsulation amount in the output module using formulas (1) to (6).

[0126] The present invention provides a design system for modified recycled FRP aggregate concrete, comprising: a data acquisition module, used to obtain initial compressive strength information of ordinary concrete, corresponding alternative compressive strength information of ordinary recycled FRP aggregate concrete at a recycled FRP substitution rate, and modified compressive strength information of recycled FRP aggregate concrete modified at the recycled FRP substitution rate; a formula construction module, used to construct an initial formula between the initial compressive strength of ordinary concrete and the corresponding alternative compressive strength of ordinary recycled FRP concrete at any recycled FRP aggregate substitution rate according to the initial compressive strength information and the alternative compressive strength information. ; A formula determination module is used to construct a target formula among the initial compressive strength of the ordinary concrete, the compressive strength of the modified recycled FRP aggregate concrete, the replacement rate of recycled FRP aggregate and the epoxy mortar coating amount according to the modified compressive strength information and the initial equation; an output module is used to obtain the structural parameters of the modified recycled FRP aggregate concrete, and input the structural parameters into the target formula, and the target formula outputs the current compressive strength of the modified recycled FRP concrete; wherein the structural parameters include the replacement rate of recycled FRP, the epoxy mortar coating amount and the initial compressive strength of the concrete with natural aggregate (corresponding to the mix ratio).

[0127] The present invention provides a method for determining structural parameters of a steel bar-modified recycled FRP aggregate concrete beam component, wherein the structural parameters include the moment bearing capacity of the steel bar-modified recycled FRP aggregate concrete beam component and structural parameters of concrete containing modified recycled FRP aggregate;

[0128] The structural parameters of the concrete containing modified recycled FRP aggregate are determined by using the above-mentioned method for determining the structural parameters of the concrete containing modified recycled FRP aggregate;

[0129] The acquisition of the moment bearing capacity of the steel bar-modified recycled FRP aggregate concrete beam component includes: converting the actual stress-strain curve of the concrete containing modified recycled FRP aggregate in the compression zone of the steel bar-modified recycled FRP aggregate concrete beam component into an equivalent rectangular stress-strain curve according to an equivalent condition, wherein the equivalent condition is that the resultant forces of the actual stress-strain curve and the equivalent rectangular stress-strain curve are equal and the positions of the action points coincide; determining dimensionless parameters k1 and k2 from the actual stress-strain curve of the concrete containing modified recycled FRP aggregate and the equivalent rectangular stress-strain curve according to the equivalent condition; k1 is determined by formula (7), and k2 is determined by formula (8);

[0130]

[0131] In formula (7) and formula (8), k1 is the ratio of the area of ​​the actual stress-strain curve of concrete containing modified recycled FRP aggregate to the area of ​​the equivalent rectangular stress-strain curve, k2 is the ratio of the distance from the resultant point to the compressive edge of the actual stress-strain curve of concrete containing modified recycled FRP aggregate to the strain of the compressive edge, and ε m is the compressive edge strain of the concrete containing modified recycled FRP aggregate in the beam section of the reinforced steel-modified recycled FRP aggregate concrete beam component; σ is the stress of the concrete containing modified recycled FRP aggregate, ε is the strain of the concrete containing modified recycled FRP aggregate, f c ' is the compressive strength of concrete containing modified recycled FRP aggregate;

[0132] Set the height of the compression zone of the equivalent rectangular stress-strain curve to βx, and the uniformly distributed equivalent stress in the equivalent rectangular stress-strain curve to αf c ', the coefficients of the equivalent rectangular stress-strain curve are β and α, where β = 2k2, α = k1 / 2k2; the height of the compressive zone of the beam section of the reinforced-modified recycled FRP aggregate concrete beam component is determined by formula (9):

[0133]

[0134] In formula (9), x is the actual compressive zone height of the beam section of the reinforced concrete beam with modified recycled FRP aggregate, β is the height coefficient of the equivalent rectangular stress-strain curve, α is the strength coefficient of the equivalent rectangular stress-strain curve, and A s is the tensile reinforcement area, f y is the tensile strength of the reinforcement, f c ' is the compressive strength of concrete containing modified recycled FRP aggregate, b is the beam width of the reinforced steel-modified recycled FRP aggregate concrete beam component;

[0135] The moment bearing capacity of the steel bar-modified recycled FRP aggregate concrete beam member is determined by formula (10):

[0136] M=αf c 'bx(h0-x / 2) Formula (10);

[0137] In formula (10), M is the moment bearing capacity of the reinforced concrete beam with modified recycled FRP aggregate, α is the strength coefficient of the equivalent rectangular stress-strain curve, and f c ' is the compressive strength of concrete containing modified recycled FRP aggregate, x is the actual compression zone height of the beam section of the steel bar-modified recycled FRP aggregate concrete beam component, b is the beam width of the steel bar-modified recycled FRP aggregate concrete beam component; h0 is the effective height of the beam section of the steel bar-modified recycled FRP aggregate concrete beam component;

[0138] The actual stress-strain curve of the concrete containing modified recycled FRP aggregate in the actual compression zone of the steel bar-modified recycled FRP aggregate concrete beam component is shown in formula (11):

[0139]

[0140] In formula (11), parameter a and parameter b1 are determined by formula (12) and formula (13), respectively:

[0141] a=1.927+0.489r+1.23r 2 -1.333r 3 Formula (12);

[0142] b1=0.129(r+0.011) -0.571 +57.371(1+rs) -39.124 s Formula (13);

[0143] In formulas (11) to (13), f c ' is the compressive strength of concrete containing modified recycled FRP aggregate, ε c ' is the peak strain of concrete containing modified recycled FRP aggregate; σ is the stress of concrete containing modified recycled FRP aggregate; ε is the strain of concrete containing modified recycled FRP aggregate; a is the shape coefficient of the rising section of the actual stress-strain curve of concrete containing modified recycled FRP aggregate; b1 is the shape coefficient of the rising and falling sections of the actual stress-strain curve of concrete containing modified recycled FRP aggregate; r is the substitution rate; s is the encapsulation amount.

[0144] In the present invention, the method for determining the structural parameters of the steel bar-modified recycled FRP aggregate concrete beam component comprises the following steps: obtaining the mix ratio, replacement rate and encapsulation amount of the concrete containing the modified recycled FRP aggregate, obtaining the compressive strength of the concrete with natural aggregate from the mix ratio, and determining the compressive strength of the concrete containing the modified recycled FRP aggregate using formulas (1) to (6);

[0145] Then, the moment bearing capacity of the steel bar-modified recycled FRP aggregate concrete beam component is obtained from the compressive strength of the concrete containing modified recycled FRP aggregate according to the following method, including: converting the actual stress-strain curve of the concrete containing modified recycled FRP aggregate in the compression zone of the steel bar-modified recycled FRP aggregate concrete beam component into an equivalent rectangular stress-strain curve according to an equivalent condition, wherein the equivalent condition is that the resultant forces of the actual stress-strain curve and the equivalent rectangular stress-strain curve are equal in magnitude and the positions of the action points coincide; determining dimensionless parameters k1 and k2 from the actual stress-strain curve of the concrete containing modified recycled FRP aggregate and the equivalent rectangular stress-strain curve according to the equivalent condition; k1 is determined by formula (7), and k2 is determined by formula (8);

[0146]

[0147] In formula (7) and formula (8), k1 is the ratio of the area of ​​the actual stress-strain curve of concrete containing modified recycled FRP aggregate to the area of ​​the equivalent rectangular stress-strain curve, k2 is the ratio of the distance from the resultant point to the compressive edge of the actual stress-strain curve of concrete containing modified recycled FRP aggregate to the strain of the compressive edge, and ε m is the compressive edge strain of the concrete containing modified recycled FRP aggregate in the beam section of the reinforced steel-modified recycled FRP aggregate concrete beam component; σ is the stress of the concrete containing modified recycled FRP aggregate, ε is the strain of the concrete containing modified recycled FRP aggregate, f c ' is the compressive strength of concrete containing modified recycled FRP aggregate;

[0148] Set the height of the compression zone of the equivalent rectangular stress-strain curve to βx, and the uniformly distributed equivalent stress in the equivalent rectangular stress-strain curve to αf c ', the coefficients of the equivalent rectangular stress-strain curve are β and α, where β = 2k2, α = k1 / 2k2; the height of the compressive zone of the beam section of the reinforced-modified recycled FRP aggregate concrete beam component is determined by formula (9):

[0149]

[0150] In formula (9), x is the actual compressive zone height of the beam section of the reinforced concrete beam with modified recycled FRP aggregate, β is the height coefficient of the equivalent rectangular stress-strain curve, α is the strength coefficient of the equivalent rectangular stress-strain curve, and A s is the tensile reinforcement area, f y is the tensile strength of the reinforcement, f c ' is the compressive strength of concrete containing modified recycled FRP aggregate, b is the beam width of the reinforced steel-modified recycled FRP aggregate concrete beam component;

[0151] The moment bearing capacity of the steel bar-modified recycled FRP aggregate concrete beam member is determined by formula (10):

[0152] M=αf c 'bx(h0-x / 2) Formula (10);

[0153] In formula (10), M is the moment bearing capacity of the reinforced concrete beam with modified recycled FRP aggregate, α is the strength coefficient of the equivalent rectangular stress-strain curve, and f c ' is the compressive strength of concrete containing modified recycled FRP aggregate, x is the actual compression zone height of the beam section of the steel bar-modified recycled FRP aggregate concrete beam component, b is the beam width of the steel bar-modified recycled FRP aggregate concrete beam component; h0 is the effective height of the beam section of the steel bar-modified recycled FRP aggregate concrete beam component;

[0154] The actual stress-strain curve of the concrete containing modified recycled FRP aggregate in the actual compression zone of the steel bar-modified recycled FRP aggregate concrete beam component is shown in formula (11):

[0155]

[0156] In formula (11), parameter a and parameter b1 are determined by formula (12) and formula (13), respectively:

[0157] a=1.927+0.489r+1.23r 2 -1.333r 3 Formula (12);

[0158] b1=0.129(r+0.011) -0.571 +57.371(1+rs) -39.124 s Formula (13);

[0159] In formulas (11) to (13), f c ' is the compressive strength of concrete containing modified recycled FRP aggregate, ε c' is the peak strain of concrete containing modified recycled FRP aggregate; σ is the stress of concrete containing modified recycled FRP aggregate; ε is the strain of concrete containing modified recycled FRP aggregate; a is the shape coefficient of the rising section of the actual stress-strain curve of concrete containing modified recycled FRP aggregate; b1 is the shape coefficient of the rising and falling sections of the actual stress-strain curve of concrete containing modified recycled FRP aggregate; r is the substitution rate; s is the encapsulation amount.

[0160] Alternatively, the determination method comprises the following steps: obtaining the moment bearing capacity of the steel bar-modified recycled FRP aggregate concrete beam component, determining the modified compressive strength using formulas (7) to (13), obtaining any two result parameters among the mix ratio, replacement rate and encapsulation amount, and when the obtained structural parameters include the mix ratio, obtaining the compressive strength of the concrete with natural aggregate from the mix ratio, and obtaining the remaining one structural parameter among the mix ratio, replacement rate and encapsulation amount using formulas (1) to (6).

[0161] Alternatively, the determination method comprises the following steps: determining a preset moment bearing capacity of the steel bar-modified recycled FRP aggregate concrete beam component, using formulas (7) to (13) to obtain a preset modified compressive strength of the concrete containing modified recycled FRP aggregate; obtaining any one of the mix ratio, substitution rate and encapsulation amount, when the obtained structural parameter is the mix ratio, obtaining the compressive strength of the concrete with natural aggregate from the mix ratio, using formulas (1) to (6) to obtain the range of the remaining two structural parameters of the mix ratio, substitution rate and encapsulation amount, the range being the range in which the moment bearing capacity of the steel bar-modified recycled FRP aggregate concrete beam component is greater than or equal to the preset moment bearing capacity under the condition that one of the mix ratio, substitution rate and encapsulation amount is determined; determining the data of the remaining two structural parameters from the range of the remaining two structural parameters, using formulas (1) to (6) to determine the modified compressive strength from the determined mix ratio, substitution rate and encapsulation amount, and using formulas (7) to (13) to determine the moment bearing capacity from the determined modified compressive strength.

[0162] In the present invention, the method for determining the structural parameters of the steel bar-modified recycled FRP aggregate concrete beam component comprises the following steps: determining the preset moment bearing capacity of the steel bar-modified recycled FRP aggregate concrete beam component, using formulas (7) to (13) to obtain the preset compressive strength of the concrete containing the modified recycled FRP aggregate; obtaining the mix ratio, obtaining the compressive strength of the concrete containing the natural aggregate from the mix ratio, using formulas (1) to (6) to obtain the range of the replacement rate and the encapsulation amount of the concrete containing the modified recycled FRP aggregate, the range being the range of the replacement rate and the encapsulation amount of the concrete containing the modified recycled FRP aggregate within the mix ratio; Under the condition of the ratio being determined, the range of the preset moment bearing capacity of the steel bar-modified recycled FRP aggregate concrete beam component ≥ the preset moment bearing capacity is obtained; the remaining replacement rate and the wrapping amount are determined by the range of the replacement rate and the wrapping amount, and the compressive strength of the concrete containing the modified recycled FRP aggregate is determined by formulas (1) to (6) according to the mix ratio, replacement rate and wrapping amount; and the preset moment bearing capacity of the steel bar-modified recycled FRP aggregate concrete beam component is determined by formulas (7) to (13) according to the compressive strength of the concrete containing the modified recycled FRP aggregate.

[0163] In order to further illustrate the present invention, the technical solutions provided by the present invention are described in detail below in conjunction with embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0164] Example 1

[0165] This embodiment designs 15 standard cylindrical compression test specimens (ф150mm×300mm). This embodiment mainly considers the volume replacement rate (r) of GFRP aggregate recycled from retired wind turbine blades (FRP aggregate recycled from retired wind turbine blades used in this embodiment) to natural coarse aggregate: 0%, 30%, 50%, 70%, 100%. The volume replacement rate r = FRP aggregate recycled from retired wind turbine blades / (FRP aggregate recycled from retired wind turbine blades + natural coarse aggregate); each volume replacement rate r has 3 repeated specimens to minimize the test error. The specific numbers of each group of specimens are shown in Table 1. For example, FRP30 means that the volume replacement rate r of GFRP aggregate recycled from retired wind turbine blades to natural coarse aggregate is 30%, and so on. The mix ratio of concrete in this embodiment (kg / m 3 ) as shown in Table 1. The water-cement ratio of this mix design is 0.45, which can make the compressive strength of the target cube (150mm×150mm×150mm cube) reach about 40MPa. All specimens were stored in an environment with a room temperature of about 25℃ after pouring and demolded after 24h. Then the specimens were placed in a standard curing room for 28 days. The temperature of the curing room was 20±2℃ and the relative humidity was 95%.

[0166] Table 1 Concrete mix ratio (kg / m 3 )

[0167]

[0168] The compression test was carried out using a 3000KN MTS servo hydraulic press, with the loading mode being displacement control of 0.3mm / min. The force was measured by a force sensor and the longitudinal displacement was monitored by four longitudinal LVDTs, and the data was collected on a computer through a Dewesoft dynamic acquisition box. The test results are summarized in Table 2. The results of the test show that as the volume replacement rate r of the GFRP aggregate recycled from retired wind turbine blades to the natural coarse aggregate increases, the compressive strength gradually decreases, and the decrease is relatively large: when the volume replacement rate r is 50%, the compressive strength decreases by 63.76%, and when the GFRP aggregate recycled from retired wind turbine blades completely replaces the natural coarse aggregate, the compressive strength is about one-seventh of the control group (FRP0). The elastic modulus of GFRP aggregate concrete (RFAC) recycled from retired wind turbine blades also gradually decreases with the increase of the volume replacement rate r of GFRP aggregate recycled from retired wind turbine blades. As for the peak strain, within the range of 0% to 50% of the volume replacement rate r, the peak strain first decreases and then increases with the increase of the volume replacement rate r; when the volume replacement rate r exceeds 50%, the same change pattern is also shown. In addition, Figure 2 The stress-strain curves of the axial compression test of GFRP aggregate concrete recycled from retired wind turbine blades under the condition of replacement rate r = 100% are compared with the experimental and predicted results. Figure 2 The replacement rate r = 100%, and the abscissa represents strain. The results show that although the experimental and predicted results of different volume replacement rates r of GFRP aggregates recycled from retired wind turbine blades are slightly different, they generally estimate the changes in stress and strain of GFRP aggregate concrete recycled from retired wind turbine blades under compression.

[0169] Table 2 Axial compression test results of GFRP aggregate concrete specimens recycled from retired wind turbine blades

[0170]

[0171] Example 2

[0172] Epoxy mortar wrapping treatment:

[0173] ① Prepare the GFRP aggregate and epoxy mortar for recycling retired wind turbine blades, where the epoxy mortar includes epoxy resin (material A, Lica-131 carbon plate glue (Nanjing Haituo Composite Materials Co., Ltd.)), curing agent (material B), cement and quartz sand (material C, the mass ratio of cement to quartz sand is 1:2), several pallets and electronic scales;

[0174] ② Weigh the mass m of retired wind turbine blades to recycle GFRP aggregates, and weigh material A, material B, and material C in a mass ratio of 1:3:16; epoxy mortar coating amount s = mass of epoxy mortar / mass of GFRP aggregates recycled from retired wind turbine blades;

[0175] ③ Pour the GFRP aggregates recovered from retired fan blades into a small mixer, and pour the weighed C material into it, and then stir for 1 to 2 minutes to make the C material fully cover the surface of the GFRP aggregates recovered from retired fan blades;

[0176] ④ Mix the weighed material A and material B in a container and stir evenly, then start the mixer and slowly and evenly pour the mixture into the mixing drum;

[0177] ⑤ After the mixture is poured in, let the mixer continue to stir for 3 to 5 minutes, then take out the wrapped retired fan blades, recycle the GFRP aggregates, place them on a tray, and put them in the curing room for curing;

[0178] ⑥ After 48 hours of curing, take out the wrapped GFRP aggregates recovered from retired fan blades and pour them into the mixer again for stirring for 1 minute. The purpose is to separate some aggregates that are bonded together due to a small amount of epoxy mortar between the particles. Finally, pour out the GFRP aggregates recovered from retired fan blades and put them into the curing room for curing for 7 days.

[0179] In this embodiment, three modified FRP aggregates recycled from retired wind turbine blades with a mass ratio (encapsulation amount s) of epoxy mortar to GFRP aggregates recycled from retired wind turbine blades of 0.25, 0.3, and 0.35 were prepared for subsequent concrete pouring.

[0180] In this embodiment, 6 groups of modified GFRP aggregate concrete (MRFAC) recycled from retired wind turbine blades were designed, with 3 repeated specimens in each group, and a total of 18 standard cylindrical compressive specimens (ф150mm×300mm). The entire experiment involves two independent variables: the epoxy mortar coating amount s and the volume replacement rate r of the GFRP aggregate recycled from retired wind turbine blades to the natural coarse aggregate. On the one hand, the modified GFRP aggregate recycled from retired wind turbine blades 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, when the volume replacement rate r was 100%, the epoxy mortar coating amount s was changed to 0.3 and 0.35 respectively as the other 2 groups, and the influence of different epoxy mortar coating amounts on the compressive performance was analyzed. The specific numbers of each specimen are shown in Table 3. For example, FRP30-S0.25 means that the ratio of the epoxy mortar coating amount of the modified GFRP aggregate recycled from retired wind turbine blades to the mass of the GFRP aggregate recycled from retired wind turbine blades (epoxy mortar coating amount s) is 0.25, and the volume replacement rate r of the GFRP aggregate recycled from retired wind turbine blades to the natural coarse aggregate is 30%, and so on.

[0181] Table 3 Design of concrete specimens with GFRP aggregates recycled from modified retired wind turbine blades

[0182] Test piece Recycled GFRP aggregate replacement rate Epoxy mortar coating volume 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

[0183] Table 4 shows the peak stress, corresponding peak strain and elastic modulus of modified GFRP aggregate concrete specimens with different GFRP replacement rates r. After the GFRP aggregates were wrapped with epoxy mortar, the overall compressive strength of the GFRP aggregates was significantly improved compared with the unmodified ones, with an increase of about 18%-86%. When the wrapping amount s was constant (s=0.25), the increase showed a trend of first decreasing and then increasing with the increase of the replacement rate. When the replacement rate r was 30%, the axial compressive strength of the modified concrete was 21.4% higher than that of the unmodified concrete, and it decreased slightly to 18.6% when the replacement rate r was 50%; and when the replacement rate r continued to increase to 70% and 100%, the increase was 29.4% and 72.2% respectively. This means that the epoxy mortar wrapping modification method has a better effect on initial defects (initial defects refer to the poor bonding between the interface of the GFRP aggregate recycled from retired wind turbine blades and the concrete matrix without epoxy mortar wrapping, the presence of holes, and the lower strength and elastic modulus.) The more modified GFRP aggregate concrete recycled from retired wind turbine blades, the better the compressive strength can be improved. In the specimens with the same replacement rate r (100%), the improvement of compressive strength by different wrapping amounts s is relatively close, about 70% to 86%, but the group with the best effect is the FRP100-S0.30 group.

[0184] Figure 3 The experimental and predicted results of the axial compressive stress-strain curve of the modified GFRP aggregate concrete recycled from retired wind turbine blades are compared. On the whole, the model proposed in the present invention has good performance at various replacement rates, especially when the epoxy mortar wrapping amount increases, the model curve shows a higher degree of consistency with the experimental curve. Figure 3 The substitution is when r is 100%, the wrapping amount s=0.25, the horizontal axis is strain, and the vertical axis is stress.

[0185] Table 4 Axial compression test results of concrete specimens made of GFRP aggregates recycled from decommissioned wind turbine blades

[0186]

[0187]

[0188] The above can obtain the initial strength of ordinary concrete, the replacement strength of ordinary recycled FRP aggregate concrete at a replacement rate of recycled FRP from retired wind turbine blades, and the modified strength and epoxy mortar dosage of modified recycled FRP aggregate concrete from retired wind turbine blades at the replacement rate of recycled FRP. It is worth noting that the replacement rate of recycled FRP from retired wind turbine blades described in this embodiment includes 30%, 50%, 70% and 100%, but is not limited to this, and can include only a few of them, or can also include other multiple replacement rates, and the recycled FRP replacement rate can also be a non-integer value such as 9%, 17%.

[0189] Then, the stress-strain curves (strain on the horizontal axis, 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 recycled from retired wind turbine blades were compared, and the constitutive equation of the peak stress of modified concrete with FRP aggregate recycled from retired wind turbine blades, the replacement rate of FRP aggregate recycled from retired wind turbine blades and the change of epoxy mortar wrapping amount was established.

[0190] According to the initial strength information and the replacement strength information, the present invention constructs an initial equation between the initial strength of ordinary concrete and the corresponding strength of ordinary recycled FRP aggregate concrete under any recycled FRP aggregate replacement rate, as shown in formula (1).

[0191] According to the modified strength information and the initial equation, the present invention constructs the target equations among the initial strength of ordinary concrete, the compressive strength of the modified FRP aggregate concrete recycled from retired wind turbine blades, the replacement rate of FRP aggregate recycled from retired wind turbine blades and the epoxy mortar wrapping amount, such as formulas (2)-(6).

[0192] Finally, the present invention obtains the target parameters of the modified FRP aggregate concrete recycled from retired wind turbine blades, and inputs the data of the target parameters into the target equation, and the target equation outputs the current compressive strength of the modified FRP aggregate concrete recycled from retired wind turbine blades; wherein the target parameters include the replacement rate of FRP recycled from retired wind turbine blades, the epoxy mortar wrapping amount, and the initial strength of ordinary concrete.

[0193] The present invention uses the constitutive equation to determine the compressive strength ( Figure 3 ).

[0194] It is understandable that the prior art is unable to determine the compressive strength of the modified FRP aggregate concrete recycled from retired fan blades by other data on the basis that the target parameters including the replacement rate of FRP aggregates recycled from retired fan blades, the amount of epoxy mortar coating and at least one of the initial strength of ordinary concrete have been determined. That is to say, after the prior art presets the target strength of the modified FRP aggregate concrete recycled from retired fan blades, it is unable to select other data (replacement rate of FRP aggregates recycled from retired fan blades, amount of epoxy mortar coating) based on the preset target strength of the modified FRP aggregate concrete recycled from retired fan blades and the determined data (such as mix ratio) so that the compressive strength of the obtained modified FRP aggregate concrete recycled from retired fan blades is greater than or equal to the preset target strength of the modified FRP aggregate concrete recycled from retired fan blades.

[0195] In some implementations, the determined data (target parameters) of the target parameters and the preset target strength of the modified FRP aggregate concrete recycled from retired wind turbine blades are obtained, the preset target strength is used as the compressive strength of the modified FRP aggregate concrete recycled from retired wind turbine blades in the target formula, and the determined data (target parameters) are input into the target equation, the target equation outputs the data range of the parameter to be confirmed, and the target data of the parameter to be confirmed is determined based on the data range; the determined data and the target data are input into the target equation, the target equation outputs the current compressive strength of the modified FRP aggregate concrete recycled from retired wind turbine blades, so that the current compressive strength is above the preset target strength.

[0196] In a first implementation of the present invention, Figure 4It is a schematic diagram of the relationship between the replacement rate r of modified FRP aggregate recycled from retired wind turbine blades, the epoxy mortar coating amount s and the compressive strength of modified FRP aggregate concrete when the strength of ordinary concrete is 35MPa; the target strength of modified FRP aggregate concrete is determined by the concrete mix ratio, that is, the target parameter is the initial strength of ordinary concrete (natural aggregate concrete). The current initial strength of ordinary concrete and the preset target compressive strength of the modified FRP aggregate concrete recycled from retired wind turbine blades are obtained, and the preset target strength is input as the compressive strength and the current initial strength into the target equation, and the target equation outputs the data ranges corresponding to the current substitution rate r and the current epoxy mortar coating amount s of the modified FRP aggregate concrete recycled from retired wind turbine blades; according to the data ranges corresponding to the current substitution rate and the current epoxy mortar coating amount of the modified FRP aggregate concrete recycled from retired wind turbine blades, the target substitution rate and the target epoxy mortar coating amount (i.e., the area above the design target plane) are determined; the initial strength, the target substitution rate and the target epoxy mortar coating amount are input into the target equation, and the target equation outputs the current compressive strength of the modified FRP aggregate concrete recycled from retired wind turbine blades, so that the current compressive strength is above the preset target strength.

[0197] Specifically, by setting the same mix ratio of concrete, adding a certain amount of FRP aggregate recycled from retired wind turbine blades, the replacement rate of FRP aggregate recycled from retired wind turbine blades varies within a certain range, and using different epoxy mortar wrapping amounts to modify it so that it reaches the target strength.

[0198] It should be noted that the target parameters can be one, two or three of the FRP paste replacement rate for recycled retired wind turbine blades, the epoxy mortar wrapping amount and the initial strength. When all three are clear, the compressive strength can be directly and accurately obtained; when only one or two data are clear, it is necessary to determine the range of the unclear data so that the compressive strength obtained according to the target equation within the range is greater than or equal to the preset target strength, and the unclear data in the corresponding range is determined as the target value, and the compressive strength is obtained by substituting it into the target equation to be above the preset target strength.

[0199] Furthermore, based on the above-mentioned method for determining the compressive bearing capacity of the modified FRP aggregate concrete recycled from retired wind turbine blades, the present invention also provides a system for determining the compressive bearing capacity of the modified FRP aggregate concrete recycled from retired wind turbine blades, wherein the system comprises:

[0200] A data acquisition module is used to obtain initial strength information of ordinary concrete, corresponding replacement strength information of ordinary concrete with FRP aggregates recycled from retired wind turbine blades at the replacement rate of FRP aggregates recycled from retired wind turbine blades, and modified strength information of epoxy mortar-wrapped modified concrete with FRP aggregates recycled from retired wind turbine blades at the replacement rate of FRP aggregates recycled from retired wind turbine blades;

[0201] An equation building module is used to build an initial equation between the initial strength of ordinary concrete and the strength of ordinary concrete with FRP aggregates recycled from retired wind turbine blades under any corresponding replacement rate of FRP aggregates recycled from retired wind turbine blades according to the initial strength information and the replacement strength information;

[0202] An equation determination module is used to construct a target equation among initial strength, compressive strength of modified FRP aggregate concrete recycled from retired wind turbine blades, replacement rate of FRP aggregate recycled from retired wind turbine blades, and epoxy mortar wrapping dosage according to modified strength information and an initial equation;

[0203] The strength generation module is used to obtain the target parameters of the modified recycled aggregate concrete and input the target parameters into the target equation, and the target equation outputs the current compressive strength of the modified retired wind turbine blade recycled FRP aggregate concrete; wherein the target parameters include the replacement rate of retired wind turbine blade recycled FRP aggregate, the epoxy mortar wrapping amount and one of the initial strength of ordinary concrete.

[0204] A second implementation method of the present invention is to use modified FRP aggregate concrete recycled from retired wind turbine blades for the preparation of steel bar-modified FRP aggregate concrete beams recycled from retired wind turbine blades, and propose a bending moment bearing capacity design method for modified FRP aggregate concrete recycled from retired wind turbine blades for steel bar-modified FRP aggregate concrete beams recycled from retired wind turbine blades based on the FRP aggregate replacement rate of retired wind turbine blades and the epoxy mortar replacement rate.

[0205] Figure 5 The beam height is 250mm, the width is 150mm, the tension reinforcement is 2 deformed steel bars with a diameter of 14mm and a strength of 400MPa. The target design bearing capacity is 26kN·m. Schematic diagram of the relationship between the recycled FRP replacement rate of modified recycled FRP aggregate, the amount of epoxy mortar wrapping and the bearing capacity of the modified recycled FRP aggregate concrete beam when the strength of ordinary concrete is 35MPa; the target moment bearing capacity is determined by the concrete mix ratio, that is, the target parameter is the initial strength of ordinary concrete. Obtain the current initial strength of ordinary concrete and the preset target strength of modified recycled FRP aggregate concrete. Then establish the relationship between the target strength and the bearing capacity of the modified recycled FRP aggregate concrete beam.

[0206] When calculating the bending moment of the modified FRP aggregate recycled from retired wind turbine blades concrete beam section, in order to simplify the calculation, the actual stress-strain curve of the concrete containing the modified FRP aggregate recycled from retired wind turbine blades in the compression zone of the steel bar-modified FRP aggregate recycled from retired wind turbine blades concrete beam component is converted into an equivalent rectangular stress-strain curve according to the equivalent condition, and the equivalent condition is that the resultant force of the actual stress-strain curve and the equivalent rectangular stress-strain curve are equal and the position of the action point coincides; according to the equivalent condition, the dimensionless parameters k1 and k2 are determined from the actual stress-strain curve of the concrete containing the modified FRP aggregate recycled from retired wind turbine blades and the equivalent rectangular stress-strain curve; k1 is determined by formula (7), and k2 is determined by formula (8);

[0207]

[0208] In formula (7) and formula (8), k1 is the ratio of the area of ​​the actual stress-strain curve of the concrete containing the modified FRP aggregate recycled from retired wind turbine blades to the area of ​​the equivalent rectangular stress-strain curve, k2 is the ratio of the distance from the resultant point of the actual stress-strain curve of the concrete containing the modified FRP aggregate recycled from retired wind turbine blades to the compressive edge strain, and ε m is the compressive edge strain of the concrete containing the modified FRP aggregate recycled from retired wind turbine blades in the beam section of the steel bar-modified FRP aggregate concrete beam component; σ is the stress of the concrete containing the modified FRP aggregate recycled from retired wind turbine blades, ε is the strain of the concrete containing the modified FRP aggregate recycled from retired wind turbine blades, f c ' is the compressive strength of concrete containing FRP aggregates recycled from modified retired wind turbine blades;

[0209] Set the height of the compression zone of the equivalent rectangular stress-strain curve to βx, and the uniformly distributed equivalent stress in the equivalent rectangular stress-strain curve to αf c ', the coefficients of the equivalent rectangular stress-strain curve are β and α, where β = 2k2, α = k1 / 2k2; the height of the compressive zone of the beam section of the reinforced concrete beam component of the FRP aggregate recycled from retired wind turbine blades is determined by formula (9):

[0210]

[0211] In formula (9), x is the actual compression zone height of the beam section of the reinforced concrete beam component made of FRP aggregate recycled from retired wind turbine blades, β is the height coefficient of the equivalent rectangular stress-strain curve, α is the strength coefficient of the equivalent rectangular stress-strain curve, and A s is the tensile reinforcement area, f y is the tensile strength of the reinforcement, f c' is the compressive strength of concrete containing modified recycled FRP aggregate, b is the beam width of the steel bar-modified recycled FRP aggregate concrete beam component of retired wind turbine blades;

[0212] The moment bearing capacity of the steel bar-modified FRP aggregate concrete beam component recycled from retired wind turbine blades is determined by formula (10):

[0213] M=αf c 'bx(h0-x / 2) Formula (10);

[0214] In formula (10), M is the moment bearing capacity of the reinforced concrete beam component made of FRP aggregates recycled from retired wind turbine blades, α is the strength coefficient of the equivalent rectangular stress-strain curve, and f c ' is the compressive strength of the concrete containing modified FRP aggregates recycled from retired wind turbine blades, x is the actual compression zone height of the beam section of the steel-reinforced-modified FRP aggregate concrete beam component, b is the beam width of the steel-reinforced-modified FRP aggregate concrete beam component; h0 is the effective height of the beam section of the steel-reinforced-modified FRP aggregate concrete beam component;

[0215] The actual stress-strain curve of the concrete containing the modified FRP aggregate recycled from retired wind turbine blades in the actual compression zone of the steel bar-modified FRP aggregate recycled from retired wind turbine blades concrete beam component is shown in formula (11):

[0216]

[0217] In formula (11), parameter a and parameter b1 are determined by formula (12) and formula (13), respectively:

[0218] a=1.927+0.489r+1.23r 2 -1.333r 3 Formula (12);

[0219] b1=0.129(r+0.011) -0.571 +57.371(1+rs) -39.124 s Formula (13);

[0220] In formulas (11) to (13), f c ' is the compressive strength of concrete containing FRP aggregates recycled from modified retired wind turbine blades, ε c' is the peak strain of concrete containing modified FRP aggregates recycled from retired wind turbine blades; σ is the stress of concrete containing modified FRP aggregates recycled from retired wind turbine blades; ε is the strain of concrete containing modified FRP aggregates recycled from retired wind turbine blades; a is the shape coefficient of the rising section of the actual stress-strain curve of concrete containing modified FRP aggregates recycled from retired wind turbine blades; b1 is the shape coefficient of the rising and falling sections of the actual stress-strain curve of concrete containing modified FRP aggregates recycled from retired wind turbine blades; r is the replacement rate; s is the encapsulation amount.

[0221] The present invention uses the compressive strength of concrete containing modified FRP aggregates recycled from retired wind turbine blades corresponding to the preset target design moment bearing capacity as the compressive strength and the current initial strength and inputs them into formulas (1) to (6). Formulas (1) to (6) output the data ranges corresponding to the current replacement rate and the current epoxy mortar coating amount of concrete containing modified FRP aggregates recycled from retired wind turbine blades; according to the data ranges corresponding to the current replacement rate and the current epoxy mortar coating amount of concrete containing modified FRP aggregates recycled from retired wind turbine blades, the target replacement rate and the target epoxy mortar coating amount (i.e., the area above the design target plane) are determined; the current replacement strength, the target replacement rate and the target epoxy mortar coating amount are input into the target equation, and the target equation outputs the current compressive strength of concrete containing modified FRP aggregates recycled from retired wind turbine blades, so that the current design bearing capacity of the modified FRP aggregates recycled from retired wind turbine blades concrete beam is above the preset target bearing capacity.

[0222] Although the above embodiment describes the present invention in detail, it is only a part of the embodiments of the present invention, not all of the embodiments. Other embodiments can be obtained based on this embodiment without creativity, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A method for determining structural parameters of concrete containing modified recycled FRP aggregate, characterized in that: The structural parameters include compressive strength, mix ratio, replacement rate and encapsulation amount, the replacement rate is the volume percentage of the modified recycled FRP aggregate in the coarse aggregate in the concrete, the modified recycled FRP aggregate is the epoxy mortar modified recycled FRP aggregate, and the encapsulation amount is the mass ratio of the epoxy mortar to the recycled FRP aggregate; The determination method comprises the following steps: obtaining three structural parameters including a mix ratio, obtaining the compressive strength of concrete containing natural coarse aggregate from the mix ratio, and determining the remaining structural parameters using formulas (1) to (6); Alternatively, the determination method comprises the following steps: obtaining the compressive strength, replacement rate and encapsulation amount, using formulas (1) to (6) to obtain the compressive strength of the concrete with natural aggregate, and determining the mix ratio according to the compressive strength of the concrete with natural aggregate; Alternatively, the determination method comprises the following steps: presetting the compressive strength, obtaining any one of the mix ratio, substitution rate and encapsulation amount, when the obtained structural parameter is the mix ratio, obtaining the compressive strength of the concrete with natural aggregate from the mix ratio, using formulas (1) to (6) to obtain the range of the remaining two structural parameters of the mix ratio, substitution rate and encapsulation amount, the range being the range when the compressive strength of the concrete containing modified recycled FRP aggregate is ≥ the preset compressive strength under the condition that any one of the mix ratio, substitution rate and encapsulation amount is determined; determining the remaining two structural parameters from the range of the remaining two structural parameters, and determining the compressive strength from the mix ratio, substitution rate and encapsulation amount using formulas (1) to (6); k s1 =1+0.449s 2 +0.928rs-0.699s(3); k s2 =-78.696s 2 -1.326rs+47.359s-5.921(5); In formulas (1) to (6): f c ' is the compressive strength of concrete containing modified recycled FRP aggregate, f co ' is the compressive strength of concrete with natural aggregate, ε c ' is the peak strain of concrete containing modified recycled FRP aggregate, r is the substitution rate, k s1 k is the elastic modulus of concrete related to the amount of wrapping, s2 is the peak strain coefficient of concrete related to the encapsulation amount, s is the encapsulation amount, E c is the elastic modulus of concrete containing modified recycled FRP aggregate, k e is the elastic modulus coefficient of concrete related to the replacement rate.

2. The determination method according to claim 1, characterized in that: The method for constructing formulas (1) to (6) includes the following steps: Providing concrete specimens, the concrete specimens comprising concrete specimens of natural aggregates, concrete specimens containing recycled FRP aggregates, and concrete specimens containing modified recycled FRP aggregates; The concrete specimens are subjected to a compression test to obtain initial compressive strength information of the concrete specimens containing natural aggregates, alternative compressive strength information of the concrete specimens containing recycled FRP aggregates, and modified compressive strength information of the concrete specimens containing modified recycled FRP aggregates; According to the initial compressive strength information and the replacement compressive strength information, construct an initial formula correlating the compressive strength of concrete with natural aggregates, the compressive strength of concrete containing recycled FRP aggregates, and the replacement rate of recycled FRP aggregates, wherein the replacement rate of recycled FRP aggregates is the volume percentage of recycled FRP aggregates in the coarse aggregates of the concrete specimen containing recycled FRP aggregates; According to the initial compressive strength information and the modified compressive strength information, formulas (2) to (6) are constructed; Formulas (2) to (6) are used to correct the initial formula to obtain formulas (1) to (6).

3. The determination method according to claim 2, characterized in that: The preparation method of the modified recycled FRP aggregate comprises the following steps: The recycled FRP aggregate and epoxy mortar are mixed and packaged and modified to obtain the modified recycled FRP aggregate; the epoxy mortar includes epoxy resin, curing agent and auxiliary agent.

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

5. The determination method according to claim 3, characterized in that: The particle size of the recycled FRP aggregate is in the range of 5 to 25 mm, and the aspect ratio is less than 1.

6.

6. A system for determining structural parameters of concrete containing modified recycled FRP aggregates, characterized in that: It includes a data acquisition module, an initial formula building module, a target formula determination module and an output module; The data acquisition module is used to collect compressive strength information obtained by performing compression tests on concrete specimens, wherein the concrete specimens include concrete specimens with natural aggregates, concrete specimens containing recycled FRP aggregates, and concrete specimens containing modified recycled FRP aggregates; the compressive strength information includes initial compressive strength information of concrete specimens with natural aggregates, alternative compressive strength information of concrete specimens containing recycled FRP aggregates, and modified compressive strength information of concrete specimens containing modified recycled FRP aggregates; The initial formula construction module obtains the initial compressive strength information and the replacement compressive strength information transmitted by the data acquisition module, and is used to construct an initial formula for the compressive strength of concrete associated with natural aggregates, the compressive strength of concrete containing recycled FRP aggregates, and the replacement rate of recycled FRP aggregates, wherein the replacement rate of recycled FRP aggregates is the volume percentage of recycled FRP aggregates in the coarse aggregates of the concrete specimen containing recycled FRP aggregates; The target formula determination module is used to construct formulas (1) to (6); k s1 =1+0.449s 2 +0.928rs-0.699s(3); k s2 =-78.696s 2 -1.326rs+47.359s-5.921(5); In formulas (1) to (6): f c ' is the compressive strength of concrete containing modified recycled FRP aggregate, f co ' is the compressive strength of concrete with natural aggregate, ε c ' is the peak strain of concrete containing modified recycled FRP aggregate, r is the substitution rate, k s1 k is the elastic modulus of concrete related to the amount of wrapping, s2 is the peak strain coefficient of concrete related to the encapsulation amount, s is the encapsulation amount, E c is the elastic modulus of concrete containing modified recycled FRP aggregate, k e is the elastic modulus coefficient of concrete related to the replacement rate; The output module is used to output the remaining structural parameters.

7. A method for determining structural parameters of a reinforced concrete beam component with modified recycled FRP aggregate, characterized in that: The structural parameters include the moment bearing capacity of the steel bar-modified recycled FRP aggregate concrete beam component and the structural parameters of the concrete containing the modified recycled FRP aggregate; The structural parameters of the concrete containing modified recycled FRP aggregate are determined by the method described in any one of claims 1 to 6; The acquisition of the moment bearing capacity of the steel bar-modified recycled FRP aggregate concrete beam component includes: converting the actual stress-strain curve of the concrete containing modified recycled FRP aggregate in the compression zone of the steel bar-modified recycled FRP aggregate concrete beam component into an equivalent rectangular stress-strain curve according to an equivalent condition, wherein the equivalent condition is that the resultant forces of the actual stress-strain curve and the equivalent rectangular stress-strain curve are equal and the positions of the action points coincide; determining dimensionless parameters k1 and k2 from the actual stress-strain curve of the concrete containing modified recycled FRP aggregate and the equivalent rectangular stress-strain curve according to the equivalent condition; k1 is determined by formula (7), and k2 is determined by formula (8); In formula (7) and formula (8), k1 is the ratio of the area of ​​the actual stress-strain curve of concrete containing modified recycled FRP aggregate to the area of ​​the equivalent rectangular stress-strain curve, k2 is the ratio of the distance from the resultant point to the compressive edge of the actual stress-strain curve of concrete containing modified recycled FRP aggregate to the strain of the compressive edge, and ε m is the compressive edge strain of the concrete containing modified recycled FRP aggregate in the beam section of the reinforced steel-modified recycled FRP aggregate concrete beam component; σ is the stress of the concrete containing modified recycled FRP aggregate, ε is the strain of the concrete containing modified recycled FRP aggregate, f c ' is the compressive strength of concrete containing modified recycled FRP aggregate; Set the height of the compression zone of the equivalent rectangular stress-strain curve to βx, and the uniformly distributed equivalent stress in the equivalent rectangular stress-strain curve to αf c ', the coefficients of the equivalent rectangular stress-strain curve are β and α, where β = 2k2, α = k1 / 2k2; the height of the compressive zone of the beam section of the reinforced-modified recycled FRP aggregate concrete beam component is determined by formula (9): In formula (9), x is the actual compressive zone height of the beam section of the reinforced concrete beam with modified recycled FRP aggregate, β is the height coefficient of the equivalent rectangular stress-strain curve, α is the strength coefficient of the equivalent rectangular stress-strain curve, and A s is the tensile reinforcement area, f y is the tensile reinforcement strength, f c ' is the compressive strength of concrete containing modified recycled FRP aggregate, b is the beam width of the reinforced steel-modified recycled FRP aggregate concrete beam component; The moment bearing capacity of the steel bar-modified recycled FRP aggregate concrete beam member is determined by formula (10): M=αf c 'bx(h0-x / 2) formula (10); In formula (10), M is the moment bearing capacity of the reinforced concrete beam with modified recycled FRP aggregate, α is the strength coefficient of the equivalent rectangular stress-strain curve, and f c ' is the compressive strength of concrete containing modified recycled FRP aggregate, x is the actual compression zone height of the beam section of the steel bar-modified recycled FRP aggregate concrete beam component, b is the beam width of the steel bar-modified recycled FRP aggregate concrete beam component; h0 is the effective height of the beam section of the steel bar-modified recycled FRP aggregate concrete beam component; The actual stress-strain curve of the concrete containing modified recycled FRP aggregate in the actual compression zone of the steel bar-modified recycled FRP aggregate concrete beam component is shown in formula (11): In formula (11), parameter a and parameter b1 are determined by formula (12) and formula (13), respectively: a=1.927+0.489r+1.23r 2 -1.333r 3 Formula (12); b1=0.129(r+0.011) -0.571 +57.371(1+rs) -39.124 s formula (13); In formulas (11) to (13), f c ' is the compressive strength of concrete containing modified recycled FRP aggregate, ε c ' is the peak strain of concrete containing modified recycled FRP aggregate; σ is the stress of concrete containing modified recycled FRP aggregate; ε is the strain of concrete containing modified recycled FRP aggregate; a is the shape coefficient of the rising section of the actual stress-strain curve of concrete containing modified recycled FRP aggregate; b1 is the shape coefficient of the rising and falling sections of the actual stress-strain curve of concrete containing modified recycled FRP aggregate; r is the substitution rate; s is the encapsulation amount.

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