Method for imaging internal corrosion state of reinforced concrete structure based on microwave detection

Abstract

The application discloses a microwave detection-based imaging method for internal corrosion state of a reinforced concrete structure, and comprises the following steps: S1, setting a moving step D1 and a scanning frequency f1 of a rectangular waveguide along an X axis and a moving step D2 and a scanning frequency f2 of the rectangular waveguide along a Y axis; S2, acquiring a position interval of a steel bar in a concrete base by scanning with the rectangular waveguide; S3, obtaining a reference value matrix Γ0 of the steel bar without corrosion by scanning the concrete base with the rectangular waveguide; S4, performing X-axis parallel scanning on the reinforced concrete base by using the rectangular waveguide to obtain a transmission coefficient matrix set Γ representing a corrosion degree of the steel bar, and labeling subsets in the transmission coefficient matrix set Γ according to the corrosion degree; and S5, importing the transmission coefficient matrix set Γ and position information of the corroded steel bar into MATLAB for data imaging processing to obtain a three-dimensional stereoscopic imaging diagram. According to the scheme, engineering and technical personnel can intuitively obtain the internal corrosion state of the reinforced concrete base.

Description

Technical Field

[0001] The present invention relates to the technical field of engineering quality inspection, and in particular to a method for imaging the internal corrosion state of a reinforced concrete structure based on microwave detection. Background Art

[0002] With the development of urbanization, reinforced concrete foundations have become a primary building material due to their superior performance, largely determining the safe and stable operation of buildings. Due to environmental factors, the steel bars within concrete can oxidize. Corrosion can alter the structural properties of the internal steel, compromising building stability. Therefore, research on the degree of internal steel corrosion during operation provides significant safety assurance for reinforced concrete foundations.

[0003] In addition to groundbreaking testing, traditional X-ray testing is used to detect corrosion within reinforced concrete foundations. This testing can be harmful to humans, and photographic testing requires the use of a fixer that is difficult to recycle and harmful to the environment. Furthermore, it is slow and expensive, making it difficult to meet the requirements of on-site testing. Ultrasonic testing uses coupling agents that directly pollute the environment, and the corrosion imaging process is cumbersome. Acoustic emission testing, due to its dynamic analysis method, cannot comprehensively detect and evaluate the characteristics of target defects. Infrared thermal imaging has certain limitations in its image resolution for smaller defects on metal surfaces. Therefore, it is urgent to develop an imaging method that can accurately and effectively detect and evaluate steel corrosion in reinforced concrete foundation structures. Summary of the Invention

[0004] The purpose of this invention is to solve the problem that the degree and location of corrosion of reinforced concrete foundations cannot be presented through images. A method for imaging the internal corrosion status of reinforced concrete foundation structures based on microwave detection is proposed. By simulating and analyzing different degrees of corrosion and different corrosion locations of reinforced concrete foundations and imaging them, engineering technicians can intuitively obtain the internal corrosion status of reinforced concrete foundations, providing data support for further formulating response strategies.

[0005] A technical solution provided in an embodiment of the present invention is a method for imaging the internal corrosion state of a reinforced concrete foundation structure based on microwave detection, which is applicable to a microwave detector; the microwave detector includes a microwave signal source, a rectangular waveguide receiving probe, and a rectangular waveguide transmitting probe. The microwave signal source is used to generate microwave signals of different scanning frequencies and record transmission signals. The rectangular waveguide receiving probe and the rectangular waveguide transmitting probe are respectively connected to the signal port of the microwave signal source. The rectangular waveguide transmitting probe sends microwave signals to the tested part of the foundation at a certain scanning frequency, and the rectangular waveguide receiving probe receives the transmission signal. The method includes the following steps:

[0006] S1, setting the moving step D1 and scanning frequency f1 of the rectangular waveguide along the X axis and the moving step D2 and scanning frequency f2 of the rectangular waveguide along the Y axis;

[0007] S2. Use a rectangular waveguide to perform Y-axis vertical scanning on the unreinforced concrete foundation and the reinforced concrete foundation to obtain the position interval of the steel bars in the concrete foundation;

[0008] S3, using a rectangular waveguide to perform X-axis parallel scanning on a reinforced concrete foundation where the steel bars are not corroded, to obtain a reference value matrix Γ0 where the steel bars are not corroded;

[0009] S4. Using a rectangular waveguide, perform X-axis parallel scanning on a reinforced concrete foundation with different steel bar corrosion degrees to obtain a transmission coefficient matrix set Γ representing the steel bar corrosion degree, and label subsets of the transmission coefficient matrix set Γ according to the corrosion degree;

[0010] S5. Import the transmission coefficient matrix set Γ and the corresponding position information of the corroded steel bars into MATLAB for data imaging processing to obtain a three-dimensional stereoscopic image.

[0011] In this scheme, the orientation of the steel bars in the reinforced concrete foundation can be determined by scanning the reinforced concrete foundation on the Y axis. Then, at this position, the reinforced concrete foundation is scanned on the X axis to obtain the transmission coefficient matrix set Γ. By comparing the transmission coefficient matrix set Γ with the elements at the corresponding positions of the reference value matrix Γ0, it is determined whether the steel bars are corroded and the specific degree of corrosion is calculated. The matrix A representing the degree of steel bar corrosion and the corresponding corrosion positions of the steel bars is calculated and imaged using MATLAB software to obtain a three-dimensional stereo image. This allows engineering technicians to intuitively understand the internal corrosion status of the reinforced concrete foundation and provide data support for further formulating response strategies.

[0012] Preferably, S2 includes the following steps:

[0013] The transmission coefficient matrix S0 is obtained by performing Y-axis vertical scanning on the unreinforced concrete foundation using a rectangular waveguide;

[0014] The rectangular waveguide is used to perform Y-axis vertical scanning on the reinforced concrete foundation to obtain the transmission coefficient column matrix S1;

[0015] Calculate the transmission coefficient column matrix S0 and the transmission coefficient column matrix S1 to obtain the transmission coefficient column difference matrix ΔS; if the value in the transmission coefficient column difference matrix ΔS is greater than the set value H, it indicates that there is a steel bar at the position corresponding to the waveguide matrix;

[0016] All values ​​greater than the set value H in the transmission coefficient column difference ΔS matrix are recorded in sequence to obtain the location interval where the steel bars exist.

[0017] Preferably, S3 includes the following steps:

[0018] The rectangular waveguide is used to scan the uncorroded reinforced concrete foundation structure parallel to the x-axis to determine the foundation transmission coefficient column matrix Γ0 of the reinforced concrete foundation.

[0019] The dimension of the foundation transmission coefficient column matrix Γ0 is the same as the number of x-axis scanning points m. The transmission coefficient matrix Γ0 is defined as the reference value matrix for judging whether the reinforced concrete foundation structure is corroded.

[0020] Preferably, S4 includes the following steps:

[0021] The rectangular waveguide is used to scan the corroded reinforced concrete foundation structure parallel to the x-axis to obtain the transmission coefficient matrix set Γ;

[0022] By comparing the difference set of each subset element at the corresponding position in the transmission coefficient matrix set Γ and the basic transmission coefficient column matrix Γ0;

[0023] The elements in the difference set are labeled according to the corrosion degree classification table, and then mapped to the elements in the corresponding transmission coefficient matrix set Γ.

[0024] Preferably, S5 includes the following steps:

[0025] Perform matrix multiplication on ΔS and the transpose of ΔΓ to obtain matrix A. Use MATLAB to perform data imaging processing using matrix A to obtain a three-dimensional stereo image.

[0026] The present invention provides beneficial effects: The microwave-based imaging method for internal corrosion status of reinforced concrete foundation structures, which simulates, analyzes, and images different corrosion levels and locations of reinforced concrete foundations, enables engineers to intuitively assess the internal corrosion status of reinforced concrete foundations, providing data support for further development of countermeasures. By leveraging the advantages of microwaves in non-contact detection of corrosion status in reinforced concrete foundations and their strong penetration into materials with poor conductivity, such as concrete, the method uses a transmission coefficient corrosion detection method to obtain corresponding data. The vertical scanning data results are then compared to determine the y-axis rebar position. This demonstrates that when detecting rebar with varying degrees of corrosion, the present invention only requires a single set of horizontal scanning data to be compared with the uncorroded parameters to locate the rebar corrosion location and identify the degree of corrosion. This method is applicable to most complex operational environments, avoiding the environmental contamination associated with coupling agents used in ultrasonic testing and the cumbersome operational process of corrosion imaging. It also addresses the shortcomings of acoustic emission detection technology in comprehensively detecting and evaluating target defects, as well as the limitations of infrared imaging detection technology in image resolution for smaller defects in metal detection.

[0027] The above brief introduction is only a summary of the technical solutions of the present application. In order to enable the technical means of the present application to be more clearly understood and implemented, the following will give a specific implementation manner of the present application in accordance with the contents of the specification, and in order to make the above and other purposes, characteristics and advantages of the present application more obvious and easy to understand, the following will give a specific implementation manner of the present application. BRIEF DESCRIPTION OF DRAWINGS

[0028] Other features, objects, and advantages of the application will become more apparent from the following detailed description of non-limiting embodiments, read in conjunction with the accompanying drawings. The drawings are only for the purpose of illustrating preferred embodiments and are not to be construed as limiting the application. Like reference numerals denote like elements throughout the drawings.

[0029] Figure 1 Flow chart of the method for imaging the internal corrosion state of a reinforced concrete structure based on microwave detection according to the present application.

[0030] Figure 2 Schematic diagram of the method for detecting the corrosion degree of a reinforced concrete foundation according to the present application. DETAILED DESCRIPTION

[0031] In order to make the purposes, technical solutions and advantages of the present application more clear and obvious, the following will give a further detailed description of the present application in conjunction with the drawings and examples. It should be understood that the specific implementation manner described herein is only a best embodiment of the present application, which is only used to explain the present application and does not limit the protection scope of the present application. All other embodiments obtained by those skilled in the art without making creative efforts fall within the protection scope of the present application.

[0032] Before discussing the example embodiments in more detail, it should be mentioned that some of the example embodiments are described as processes or methods depicted as flow charts. Although the flow charts describe the operations (or steps) as sequential processes, many of the operations (or steps) can be implemented in parallel, concurrently or simultaneously. In addition, the order of the operations can be rearranged. The processes can be terminated when their operations are completed, but can also have additional steps not included in the figures; the processes can correspond to methods, functions, routines, subroutines, etc.

[0033] Embodiment: As Figure 1As shown, a method for imaging the internal corrosion state of a reinforced concrete foundation structure based on microwave detection is applicable to a microwave detector; the microwave detector includes a microwave signal source, a rectangular waveguide receiving probe, and a rectangular waveguide transmitting probe. The microwave signal source is used to generate microwave signals of different scanning frequencies and record transmission signals. The rectangular waveguide receiving probe and the rectangular waveguide transmitting probe are respectively connected to the signal port of the microwave signal source. The rectangular waveguide transmitting probe sends microwave signals to the tested part of the foundation at a certain scanning frequency, and the rectangular waveguide receiving probe receives the transmission signal. The method includes the following steps:

[0034] S1, setting the moving step D1 and scanning frequency f1 of the rectangular waveguide along the X axis and the moving step D2 and scanning frequency f2 of the rectangular waveguide along the Y axis;

[0035] S2. Use a rectangular waveguide to perform Y-axis vertical scanning on the unreinforced concrete foundation and the reinforced concrete foundation to obtain the position interval of the steel bars in the concrete foundation;

[0036] S3, using a rectangular waveguide to perform X-axis parallel scanning on a reinforced concrete foundation where the steel bars are not corroded, to obtain a reference value matrix Γ0 where the steel bars are not corroded;

[0037] S4. Using a rectangular waveguide, perform X-axis parallel scanning on a reinforced concrete foundation with different steel bar corrosion degrees to obtain a transmission coefficient matrix set Γ representing the steel bar corrosion degree, and label subsets of the transmission coefficient matrix set Γ according to the corrosion degree;

[0038] S5. Import the transmission coefficient matrix set Γ and the corresponding position information of the corroded steel bars into MATLAB for data imaging processing to obtain a three-dimensional stereoscopic image.

[0039] In this embodiment, by scanning the reinforced concrete foundation on the Y axis, the orientation of the steel bars in the reinforced concrete foundation can be determined. Then, at this position, the reinforced concrete foundation is scanned on the X axis to obtain the transmission coefficient matrix set Γ. By comparing the transmission coefficient matrix set Γ with the elements at corresponding positions of the reference value matrix Γ0, it is determined whether the steel bars are corroded and the specific degree of corrosion is calculated. The matrix A representing the degree of steel bar corrosion and the corresponding corrosion positions of the steel bars is calculated, and imaging is performed using MATLAB software to obtain a three-dimensional stereoscopic image, so that engineering and technical personnel can intuitively understand the internal corrosion status of the reinforced concrete foundation, providing data support for further formulating response strategies.

[0040] like Figure 2The diagram shows a schematic diagram of corrosion detection for reinforced concrete foundations, including concrete block A, uncorroded rebar B, a corroded layer C, and a rectangular waveguide D. Rectangular waveguide D consists of a rectangular waveguide receiving probe and a rectangular waveguide transmitting probe, each located 2 mm from the side of concrete block A. The rectangular waveguide D's range of motion along the X-axis is -175 mm to 175 mm, and along the Y-axis is -75 mm to 75 mm. In the side view, 1 represents the corroded layer, and 2 represents the uncorroded layer. The corroded layer adheres to the uncorroded rebar, and both are embedded in the center of the concrete block. The principle of this embodiment is that a microwave signal generated by a signal source scans the reinforced concrete foundation module through the rectangular waveguides at both ends, and the internal corrosion status is determined by the difference in the transmitted signals.

[0041] S2 includes the following steps:

[0042] The transmission coefficient matrix S0 is obtained by performing Y-axis vertical scanning on the unreinforced concrete foundation using a rectangular waveguide;

[0043] The rectangular waveguide is used to perform Y-axis vertical scanning on the reinforced concrete foundation to obtain the transmission coefficient column matrix S1;

[0044] Calculate the transmission coefficient column matrix S0 and the transmission coefficient column matrix S1 to obtain the transmission coefficient column difference matrix ΔS; if the value in the transmission coefficient column difference matrix ΔS is greater than the set value H, it indicates that there is a steel bar at the position corresponding to the waveguide matrix;

[0045] All values ​​greater than the set value H in the transmission coefficient column difference ΔS matrix are recorded in sequence to obtain the location interval where the steel bars exist.

[0046] In S3, the following steps are included:

[0047] The rectangular waveguide is used to scan the uncorroded reinforced concrete foundation structure parallel to the x-axis to determine the foundation transmission coefficient column matrix Γ0 of the reinforced concrete foundation.

[0048] The dimension of the foundation transmission coefficient column matrix Γ0 is the same as the number of x-axis scanning points m. The transmission coefficient matrix Γ0 is defined as the reference value matrix for judging whether the reinforced concrete foundation structure is corroded.

[0049] Preferably, S4 includes the following steps:

[0050] The rectangular waveguide is used to scan the corroded reinforced concrete structure parallel to the x-axis to obtain the transmission coefficient matrix set Γ;

[0051] By comparing the difference set of each subset element at the corresponding position in the transmission coefficient matrix set Γ and the basic transmission coefficient column matrix Γ0;

[0052] The elements in the difference set are labeled according to the corrosion degree classification table, and then mapped to the elements in the corresponding transmission coefficient matrix set Γ.

[0053] S5 includes the following steps:

[0054] Perform matrix multiplication on ΔS and the transpose of ΔΓ to obtain matrix A. Use MATLAB to perform data imaging processing using matrix A to obtain a three-dimensional stereo image.

[0055] The specific implementation described above is a preferred implementation of the method for imaging the internal corrosion state of reinforced concrete structures based on microwave detection of the present invention, and is not intended to limit the specific implementation scope of the present invention. The scope of the present invention includes but is not limited to this specific implementation. Any equivalent changes made in accordance with the shape and structure of the present invention are within the scope of protection of the present invention.

Claims

1. A method for imaging the internal corrosion state of reinforced concrete structures based on microwave detection, which is suitable for a microwave detector; the microwave detector includes a microwave signal source, a rectangular waveguide receiving probe, and a rectangular waveguide transmitting probe. The microwave signal source is used to generate microwave signals with different scanning frequencies and record transmission signals. The rectangular waveguide receiving probe and the rectangular waveguide transmitting probe are respectively connected to the signal port of the microwave signal source. The rectangular waveguide transmitting probe sends microwave signals to the basic tested part at a certain scanning frequency, and the rectangular waveguide receiving probe receives the transmission signal. It is characterized in that The steps include: S1, setting the moving step D1 and scanning frequency f1 of the rectangular waveguide along the X axis and the moving step D2 and scanning frequency f2 of the rectangular waveguide along the Y axis; S2. Use a rectangular waveguide to perform Y-axis vertical scanning on the unreinforced concrete and the reinforced concrete to obtain the position interval of the steel bars in the concrete foundation; S3, using a rectangular waveguide to perform X-axis parallel scanning on reinforced concrete where the steel bars are not corroded, to obtain a reference value matrix Γ0 where the steel bars are not corroded; S4. Using a rectangular waveguide, perform X-axis parallel scanning on reinforced concrete with different steel bar corrosion degrees to obtain a transmission coefficient matrix set Γ representing the steel bar corrosion degree, and label subsets in the transmission coefficient matrix set Γ according to the corrosion degree; S5, importing the transmission coefficient matrix set Γ and the corresponding position information of the corroded steel bars into MATLAB for data imaging processing to obtain a three-dimensional stereo image; S2 includes the following steps: The transmission coefficient matrix S0 is obtained by performing Y-axis vertical scanning on unreinforced concrete using a rectangular waveguide; The transmission coefficient matrix S1 is obtained by performing Y-axis vertical scanning on reinforced concrete using a rectangular waveguide; Calculate the transmission coefficient column matrix S0 and the transmission coefficient column matrix S1 to obtain the transmission coefficient column difference matrix ΔS; if the value in the transmission coefficient column difference matrix ΔS is greater than the set value H, it indicates that there is a steel bar at the position corresponding to the waveguide matrix; Record all the values ​​greater than the set value H in the transmission coefficient column difference ΔS matrix in sequence to obtain the location interval where the steel bars exist; S4 includes the following steps: The rectangular waveguide is used to scan the corroded reinforced concrete structure parallel to the x-axis to obtain the transmission coefficient matrix set Γ; By comparing the difference set ΔΓ of each subset element at the corresponding position in the transmission coefficient matrix set Γ and the basic transmission coefficient column matrix Γ0; The elements in the difference value set ΔΓ are labeled according to the corrosion degree classification table, and then mapped to the elements in the corresponding transmission coefficient matrix set Γ; S5 includes the following steps: The transmission coefficient column difference matrix ΔS is multiplied by the transpose of the difference set ΔΓ to obtain the matrix A. The A matrix is ​​used to perform data imaging processing through MATLAB to obtain a three-dimensional stereo image.

2. The method for imaging the internal corrosion state of reinforced concrete structures based on microwave detection according to claim 1, characterized in that: In S3, the following steps are included: The rectangular waveguide is used to scan the uncorroded reinforced concrete structure parallel to the x-axis to determine the basic transmission coefficient column matrix Γ0 of the reinforced concrete; The dimension of the basic transmission coefficient column matrix Γ0 is the same as the number of x-axis scanning points m. The transmission coefficient matrix Γ0 is defined as the reference value matrix for judging whether corrosion occurs in reinforced concrete structures.

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