Intelligent sensing monitoring system based on high-performance concrete
By introducing a high-performance tensile concrete layer into the intelligent concrete sensor, combining conductive materials and PVA fibers, the problem of poor tensile resistance of traditional intelligent concrete sensing elements is solved, the tensile strength and toughness are improved, the service life is extended and the detection accuracy is ensured.
Patent Information
- Application Number
- CN202421296109.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-06-06
- Publication Date
- 2025-06-17
- Estimated Expiration
- 2034-06-06
AI Technical Summary
The existing intelligent concrete sensing elements have poor tensile resistance and are prone to cracks, affecting their safety and durability.
Using an intelligent sensing monitoring system based on high-performance concrete, the intelligent concrete piezoresistive sensor consists of an intelligent concrete piezoresistive sensing layer and a high-performance tensile concrete layer. The built-in electrodes are connected to the data processing module through wires, and the tensile strength and toughness are improved by materials such as conductive materials and PVA fibers.
It improves the tensile strength of the intelligent concrete sensor, effectively prevents and prevents crack expansion, extends the service life of the sensor, and ensures the sensitivity and accuracy of detection.
Smart Images
Figure CN222994379U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of concrete monitoring, and particularly relates to an intelligent sensing monitoring system based on high-performance concrete. Background Technique
[0002] Disclosing the information of this background technique section is only intended to enhance the overall understanding of the utility model, and it is not necessarily regarded as an admission or an implication in any form that this information constitutes the prior art already known to those of ordinary skill in the art.
[0003] Concrete structures are widely used in various fields of civil engineering due to their significant advantages. As a brittle material, the failure of concrete has suddenness, which makes its failure unpredictable and prone to causing casualties and property losses. Therefore, for concrete structures, structural health monitoring is particularly important. Currently, the common practice is to embed sensors in concrete structures, such as magnetostrictive material sensors, fiber optic sensors, etc. The disadvantages of such sensors are short lifespan, poor anti-interference ability, high cost, and low survival rate after being implanted in concrete structures. In addition, such materials generally have low compatibility with concrete structures, thus affecting the performance of the concrete structures themselves.
[0004] The emergence of intelligent concrete provides a new option for structural health monitoring. By adding carbon-based materials with good conductivity to cement-based materials, a carbon-based cement-based composite material with smart performance is made. Researchers directly use this composite material as a sensing element, and can conduct structural safety monitoring without the need to rely on other sensors. The main raw material of this composite material is cement-based material, which has good compatibility with existing concrete structures, and has long-term reliable stability and strong durability. The carbon-based material has good mechanical properties, chemical stability, thermal stability, electrical conductivity, and low density, which can also improve the mechanical properties, functional properties, and durability of the cement-based material.
[0005] However, the concrete in the existing intelligent concrete sensing elements has poor tensile resistance, so the existing intelligent concrete sensing elements are prone to cracking, affecting the safety and durability of the intelligent concrete sensing elements. Content of the Utility Model
[0006] In order to solve the above problems, the utility model provides an intelligent sensing monitoring system based on high-performance concrete.
[0007] To achieve the above technical objectives, the utility model adopts the following technical solutions:
[0008] An intelligent sensing and monitoring system based on high-performance concrete, comprising an intelligent concrete piezoresistive sensor and a data processing module; the intelligent concrete piezoresistive sensor includes an intelligent concrete piezoresistive sensing layer, and a high-performance tensile concrete layer is arranged at the bottom of the intelligent concrete piezoresistive sensing layer; built-in electrodes are arranged inside the intelligent concrete piezoresistive sensing layer, and the built-in electrodes are connected to the data processing module through wires.
[0009] In one or more embodiments, the data processing module includes an LCR tester and an information server, and the LCR tester communicates with the information server.
[0010] In one or more embodiments, high-performance tensile concrete layers are arranged around and at the bottom of the concrete piezoresistive sensing layer.
[0011] In one or more embodiments, the material of the intelligent concrete piezoresistive sensing layer includes a concrete matrix and a conductive material.
[0012] Preferably, the concrete matrix material is composed of cement, aggregates (such as sand and gravel), admixtures, and water.
[0013] Preferably, the conductive material includes one or both of carbon fiber or carbon nanotube.
[0014] In one or more embodiments, the material of the high-performance tensile concrete layer is Engineered Cementitious Composite (ECC).
[0015] Preferably, the ECC includes a concrete matrix material and polyvinyl alcohol (PVA) fibers, and the concrete matrix material is the same as the concrete matrix material in the intelligent concrete piezoresistive sensing layer, thus ensuring the compatibility of the intelligent concrete piezoresistive sensing layer and the high-performance tensile concrete layer in physical and chemical properties.
[0016] In one or more embodiments, the height ratio of the intelligent concrete piezoresistive sensing layer to the high-performance tensile concrete layer is 4:3 to 2:1.
[0017] In one or more embodiments, the wire is an anti-interference wire. On the one hand, the anti-interference wire can prevent the leakage of electrical signals into the external environment, and on the other hand, it can better resist the interference of external electromagnetic interference signals, thereby improving the working reliability of the circuit and reducing the radiation interference to surrounding electronic devices.
[0018] In one or more embodiments, the built-in electrode is a grid-like structure formed by vertically and horizontally intersecting metal wires. The grid-like structure, as an electrode, is beneficial to the integrity of the sensor. The spacing between the horizontal metal wires and the spacing between the vertical metal wires of the built-in electrode are equal, preferably both between 2 and 15 mm.
[0019] The beneficial effects of the present utility model are as follows:
[0020] (1) Since the traditional concrete material has low tensile strength, the traditional intelligent concrete sensor will have cracks in the concrete base material due to low tensile strength during actual use, thereby shortening the service life of the intelligent concrete sensor. Therefore, it is necessary to modify the concrete material in the traditional intelligent concrete sensor. Since the compatibility between PVA fiber and carbon fiber or carbon nanotube is poor, directly adding PVA fiber to the intelligent concrete piezoresistive sensing layer will affect the sensitivity and accuracy of sensor detection. The present utility model is provided with a high-performance tensile concrete layer at the bottom of the intelligent concrete piezoresistive sensing layer. The two layers have the same concrete matrix material, so their compatibility is good. It can not only ensure the sensitivity and accuracy of the intelligent concrete piezoresistive sensing layer detection, but also enable the intelligent concrete sensor to have good tensile strength, effectively prevent cracks, prevent crack expansion, and thus improve the service life of the intelligent concrete sensor.
[0021] (2) The working principle of the intelligent sensing and monitoring system based on high-performance concrete is as follows: When the concrete structure to be detected bears a load or undergoes deformation, due to the change in the microstructure and conductive path of the conductive material in the intelligent concrete piezoresistive sensing layer under stress, its resistance changes; the electrodes buried in the intelligent concrete piezoresistive sensing layer lead out the resistance change signal and transmit it to the LCR tester through anti-interference wires; the LCR tester measures the impedance value of the intelligent concrete by the AC bridge measurement method, converts the measured impedance value into a digital signal, and the digital signal is transmitted to the information server in a wired or wireless manner; the information server converts the digital signal into strain and load data according to the constitutive relationships such as strain-resistance change rate in the pre-established database, and through real-time monitoring and matching analysis of the strain and load data, identifies and warns of abnormal states of the concrete structure, such as cracks, stress concentration, etc., and comprehensively evaluates the overall long-term health status of the concrete structure to be detected. Description of the Drawings
[0022] The specification drawings forming a part of the present utility model are used to provide a further understanding of the present utility model. The schematic embodiments of the present utility model and their descriptions are used to explain the present utility model and do not constitute an improper limitation of the present utility model.
[0023] Figure 1It is a schematic diagram of the overall intelligent concrete piezoresistive sensor in Embodiment 1;
[0024] Figure 2 It is a structural cross-sectional view of the intelligent concrete piezoresistive sensor in Embodiment 1;
[0025] Among them, 1-intelligent concrete piezoresistive sensing layer, 2-high-performance tensile concrete layer, 3-built-in electrode, 4-concrete matrix, 5-conductive material, 6-PVA fiber. Specific implementation manners
[0026] It should be noted that the following detailed description is exemplary and is intended to provide further illustration of the present invention. Unless otherwise specified, all technical and scientific terms used in the present invention have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention belongs.
[0027] It should be noted that the terms used herein are only for describing specific implementation manners and are not intended to limit the exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular forms are also intended to include the plural forms. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.
[0028] The following is a further detailed description of the present invention in conjunction with specific embodiments. It should be noted that the specific embodiments are interpretations rather than limitations of the present invention.
[0029] Embodiment 1
[0030] See Figure 1 and Figure 2 , an intelligent sensing and monitoring system based on high-performance concrete, including an intelligent concrete piezoresistive sensor and a data processing module; the intelligent concrete piezoresistive sensor includes an intelligent concrete piezoresistive sensing layer 1, and a high-performance tensile concrete layer 2 is arranged at the bottom of the intelligent concrete piezoresistive sensing layer 1; built-in electrodes 3 are arranged inside the intelligent concrete piezoresistive sensing layer 2, and the built-in electrodes 3 are connected to the data processing module through wires.
[0031] As another implementation manner, high-performance tensile concrete layers 2 are arranged around and at the bottom of the concrete piezoresistive sensing layer 1. In special engineering structures such as tunnels and underground projects, due to the variable stress directions, the method of surrounding on all sides will provide better protection for the concrete piezoresistive sensing layer 1.
[0032] Among them, the data processing module includes an LCR tester and an information server, and the LCR tester communicates with the information server. The LCR tester measures the impedance value of the smart concrete through the AC bridge measurement method, converts the measured impedance value into a digital signal, and the digital signal is transmitted to the information server by wired or wireless means; the information server converts the digital signal into strain and load data according to the constitutive relations such as strain-resistance change rate in the pre-established database, and through real-time monitoring and matching analysis of the strain and load data, identifies and warns of abnormal states of the concrete structure, such as cracks, stress concentration, etc., and comprehensively evaluates the overall long-term health status of the concrete structure. In this embodiment, the above-mentioned information server uses a high-performance computer, and the methods of using the information server for data processing, matching, identification, and warning are all conventional processing methods in the art and will not be elaborated here.
[0033] The material of the piezoresistive sensing layer 1 of the smart concrete includes a concrete matrix 4 and a conductive material 5. The material of the concrete matrix 4 is composed of cement, aggregates (such as sand and gravel), admixtures, and water. The piezoresistive sensing layer 1 of the smart concrete has the compactness, strength, and durability of ordinary concrete to ensure stable performance under different environmental conditions. The conductive material 5 includes one or both of carbon fiber or carbon nanotubes. When the concrete structure to be detected bears a load or undergoes deformation, due to the change in the microstructure and conductive path of the conductive material in the piezoresistive sensing layer 1 of the smart concrete under stress, its resistance changes, and the overall long-term health status of the concrete structure to be detected can be comprehensively evaluated by detecting this change in resistance.
[0034] The material of the high-performance tensile concrete layer 2 is Engineered Cementitious Composite (ECC). ECC includes a concrete matrix material 4 and polyvinyl alcohol (PVA) fibers 6. The concrete matrix material 4 in ECC is the same as the concrete matrix material 4 in the piezoresistive sensing layer 1 of the smart concrete, thus ensuring the compatibility of the piezoresistive sensing layer 1 of the smart concrete and the high-performance tensile concrete layer 2 in physical and chemical properties; the PVA fibers 6 have excellent tensile strength and toughness, can effectively improve the tensile performance and ductility of the concrete, and the PVA fibers 6 are evenly distributed in the concrete matrix to form a reinforced three-dimensional network structure to prevent the expansion of microcracks and improve the overall performance of the concrete structure.
[0035] The height ratio of the intelligent concrete piezoresistive sensing layer 1 to the high-performance tensile concrete layer 2 is determined by the ratio of Young's (elastic) moduli. In a composite beam, due to the different Young's moduli of different layers, the position of the neutral axis will tend towards the material with a larger Young's modulus. To ensure the stability and a definite position of the neutral layer, h1 / h2 = E2 / E1 is calculated based on the moment balance and the section moment of inertia balance. According to the experimental data, the Young's modulus (E1) of the intelligent concrete is 22.5 - 25 GPa, and the Young's modulus (E2) of the high-performance tensile concrete is 35 - 37.5 GPa. Therefore, the height ratio of the intelligent concrete piezoresistive sensing layer 1 to the high-performance tensile concrete layer 2 can be determined to be 4:3 - 2:1.
[0036] The built-in electrode 3 is connected to the data processing module through an anti-interference wire. On the one hand, this anti-interference wire can prevent the leakage of electrical signals into the external environment, and on the other hand, it can better resist the interference of external electromagnetic interference signals, thereby improving the working reliability of the circuit, reducing the radiation interference to surrounding electronic devices, and further improving the accuracy of the intelligent concrete piezoresistive sensor monitoring.
[0037] The built-in electrode 3 is a grid-like structure formed by the vertical and horizontal interlacing of metal wires. The material of the metal wires is copper. The grid-like structure as an electrode is beneficial to the integrity of the sensor. The spacing between the horizontal metal wires and the spacing between the vertical metal wires of the built-in electrode are equal, preferably both in the range of 2 - 15 mm.
[0038] The preparation method of the intelligent concrete piezoresistive sensor in this embodiment:
[0039] S1. Pouring of the high-performance tensile concrete layer 2: Weigh cement, aggregates, admixtures, water, and PVA. The actual proportion is determined according to the engineering strength. Use a planetary mixer for preparation and use a two-step method to mix the slurry: Pour the cement, aggregates, and water into the mixer in proportion and stir slowly for 2 minutes, pause for 30 seconds, add PVA fibers and admixtures, and stir quickly for 2 minutes to ensure uniform distribution of the fibers. Pour the stirred ECC evenly into the mold and vibrate it on a vibrating table for 1 - 3 minutes to ensure that the concrete is dense and bubble-free. At room temperature, wait for it to initially harden for about 24 hours to ensure that the high-performance tensile concrete layer 2 has sufficient strength and stability.
[0040] S2. Pour the upper intelligent concrete piezoresistive sensing layer 1 on the initially hardened high-performance tensile concrete layer 2.
[0041] First, prepare the conductive material 5 dispersion: Add carbon nanotubes (CNTs) to dimethylformamide (DMF) and disperse them using an ultrasonic disperser for 1 hour. Transfer the mixture to a vacuum drying oven at 80 °C and dry for 1 hour. In a glass beaker, prepare an aqueous dispersion of carbon fiber (CFs) and methylcellulose (MC) at a mass ratio of 1:0.5 and stir with a glass rod for 15 minutes. The dosage of the conductive material 5 dispersion is 0.1 - 1% of the total mass of the concrete.
[0042] The proportions of cement, aggregate, water, and admixture in the intelligent concrete piezoresistive sensing layer 1 are the same as those in the high-performance tensile concrete layer 2. Use the two-step method to stir the slurry to ensure good compatibility and bonding force between the two layers of materials. Cure preliminarily for about 24 hours under the same temperature and humidity conditions.
[0043] S3. Hardening and curing
[0044] Before the intelligent concrete piezoresistive sensing layer 1 is preliminarily hardened, evenly arrange the copper mesh inside the sensing layer, and at the same time ensure that the position of the built-in electrode 3 is fixed and in good contact with the concrete. After completing the arrangement of the built-in electrode 3, continue to cure under the same environmental conditions to ensure preliminary hardening within 24 hours. Then cure completely in a standard curing environment.
[0045] Through the above construction procedures, ensure good bonding of the upper and lower layers of concrete, avoid weakening of the interfacial layer, and thus form a composite structure with excellent mechanical properties and sensing functions.
[0046] In this utility model, by setting a high-performance tensile concrete layer at the bottom of the intelligent concrete piezoresistive sensing layer, the two layers have the same concrete matrix material, so their compatibility is good. It can not only ensure the sensitivity and accuracy of the detection of the intelligent concrete piezoresistive sensing layer, but also enable the intelligent concrete sensor to have good tensile strength, effectively prevent cracks and prevent crack expansion, thereby improving the service life of the intelligent concrete sensor.
[0047] The working principle of the intelligent sensing and monitoring system based on high-performance concrete in this utility model is as follows:
[0048] When the concrete structure to be detected bears loads or undergoes deformation, due to the change in the microstructure and conductive path of the conductive material in the intelligent concrete piezoresistive sensing layer under stress, its resistance changes; the electrodes buried in the intelligent concrete piezoresistive sensing layer lead out the resistance change signal and transmit it to the LCR tester through anti-interference wires; the LCR tester measures the impedance value of the intelligent concrete through the AC bridge measurement method, converts the measured impedance value into a digital signal, and the digital signal is transmitted to the information server by wired or wireless means; the information server converts the digital signal into strain and load data according to the constitutive relationships such as strain-resistance change rate in the pre-established database, and through real-time monitoring and matching analysis of the strain and load data, identifies and warns of abnormal states of the concrete structure, such as cracks, stress concentration, etc., and comprehensively evaluates the overall long-term health status of the concrete structure to be detected.
[0049] Finally, it should be noted that the above are only the preferred embodiments of the present invention and are not used to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments, or perform equivalent substitution on some of them. Any modification, equivalent substitution, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.
Claims
1. An intelligent sensor monitoring system based on high performance concrete, characterized in that: It includes an intelligent concrete piezoresistive sensor and a data processing module; the intelligent concrete piezoresistive sensor includes an intelligent concrete piezoresistive sensing layer, and a high-performance tensile concrete layer is arranged at the bottom of the intelligent concrete piezoresistive sensing layer; a built-in electrode is arranged inside the intelligent concrete piezoresistive sensing layer, and the built-in electrode is connected to the data processing module through a wire.
2. The intelligent sensor monitoring system based on high performance concrete according to claim 1, characterized in that: The data processing module includes an LCR tester and an information server, and the LCR tester communicates with the information server.
3. The intelligent sensor monitoring system based on high performance concrete according to claim 1, characterized in that: The material of the smart concrete piezoresistive sensing layer includes a concrete matrix and a conductive material.
4. The intelligent sensor monitoring system based on high performance concrete according to claim 1, characterized in that: The material of the high-performance tensile concrete layer is a cement-based reinforced composite material for engineering.
5. The intelligent sensor monitoring system based on high performance concrete as claimed in claim 1, characterized in that: The height ratio of the smart concrete piezoresistive sensing layer to the high-performance tensile concrete layer is 4:3 to 2:
1.
6. The intelligent sensor monitoring system based on high performance concrete according to claim 1, characterized in that: High-performance tensile concrete layers are arranged around and on the bottom of the concrete piezoresistive sensing layer.
7. The intelligent sensor monitoring system based on high performance concrete according to claim 1, characterized in that: The built-in electrode is a grid structure formed by metal wires that are vertically and horizontally staggered.