A recoverable reinforced concrete component based on thermal triggering and a preparation and recovery method thereof

Abstract

The present application relates to a kind of recoverable reinforced concrete components based on heat trigger and its preparation and recycling method, and reinforced concrete component includes: steel structure and the concrete structure poured outside steel structure, wherein the steel structure includes steel bar (1), the resistance wire (2) around the steel bar (1) outside, and the thermoplastic polymer coating (3) covered outside steel bar (1) and resistance wire (2). Compared with prior art, the present application uses thermoplastic polymer coating as the functionalized sacrificial layer in the recycling stage, passes into low-voltage safety current to resistance wire, converts electric energy into heat energy, heats steel bar and then induces polymer coating to melt or soften, weakens the bonding effect between steel bar and concrete, and then gradually crushes concrete, realizes the complete separation and resource recovery of steel bar and concrete.

Description

Technical Field

[0001] This invention belongs to the field of building material recycling technology, and relates to a heat-triggered recyclable reinforced concrete component and its preparation and recycling method. Background Technology

[0002] According to Chinese Patent No. CN114182725B, this invention relates to the field of building construction, specifically to a partially prestressed concrete retaining pile with adjustable prestressed steel bars and recyclable reinforcement. The pile includes a first guide slider, a transmission device, a limiting device, ordinary steel bars, a plastic pipe, a support device, prestressed steel bars, and a corrugated metal pipe. The inner end face of the limiting device is rotatably engaged with the transmission device for limiting the position. Four sets of first guide sliders are threadedly connected to the inner end face of the limiting device through the transmission device. Prestressed steel bars are threadedly connected to the inner end face of the first guide sliders. This invention allows for adjustable prestress; by adjusting the tension of the prestressed steel bars according to the stress on the retaining pile, the prestress on the pile body can be adjusted, thereby adjusting the flexural bearing capacity and cracking moment of the retaining pile.

[0003] Against the backdrop of urban renewal, and with people's increasing demands for living environments, the need for demolition and renovation of existing buildings is growing, leading to a significant increase in construction waste. In recent years, the construction waste recycling industry has experienced rapid development. Due to the synergistic and complementary properties of steel reinforcement and concrete, both are widely used in construction projects. However, during the recycling stage, the bond between steel reinforcement and concrete makes it difficult to effectively peel off the concrete adhering to the steel reinforcement surface. This results in commonly used crushing technologies, such as mechanical crushing, hydraulic crushing, and static crushing, facing problems such as low crushing efficiency, high noise levels, and excessive dust. This situation restricts the resource-based recycling and high-quality utilization of concrete and steel reinforcement in demolished components.

[0004] The key to achieving efficient and high-quality recycling of steel reinforcement and concrete lies in the bond performance between the two. During the manufacturing stage, sufficient bond strength must be ensured between the steel reinforcement and concrete to guarantee structural safety; during the demolition and recycling stage, the bond performance needs to be weakened to achieve complete separation of the two materials. Currently, the ease of recycling is not fully considered in the manufacturing process of reinforced concrete components, resulting in low recycling efficiency of both steel reinforcement and concrete, making it difficult to achieve high-quality reuse. Summary of the Invention

[0005] The purpose of this invention is to provide a heat-triggered recyclable reinforced concrete component and its preparation and recycling method, which can effectively solve the problem of efficient separation of steel bars and concrete in building structures.

[0006] The objective of this invention can be achieved through the following technical solutions: A first aspect of the present invention provides a heat-triggered recyclable reinforced concrete member, comprising: a reinforcing steel structure and a concrete structure cast outside the reinforcing steel structure. The steel reinforcement structure includes steel bars, resistance wires wound around the steel bars, and a thermoplastic polymer coating covering the steel bars and resistance wires.

[0007] In some specific embodiments, the reinforcing bars are hot-rolled plain round steel bars, hot-rolled ribbed steel bars, or welded steel mesh.

[0008] In some specific embodiments, the resistance wire is wound around the main reinforcing bars of the steel structure.

[0009] In some specific embodiments, the resistance wire is fixed by binding or tightly wrapping it to the end of the reinforcing bar.

[0010] In some specific implementations, the main reinforcement bars are longitudinal reinforcement bars of beams, one-way slab columns or strip foundation members, vertical reinforcement bars of column members, and bidirectional reinforcing bars of two-way slabs, walls or slab foundation members.

[0011] In some specific embodiments, the resistance wire is used to heat the reinforcing bar and the thermoplastic polymer coating, and is selected from nickel-chromium wire or iron-chromium-aluminum wire.

[0012] In some specific embodiments, the diameter d of the resistance wire and the diameter D of the reinforcing bar satisfy the following relationship: d = D / 10 - D / 4. Preferably, the diameter of the resistance wire is 2-3 mm. The spiral winding pitch of the resistance wire is 2-5d. Preferably, the resistance wire is loosely wound.

[0013] In some specific embodiments, the glass transition temperature of the thermoplastic polymer used in the thermoplastic polymer coating is... T g ≥70℃, ensuring it is higher than the internal temperature during concrete hydration to prevent softening during hydration.

[0014] In some specific embodiments, the thermoplastic polymer is selected from at least one of polyetherimide, polyetheretherketone, polyethersulfone, polysulfone, or polyphenylene sulfide, preferably polyphenylene sulfide.

[0015] In some specific embodiments, the thickness of the thermoplastic polymer coating is 0.1-1 mm.

[0016] The thermoplastic polymer coating described in this invention acts as an adhesive or sacrificial layer between the reinforcing steel and concrete. During normal use, it can also isolate the reinforcing steel from contact with chloride ions, thus preventing corrosion of the reinforcing steel.

[0017] In some specific embodiments, the concrete structure is selected from one of ordinary silicate concrete structure, hydraulic cementitious concrete structure, air-hardening cementitious concrete structure, or alkali-activated cementitious concrete structure. Preferably, the concrete structure is an ordinary silicate concrete structure.

[0018] In some specific embodiments, the recyclable reinforced concrete components can be used in cast-in-place or precast building construction. Specifically, the recyclable reinforced concrete components can be used as beams, slabs, columns, walls, or foundations.

[0019] In some specific implementations, for fire-resistant design scenarios, including buildings, bridges, roads, tunnels, geotechnical engineering, or marine engineering, the recyclable reinforced concrete components can be designed with fire resistance in terms of protective layers, aggregate type, or cross-sectional dimensions.

[0020] A second aspect of the present invention provides a method for preparing a heat-triggered recyclable reinforced concrete member as described above, comprising the following steps: S1: The resistance wire is wound around the steel bar and then made into a steel cage; S2: A thermoplastic polymer coating is applied to the surface of the reinforcing cage to obtain a reinforcing steel structure; S3: Pour concrete outside the steel structure and cure it to form a concrete structure, thereby obtaining the recyclable reinforced concrete component.

[0021] In some specific embodiments, in step S1, the resistance wire is wound along the direction of the main reinforcement in the reinforced concrete member, including unidirectional or bidirectional arrangement.

[0022] In some specific embodiments, in step S1, the method for preparing the reinforcing cage includes: binding, welding or mechanical connection, preferably, the mechanical connection includes sleeve connection.

[0023] In some specific embodiments, step S2, the coating process sequentially includes: pretreatment, preheating, spraying, and curing; The pretreatment includes one of degreasing, sandblasting, or shot blasting to enhance the adhesion between the reinforcing cage and the thermoplastic polymer. During the preheating process, the preheating temperature is higher than the melting temperature of the thermoplastic polymer but lower than its decomposition temperature, and the preheating time is 10-20 minutes. The spraying process includes spraying thermoplastic polymer powder in layers, 3-4 times; The curing process involves cooling to room temperature to solidify the thermoplastic polymer coating. Cooling methods include natural cooling, air cooling, and indirect water cooling.

[0024] In some specific embodiments, the spraying is selected from air spraying, airless spraying, electrostatic spraying, or other spraying processes derived from the above three processes, preferably electrostatic spraying.

[0025] A third aspect of the present invention provides a method for recycling recyclable reinforced concrete components based on heat triggering as described above, comprising: directly heating or induction heating a resistance wire to soften a thermoplastic polymer coating, breaking up concrete, separating the reinforcing steel structure from the concrete structure, and obtaining the reinforcing steel structure and concrete waste.

[0026] In some specific embodiments, the recycling method further includes cutting recyclable reinforced concrete components from the building to be demolished. The method for cutting the recyclable reinforced concrete components is mechanical cutting, and further, the mechanical cutting includes diamond wire saw cutting, disc cutting, or high-pressure water jet cutting.

[0027] In some specific implementations, the direct electric heating is as follows: a distribution box is installed, and after being processed by a low-voltage transformer, a resistance wire is connected. The resistance wire converts electrical energy into heat energy to heat the steel bars. The induction heating is performed by placing the dismantled reinforced concrete component into an induction coil, passing a high-frequency alternating current through it, generating an alternating magnetic field inside the coil, which causes eddy currents to be generated inside the reinforcing steel, thereby achieving the heating effect.

[0028] In some specific implementations, the heating temperature is monitored during the heating process using contact or non-contact temperature measurement.

[0029] In some specific embodiments, the concrete waste is processed by multi-stage crushing and screening to form multi-stage recycled products, including recycled coarse and fine aggregates and recycled powder, for use in the production of recycled concrete.

[0030] In some specific embodiments, the crushing includes mechanical resonance crushing, hydraulic crushing, or static crushing; In the aforementioned mechanical resonance crushing, the resonance frequency is 10-100Hz; more specifically, the resonance crushing frequency can be "scanned" from low to high to match the crushing frequency of components of different sizes. Furthermore, the resonance crushing proceeds gradually from the outside of the component to the inside, achieving overall crushing through multiple excitations. The separation also includes replacing the resistance wire, repairing the thermoplastic polymer coating, or removing the thermoplastic polymer coating, depending on the condition of the surface resistance wire and the polymer coating. The method for removing the thermoplastic polymer coating includes one of chemical stripping, thermal stripping, or sandblasting stripping.

[0031] In some specific implementations, the recycling method includes the following steps: 1) Cutting recyclable reinforced concrete components from the building to be demolished; 2) The resistance wire is connected to the distribution box through a low-voltage transformer, converting electrical energy into heat energy, which heats the steel bars in the component, raising their temperature above the glass transition temperature of the thermoplastic polymer. T g This, in turn, induces softening of the polymer coating; 3) Breaking the concrete separates the reinforcing steel from the concrete, and then they are processed separately before being used in the construction project.

[0032] This invention provides a heat-triggered recyclable reinforced concrete component, which adds a heating resistance wire and a thermoplastic polymer coating to the reinforcing steel structure. In the production stage, the resistance wire is spirally wound onto the reinforcing steel, and thermoplastic polymer powder is sprayed onto the steel surface to form a uniform coating. Then, concrete is poured to prepare the reinforced concrete component. In the demolition and recycling stage, the polymer coating serves as a functional sacrificial layer. A low-voltage, safe current is passed through the resistance wire, converting electrical energy into heat energy. This heats the reinforcing steel, inducing the polymer coating to melt or soften, weakening the bond between the steel and concrete. The concrete is then gradually broken down, achieving complete separation and resource recycling of the steel and concrete. This invention, by adding a heat-triggered layer (i.e., a "sacrificial" layer) at the interface of raw materials at the front end of the construction process, and considering the recycling of building materials at the back end, can significantly reduce the cost and difficulty of resource recovery of building materials, improve recycling efficiency and quality, and promote the sustainable development of the construction industry. This invention features a simple process, is environmentally friendly and energy-saving, and has controllable costs, enabling efficient and high-quality recycling of demolished reinforced concrete components.

[0033] Compared with the prior art, the present invention has the following beneficial effects: This invention addresses the problems of difficult separation and low crushing efficiency of recycled materials in reinforced concrete components during recycling. It involves spraying a thermoplastic polymer coating onto the surface of the reinforcing steel as a "sacrificial" layer during the recycling stage; simultaneously, a resistance wire is spirally wound around the steel structure as a thermal trigger switch. During use, the thermoplastic polymer is in a glassy state, exhibiting good adhesion to concrete and effectively transferring stress between the steel and concrete. During recycling, a low-voltage current is applied to the resistance wire, converting electrical energy into heat energy, heating the steel to a temperature exceeding the glass transition temperature of the thermoplastic polymer. T g Subsequently, the polymer transforms into a highly elastic state, weakening the bond between the steel reinforcement and concrete, thus facilitating the efficient separation and recycling of the two materials. Thermoplastic polymer materials, serving as both a bonding layer and a "sacrificial" layer in reinforced concrete components, can respectively meet the usage and recycling requirements of the components. By considering the recycling of reinforced concrete components during the design and production stages, they promote the recycling and high-quality regeneration of building materials, contributing to the sustainable development of construction projects.

[0034] The recyclable reinforced concrete components prepared by this invention feature a uniform thermoplastic polymer coating with high adhesion. The preparation process is simple, and the use of resistance wire wrapped around the reinforcing cage reduces the difficulty of recycling, making it easy to implement and promote. For different types of components, the process parameters of the thermoplastic polymer and resistance wire can be adjusted in a timely manner to achieve adaptability and control across various scenarios. Furthermore, the thermoplastic polymer coating method described in this invention is also applicable to the recycling of steel-concrete composite components, steel-plate-concrete composite components, steel-concrete composite components, or corrugated steel-concrete composite components. Attached Figure Description

[0035] Figure 1 This is a flowchart illustrating the preparation and recycling process of the recyclable reinforced concrete components of this invention.

[0036] Figure 2 The flowchart and detailed view of the recyclable reinforced concrete component reinforcement treatment according to the present invention are as follows: (a) plain round steel bar, (b) winding resistance wire, (c) forming thermoplastic polymer coating, (c-I) side view of the treated steel bar, (c-II) front view, (c-III) top view, wherein, 1-steel bar, 2-resistance wire, 3-thermoplastic polymer coating.

[0037] Figure 3 This is a schematic diagram of the resistance wire arrangement in the recyclable reinforced concrete component of the present invention, (a) unidirectional arrangement, (b) bidirectional arrangement, wherein 81-main reinforcement, 9-concrete.

[0038] Figure 4 This is a schematic diagram of the recycling process of the recyclable reinforced concrete components of the present invention, wherein 4-distribution box, 5-low voltage transformer, 6-cutting recyclable reinforced concrete beam, 7-electric wire, 8-reinforcing cage, 81-main reinforcement, and 9-concrete. Detailed Implementation

[0039] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. These embodiments are based on the technical solution of the present invention and provide detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.

[0040] The following are more detailed implementation examples, which further illustrate the technical solution of the present invention and the technical effects that can be obtained.

[0041] In the following embodiments, unless otherwise specified, the raw materials, reagents or processing techniques are all conventional commercial products or conventional processing techniques in the art.

[0042] In this embodiment of the invention, the preparation and recycling process of the heat-triggered recyclable reinforced concrete component is as follows: (1) Binding reinforcing bars and winding resistance wire: Bind the reinforcing bars 1 to form a reinforcing cage 8, and spirally wind the resistance wire 2 along the main reinforcing bars 81 of the reinforcing cage 8. Beams, columns, one-way slabs, or strip foundations are arranged in one direction, while two-way slabs or slab foundations are arranged in two directions. Walls can be arranged in one or two directions depending on the actual reinforcement. When arranged in two directions, contact between resistance wires 2 at intersections should be avoided to prevent melting due to heat. The diameter of the resistance wire 2 is calculated based on the diameter of the main reinforcing bar 81, and the wire spacing is dynamically adjusted within the range calculated based on the diameter of the resistance wire 2 and the actual situation. In the same component, the length and diameter of the resistance wire 2 wound around different main reinforcing bars 81 should be consistent. The resistance of the resistance wire 2 can be calculated using the following formula: in, The resistivity of resistance wire 2 is... The length of resistance wire 2, This is the cross-sectional area of ​​the resistance wire 2. At the end of the main reinforcing bar 81, the resistance wire 2 is fixed by binding it to the end of the reinforcing bar 1, as shown below. Figure 2 As shown.

[0043] (2) Apply thermoplastic polymer coating to the surface of steel bars: select the glass transition temperature T g Thermoplastic polymer with a temperature ≥70℃. The reinforcing cage 8 is subjected to sandblasting, preheating to 360℃ for 10 minutes, electrostatic spraying in 3 applications, and natural air cooling to room temperature for curing, thereby forming a continuous and dense thermoplastic polymer coating 3 on the surface of the reinforcing steel 1. The thickness of the thermoplastic polymer coating 3 should be ≤0.6mm as much as possible.

[0044] (3) Concrete pouring and component preparation: Place the treated steel cage 8 into the component formwork. During placement, avoid contact between the steel cage 8 and sharp objects to prevent damage to the thermoplastic polymer coating 3. Prepare and pour concrete 9 according to a certain mix ratio. After the concrete 9 has cured, demold the component and use it in the project. The above methods are applicable to cast-in-place or precast reinforced concrete beams, slabs, columns, walls or foundation components that do not require fire-resistant design.

[0045] (4) Component cutting: From the building to be demolished, according to a specific cutting sequence, appropriate mechanical cutting methods are used to cut off the reinforced concrete components 6. Among them, the cutting of slabs, walls or slab foundation components is done by disc cutting, and the cutting of beams, columns or strip foundation components can be done by diamond wire saw or high-pressure water jet cutting.

[0046] (5) Heating the reinforcing steel and softening the polymer coating: After crushing and cutting the end concrete of the reinforced concrete component 6, the reinforcing steel 1 and the resistance wire 2 are exposed. The resistance wire 2 is connected to the distribution box 4 through the low-voltage transformer 5 (the output voltage should not exceed the rated working voltage of the resistance wire). At the same time, a non-contact temperature probe is used to measure the temperature of the reinforcing steel 1. The resistance wire 2 converts electrical energy into heat energy, thereby heating the reinforcing steel 1 in the component and making its temperature higher than the glass transition temperature of the thermoplastic polymer. T g This, in turn, induces the softening of the thermoplastic polymer coating 3.

[0047] The induction heating method is as follows: the cut reinforced concrete component 6 is placed into an induction coil, and a high-frequency alternating current is passed through it, thereby generating an alternating magnetic field inside the coil, which causes eddy currents to be generated inside the steel bar 1, thus achieving the heating effect.

[0048] (6) Breaking concrete and separating reinforcing bars: After the temperature of reinforcing bar 1 exceeds the glass transition temperature of thermoplastic polymer and is maintained for a certain period of time, a variable frequency hydraulic vibrator is used to generate a certain frequency of excitation force. The frequency is "scanned" from 10-100Hz to match the resonant frequency of the component, and the concrete 9 is broken up gradually, so that the reinforcing bar 1 (or reinforcing cage 8) is completely separated from the concrete 9.

[0049] According to the above method, the steel bars 1 and concrete 9 are separated. After multi-stage crushing and screening, the concrete 9 blocks form recycled products, including recycled coarse and fine aggregates and recycled powder, which are used to produce recycled concrete. The steel bars 1 (or main bars 81) need to be repaired, replaced or removed according to the condition of the surface resistance wires 2 and thermoplastic polymer coatings 3, and then used for binding the steel cage 8. The removal methods of thermoplastic polymer coatings 3 include chemical, thermal and sandblasting peeling.

[0050] Example 1 A heat-triggered recyclable reinforced concrete beam member is disclosed, with a beam length of 2600 mm and a cross-sectional dimension of 200 mm × 400 mm. Longitudinal reinforcement uses HRB400 steel bars, with two 12 mm diameter compression bars and two 16 mm diameter tension bars at the top and bottom of the beam, respectively. Stirrups are made of 8 mm diameter HPB300 steel bars, spaced 100 mm apart. The reinforcement is tied to form a reinforcement cage, with the main reinforcement bars spirally wound with nichrome wire. The nichrome wire has a diameter of 2 mm and a spacing of 10 mm, and is fixed to the ends of the main reinforcement bars by tying. The thermoplastic polymer used is 300 mesh DURAFIDE 1130A1 polyphenylene sulfide (PPS) powder manufactured by Polyplastics Co., Ltd. of Japan. A uniform coating is formed on the surface of the reinforcement using an electrostatic spraying process. The electrostatic voltage is 55 kV, the spray gun distance is approximately 220 mm, the powder feed rate is 50 g / min, and the final coating thickness is 0.46 mm. C40 ordinary silicate concrete was used for pouring, with a protective layer thickness of 35mm (the thickness between the concrete surface and the rebar surface, used to prevent corrosion of the rebar during use; this ensures the outer contour of the concrete is larger than the outer contour of the rebar cage during pouring, thus providing protection). After 28 days of standard curing, a resistance wire was connected to the distribution box via a low-voltage transformer (output voltage 90V). Upon powering on, the rebar and PPS coating were heated, and the temperature of the end rebar was measured using a non-contact temperature sensor. Once the temperature exceeded the glass transition temperature of PPS by 150°C and was maintained for 10 minutes, a variable frequency hydraulic vibrator was used to break the concrete from the outside in using a "frequency sweep" method.

[0051] Following the steps outlined above, recyclable reinforced concrete beam members based on thermal triggering were prepared and recycled. Referring to GB / T50152-2012 "Standard for Test Methods of Concrete Structures," a four-point bending test was conducted on the recyclable reinforced concrete beam, and its flexural capacity was measured to be 53.6 kN·m. According to GB / T 50010-2010 (2024 edition) "Standard for Design of Concrete Structures," the flexural capacity of a typical reinforced concrete beam under the same reinforcement conditions is 48.25 kN·m. Therefore, the experimental value / theoretical value = 53.6 / 48.25 = 1.11 > 1.05, indicating that the recyclable reinforced concrete beam meets the corresponding mechanical performance requirements. Through gradual concrete crushing, complete separation of the reinforcing steel from the concrete was achieved, and no adhering concrete was found on the surface of the reinforcing steel.

[0052] Example 2 A heat-triggered recyclable reinforced concrete two-way slab member with slab dimensions of 2000mm × 2000mm and a thickness of 150mm is disclosed. Double-layer, bidirectional reinforcement is employed, using 12mm diameter HRB400 steel bars spaced 200mm apart. The reinforcement is tied to form a reinforcing mesh, with bidirectional spiral winding of ferrochrome-aluminum wire. The ferrochrome-aluminum wire has a diameter of 2mm and a spacing of 10mm, with the ends of the main reinforcement bars secured by tying. The thermoplastic polymer used is 300-mesh polyetheretherketone (PEEK) 450PF powder manufactured by Vigus Ltd. (UK), which forms a uniform coating on the reinforcement surface using an electrostatic spraying process. The electrostatic voltage is 50kV, the spray gun distance is approximately 230mm, the powder feed rate is 50g / min, and the final coating thickness is 0.52mm. C40 ordinary silicate concrete is used for pouring, with a protective layer thickness of 15mm. After 28 days of standard curing, the resistance wire is connected to the distribution box through a low-voltage transformer (output voltage 90V). After power is supplied, the reinforcing steel and PEEK coating are heated, and the temperature of the end reinforcing steel is measured using a non-contact temperature sensor. When the temperature exceeds the glass transition temperature of PEEK by 160°C and is maintained for 5 minutes, a variable frequency hydraulic vibrator is used to break the concrete from the outside to the inside in a "frequency sweep" manner.

[0053] Following the steps outlined above, recyclable reinforced concrete two-way slab members based on thermal triggering were prepared and recycled. Referring to GB / T50152-2012 "Standard for Test Methods of Concrete Structures," flexural capacity tests were conducted on the recyclable reinforced concrete two-way slab, and its flexural capacity per unit width was measured to be 30.7 kN·m. According to GB / T 50010-2010 (2024 edition) "Standard for Design of Concrete Structures," the calculated flexural capacity per unit width of ordinary reinforced concrete two-way slabs under the same reinforcement conditions is 28.22 kN·m. Therefore, the experimental value / theoretical value = 30.7 / 28.22 = 1.08 > 1.05, indicating that the recyclable reinforced concrete two-way slab meets the corresponding mechanical performance requirements. Through gradual concrete crushing, complete separation of the reinforcing steel from the concrete was achieved, and no adhering concrete was found on the surface of the reinforcing steel.

[0054] The crushed concrete in Examples 1 and 2, after being crushed by jaw crusher, cone crusher, and vibrating screen, forms recycled products comprising recycled coarse and fine aggregates and recycled powder. According to GB / T 25177-2010 "Recycled Coarse Aggregate for Concrete", GB / T25176-2010 "Recycled Fine Aggregate for Concrete and Mortar", and JG / T 573-2020 "Recycled Micro Powder for Concrete and Mortar", the recycled products all meet the performance requirements of Class II recycled products and can be used to produce recycled concrete. The deformation of the reinforcing steel after separation is minimal. Depending on the condition of the surface resistance wire and polymer coating, it can be repaired, replaced, or removed for use in reinforcing cage / mesh binding. Figure 1 As shown.

[0055] The above description of the embodiments is provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.

Claims

1. A heat-triggered recyclable reinforced concrete member, comprising: A reinforced concrete structure and a concrete structure cast outside the reinforced concrete structure, characterized in that, The steel reinforcement structure includes steel bars (1), resistance wires (2) wound around the steel bars (1), and a thermoplastic polymer coating (3) covering the steel bars (1) and resistance wires (2).

2. The recyclable reinforced concrete member based on thermal triggering according to claim 1, characterized in that, The diameter d of the resistance wire (2) and the diameter D of the reinforcing bar satisfy the following relationship: d = D / 10 - D / 4. Preferably, the diameter of the resistance wire (2) is 2-3 mm; the spiral winding pitch of the resistance wire (2) is 2-5 d.

3. The recyclable reinforced concrete member based on thermal triggering according to claim 1, characterized in that, In the thermoplastic polymer coating (3), the glass transition temperature of the thermoplastic polymer used is... T g ≥70℃.

4. The recyclable reinforced concrete member based on thermal triggering according to claim 3, characterized in that, The thermoplastic polymer is selected from at least one of polyetherimide, polyetheretherketone, polyethersulfone, polysulfone, or polyphenylene sulfide.

5. The recyclable reinforced concrete member based on thermal triggering according to claim 1, characterized in that, The thickness of the thermoplastic polymer coating (3) is 0.1-1 mm.

6. A method for preparing a heat-triggered recyclable reinforced concrete member as described in any one of claims 1 to 5, characterized in that, Includes the following steps: S1: Wrap the resistance wire (2) around the steel bar (1) and then make a steel cage (8); S2: A thermoplastic polymer coating (3) is applied to the surface of the steel cage (8) to obtain a steel structure; S3: Pour concrete outside the steel structure and cure it to form a concrete structure, thereby obtaining the recyclable reinforced concrete component.

7. The method for preparing a recyclable reinforced concrete component based on thermal triggering according to claim 6, characterized in that, In step S1, the resistance wire (2) is wound along the direction of the main reinforcement (81) in the reinforced concrete member, including unidirectional or bidirectional arrangement.

8. The method for preparing a recyclable reinforced concrete component based on thermal triggering according to claim 6, characterized in that, In step S2, the coating process sequentially includes: pretreatment, preheating, spraying, and curing; The pretreatment includes one of degreasing, sandblasting, or shot blasting. During the preheating process, the preheating temperature is higher than the melting temperature of the thermoplastic polymer but lower than its decomposition temperature, and the preheating time is 10-20 minutes. The spraying process includes spraying thermoplastic polymer powder in layers, 3-4 times; The curing process involves cooling to room temperature to cure the thermoplastic polymer coating (3). Cooling methods include natural cooling, air cooling, and indirect water cooling.

9. A method for recycling recyclable reinforced concrete components based on thermal triggering as described in any one of claims 1 to 5, characterized in that, include: The resistance wire (2) is directly heated by electricity or by induction heating to soften the thermoplastic polymer coating (3), break the concrete (9), separate the steel structure from the concrete structure, and obtain the steel structure and concrete waste.

10. The recycling method for recyclable reinforced concrete components based on heat triggering according to claim 9, characterized in that, The crushing includes mechanical resonance crushing, hydraulic crushing, or static crushing; In the aforementioned mechanical resonance crushing, the resonance frequency is 10-100Hz; The separation also includes replacing the resistance wire, repairing the thermoplastic polymer coating (3), or removing the thermoplastic polymer coating (3); The removal method of the thermoplastic polymer coating (3) includes one of chemical stripping, thermal stripping or sandblasting stripping.

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