Self-powered sensing cement composite based on alkali-resistant textile-based TENG, and preparation method and application thereof

Abstract

The application relates to the field of building materials, in particular to a self-powered sensing cement composite material based on alkali-resistant textile TENG and a preparation method and application thereof, which comprises a cement base, a modified protective mortar and a yarn fabric sensing-energy supply prefabricated body, the modified protective mortar is located between the cement base and the yarn fabric sensing-energy supply prefabricated body. The material realizes the dual functions of efficient self-sensing and environmental mechanical energy collection-conversion on the basis of keeping good mechanical properties of the cement base, and has excellent alkali corrosion resistance and long-term stability.

Description

Technical Field

[0001] This invention relates to the interdisciplinary field of building materials and smart structural composite materials. Specifically, it relates to a textile-based triboelectric nanogenerator cement composite material with self-sensing, energy harvesting and conversion, and alkali-resistant corrosion resistance functions, its preparation method, and its application in self-powered sensing smart infrastructure. Background Technology

[0002] Cement-based materials are currently the most widely used building materials globally, but their traditional function is mainly limited to providing structural load-bearing capacity, classifying them as passive materials. With the rapid development of smart cities and new infrastructure construction, there is an urgent need for multifunctional and intelligent building materials. The aim is for these materials not only to withstand loads but also to sense their own health status (such as stress, strain, and damage) and external environmental information (such as traffic flow and vibration) in real time, and to possess a certain degree of autonomous energy supply capability, in order to achieve real-time, online, and intelligent monitoring and management of infrastructure.

[0003] To endow cement-based materials with intelligent sensing capabilities, existing technologies mainly attempt to incorporate various functional fillers (such as conductive materials like carbon fibers, carbon nanotubes, and graphene, or piezoelectric materials like piezoelectric ceramics and piezoelectric polymers) into the cement matrix. However, these methods generally suffer from the following technical bottlenecks: First, nano- or micro-scale functional fillers are prone to agglomeration in cement slurry, resulting in poor dispersion uniformity, unstable material properties, and low reproducibility. Second, high-performance functional fillers are expensive, and the required dosage to achieve an effective conductive network is often large, limiting their large-scale engineering applications. Third, the composite materials prepared by the above methods have weak signal output, poor anti-interference ability, and limited electromechanical conversion efficiency, making it difficult to achieve effective energy harvesting and self-powered operation.

[0004] In recent years, triboelectric nanogenerator (TENG) technology has provided a new approach to extracting electrical energy from environmental micromechanical energy. Based on contact electrification and electrostatic induction coupling mechanisms, it can efficiently convert mechanical energy such as minute vibrations and deformations into electrical energy. Textile structures (such as yarns and fabrics) are considered ideal carriers for constructing TENGs due to their flexibility, weavability, and high degree of structural design freedom. In particular, the fuzzy structure on the surface of yarn can increase the contact area and friction interface, improving electrical output performance. However, how to effectively combine textile-based TENGs with cement matrices to develop smart cement composite materials that possess high mechanical properties, strong electrical output, long-term alkali resistance, and suitability for engineering applications remains an unresolved technical challenge in this field.

[0005] Therefore, there is an urgent need to propose a novel textile-based TENG cement composite material, its preparation method, and its application to solve the problems of difficult dispersion of functional fillers, high cost, weak signal, insufficient durability, and difficulty in large-scale preparation in the existing technology, so as to achieve the synergistic integration of self-sensing, energy harvesting, and structural enhancement. Summary of the Invention

[0006] This invention aims to overcome the shortcomings of existing smart cement materials in terms of functional integration, cost, large-scale preparation, and environmental durability, and provides a self-powered sensing cement composite material based on textile-based TENG and its preparation method. This material achieves the dual functions of efficient self-sensing and environmental mechanical energy harvesting and conversion while maintaining the good mechanical properties of the cement matrix, and also possesses excellent resistance to alkali corrosion and long-term stability.

[0007] In a first aspect, the present invention provides a smart cement composite material based on textile-based TENG, comprising a cement matrix, modified protective mortar and yarn fabric sensing-powering prefabricated body, wherein the modified protective mortar is located between the cement matrix and the yarn fabric sensing-powering prefabricated body. The yarn fabric sensing-powering prefabricated body includes: a metal wire, a first polymer fiber yarn, a second high-strength fiber yarn arranged sequentially from the inside out, and a flexible protective film formed by curing water-based polyurethane; the first polymer fiber yarn covers the surface of the metal wire, the second high-strength fiber yarn covers the surface of the first polymer fiber yarn, and the flexible protective film covers the surface of the second high-strength fiber yarn. The material of the second high-strength fiber yarn has a different triboelectric sequence than the material of the first polymer fiber yarn.

[0008] The aforementioned yarn fabric sensing-powering prefabricated body is woven from yarns with a three-layer coaxial structure of "core-sheath". Its structure, from the inside out, is as follows: Core layer (charge collection / conduction layer): This is a metallic wire used for charge collection and conduction.

[0009] Intermediate layer (triboelectric layer): Composed of a first polymer fiber yarn wrapped around the outer surface of the core layer in a woven or tightly spiral wound manner. The first polymer fiber yarn is a polyvinylidene fluoride long fiber yarn or a polyimide long fiber yarn with a linear density of 100-150 tex.

[0010] To achieve functional enhancement, the surface of the intermediate layer fiber yarn requires any one or a combination of the following modification treatments: 1) Silane coupling agent surface treatment: impregnation and curing with an ethanol solution of silane coupling agent to significantly enhance its surface charge density, triboelectric output stability, and interfacial adhesion with adjacent coatings. 2) Conductive / triboelectric enhancement coating treatment: coating the fiber surface with a conductive material coating, including but not limited to conductive silver paste, graphene dispersion, MXene suspension, or a composite coating thereof. This coating can be applied by dip coating, spraying, or printing, and then dried and cured to form a continuous or patterned conductive network. This treatment effectively improves the charge trapping capacity, charge transfer rate, and overall electrical output performance of the fiber surface, while maintaining its flexibility and abrasion resistance.

[0011] Outer layer (protective reinforcement layer): This layer is woven from a second high-strength fiber yarn and wrapped around the outer surface of the intermediate layer. The second high-strength fiber yarn is poly(p-phenylene benzodioxazole) fiber yarn or aramid yarn with a linear density of 50-100 tex. This outer layer has a dual function: firstly, as a friction pair material, it has a different triboelectric electrode sequence from the intermediate layer material, together forming a highly efficient triboelectric couple, which is the key interface for generating triboelectric charge; secondly, as a physical protective layer, it resists the strong alkaline erosion of cement hydration products and improves the overall mechanical strength of the yarn.

[0012] Before being embedded in the cement matrix, the yarn fabric is coated with a flexible protective film formed by the curing of an aqueous polyurethane emulsion. Specifically, the smart yarn is first woven into a two-dimensional plain weave, twill weave, or three-dimensional spaced fabric structure to form a sensing-powering fabric. This fabric is then impregnated in an aqueous polyurethane emulsion with a solid content of 5-10%, and after drying and curing, a continuous and dense flexible protective film is formed on the fabric surface and at the yarn interlacing points. This film further blocks alkaline ion erosion and provides a stress-buffered interface between the rigid cement and the flexible fabric.

[0013] To optimize the interface transition, the portion of the cement matrix in direct contact with the sensing-powering precast body is a specially modified protective mortar layer. By weight, it comprises: 100 parts ordinary Portland cement, 10-15 parts silica fume, 150-250 parts quartz sand, 35-45 parts water, 5 parts styrene-butadiene latex, 0.5-1.0 parts polycarboxylate superplasticizer, and 0.1-0.3 parts organosilicon defoamer.

[0014] Furthermore, the silane coupling agent is selected from at least one of aminosilane and epoxysilane, preferably γ-aminopropyltriethoxysilane or γ-glycidoxypropyltrimethoxysilane. Furthermore, the thickness of the flexible protective film is 5-20µm.

[0015] Furthermore, the metal wire is copper wire, silver-plated copper wire, high-purity annealed copper wire, or stainless steel microwire.

[0016] Secondly, the present invention provides a method for preparing the above-mentioned textile-based smart cement composite material, comprising the following steps: S1. Surface functionalization modification of intermediate layer fiber yarn: If silane coupling agent treatment is used: Immerse the selected polymer fiber yarn in a silane coupling agent ethanol solution and perform ultrasonic-assisted treatment for 10 minutes. 30 minutes later, remove and then at 60 Dry and cure at 90℃; if a conductive coating is used: uniformly coat the selected polymer fiber yarn with a conductive paste (such as conductive silver paste, graphene dispersion, MXene suspension) by dip coating or spraying, and then cure at 80℃. The functionalized coating is formed by drying and curing at 120℃. If a combined treatment is used, the silane coupling agent is applied first, followed by the conductive coating treatment.

[0017] S2. Core-Sheath Structure Intelligent Yarn Weaving: First, the metal conductor, as the core yarn, is smoothly unwound from the bobbin and directly guided to the twisting convergence point. Then, the functionalized intermediate layer fiber yarn, modified by S1 surface treatment, is used as the first sheath yarn, evenly distributed on multiple guide rollers of the braiding machine. It is guided through multiple roughened guide holes and tightly and evenly wrapped around the straight-feeding metal core yarn with a certain tension angle and wrapping method. The spindle speed is controlled within the range of 40 r / min to 60 r / min to form a primary composite yarn. Then, using the above primary composite yarn as the core, the outer high-strength fiber yarn is used as the second sheath yarn, evenly distributed on multiple guide rollers of the doubling machine, and passed through the guide holes for secondary wrapping and weaving with the same or opposite twist direction. Finally, the core-sheath structure intelligent yarn with a three-layer coaxial structure of "core layer-friction layer-protective layer" is obtained. The roughening treatment described above aims to perform controlled scraping and fuzzing on the yarn, thereby creating micro-hair or microfibrillated structures on its surface to significantly increase the effective frictional contact area and charge transfer efficiency.

[0018] S3. Preparation of surface-coated smart yarn fabric: The core-sheath structure smart yarn obtained in step S2 is woven into a fabric of a predetermined shape, and then impregnated in a water-based polyurethane diluted emulsion. The "impregnation-rolling-drying" process is used to control the weight gain rate at 3-6%, so that a continuous and dense flexible protective film is formed on the fabric surface and between the yarns, forming a yarn fabric sensing-powering prefabricated body.

[0019] S4. Preparation of modified protective mortar: Weigh cement, silica fume, quartz sand, water and styrene-butadiene latex according to the weight ratio; mix the above raw materials evenly to prepare modified protective mortar.

[0020] Raw material ratio: 100 parts ordinary silicate cement, 10-15 parts silica powder, 150-250 parts quartz sand, 35-45 parts water, 5 parts styrene-butadiene latex, 0.5-1.0 parts polycarboxylate superplasticizer, and 0.1-0.3 parts organosilicon defoamer.

[0021] S5. Layered Casting and Curing: First, pour a layer of modified protective mortar prepared in step S4 into the bottom of the mold as the base layer. Then, place the precast coated fabric obtained in step S3 onto this mortar layer, ensuring it is flat and wrinkle-free. Next, cover the fabric with a second layer of modified protective mortar and gently vibrate it to fully impregnate the fabric. Finally, pour ordinary cement mortar or concrete to cover the designed thickness, vibrate it, cover it with a plastic film, and cure it according to standard until the specified age. Demolding yields the textile-based TENG intelligent cement composite material.

[0022] Furthermore, in step S2, the yarn guide hole is a ceramic yarn guide hole or a yarn guide hook, and its roughening treatment is carried out by photolithography, plasma etching, electrochemical corrosion, sandpaper polishing or sandblasting, etc., so that its surface roughness Ra is not less than 3.2µm.

[0023] Furthermore, in step S2, the braiding machine and the twisting machine are either ply twisting machines or hollow spindle fancy twisting machines.

[0024] Thirdly, the present invention also provides the application of the above-mentioned composite material in self-powered sensing intelligent infrastructure. Specifically, the composite material is integrated with a standardized peripheral circuit module as a multifunctional component that combines energy harvesting and conversion with structural load-bearing functions. The embedded metal core layer of the yarn fabric sensing-powering prefabricated body serves as an electrode lead-out, connected to an external rectifier unit, energy storage and buffer unit, functional load, and optional signal conditioning unit.

[0025] When composite material components undergo micro-deformation due to environmental excitations (such as road vibration caused by vehicle traffic, light pole swaying caused by wind loads, or micro-motion of the base caused by pedestrian footsteps), relative sliding occurs between adjacent yarns with different triboelectric electrode sequences embedded within the component. This generates alternating electrical signals / energy through the coupling effect of triboelectric charging and electrostatic induction. The generated raw AC signal is processed and directly powers low-power functional loads, such as LED lighting modules, environmental sensors (temperature, humidity, photosensitivity), and wireless data transmission modules (such as NB-IoT and LoRa modules). Simultaneously, the extracted sensor signals are transmitted wirelessly to a monitoring center for assessing structural health (vibration modes, damage warning) or monitoring traffic parameters (traffic flow, vehicle speed).

[0026] Compared with the prior art, the embodiments of the present invention have at least the following advantages or beneficial effects: Through the "core-sheath" yarn structure design of "core layer-friction layer-protective layer", a stable friction interface is naturally formed in the yarn and fabric weaving structure by utilizing the inherent difference in triboelectric electrode sequence between the middle layer and the outer layer. This achieves the simultaneous integration of efficient charge collection and conduction, triboelectric charging and durable protection in the cement matrix.

[0027] The triple protection system, consisting of alkali-resistant outer fiber, water-based polyurethane flexible protective film, and styrene-butadiene latex modified mortar interface layer, significantly improves alkali resistance and interface stability, ensuring the long-term electrical and mechanical stability of the material under harsh working conditions.

[0028] The "flexible-rigid" gradient interface formed by the flexible protective film and the modified protective mortar can effectively buffer stress, prevent interface debonding, and ensure the reliability of sensor signal transmission. Attached Figure Description

[0029] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0030] Figure 1 This is a flowchart illustrating the preparation process of the alkali-resistant textile-based self-powered sensing cement composite material of the present invention.

[0031] Figure 2 The diagram (a) and the physical image (b) show the structure of the yarn fabric sensing-powering prefabricated body according to Embodiment 1 of the present invention.

[0032] Figure 3 This is a process diagram for preparing the plain weave fabric of Embodiment 1 of the present invention.

[0033] Figure 4 This is a flow chart of the impregnation-rolling-drying process for plain weave fabric in Embodiment 1 of the present invention.

[0034] Figure 5 The following is a schematic diagram of the triboelectric power generation principle of the yarn fabric sensing-powering prefabricated structure in Embodiment 1 of the present invention: (a) Yarn cross-sectional structure; (b) Increase of micro-hair through the scraping action of the yarn guide hole; (c)-(f) Triboelectric power generation process of textile-based TENG.

[0035] Figure 6 This describes the short-circuit charge transfer of the cement composite material in Embodiment 2 of the present invention at different loading frequencies.

[0036] Figure 7 The open-circuit voltage of the cement composite material of Embodiment 2 of the present invention at different loading frequencies.

[0037] Figure 8 The short-circuit currents of the cement composite material in Embodiment 2 of the present invention at different loading frequencies are shown.

[0038] Figure 9 This is a durability test of the cement composite material in Example 2 of the present invention.

[0039] Figure 10 The diagram shows the circuit diagram (a) of the self-powered intelligent street light system in Embodiment 3 of the present invention, the physical image (b) of the textile-based intelligent cement composite material, and the voltage-time curve (c) of the capacitor.

[0040] Figure 11 This is a schematic diagram illustrating the application of the self-powered sensing intelligent infrastructure of the present invention.

[0041] Icons: 1. Aramid yarn; 2. Polyimide yarn; 3. Metal wire; 4. Plain weave fabric; 5. Water-based polyurethane diluted emulsion; 6. Yarn guide hole; 7. LED lighting module and control unit; 8. Energy storage and buffer unit; 9. Rectifier unit; 10. Lamp pole base component. Detailed Implementation

[0042] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0043] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other. The present invention will now be described in detail with reference to specific embodiments.

[0044] Example 1 Example 1: Preparation and basic performance testing of smart yarns and coated fabrics This embodiment aims to prepare a smart yarn and surface-coated fabric preform with a "core-sheath" structure, and to verify its basic triboelectric power generation and alkali resistance properties. The specific implementation method is as follows: Materials preparation: Core material: Annealed copper wire with a diameter of 0.08 mm is selected as the metal conductor 3.

[0045] Intermediate layer material: Polyimide yarn 2 with a linear density of 120 tex was selected. Before use, it was immersed in a 2 wt% γ-aminopropyltriethoxysilane ethanol solution, ultrasonically treated for 20 minutes, and then dried and cured in an oven at 80°C to obtain surface-modified polyimide yarn 2. This treatment aims to improve its surface charge density and interfacial adhesion with subsequent coatings.

[0046] Outer layer material: Meta-aramid yarn 1 with a linear density of 80 tex and treated with alkali resistance is selected as the friction and protective layer. The coating solution is an 8% solids content waterborne polyurethane emulsion.

[0047] Auxiliary components of the braiding machine: The yarn guide hole 6 is made of ceramic and is pre-roughened by processes such as photolithography, plasma etching, and electrochemical corrosion to increase its surface roughness Ra to about 4.0 µm, so as to be used for subsequent control of the microstructure of the yarn surface.

[0048] Coating solution: 8% solids content waterborne polyurethane emulsion; Preparation steps, S1-S3 (see attached) Figure 3 See S4 Figure 4 : S1 core yarn feeding: Prepared using a six-spindle coaxial wrapping braiding machine, the copper wire is smoothly unwound from the spool, maintaining constant tension, and directly guided to the twisting convergence point.

[0049] S2 First Layer Coating (Forming a Triboelectric Layer): Surface-modified polyimide yarn 2 is used as the sheath yarn, evenly passing through multiple sets of ceramic yarn guide holes and braiding machine guide rollers, with a pre-braided length of 5 cm to ensure the yarn remains straight. The braiding machine spindle speed is controlled at 40 r / min, causing the polyimide yarn 2 to be tightly and evenly spirally wound around the surface of the straight-moving copper wire core yarn at a wrapping angle of approximately 45°, forming a "copper wire-polyimide" primary composite yarn. During this process, the roughened yarn guide holes 6 generate a controllable scraping effect on the surface of the polyimide yarn 2, inducing the generation of micro-hairs and increasing its effective friction area.

[0050] S3 Second Layer Covering (Forming a Protective-Friction Layer): Subsequently, using the primary composite yarn as the core layer, alkali-resistant aramid yarn 1 is used as the outer sheath yarn, similarly guiding the yarn through the ceramic yarn guide hole 6 and the braiding machine guide roller. The spindle speed is controlled at 50 r / min, and with the same twist direction as the first layer covering, the aramid yarn 1 is braided and covered onto the outer layer of the primary composite yarn, ultimately producing a three-layer coaxial "core-sheath" structure intelligent yarn with a "metal core layer - polyimide intermediate layer - aramid outer layer," as shown below. Figure 2 As shown, aramid yarn is also pulled by the yarn guide holes during the secondary wrapping and weaving process, forming a microfibrilated surface.

[0051] S4 Smart Fabric Surface Coating: The smart yarn prepared in the above steps is fixed on the spinning propulsion device of a small weaving machine. A syringe and a spinneret are connected by a plastic hose to weave a 10cm × 10cm plain weave fabric 4. The "impregnation-rolling-drying" process is adopted (see...). Figure 4The fabric is completely immersed in the diluted aqueous polyurethane emulsion 5 for 10 seconds to ensure full saturation. A two-roller press is then used to roll the fabric under uniform pressure, controlling the roll-up percentage to 120% (i.e., the amount of liquid carried by the fabric). The fabric is then placed in an 80°C forced-air oven for curing for 10 minutes. This process results in a continuous, dense, flexible polyurethane protective film approximately 10 µm thick forming on the fabric surface and at the yarn interlacing points, yielding a coated fabric preform, i.e., a yarn fabric sensing-powering preform, such as... Figure 2 As shown.

[0052] Performance testing and results analysis: A prefabricated uncoated fabric (5 cm × 5 cm) was cut and fixed onto a stage. Another resin plate with a polyimide interlayer was connected to a vibrating surface driven by a servo motor. When the servo motor operates, it controls the resin plate to periodically contact the uncoated fabric prefabricated fabric with a specified force and frequency. Motion parameters were set as follows: contact-separation frequency 2 Hz, spacing 2 mm, and contact pressure 20 N. The open-circuit voltage and short-circuit current were measured in real time using a high-resistivity electrometer (Keithley 6514). Test results showed that the structure produced excellent electrical output performance, with an average open-circuit voltage of 38 V and an average short-circuit current of 0.15 µA. These values ​​indicate that the structure has good basic triboelectric generation capability (see principle). Figure 5 As Comparative Example 1a, yarns and fabrics were prepared using the same raw materials without roughening the yarn guide holes. Under the same test conditions, the open-circuit voltage and short-circuit current decreased to approximately 26.6 V and 0.13 µA, respectively. This demonstrates that the micro-hair generated by surface roughening treatment can effectively improve the triboelectric contact area and charge transfer efficiency. In Comparative Example 1b, the outer layer was replaced with glass fiber yarn. Under the same conditions, the open-circuit voltage and short-circuit current decreased to approximately 8 V and 0.09 µA, respectively. This confirms the effectiveness of selecting aramid / polyimide with significant differences in triboelectric electrode sequence as a triboelectric couple.

[0053] The precast coated fabric sample was completely immersed in simulated cement pore liquid (saturated Ca(OH)2 solution) at pH=13.5 and left to stand at room temperature for 7 days. After removal, it was gently rinsed with deionized water and air-dried. The surface polyurethane film was carefully peeled off in the test area to expose the inner aramid and polyimide fiber layers, and the above triboelectric performance test was performed again. After strong alkali erosion, the average open-circuit voltage of the sample was 32 V, the average short-circuit current was 0.14 µA, the electrical output performance retention rate was above 80%, and the signal attenuation was less than 20%. The results show that the composite protective system composed of the aramid outer layer and the waterborne polyurethane flexible protective film can effectively block the erosion of the inner polyimide friction layer and metal core layer by alkaline ions, ensuring the long-term stability of the material in the alkaline environment of cement.

[0054] Example 2: Preparation and Mechanical-Electrical Comprehensive Evaluation of Cement Composite Materials Based on Textile-Based TENG This embodiment aims to prepare a complete cement-based composite material specimen integrating the aforementioned smart fabric, as shown in the attached document. Figure 1 As shown, its basic mechanical properties and its self-sensing and energy harvesting / conversion capabilities under stress are comprehensively evaluated. The specific implementation method is as follows: Materials preparation: Smart fabric preform: The coated fabric preform prepared in Example 1 is used, namely the yarn fabric sensing-powering preform.

[0055] Modified protective mortar: Prepare according to the weight ratio, stir evenly and set aside.

[0056] Mixing ratio: 100 parts of PO 42.5 ordinary silicate cement, 12 parts of silica powder, 200 parts of quartz sand, 40 parts of water, 5 parts of styrene-butadiene latex, 0.8 parts of polycarboxylate superplasticizer, and 0.2 parts of organosilicon defoamer.

[0057] Substrate concrete: C40 ordinary concrete.

[0058] Preparation steps: A modified protective mortar layer approximately 10 mm thick was poured at the bottom of a 40 mm × 40 mm × 160 mm specimen mold as the base layer. A prefabricated coated fabric (slightly smaller than the mold cavity width) was then laid flat on the uncured mortar base layer, ensuring no wrinkles and complete adhesion. A second layer of modified protective mortar, approximately 10 mm thick, was poured on the fabric and gently tamped with a thin rod to ensure the mortar fully penetrated the fabric gaps. Finally, C40 concrete was poured to fill the remaining mold space, and the mold was vibrated on a vibrating table. The surface was covered with a plastic film to retain moisture. After standing for 24 hours under standard curing conditions of 20±2℃ and >95% relative humidity, the specimen was demolded and continued to cure in a standard curing room for 28 days to obtain the final textile-based smart cement composite specimen. In the specimen, the electrode leads of the fabric prefabricated fabric were pre-leading out from the side of the mold.

[0059] Performance Testing and Result Analysis: The flexural and compressive strength of the composite material specimens were tested using a universal testing machine. The average flexural strength of the composite material after 28 days was measured to be 8.5 MPa, and the average compressive strength was 52 MPa. These strength data are essentially equivalent to those of a reference concrete specimen with the same mix design but without any embedded fabric (flexural strength 8.3 MPa, compressive strength 51 MPa). This indicates that the sensing-powering precast body of this invention incorporates the mechanical properties of a non-degraded matrix, achieving compatibility between functional integration and structural load-bearing capacity.

[0060] Three-point bending tests were performed on the composite material specimens. On a universal testing machine, the specimens were cyclically loaded at a frequency of 2–4 Hz, with a fixed load of 20 N. Simultaneously, the fabric electrodes were connected to a high-resistance electrometer (Keithley 6514) and a multimeter (DMM7510) for testing, and the electrical signals generated by the specimens under cyclic loading were acquired synchronously. The obtained short-circuit charge transfer curves, open-circuit voltage curves, and short-circuit current curves are shown below. Figure 6 , Figure 7 and Figure 8 As shown in the figure. The results indicate that, with the increase of the applied impact load frequency, the cement composite material based on alkali-resistant textile-based TENG generates a stable electrical signal under cyclic loading, and the amplitudes of the open-circuit voltage and short-circuit current increase accordingly, while the overall short-circuit charge transfer remains relatively unchanged. This indicates that the composite material can directly convert the mechanical stress / strain it experiences into a monitorable electrical signal. To further verify its durability, the specimen was subjected to 5000 cycles of loading at a frequency of 2 Hz under a load of 20 N. The test results are shown in the figure. Figure 9 As shown, after 5000 cycles of loading, the open-circuit voltage of the specimen did not change significantly compared to the initial test value.

[0061] Example 3: Integration of a self-powered intelligent street light system This embodiment aims to integrate the textile-based smart cement composite material component into a smart street light system to achieve energy harvesting from environmental vibrations and self-powered lighting functions. The specific implementation method is as follows: A cement-based composite columnar component with dimensions of 300 mm × 300 mm × 600 mm (length × width × height) is provided as the base of the street light pole. During the component casting process, the prefabricated coated fabric (280 mm × 280 mm) prepared in Example 1 is laid in layers between modified protective mortar layers 50 mm from the bottom and 50 mm from the top of the component, for a total of two layers, with the fabric plane kept parallel to the ground. Before the component is cast, sufficient length is reserved at both ends of the metal core layer (copper wire) of the "core-sheath" structure smart yarn in each layer of the fabric prefabricated fabric. After the component is cast and cured, the ends are cleaned and insulated wires are welded as positive and negative electrode leads, which are connected to the rectifier bridge and energy storage capacitor to form a self-powered smart street light system.

[0062] The overall circuit structure of the self-powered intelligent street light system is as follows: Figure 10 As shown in Figure a, the external structure of the self-powered intelligent street light system is as follows: Figure 11 As shown, it mainly includes: lamp post base component 10 (made of textile-based cement composite material, as shown in the actual picture). Figure 10As shown in b), the system includes a rectifier unit 9 (a full-wave rectifier bridge that converts AC power generated by the textile-based TENG into DC power), an energy storage and buffer unit 8 (a capacitor bank for storing electrical energy), a load switch control circuit, and an LED lighting module 7 (a low-power LED module used as a street light source). When a vehicle passes by, causing micro-vibrations in the base, the material generates an electrical signal, which is stored and used to drive the low-power LED marker lights on the base at night, achieving self-powered operation. Simultaneously, the frequency and amplitude of the output signal can be wirelessly transmitted in real time for monitoring traffic flow on that road segment.

[0063] The integrated streetlight base component was installed in an open outdoor test field. A horizontal harmonic excitation (frequency 5 Hz, amplitude ±3 mm) simulating wind-induced vibration was applied to the top of the component using a vibrator. An oscilloscope connected to the circuit input was used to monitor the original AC signal, recording the voltage rise curves across the capacitors (capacities of 0.9 µF, 1.8 µF, and 3.6 µF, respectively). Figure 10 As shown in c. Tests show that, under continuous excitation, the voltage of capacitors of different capacities can rise steadily to 1 V in a short time (120s).

[0064] The embodiments described above are some, but not all, embodiments of the present invention. The detailed description of the embodiments of the present invention is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

Claims

1. A self-powered sensing cement composite material based on alkali-resistant textile-based TENG, characterized in that, It includes a cement matrix, a modified protective mortar, and a yarn fabric sensing-powering prefabricated body, wherein the modified protective mortar is located between the cement matrix and the yarn fabric sensing-powering prefabricated body; The yarn fabric sensing-powering prefabricated body includes: a metal wire, a first polymer fiber yarn, a second high-strength fiber yarn arranged sequentially from the inside out, and a flexible protective film formed by curing water-based polyurethane; the first polymer fiber yarn covers the surface of the metal wire, the second high-strength fiber yarn covers the surface of the first polymer fiber yarn, and the flexible protective film covers the surface of the second high-strength fiber yarn. The material of the second high-strength fiber yarn has a different triboelectric sequence than the material of the first polymer fiber yarn.

2. The self-powered sensing cement composite material based on alkali-resistant textile-based TENG according to claim 1, characterized in that, The first polymer fiber yarn is a polyimide long fiber yarn or a polyvinylidene fluoride long fiber yarn with a linear density of 100-150 tex.

3. The self-powered sensing cement composite material based on alkali-resistant textile-based TENG according to claim 1, characterized in that, The second high-strength fiber yarn is aramid yarn or poly(p-phenylenebenzodioxazole) fiber yarn with a linear density of 50-100 tex.

4. The self-powered sensing cement composite material based on alkali-resistant textile-based TENG according to claim 1, characterized in that, The thickness of the flexible protective film is 5-20 µm.

5. The self-powered sensing cement composite material based on alkali-resistant textile-based TENG according to claim 1, characterized in that, The metal wire is at least one of copper wire, silver-plated copper wire, high-purity annealed copper wire, and stainless steel microwire.

6. The self-powered sensing cement composite material based on alkali-resistant textile-based TENG according to claim 1, characterized in that, The modified protective mortar layer comprises the following raw materials by weight: 100 parts ordinary silicate cement, 10-15 parts silica powder, 150-250 parts quartz sand, 35-45 parts water, 5 parts styrene-butadiene latex, 0.5-1.0 parts polycarboxylate superplasticizer, and 0.1-0.3 parts organosilicon defoamer.

7. A method for preparing a self-powered sensing cement composite material based on alkali-resistant textile-based TENG as described in any one of claims 1-6, characterized in that, Includes the following steps: S1. Functional modification pretreatment of the first polymer fiber yarn: impregnation treatment with silane coupling agent solution; or coating with conductive or triboelectric reinforcing material; S2. Using a metal wire as the core yarn and the first polymer fiber yarn pretreated in step S1 as the first sheath yarn, a first wrapping weaving is performed to obtain a primary composite yarn; then, using the primary composite yarn as the core yarn and the second high-strength fiber yarn as the second sheath yarn, a second wrapping weaving is performed to obtain a smart yarn with a three-layer coaxial structure. S3. The smart yarn obtained in step S2 is woven into a fabric, then impregnated in an aqueous polyurethane emulsion, and then rolled, dried and cured to form a flexible protective film on the surface of the fabric, thus obtaining a yarn fabric sensing-powering prefabricated body. S4. Prepare modified protective mortar; S5. First, pour a layer of modified protective mortar prepared in step S4 into the mold, then lay the precast coated fabric obtained in step S3, then pour a second layer of modified protective mortar, and finally pour ordinary cement mortar or concrete to the designed thickness, and cure and shape.

8. The method for preparing the self-powered sensing cement composite material based on alkali-resistant textile-based TENG according to claim 7, characterized in that, In step S2, the first covering weaving is carried out using a weaving machine. The yarn guide hole or yarn guide hook of the weaving machine is roughened so that its surface roughness Ra is not less than 3.2 µm.

9. The preparation method of the self-powered sensing cement composite material based on alkali-resistant textile-based TENG according to claim 7, characterized in that, The silane coupling agent is selected from at least one of aminosilane and epoxysilane; the coating material is selected from at least one of conductive silver paste, graphene, and MXene.

10. The application of a self-powered sensing cement composite material based on alkali-resistant textile-based TENG as described in any one of claims 1-5 in a self-powered smart infrastructure, characterized in that, The composite material is used as a functional component, and the metal core layer of the yarn fabric sensing-powering prefabricated body embedded inside it is used as an electrode to be led out and connected to an external circuit module; an electrical signal is generated by the relative sliding and frictional electrification effect between the internal yarns or fabric layers to power low-power electronic devices, and / or to extract sensing signals for structural health monitoring or environmental parameter monitoring.

Images