Rebar electrochemical corrosion instrument and test method

Abstract

The invention discloses a steel bar electrochemical corrosion instrument and a test method and relates to the field of civil engineering material durability test technologies and equipment. The invention aims to solve the problems of detection lag, destructiveness, low test control precision, poor repeatability and insufficient data dimension of the existing method for preparing the corrosion damage test piece. The electrolytic cell is used for containing an electrode system composed of a test piece and an electrolyte; the EIS module is used for periodically scanning an electrochemical impedance spectrum of a test piece in a corrosion process and extracting polarization resistance through equivalent circuit fitting; the central control unit is used for calculating the real-time corrosion rate and the accumulated corrosion rate according to the polarization resistance and adjusting the electric signal applied to the electrode system according to the relation between the accumulated corrosion rate and the target corrosion rate. The device and the method are suitable for high-precision, repeatable and intelligent tests of reinforced concrete durability research.

Description

Technical Field

[0001] This application belongs to the field of durability testing technology and equipment for civil engineering materials. Background Technology

[0002] Steel corrosion is a major cause of durability failure in concrete structures. In laboratory studies, the rapid preparation of specimens with varying degrees of corrosion damage using electrochemical accelerated corrosion technology is a crucial method for evaluating material properties and reinforcement effectiveness. However, existing technologies suffer from the following significant drawbacks:

[0003] First, corrosion detection is severely delayed and destructive. Currently, the galvanostatic / potentialostatic instruments commonly used in laboratories can only control electrochemical parameters and cannot directly measure the degree of corrosion of the reinforcing bars during the corrosion process. Researchers can only calculate the corrosion rate by measuring mass loss after the experiment through "destructive testing of the reinforcing bars" using a weighing method. This method completely destroys the integrity of the specimen, making it unusable for subsequent mechanical property tests and failing to obtain dynamic process data on corrosion development.

[0004] Secondly, the test control accuracy is low and repeatability is poor. Due to the lack of real-time feedback on corrosion degree, the test can only rely on preset current and time for open-loop control. The actual corrosion rate is affected by factors such as concrete mix proportion, protective layer thickness, and density, resulting in large dispersion of the final corrosion rate between different specimens under the same preset conditions, making it difficult to guarantee the repeatability of the test.

[0005] Third, the instruments have limited functionality and insufficient data dimensions. Traditional equipment can only output basic current-time curves and cannot provide key parameters reflecting the state of the steel / concrete interface, making it difficult to support in-depth corrosion mechanism analysis.

[0006] Therefore, developing an intelligent electrochemical corrosion instrument that can integrate in-situ, real-time, and non-destructive corrosion detection and realize closed-loop feedback control based on the detection results has become a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0007] This application aims to address the problems of existing methods for preparing rust-damaged specimens, such as detection lag, destructive nature, low test control accuracy and poor repeatability, and insufficient data dimensions. It provides an instrument and test method for electrochemical corrosion of steel bars that integrates real-time detection and feedback control of corrosion degree. This instrument and method can be used for durability research of reinforced concrete structures, accurately control the electrochemical corrosion process of steel bars, and realize intelligent testing of in-situ, real-time, and non-destructive detection of corrosion degree.

[0008] The first aspect of this application provides an instrument for electrochemical corrosion of reinforcing bars, including: a central control unit, an EIS module, and an electrolytic cell;

[0009] The electrolytic cell is used to hold an electrode system consisting of a test specimen and an electrolyte.

[0010] The EIS module is used to periodically scan the electrochemical impedance spectrum of the specimen during the corrosion process and extract the polarization resistance through equivalent circuit fitting.

[0011] The central control unit is used to calculate the real-time corrosion rate and cumulative corrosion rate based on the polarization resistance, and adjust the electrical signal applied to the electrode system according to the relationship between the cumulative corrosion rate and the target corrosion rate.

[0012] In one possible design, the aforementioned steel bar electrochemical corrosion instrument further includes: a fiber optic demodulator, which monitors the rust expansion strain on the surface of the specimen in real time through a fiber optic grating sensor disposed on the surface of the specimen.

[0013] In one possible design, the aforementioned steel bar electrochemical corrosion instrument also includes a human-machine interaction unit, which includes a touch screen and a data interface for parameter setting, real-time data display, and test result export.

[0014] In one possible design, the aforementioned electrochemical corrosion instrument for steel bars further includes an electrolyte circulation system, which comprises a temperature control module, a storage tank, and a peristaltic pump. The temperature control module is used to control the electrolyte to maintain a constant temperature. The storage tank is connected to the electrolytic cell and the peristaltic pump stably pumps the electrolyte into the electrolytic cell.

[0015] In one possible design, the aforementioned steel bar electrochemical corrosion instrument further includes a machine vision module, which is used to acquire images of the specimen surface and analyze the rust seepage and crack expansion state through a preset image processing algorithm.

[0016] In one possible design, the calculation of real-time corrosion rate and cumulative corrosion rate based on the polarization resistance includes:

[0017] The real-time corrosion rate is calculated using the following formula:

[0018] ,

[0019] The cumulative corrosion rate is calculated using the following formula:

[0020] ,

[0021] in, For real-time corrosion rate, This represents the instantaneous corrosion current density. The molar mass of the specimen. The number of electrons transferred during the corrosion reaction of the specimen. It is Faraday's constant. The initial mass of the specimen. The effective surface area of ​​the specimen exposed to the electrolyte. This represents the cumulative corrosion rate.

[0022] In one possible design, the instantaneous corrosion current density is calculated according to the following formula:

[0023] ,

[0024] in, Let be the electrode system constant. This is the polarization resistor.

[0025] In one possible design, adjusting the electrical signal applied to the electrode system based on the relationship between the cumulative corrosion rate and the target corrosion rate includes:

[0026] when At that time, the electrical signal applied to the electrode system is increased;

[0027] when When entering the target range, maintain constant control;

[0028] when The corrosion test shall be terminated when the time is right.

[0029] For the target corrosion rate, This is the allowable error.

[0030] The second aspect of this application provides a method for testing the electrochemical corrosion of reinforcing bars. The method is based on an electrochemical corrosion instrument for reinforcing bars, which includes an EIS module and an electrolytic cell. The electrolytic cell is used to hold an electrode system consisting of a specimen and an electrolyte. The EIS module is used to periodically scan the electrochemical impedance spectrum of the specimen during the corrosion process and extract the polarization resistance through equivalent circuit fitting.

[0031] The electrochemical corrosion test method for steel bars includes:

[0032] The real-time corrosion rate and cumulative corrosion rate are calculated based on the polarization resistance.

[0033] The electrical signal applied to the electrode system is adjusted according to the relationship between the cumulative corrosion rate and the target corrosion rate.

[0034] In one possible design, adjusting the electrical signal applied to the electrode system based on the relationship between the cumulative corrosion rate and the target corrosion rate includes:

[0035] when At that time, the electrical signal applied to the electrode system is increased;

[0036] when When entering the target range, maintain constant control;

[0037] when The corrosion test shall be terminated when the time is right.

[0038] in, For the target corrosion rate, To allow for error, This represents the cumulative corrosion rate.

[0039] The beneficial effects of this application are:

[0040] This application integrates an electrochemical impedance spectroscopy module, a distributed fiber optic sensing module, and a machine vision module, enabling real-time, non-destructive monitoring of the corrosion rate, rust expansion strain, and surface morphology changes of reinforcing steel. The central control unit, based on a comparison of the real-time corrosion rate with a preset target value, adjusts the corrosion current through a closed-loop feedback control algorithm to accurately achieve the target corrosion rate. This application solves the problems of traditional methods, such as lag in corrosion detection, specimen damage, low control accuracy, and limited data dimensions, making it suitable for high-precision, repeatable, and intelligent testing in reinforced concrete durability research. Attached Figure Description

[0041] Figure 1 This is a schematic diagram of the overall structure of the instrument for electrochemical corrosion of reinforcing bars.

[0042] In the diagram, 1-main cabinet, 2-central control unit, 3-EIS module (Enterprise Information System module in Manufacturing Execution System), 4-fiber demodulator, 5-electrolytic cell, 6-human-machine interface unit, 7-storage tank, 8-peristaltic pump, 9-electrolyte circulation system, 10-sample, 11-electrolyte circulation pipeline, 12-signal power line, 13-electrode control line, 14-FBG (Bragg grating fiber) sensing fiber, 15-camera. Detailed Implementation

[0043] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of this application can be combined with each other.

[0044] Specific implementation method one: Refer to Figure 1 This embodiment describes the steel bar electrochemical corrosion instrument as follows: a central control unit, an EIS module, and an electrolytic cell.

[0045] The electrolytic cell is used to hold an electrode system consisting of a test specimen and an electrolyte.

[0046] The EIS module is used to periodically scan the electrochemical impedance spectrum of the specimen during the corrosion process and extract the polarization resistance through equivalent circuit fitting.

[0047] The central control unit is used to calculate the real-time corrosion rate and cumulative corrosion rate based on the polarization resistance, and adjust the electrical signal applied to the electrode system according to the relationship between the cumulative corrosion rate and the target corrosion rate.

[0048] In one embodiment, the steel bar electrochemical corrosion instrument further includes: an optical fiber demodulator, which monitors the rust expansion strain on the surface of the specimen in real time through a fiber optic grating sensor disposed on the surface of the specimen.

[0049] In one embodiment, the steel bar electrochemical corrosion instrument further includes a human-machine interaction unit, which includes a touch screen and a data interface for parameter setting, real-time data display, and test result export.

[0050] In one embodiment, the steel bar electrochemical corrosion instrument further includes an electrolyte circulation system, which includes a temperature control module, a storage tank, and a peristaltic pump. The temperature control module is used to control the electrolyte to maintain a constant temperature. The storage tank is connected to the electrolytic cell and the peristaltic pump stably pumps the electrolyte into the electrolytic cell.

[0051] In one embodiment, the steel bar electrochemical corrosion instrument further includes a machine vision module, which is used to acquire images of the surface of the specimen and analyze the rust seepage and crack expansion state through a preset image processing algorithm.

[0052] In one embodiment, calculating the real-time corrosion rate and cumulative corrosion rate based on the polarization resistance includes:

[0053] The real-time corrosion rate is calculated using the following formula:

[0054] ,

[0055] The cumulative corrosion rate is calculated using the following formula:

[0056] ,

[0057] in, For real-time corrosion rate, This represents the instantaneous corrosion current density. The molar mass of the specimen. The number of electrons transferred during the corrosion reaction of the specimen. It is Faraday's constant. The initial mass of the specimen. The effective surface area of ​​the specimen exposed to the electrolyte. This represents the cumulative corrosion rate.

[0058] In one implementation, the instantaneous corrosion current density is calculated according to the following formula:

[0059] ,

[0060] in, Let be the electrode system constant. This is the polarization resistor.

[0061] In one embodiment, adjusting the electrical signal applied to the electrode system based on the relationship between the cumulative corrosion rate and the target corrosion rate includes:

[0062] when At that time, the electrical signal applied to the electrode system is increased;

[0063] when When entering the target range, maintain constant control;

[0064] when The corrosion test shall be terminated when the time is right.

[0065] For the target corrosion rate, This is the allowable error.

[0066] Specific Implementation Method 2: The steel bar electrochemical corrosion test method described in this implementation method is based on a steel bar electrochemical corrosion instrument, which includes: an EIS module and an electrolytic cell. The electrolytic cell is used to hold an electrode system composed of a specimen and an electrolyte. The EIS module is used to periodically scan the electrochemical impedance spectrum of the specimen during the corrosion process and extract the polarization resistance through equivalent circuit fitting.

[0067] The electrochemical corrosion test method for steel bars includes:

[0068] The real-time corrosion rate and cumulative corrosion rate are calculated based on the polarization resistance.

[0069] The electrical signal applied to the electrode system is adjusted according to the relationship between the cumulative corrosion rate and the target corrosion rate.

[0070] In one embodiment, adjusting the electrical signal applied to the electrode system based on the relationship between the cumulative corrosion rate and the target corrosion rate includes:

[0071] when At that time, the electrical signal applied to the electrode system is increased;

[0072] when When entering the target range, maintain constant control;

[0073] when The corrosion test shall be terminated when the time is right.

[0074] in, For the target corrosion rate, To allow for error, This represents the cumulative corrosion rate.

[0075] To further illustrate the implementation scheme of this application, Figure 1 An integrated real-time corrosion detection and feedback control instrument for steel bars is provided, comprising: a main unit cabinet 1, a central control unit 2, an EIS module 3, a fiber optic demodulator 4, an electrolytic cell 5, a human-machine interface unit 6, an electrolyte circulation system 9, and a machine vision module. Each unit is described in detail below:

[0076] The central control unit 2, EIS module 3, and fiber optic demodulator 4 are all located in the main unit cabinet 1.

[0077] The temperature-controlled electrolyte circulation system 9 includes a storage tank 7 and a peristaltic pump 8. The electrolyte circulation system 9 maintains a constant electrolyte temperature and continuously circulates the electrolyte, ensuring a stable corrosive environment.

[0078] The specimen 10 is located inside the electrolytic cell 5, which contains a high-precision bidirectional potentiostat / current galvanometer. The potentiostat / current galvanometer receives commands and outputs electrical signals to the electrode system within the electrolytic cell 5.

[0079] A fiber optic grating sensor and a fiber optic demodulator 4 are pre-embedded or pasted on the surface of specimen 10 for real-time monitoring of rust expansion strain on the surface of specimen 10.

[0080] The machine vision module includes a camera 15 and a side illumination source. The camera 15 is used to capture images of the surface of the specimen 10 and analyze rust seepage and crack propagation through image processing algorithms.

[0081] The human-computer interaction unit 6 includes a touch screen and a data interface for parameter setting, real-time data display, and result export.

[0082] EIS module 3 is connected to the central control unit 2, the electrode system, and the human-machine interface unit 6. Its main functions include: automatically and periodically scanning the electrochemical impedance spectroscopy of the reinforced concrete corrosion electrochemical system during corrosion to obtain the electrochemical response signal on the surface of specimen 10. The reinforcing steel serves as the working electrode, the concrete as the ion transport medium, and the electrolyte as the external corrosion medium. The counter electrode and reference electrode control and measure the potential of the working electrode. EIS module 3 also extracts polarization resistance through equivalent circuit fitting. This provides data input for real-time corrosion rate calculation.

[0083] The central control unit 2 has a built-in industrial computer that runs control and data analysis software to calculate the corrosion rate in real time, execute feedback control algorithms, and simultaneously store multi-source data. Specifically, this includes: calculating the target corrosion rate... Set the initial current or potential and calculate the real-time corrosion rate.

[0084] Instantaneous corrosion current density calculated based on the Stern-Geary formula. :

[0085] ,

[0086] in, It is a constant related to metallic materials and corrosion systems; in this embodiment, the initial value is taken as 26.

[0087] Calculate the real-time corrosion rate based on Faraday's law. and cumulative corrosion rate :

[0088] ,

[0089] ,

[0090] in, The molar mass of the reinforcing steel bar This represents the number of electrons transferred in the steel reinforcement corrosion reaction. It is Faraday's constant. Indicates from time 0 to The cumulative corrosion quality, The initial mass of the reinforcing steel. This refers to the effective surface area of ​​the reinforcing steel exposed to the electrolyte.

[0091] If the cumulative corrosion rate Deviation from target corrosion rate The central control unit 2 sends adjustment commands to the constant potential / constant current meter to dynamically adjust the output current, achieving precise control of the target corrosion rate. Let... To allow for error, specifically:

[0092] when At that time, increase the current;

[0093] when When entering the target range, constant current control is activated;

[0094] when The corrosion should be stopped immediately.

[0095] Cumulative corrosion rate Achieve target corrosion rate Afterwards, the potentiostat / galvanometer automatically stops outputting, the test terminates, and the data is saved.

[0096] While specific embodiments of this application have been described herein with reference to them, it should be understood that these embodiments are merely examples of the principles and applications of this application. Therefore, it should be understood that many modifications can be made to the exemplary embodiments, and other arrangements can be designed without departing from the spirit and scope of this application as defined by the appended claims. It should be understood that different dependent claims and features described herein can be combined in ways different from those described in the original claims. It is also understood that features described in conjunction with individual embodiments can be used in other described embodiments.

Claims

1. An instrument for electrochemical corrosion of reinforcing bars, characterized in that, include: Central control unit, EIS module, and electrolytic cell; The electrolytic cell is used to hold an electrode system consisting of a test specimen and an electrolyte. The EIS module is used to periodically scan the electrochemical impedance spectrum of the specimen during the corrosion process and extract the polarization resistance through equivalent circuit fitting. The central control unit is used to calculate the real-time corrosion rate and cumulative corrosion rate based on the polarization resistance, and adjust the electrical signal applied to the electrode system according to the relationship between the cumulative corrosion rate and the target corrosion rate.

2. The instrument for electrochemical corrosion of reinforcing bars according to claim 1, characterized in that, Also includes: Fiber optic demodulator, The fiber optic demodulator monitors the rust expansion strain on the surface of the specimen in real time using a fiber optic grating sensor mounted on the specimen surface.

3. The instrument for electrochemical corrosion of reinforcing bars according to claim 1, characterized in that, Also includes: Human-computer interaction unit The human-computer interaction unit includes a touch screen and a data interface, which are used for parameter setting, real-time data display, and test result export.

4. The instrument for electrochemical corrosion of reinforcing bars according to claim 1, characterized in that, Also includes: An electrolyte circulation system, comprising: a temperature control module, a storage tank, and a peristaltic pump; The temperature control module is used to control the electrolyte to maintain a constant temperature. The storage tank is connected to the electrolytic cell, and the electrolyte is steadily pumped into the electrolytic cell by the peristaltic pump.

5. The instrument for electrochemical corrosion of reinforcing bars according to claim 1, characterized in that, Also includes: Machine vision module, The machine vision module is used to acquire images of the surface of the specimen and analyze the rust seepage and crack expansion state through a preset image processing algorithm.

6. The instrument for electrochemical corrosion of reinforcing bars according to claim 1, characterized in that, The calculation of real-time corrosion rate and cumulative corrosion rate based on the polarization resistance includes: The real-time corrosion rate is calculated using the following formula: ， The cumulative corrosion rate is calculated using the following formula: ， in, For real-time corrosion rate, This represents the instantaneous corrosion current density. The molar mass of the specimen. The number of electrons transferred during the corrosion reaction of the specimen. It is Faraday's constant. The initial mass of the specimen. The effective surface area of ​​the specimen exposed to the electrolyte. This represents the cumulative corrosion rate.

7. The instrument for electrochemical corrosion of reinforcing bars according to claim 6, characterized in that, The instantaneous corrosion current density is calculated using the following formula: ， in, Let be the electrode system constant. This is the polarization resistor.

8. The instrument for electrochemical corrosion of reinforcing bars according to claim 1, characterized in that, The step of adjusting the electrical signal applied to the electrode system based on the relationship between the cumulative corrosion rate and the target corrosion rate includes: when At that time, the electrical signal applied to the electrode system is increased; when When entering the target range, maintain constant control; when The corrosion test shall be terminated when the time is right. For the target corrosion rate, This is the allowable error.

9. A test method for electrochemical corrosion of reinforcing steel bars, characterized in that, The aforementioned electrochemical corrosion test method for steel bars is based on an electrochemical corrosion instrument for steel bars, which includes an EIS module and an electrolytic cell. The electrolytic cell is used to hold an electrode system consisting of a specimen and an electrolyte. The EIS module is used to periodically scan the electrochemical impedance spectrum of the specimen during the corrosion process and extract the polarization resistance through equivalent circuit fitting. The electrochemical corrosion test method for steel bars includes: The real-time corrosion rate and cumulative corrosion rate are calculated based on the polarization resistance. The electrical signal applied to the electrode system is adjusted according to the relationship between the cumulative corrosion rate and the target corrosion rate.

10. The method for testing electrochemical corrosion of reinforcing steel bars according to claim 9, characterized in that, The step of adjusting the electrical signal applied to the electrode system based on the relationship between the cumulative corrosion rate and the target corrosion rate includes: when At that time, the electrical signal applied to the electrode system is increased; when When entering the target range, maintain constant control; when The corrosion test shall be terminated when the time is right. in, For the target corrosion rate, To allow for error, This represents the cumulative corrosion rate.

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