Electromagnetic field-based steel reinforcement corrosion quantification monitoring method and probe monitoring device

Abstract

The application relates to the technical field of civil engineering structure health monitoring, and discloses a reinforcing steel bar corrosion quantitative monitoring method based on an electromagnetic field and a probe type monitoring device, wherein the electromagnetic field is generated by a first probe and a second probe in the probe type monitoring device, and the first probe and the second probe are arranged on the two sides of a target position of a reinforcing steel bar to be measured; the method comprises the following steps: detecting the current magnetic field intensity on the two sides of the target position through the first probe and the second probe, and determining the magnetic field intensity change rate of the current magnetic field intensity relative to a preset reference magnetic field intensity; based on the reinforcing steel bar spacing between the reinforcing steel bar to be measured and an interfering reinforcing steel bar, a sensitivity correction coefficient is determined, and the theoretical sensitivity is corrected based on the sensitivity correction coefficient, wherein the theoretical sensitivity refers to the sensitivity of the magnetic field intensity change on the two sides of the target position to the reinforcing steel bar corrosion when the reinforcing steel bar is not interfered by the interfering reinforcing steel bar; and based on the magnetic field intensity change rate and the corrected sensitivity, the corrosion rate of the target position is determined. The application can achieve the technical effect of improving monitoring precision.

Description

Technical Field

[0001] This application relates to the field of structural health monitoring technology in civil engineering, and in particular to a quantitative monitoring method for steel corrosion based on electromagnetic fields and a probe-type monitoring device. Background Technology

[0002] Reinforced concrete structures possess excellent mechanical properties and are widely used in civil engineering. However, during application, reinforcing bars inevitably suffer from corrosive media erosion or concrete carbonation, which damages their surface passivation film and leads to corrosion. Once corroded, the effective cross-section of the reinforcing bars decreases, reducing their load-bearing capacity and compromising the safety of the reinforced concrete structure. Therefore, regularly monitoring the corrosion of reinforcing bars and conducting scientific maintenance and repair of the reinforced concrete structure based on the monitoring results are effective means to ensure structural safety.

[0003] Currently, steel corrosion monitoring technologies based on macroscopic battery principles and linear polarization principles are relatively mature. However, due to environmental and material factors, these technologies cannot provide quantitative analysis of steel corrosion, and the monitoring results are not very meaningful. Electromagnetic field-based steel corrosion monitoring technologies can quantitatively analyze the corrosion status of steel bars, but the accuracy of the monitoring results is not high due to the interaction between steel bars. Therefore, there is an urgent need for a method to improve the accuracy of steel corrosion monitoring. Summary of the Invention

[0004] This application provides a quantitative monitoring method and probe-type monitoring device for steel reinforcement corrosion based on electromagnetic fields, which achieves the technical effect of improving the monitoring accuracy of steel reinforcement corrosion. It is applicable to in-service and newly built reinforced concrete structures and can monitor steel reinforcement at any location.

[0005] To achieve the above objectives, the main technical solutions adopted in this application include: In a first aspect, embodiments of this application provide a method for quantitative monitoring of steel reinforcement corrosion based on an electromagnetic field. The electromagnetic field is generated by a first probe and a second probe in a probe-type monitoring device, and the first probe and the second probe are deployed on either side of the target location of the steel reinforcement to be tested. The method includes: The current magnetic field strength on both sides of the target position is detected by the first probe and the second probe, and the rate of change of the current magnetic field strength relative to the preset reference magnetic field strength is determined. Based on the spacing between the steel bars to be tested and the interfering steel bars, a sensitivity correction coefficient is determined, and based on the sensitivity correction coefficient, the theoretical sensitivity is corrected. The theoretical sensitivity refers to the sensitivity of the steel bar corrosion to the change in magnetic field strength on both sides of the target position when it is not affected by the interfering steel bars. The corrosion rate at the target location is determined based on the rate of change of the magnetic field strength and the corrected sensitivity.

[0006] Secondly, embodiments of this application provide a probe-type monitoring device, the device comprising: The first and second probes are used to generate an electromagnetic field; A controller for executing the electromagnetic field-based quantitative monitoring method for steel corrosion as described in any of the preceding items.

[0007] In some embodiments of this application, a sensitivity correction coefficient is determined based on the spacing between the reinforcing bar to be tested and interfering reinforcing bars, and the theoretical sensitivity is corrected based on the sensitivity correction coefficient. This eliminates the influence of interfering reinforcing bars on the electromagnetic field around the target location, allowing the corrected sensitivity to accurately reflect the impact of corrosion at the target location on the magnetic field strength. Furthermore, the corrosion rate determined based on the rate of change of magnetic field strength and the corrected sensitivity accurately reflects the true degree of corrosion at the target location. This application achieves the technical effect of improving the accuracy of reinforcing bar corrosion monitoring through sensitivity correction. Attached Figure Description

[0008] To more clearly illustrate the technical solutions in the specific embodiments of this application or the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0009] Figure 1 Schematic diagrams of the structure of a probe-type monitoring device provided for some embodiments of this application; Figure 2 A schematic diagram illustrating the positional relationship between the probe and the reinforcing bar to be tested, provided for some embodiments of this application; Figure 3 Schematic diagrams showing the positional relationship between the probe and the reinforcing bar to be tested, provided for other embodiments of this application; Figure 4 Schematic diagrams of probe structures provided for some embodiments of this application; Figure 5 A simplified cross-sectional schematic diagram of a first probe provided for some embodiments of this application; Figure 6 A partially detailed cross-sectional schematic diagram of a first probe provided for some embodiments of this application; Figure 7 A schematic diagram illustrating the relationship between probe spacing, rebar diameter, and coupling distance for some embodiments of this application; Figure 8Cross-sectional views of steel reinforcement corrosion monitoring in existing reinforced concrete structures provided for some embodiments of this application; Figure 9 Cross-sectional views of probes embedded in newly constructed reinforced concrete structures provided for some embodiments of this application; Figure 10 A top view of a probe embedded in a newly constructed reinforced concrete structure, provided for some embodiments of this application; Figure 11 A cross-sectional view of a hollow tube sleeve embedded in a newly constructed reinforced concrete structure, provided for some embodiments of this application; Figure 12 Cross-sectional views of steel reinforcement corrosion monitoring in hollow tube sleeves provided for some embodiments of this application; Figure 13 A flowchart illustrating a quantitative monitoring method for steel reinforcement corrosion provided for some embodiments of this application; Figure 14 A schematic diagram illustrating the positional relationship between the reinforcing bar to be tested and interfering reinforcing bars provided for some embodiments of this application; Figure 15 Schematic diagram of steel bar corrosion calibration test provided for some embodiments of this application; Figure 16 Corrosion rate-magnetic field strength variation rate curves corresponding to different steel bar diameters are provided for experimental fitting in some embodiments of this application; Figure 17 The corrosion rate-magnetic field strength variation rate curves corresponding to different steel bar diameters are provided by numerical simulation for some embodiments of this application; Figure 18 The correlation between probe spacing and theoretical sensitivity is provided for some embodiments of this application; Figure 19 The graphs showing the relationship between rebar spacing and actual sensitivity are provided for some embodiments of this application; Figure 20 The graphs showing the correlation between rebar spacing and monitoring error are provided for some embodiments of this application; Figure 21 Multiple corrosion rate-magnetic field strength change rate curves were obtained after the probe corresponding to a 20mm diameter steel bar was moved upward (positive Y direction); Figure 22 Multiple corrosion rate-magnetic field strength change rate curves were obtained after the probe corresponding to a 20mm diameter steel bar was moved downward (negative Y direction); Figure 23 Multiple corrosion rate-magnetic field strength change rate curves were obtained after the probe corresponding to a 22mm diameter steel bar was moved upward (positive Y direction); Figure 24Multiple corrosion rate-magnetic field strength change rate curves were obtained after the probe corresponding to a 22mm diameter steel bar was moved downward (in the negative Y direction); Figure 25 Multiple corrosion rate-magnetic field strength change rate curves were obtained after the probe corresponding to a 25mm diameter steel bar was moved upward (positive Y direction); Figure 26 Multiple corrosion rate-magnetic field strength change rate curves were obtained after the probe corresponding to a 25mm diameter steel bar was moved downward (negative Y direction); Figure 27 Theoretical sensitivity-probe Y-axis movement distance curves are provided for some embodiments of this application. Detailed Implementation

[0010] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, 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 some embodiments of this application, not all embodiments. 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.

[0011] Every reinforced concrete structure consists of multiple steel bars and concrete, with the steel bars embedded in the concrete. Normally, the surface of the steel bars has a passivation film to prevent corrosion. However, when the steel bars are exposed to corrosive media or when the concrete carbonizes, this passivation film is destroyed, leading to corrosion. Corrosion primarily occurs on the surface of the steel bars. After corrosion, on the one hand, the corrosion products (such as rust) expand in volume, potentially cracking the reinforced concrete structure from the inside, thus affecting structural safety. On the other hand, the effective cross-section of the steel bars decreases, reducing their load-bearing capacity, which also impacts structural safety. Therefore, regularly monitoring the corrosion of the steel bars and, based on the monitoring results, conducting scientific maintenance and repair of the reinforced concrete structure are effective means to ensure structural safety.

[0012] Currently, electromagnetic field-based steel reinforcement corrosion monitoring technology can quantitatively analyze the degree of steel reinforcement corrosion and has been widely applied. The principle of this technology is to construct an electromagnetic field around the steel reinforcement and quantitatively analyze the degree of corrosion based on the steel reinforcement's influence on the magnetic field. Simply put, the magnetic permeability (i.e., magnetic field transmission capacity) of the area where the steel reinforcement is located is related to the degree of corrosion. When the steel reinforcement is uncorroded, its effective cross-section is large, the magnetic permeability of the area around the steel reinforcement is high, and the magnetic field strength around the steel reinforcement is large. As the steel reinforcement gradually corrodes, its effective cross-section gradually decreases, and the magnetic permeability of the corrosion products is much lower than that of the steel reinforcement. Therefore, the magnetic permeability of the area around the steel reinforcement gradually decreases, and the magnetic field strength around the steel reinforcement also gradually decreases. Based on this principle, the degree of steel reinforcement corrosion can be quantitatively calculated by detecting the rate of change of the magnetic field strength around the steel reinforcement. The rate of change of magnetic field strength refers to the ratio between the change in magnetic field strength after corrosion and the original magnetic field strength before corrosion. For example, assuming the original magnetic field strength before corrosion is B0 and the magnetic field strength after corrosion is B1, then the change in magnetic field strength after corrosion is B0 - B1, and the rate of change of magnetic field strength is... Based on the rate of change of magnetic field strength This allows us to estimate the degree of corrosion of the reinforcing steel.

[0013] However, in practical applications, each reinforced concrete structure typically consists of multiple reinforcing bars, which are closely spaced. When monitoring the corrosion of a specific target reinforcing bar, the electromagnetic field surrounding it usually has a large range of influence. This means that the magnetic field strength is affected not only by the target reinforcing bar and its corrosion products, but also by adjacent reinforcing bars and their corrosion products. Therefore, the degree of corrosion obtained based on the rate of change of magnetic field strength cannot accurately reflect the true degree of corrosion of the target reinforcing bar, resulting in low precision.

[0014] Furthermore, current electromagnetic field-based rebar corrosion monitoring sensors are mainly divided into built-in sensors and external sensors. Built-in sensors are sensors pre-embedded around the rebar during the construction of reinforced concrete structures. These sensors are fixed in the reinforced concrete structure and monitor corrosion at fixed locations on the rebar. However, the degree of corrosion at different locations on the same rebar is usually different, and the monitoring results at a fixed location cannot represent the overall corrosion level of the entire rebar. Therefore, the monitoring results obtained based on built-in sensors are not comprehensive enough. Additionally, built-in sensors are only suitable for newly constructed reinforced concrete structures, not for existing reinforced concrete structures, thus limiting their application scenarios. External sensors are sensors used to monitor rebar corrosion on the outside of reinforced concrete structures. External sensors can monitor corrosion at different locations on the same rebar, providing more comprehensive monitoring results. However, current external sensors are only suitable for monitoring corrosion of rebar close to the surface of the reinforced concrete structure; for example, they can only monitor corrosion of corner rebar in reinforced concrete structures such as beams and columns, and cannot monitor corrosion of non-corner rebar, again limiting their application scenarios. Furthermore, the current monitoring method does not take into account the impact of nearby interfering reinforcing bars on the detection accuracy.

[0015] In view of this, on the one hand, this application provides a probe-type monitoring device, which can solve the problems of incomplete monitoring results and limited applicability. On the other hand, this application provides a quantitative monitoring method for steel corrosion based on electromagnetic fields, which takes into account the influence of nearby interfering steel bars and can solve the problem of low corrosion monitoring accuracy.

[0016] See also Figure 1 This is a schematic diagram of the structure of a probe-type monitoring device 100 provided in some embodiments of this application. Figure 1 In this application, the probe-type monitoring device 100 includes a controller 15, a first probe 11, and a second probe 12. The first probe 11 and the second probe 12 are deployed on either side of the target location of the reinforcing bar 16 to be monitored. The target location represents the position to be monitored for corrosion, or a position adjacent to the next monitoring location. For example, the target location could be the middle position of the reinforcing bar 16 to be monitored, or a position adjacent to the middle position. In practical applications, the target location can be set according to actual needs, and this application does not impose any restrictions on this.

[0017] The first probe 11 and the second probe 12 can be used to generate an electromagnetic field. The magnetic permeability of the region where the target location is located affects the magnetic field strength on both sides of the target location. For example, when the reinforcing bar 16 at the target location is not corroded, the magnetic permeability of the region where the target location is located is high, and the magnetic field strength on both sides of the target location can be relatively large. After the reinforcing bar at the target location is locally corroded, the magnetic permeability of the region where the target location is located gradually decreases, and the magnetic field strength on both sides of the target location can gradually decrease.

[0018] The controller 15 can monitor the rate of change of magnetic field strength on both sides of the target location, and calculate the degree of corrosion at the target location based on the fitted correlation between the rate of change of magnetic field strength and the degree of corrosion.

[0019] The probe-type monitoring device 100 of this application can quantitatively analyze the corrosion rate of steel bars at the target location based on the change rate of magnetic field strength on both sides of the target location, which facilitates maintenance personnel to carry out targeted maintenance and repair of reinforced concrete structures, thereby ensuring structural safety.

[0020] In some embodiments, the probe-type monitoring device 100 may include multiple sets of first probes 11 and second probes 12. For example... Figure 1 The device, exemplarily, includes two sets of first probes 11 and second probes 12. Different sets of first probes 11 and second probes 12 can be located on either side of different positions on the reinforcing bar 16 to be tested. For example, the first set of first probes 11 and second probes 12 can be located on either side of the middle position of the reinforcing bar 16, while the second set can be located on either side of the end position of the reinforcing bar 16. Thus, a single probe-type monitoring device 100 can simultaneously monitor corrosion at multiple locations on the reinforcing bar 16, resulting in high efficiency.

[0021] In some embodiments, the probe-type monitoring device 100 further includes a data acquisition unit 13. A controller 15 is connected to the data acquisition unit 13, which is connected to each set of first probes 11 and second probes 12. The first probes 11 and second probes 12 can generate electromagnetic fields and also detect the current magnetic field strength on both sides of their corresponding locations. The controller 15 receives electrical signals representing the current magnetic field strength output by the first probes 11 and second probes 12 through the data acquisition unit 13.

[0022] For ease of understanding, let's take the first probe 11 and the second probe 12 located on either side of the target position as an example. A first magnetic sensing device can be deployed in the area of ​​the first probe 11 opposite to the target position, and a second magnetic sensing device can be deployed in the area of ​​the second probe 12 opposite to the target position. The first and second magnetic sensing devices can sense the current magnetic field strength at their respective locations and output a voltage signal corresponding to the current magnetic field strength. The data acquisition unit 13 converts the voltage signal output by the magnetic sensing device into a digital signal through four processes: sampling, holding, quantization, and encoding, and sends the digital signal to the controller 15. Based on this digital signal, the controller 15 can determine the current magnetic field strength on both sides of the target position, and the rate of change of the current magnetic field strength relative to a preset reference magnetic field strength. The preset reference magnetic field strength refers to the magnetic field strength on both sides of the target position when the tested reinforcing steel bar is not corroded.

[0023] Specifically, the controller 15 can perform a fusion calculation (e.g., average calculation, average weighted fusion calculation) on the current magnetic field strength sensed by the first probe 11 and the second probe 12, and use the fusion calculation result as the current magnetic field strength around the target location. Based on the pre-fitted correlation between the rate of change of magnetic field strength and the corrosion rate, the controller 15 can determine the current corrosion rate of the target location. Here, the corrosion rate refers to the ratio between the mass of the corroded steel bar and the mass of the original steel bar before corrosion. The corrosion rate can reflect the degree of corrosion of the steel bar. For example, the higher the corrosion rate, the deeper the corrosion. Based on the above description, the pre-fitted correlation between the rate of change of magnetic field strength and the corrosion rate can be exemplarily shown in expression (1).

[0024] (1) in, This represents the rate of change of magnetic field strength. Indicates the corrosion rate. This represents the known coefficients obtained through pre-fitting, characterizing the sensitivity of the magnetic field strength change to steel corrosion.

[0025] The controller 15 substitutes the rate of change of the current magnetic field strength relative to the preset reference magnetic field strength into expression (1) to determine the current corrosion rate at the target location. .

[0026] See also Figure 1 The probe-type monitoring device 100 also includes a power supply 14. The power supply 14 is used to power the first probe 11, the second probe 12, the data acquisition unit 13, and the controller 15.

[0027] See also Figure 2 This is a schematic diagram showing the positional relationship between the probe and the reinforcing bar 16 to be tested, provided for some embodiments of this application. Figure 2 In this test, the axial direction of the reinforcing bar 16 to be tested is perpendicular to the axial direction of the probe. For example, the axial direction of the first probe 11 and the second probe 12 is along the Y direction, and the axial direction of the reinforcing bar 16 to be tested is along the Z direction.

[0028] See also Figure 3 This is a schematic diagram showing the positional relationship between the probe and the reinforcing bar 16 to be tested, provided for some other embodiments of this application. Figure 3 In this test, the axial direction of the reinforcing bar 16 to be tested is parallel to the axial direction of the probe. For example, the axial directions of the first probe 11, the second probe 12, and the reinforcing bar 16 to be tested are all along the Y direction.

[0029] In practical applications, the relative positional relationship between the probe and the reinforcing bar 16 to be tested can be planned according to the orientation of the reinforcing bar 16 in the reinforced concrete structure.

[0030] See also Figure 4 The diagram below shows a probe structure provided for some embodiments of this application. Figure 4 In this design, the first probe 11 includes a first magnetic component 111, a first magnetically conductive component 112, a first magnetic induction device 113, a first circuit board 114, a first housing 115, and a first cable 116. The second probe 12 includes a second magnetic component 121, a second magnetically conductive component 122, a second magnetic induction device 123, a second circuit board 124, a second housing 125, and a second cable 126. The first cable 116 and the second cable 126 are used to connect to the data acquisition unit 13.

[0031] For either the first probe 11 or the second probe 12, the magnetic component, magnetically conductive component, circuit board, and cable of the probe are located within a housing space. The magnetic component generates an electromagnetic field. The magnetically conductive component transmits the electromagnetic field. A magnetic induction device is located at the end of the magnetically conductive component and is positioned opposite the target location of the steel bar 16 to be measured, used to sense the current magnetic field strength around the target location. The voltage signal representing the current magnetic field strength output by the magnetic induction device can be transmitted to the data acquisition unit 13 via the circuit board and cable. The data acquisition unit 13 converts the voltage signal into a digital signal and outputs the digital signal to the controller 15.

[0032] In this embodiment, the magnetic component includes a permanent magnet. The magnetic induction device includes a silicon steel rod. The magnetic induction device includes a Hall sensor. The data acquisition unit includes a 24-bit high-precision analog-to-digital converter (ADC) for converting the voltage signal into a digital signal. The voltage resolution of this ADC can be 0.1mV, and the measurement accuracy can be 0.01%. Of course, it is understood that in practical applications, the accuracy of the ADC can be selected according to actual needs.

[0033] See also Figure 5 and Figure 6 . Figure 5 A simplified cross-sectional schematic diagram of the first probe 11 provided for some embodiments of this application. Figure 6 A partially detailed cross-sectional schematic diagram of the first probe 11 provided for some embodiments of this application. Figure 5 In the diagram, the dashed lines within the first housing 115 represent the first magnetic component 111, the first magnetically conductive component 112, the first magnetic induction device 113, the first circuit board 114, and the first cable 116 located within the first housing 115. As can be seen from the schematic diagram, all these components are located within the accommodating space enclosed by the housing 115. The first housing 115 protects these components from damage. Figure 6In this design, a mounting groove is provided on the first circuit board 114. The first magnetic sensing device 113 can be located within this mounting groove. The first circuit board 114 can be fitted into the first magnetically conductive member 112. The first housing 115 can be provided with an opening for the first magnetic sensing device 113 to sense the magnetic field strength at its location. It is understood that the second probe 12 has a cross-sectional view similar to that of the first probe 11, which will not be described in detail here.

[0034] In some embodiments, the distance between the probe and the target location can be referred to as the coupling distance. Typically, the coupling distance between the first probe 11 and the target location can be equal to the coupling distance between the second probe 12 and the target location, and the coupling distance can be a fixed value, such as 11 mm. When there are many types of rebar, and if different types of rebar have different diameters, different types of rebar-specific probe monitoring devices 100 can be customized. In different types of probe monitoring devices 100, the probe spacing between the first probe 11 and the second probe 12 can be different, thus adapting to rebars of different diameters.

[0035] For ease of understanding, please refer to the following: Figure 7 The diagram illustrates the relationship between probe center distance L, rebar diameter d, and coupling distance S, as provided in some embodiments of this application. Figure 7 In this context, the probe center distance L refers to the center-to-center distance between the first probe 11 and the second probe 12. The coupling distance S refers to the relative distance between the center of each probe and the surface of the target rebar location. The coupling distance between the center of the first probe 11 and the target rebar location surface can be equal to the coupling distance between the center of the second probe 12 and the target rebar location surface. For example, when the coupling distance is 11 mm, the first coupling distance between the center of the first probe 11 and the target rebar location surface is 11 mm, and the second coupling distance between the center of the second probe 12 and the target rebar location surface is also 11 mm. The probe center distance L = first coupling distance + second coupling distance + rebar diameter. The probe center distance L can be different for different rebar diameters. For example, when the coupling distance is 11 mm, Table 1 provides exemplary examples of the probe center distance L corresponding to some rebar diameters d.

[0036] Table 1. Probe center distance L corresponding to some reinforcing bar diameters d Different probe-type monitoring devices 100 can be customized for different probe center distances L, or the probe center distance L in the same probe-type monitoring device 100 can be set to an adjustable spacing.

[0037] Based on the above description, in some embodiments, when using the probe-type monitoring device 100 to monitor the corrosion of reinforcing steel in existing reinforced concrete structures, the first probe 11 and the second probe 12 can be deployed on both sides of the target location of the reinforcing steel 16 to be tested by drilling holes in the reinforced concrete structure. For ease of understanding, an example is given where the axial direction of the reinforcing steel 16 to be tested is perpendicular to the axial direction of the probe. (Refer to the reference...) Figure 8 This is a cross-sectional view of monitoring steel corrosion in an existing reinforced concrete structure 181, provided for some embodiments of this application. Figure 8 In China, the monitoring of steel reinforcement corrosion includes the following steps: 1) Use a rebar detector to determine the position of the rebar to be tested and its adjacent rebars, and draw the axial positions of these rebars.

[0038] 2) Draw lines on both sides of the target location of the reinforcing bar 16 to be tested, perpendicular to the axis of the reinforcing bar, and mark the locations on the left and right sides that are the coupling distances from the target location surface. These locations are the center axis points of the probe.

[0039] 3) Drill holes along the central axis, with the drilling depth ≥ the target distance. The target distance is the distance between the reinforced concrete surface and the surface of the reinforcing bar being measured, plus the radius of the reinforcing bar.

[0040] 4) Insert the first probe 11 and the second probe 12 into their respective holes. With the magnetic sensing devices of the two probes facing the target position, fix the probes with tools such as clamps to ensure that the depth of the probes inserted into the holes remains unchanged, that is, to ensure that the magnetic sensing devices of the probes are facing the target position.

[0041] 5) Control the two probes to generate an electromagnetic field and read the current magnetic field strength detected by the two probes.

[0042] 6) Obtain the preset reference magnetic field strength obtained through simulation or other means, and determine the rate of change of the current magnetic field strength relative to the preset reference magnetic field strength.

[0043] 7) Substitute the magnetic field strength change rate obtained in step 6) into the pre-fitted correlation between the magnetic field strength change rate and the corrosion rate to obtain the current corrosion rate at the target location.

[0044] The following describes how to use the probe-type monitoring device 100 to monitor the corrosion of steel bars in newly built reinforced concrete structures.

[0045] In some embodiments, when using the probe-type monitoring device 100 to monitor the corrosion of reinforcing steel in a newly constructed reinforced concrete structure, probes can be pre-embedded during the construction of the reinforced concrete structure. For ease of understanding, please refer to the following references. Figure 9 and Figure 10 . Figure 9A cross-sectional view of a probe embedded in a newly constructed reinforced concrete structure 182, provided for some embodiments of this application. Figure 10 A top view of a probe embedded in a newly constructed reinforced concrete structure 182, provided for some embodiments of this application. Figure 9 and Figure 10 In this process, probe pre-embedding and corrosion monitoring include the following steps: 1) Use the matching clamp 183 to place the first probe 11 and the second probe 12 on both sides of the target position of the steel bar 16 to be tested, and adjust the position of the clamp 183 and the probe so that the detection points on the left and right sides of the probe are aligned with the center of the steel bar to be tested, and perform symmetrical testing of the left and right test points to ensure that the magnetic field strength detected by the two probes is basically the same, and then lock the clamp 183.

[0046] 2) Protect the probe during the process of reinforcing bar binding and concrete pouring and curing to prevent it from being damaged.

[0047] 3) After the concrete has solidified, read the magnetic field strength detected by the first probe 11 and the second probe 12 as the preset reference magnetic field strength of the target location.

[0048] 4) Every preset time interval (e.g., 3 months), read the magnetic field strength detected by the first probe 11 and the second probe 12 again, and use it as the current magnetic field strength at the target location.

[0049] 5) Substitute the rate of change of the current magnetic field strength relative to the preset reference magnetic field strength into the pre-fitted correlation between the rate of change of magnetic field strength and the corrosion rate to obtain the current corrosion rate at the target location.

[0050] It should be noted that, in Figure 9 and Figure 10 In this case, directly embedding the probe in the reinforced concrete structure 182 is not conducive to probe maintenance and replacement. Therefore, a hollow tube sleeve can be embedded. When monitoring for rebar corrosion is required, the probe can be inserted into the hollow tube sleeve. For ease of understanding, please refer to the relevant documentation. Figure 11 and Figure 12 . Figure 11 A cross-sectional view of a hollow tube sleeve embedded in a newly constructed reinforced concrete structure 182, provided for some embodiments of this application. Figure 12 Cross-sectional views of steel reinforcement corrosion monitoring in hollow tube sleeves provided for some embodiments of this application. Figure 11 and Figure 12 In the process of monitoring hollow probe sleeves and corrosion, the following steps are included: 1) Using the matching clamp 183, place the first hollow tube sleeve 110 and the second hollow tube sleeve 120 on both sides of the target position of the steel bar 16 to be tested, and adjust the positions of the clamp 183 and the hollow tube sleeves to make the hollow tube sleeves symmetrical. Insert the first probe 11 into the first hollow tube sleeve 110 and the second probe 12 into the second hollow tube sleeve 120 to determine whether the magnetic field strength detected by the two probes is basically the same. If so, lock the clamp 183.

[0051] 2) Pull out the probe, cover the first hollow tube sleeve 110 with the first tube cap 1101, and cover the second hollow tube sleeve 120 with the second tube cap 1201 to prevent concrete or debris from entering the hollow tube sleeve.

[0052] 3) Protect the hollow pipe sleeve during the process of reinforcing bar binding and concrete pouring and curing to prevent damage to the hollow pipe sleeve.

[0053] 3) After the concrete has solidified, open the pipe cover and insert a probe into the hollow pipe sleeve to read the magnetic field strength detected by the probe, which will serve as the preset reference magnetic field strength for the target location.

[0054] 4) Every preset time interval (e.g., 3 months), open the tube cover again and insert a probe into the hollow tube sleeve to read the magnetic field strength detected by the probe, which will be used as the current magnetic field strength at the target location.

[0055] 5) Substitute the rate of change of the current magnetic field strength relative to the preset reference magnetic field strength into the pre-fitted correlation between the rate of change of magnetic field strength and the corrosion rate to obtain the current corrosion rate at the target location.

[0056] Figure 11 and Figure 12 In this method, by pre-embedding a hollow tube sleeve in the reinforced concrete structure 182, it is not necessary to permanently bury the probe in the reinforced concrete structure 182, thus facilitating the replacement and maintenance of the probe.

[0057] Based on the above description, the probe-type monitoring device 100 in some embodiments of this application utilizes the principle of electromagnetic fields to monitor steel reinforcement corrosion, enabling quantitative monitoring of corrosion. Simultaneously, this probe-type monitoring device can support corrosion monitoring of steel reinforcement in both existing and newly constructed reinforced concrete structures, thus having a wide range of applications. Furthermore, the probe's small size minimizes damage to existing projects during corrosion monitoring, ensuring structural safety.

[0058] This application also provides a quantitative monitoring method for steel reinforcement corrosion based on electromagnetic fields. This method can be applied to the controller 15 in a probe-type monitoring device 100. (See also...) Figure 13 This is a flowchart illustrating a quantitative monitoring method for steel reinforcement corrosion provided in some embodiments of this application. Figure 13 The quantitative monitoring method for steel reinforcement corrosion includes the following steps: Step S131: Detect the current magnetic field strength on both sides of the target position using the first probe 11 and the second probe 12, and determine the rate of change of the current magnetic field strength relative to the preset reference magnetic field strength.

[0059] Specifically, regarding the current magnetic field strength and the preset reference magnetic field strength, please refer to the relevant description of the probe-type monitoring device 100 above, which will not be repeated here.

[0060] Step S132: Based on the spacing between the reinforcing bars 16 to be tested and the interfering reinforcing bars, determine the sensitivity correction coefficient, and based on the sensitivity correction coefficient, correct the theoretical sensitivity. The theoretical sensitivity refers to the sensitivity of the change in magnetic field strength on both sides of the target position to the corrosion of the reinforcing bars when there is no interference from the interfering reinforcing bars.

[0061] Specifically, interfering reinforcing bars refer to reinforcing bars adjacent to the reinforcing bar 16 to be tested. "Adjacent" means that the distance between the interfering reinforcing bar and the reinforcing bar 16 to be tested does not exceed a distance threshold.

[0062] In this embodiment, the aforementioned distance threshold can be determined based on the electromagnetic field range generated by the first probe 11 and the second probe 12. For example, if the target position of the steel bar 16 to be tested is taken as the center, and the electromagnetic field range is within a radius of 50mm, then the distance threshold can be 50mm.

[0063] For ease of understanding, please refer to the following: Figure 14 This is a schematic diagram showing the positional relationship between the reinforcing bar 16 to be tested and the interfering reinforcing bar, provided for some embodiments of this application. Figure 14 In this context, n represents the spacing between the tested rebar 16 and the interfering rebar. If n does not exceed the distance threshold, when the first probe 11 and the second probe 12 monitor the corrosion at the target location of the tested rebar 16, the interfering rebar will be within the range of the electromagnetic field generated by the first probe 11 and the second probe 12, affecting the magnetic field strength. That is, the current magnetic field strength detected by the first probe 11 and the second probe 12 is not the result of the target location of the tested rebar 16 acting alone. In this case, if the corrosion rate of the rebar is determined directly based on the current magnetic field strength, the obtained corrosion rate cannot reflect the true degree of corrosion at the target location.

[0064] Therefore, a sensitivity correction coefficient can be determined based on the spacing between the reinforcing bar 16 to be tested and the interfering reinforcing bar, and the theoretical sensitivity can be corrected based on the sensitivity correction coefficient. Specifically, the theoretical sensitivity is used to characterize the correlation between the rate of change of magnetic field strength on both sides of the target location and the rate of corrosion of the reinforcing bar when there is no interference from the interfering reinforcing bar. This correlation can be shown in the above expression (1). In expression (1), k is the theoretical sensitivity. By fitting, the correlation between the reinforcing bar spacing and the sensitivity correction coefficient can be obtained. The larger the reinforcing bar spacing, the smaller the influence of the interfering reinforcing bar on the magnetic field strength, and the smaller the correction amount of the theoretical sensitivity after correcting the theoretical sensitivity according to the sensitivity correction coefficient. Based on the above description, the correction formula for the theoretical sensitivity can be shown in expression (2).

[0065] (2) in, Here, k is the sensitivity correction coefficient, and k is the theoretical sensitivity. To correct the obtained sensitivity.

[0066] Step S133: Determine the corrosion rate at the target location based on the rate of change of magnetic field strength and the corrected sensitivity.

[0067] Specifically, the rate of change of magnetic field strength and the corrected sensitivity can be substituted into expression (3) to obtain the corrosion rate at the target location.

[0068] (3) in, and The meaning is the same as that of expression (1). To correct the obtained sensitivity.

[0069] In summary, in some embodiments of this application, a sensitivity correction coefficient is determined based on the spacing between the reinforcing bar to be tested and the interfering reinforcing bars, and the theoretical sensitivity is corrected based on the sensitivity correction coefficient. This eliminates the influence of interfering reinforcing bars on the electromagnetic field around the target location, allowing the corrected sensitivity to accurately reflect the impact of corrosion on the magnetic field strength at the target location. Furthermore, the corrosion rate determined based on the rate of change of magnetic field strength and the corrected sensitivity accurately reflects the true degree of corrosion at the target location. This application achieves the technical effect of improving the accuracy of reinforcing bar corrosion monitoring through sensitivity correction.

[0070] In some embodiments, the theoretical sensitivity can be obtained through the following fitting steps.

[0071] 1) Among multiple steel bars of the same length (e.g., all 15cm) but different diameters, the same position of each steel bar is used as the fitting position. For example, the middle 10cm of each steel bar is used as the fitting position.

[0072] 2) Measure the mass of each steel bar using an electronic scale, and calculate the mass *m* at the fitted position (e.g., 10cm from the middle) of each steel bar. Set the coupling distance to 11mm, and monitor the magnetic field strength on both sides of the fitted position of each steel bar using a probe. This magnetic field strength will serve as the preset reference magnetic field strength for the corresponding steel bar. .

[0073] 3) Weld wires to one side of each reinforcing bar, apply epoxy resin to the reinforcing bar areas other than the fitting position, and after the epoxy resin has solidified, wrap waterproof tape around the epoxy resin surface. This is to achieve the purpose of only causing the reinforcing bar at the fitting position to be corroded.

[0074] 4) After the waterproof tape is wrapped, measure the sample weight of each steel bar. .

[0075] 5) The initial magnetic field strength on both sides of the fitting position of each steel bar is monitored by probes, which serves as the preset reference magnetic field strength for the corresponding probe.

[0076] 6) Perform corrosion treatment on each steel bar individually. For details, please refer to the relevant documentation. Figure 15 This diagram illustrates a steel reinforcement corrosion calibration test provided in some embodiments of this application. For any given steel reinforcement, it can be placed in a 5% NaCl solution and then placed under an auxiliary electrode 191. The auxiliary electrode 191 and the steel reinforcement are connected to a power source with a current density of 300 μA / cm². 2 This accelerates the corrosion process of each steel bar. Then, after a preset time interval (e.g., 24 hours), the corroded steel bars are removed, and the coupling distance is set to 11 mm. The magnetic field strength on both sides of the fitting position of each steel bar is monitored by a probe. .in, This represents the magnetic field strength on both sides of the fitted position obtained after the i-th rusted rebar is removed. The value of i is an integer greater than 1. Then, the external rust layer of each rebar is removed with a rebar rust remover, and after drying, the mass of each rebar after rusting is measured using an electronic scale. .in, This represents the mass of the corroded steel bar after the i-th removal of the corroded steel bar.

[0077] 7) Based on expression (4), calculate the rate of change of magnetic field strength of each steel bar after the i-th measurement. Based on expression (5), the corrosion rate of each steel bar after the i-th measurement is calculated. .

[0078] (4) (5) In this way, a set of test data can be obtained for each steel bar. , ... .

[0079] 8) Based on a set of test data corresponding to each steel bar, with the corrosion rate as the abscissa and the rate of change of magnetic field strength as the ordinate, similar results can be obtained. Figure 16 The multiple corrosion rate-magnetic field strength change rate curves are shown. Figure 16 In this context, the slope of each curve represents the theoretical sensitivity k corresponding to the steel bar of that diameter. From... Figure 16 It can be seen that, under the same coupling distance, different diameters can have different theoretical sensitivities k, that is, each diameter of steel bar has its own corresponding relationship between the rate of change of magnetic field strength and the corrosion rate. For example, the relationship between the rate of change of magnetic field strength and the corrosion rate of steel bar with a diameter of 20mm is shown in expression (6).

[0080] (6) The relationship between the rate of change of magnetic field strength and the corrosion rate of a steel bar with a diameter of 22 mm is shown in expression (7).

[0081] (7) Where k1 is the theoretical sensitivity corresponding to a steel bar with a diameter of 20mm, and k2 is the theoretical sensitivity corresponding to a steel bar with a diameter of 22mm.

[0082] 9) Numerical simulation analysis was performed using numerical simulation software to obtain the corrosion rate-magnetic field strength change rate curves corresponding to steel bars of different diameters, as shown in the following figure. Figure 17 As shown. (Through) Figure 16 and Figure 17 The comparison shows that the corrosion rate-magnetic field strength change rate curve obtained by software simulation is quite close to the corrosion rate-magnetic field strength change rate curve obtained by experimental fitting. This demonstrates the reliability of the experimental fitting data.

[0083] 10) When the coupling distance is 11mm and the rebar diameters are different, Figure 16 The curves in the diagram are equivalent to the corrosion rate versus magnetic field strength change rate curves corresponding to different probe center distances L when the coupling distance is 11 mm. For example, the curve corresponding to a 20 mm diameter rebar is essentially the curve corresponding to a probe spacing of 42 mm, and the curve corresponding to a 22 mm diameter rebar is essentially the curve corresponding to a probe spacing of 44 mm. Figure 16By fitting each curve shown, the relationship between the slope (i.e., theoretical sensitivity) of each curve and the probe center distance L can be obtained, as shown in expression (8).

[0084] (8) Since different curves have different slopes, this is equivalent to different probe center distances L having their own corresponding parameter sets (a, b). For example, the parameter set corresponding to a probe spacing of 42 mm is (a1, b1), and the parameter set corresponding to a probe spacing of 44 mm is (a2, b2).

[0085] Since the above steps were all obtained at a specific fitting position and a coupling distance of 11mm, it can be understood that the parameter sets (a,b) corresponding to different probe center distances L refer to the parameter sets (a,b) corresponding to different probe center distances L at a specific fitting position and a coupling distance of 11mm. After changing the fitting position and coupling distance, based on steps 1) to 10) in the above fitting process, new parameter sets (a,b) corresponding to different probe center distances L can be obtained. Simply put, when the fitting position is position 1, the coupling distance between the fitting position and the probe is set as the target coupling distance, and based on the correspondence between the magnetic field strength change rate and the corrosion rate of each rebar, a parameter set corresponding to the fitting position and the target coupling distance is fitted. The target coupling distance can be any coupling distance, such as 11mm, 13mm, 14mm, etc. When the fitting position is position 2, the coupling distance between the fitting position and the probe is again set as the target coupling distance, and based on the correspondence between the magnetic field strength change rate and the corrosion rate of each rebar, a parameter set corresponding to the fitting position and the target coupling distance is fitted.

[0086] For example, when fitting position 1 and coupling spacing is 11mm, the parameter set corresponding to probe spacing of 42mm is (a11, b12), and the parameter set corresponding to probe spacing of 44mm is (a21, b22).

[0087] When fitting position 1 and coupling spacing is 13mm, the parameter set corresponding to probe spacing of 42mm is (a13, b14), and the parameter set corresponding to probe spacing of 44mm is (a23, b24).

[0088] When fitting position 2 and coupling spacing is 11mm, the parameter set corresponding to probe spacing of 42mm is (a15, b16), and the parameter set corresponding to probe spacing of 44mm is (a25, b26).

[0089] When fitting position 2 and coupling spacing is 13mm, the parameter set corresponding to probe spacing of 42mm is (a17, b18), and the parameter set corresponding to probe spacing of 44mm is (a27, b28).

[0090] Based on the above description, before correcting the theoretical sensitivity in step S132, the method of this application further includes: Obtain the probe spacing between the first probe 11 and the second probe 12, and the coupling distance between the target position and the probe; The theoretical sensitivity is determined based on the probe spacing and coupling spacing. When the coupling spacing is fixed, the probe spacing is directly proportional to the theoretical sensitivity, and when the probe spacing is fixed, the coupling spacing is inversely proportional to the theoretical sensitivity.

[0091] Specifically, based on the target location, multiple preset parameter groups corresponding to the target location can be found. Among these preset parameter groups, the target parameter group corresponding to the target location and the coupling distance can be found based on the coupling distance. Then, the parameters in the target parameter group are used as linear transformation coefficients to transform the probe spacing, thereby obtaining the theoretical sensitivity.

[0092] In simple terms, the probe spacing and the target parameter set found are substituted into the above expression (8) to solve for the theoretical sensitivity in the corresponding monitoring scenario.

[0093] Based on the above description, the above expression (1) can be transformed into expression (9).

[0094] (9) In expression (9), parameters a and b can be regarded as parameters related to the target position, coupling distance, and probe structure.

[0095] In the above embodiments, after obtaining multiple sets of parameters in advance through fitting, the corresponding target parameter set can be found based on the coupling distance and target position in the actual monitoring scenario. Based on the target parameter set and probe spacing, the theoretical sensitivity under the corresponding monitoring scenario can be calculated, which greatly improves the convenience of the monitoring process.

[0096] Furthermore, for any coupling distance at any target location, after obtaining different theoretical sensitivities based on different probe spacings, the probe spacing can be used as the x-axis and the theoretical sensitivity as the y-axis to obtain... Figure 18 The relationship between probe spacing and theoretical sensitivity is shown. From Figure 18It can be seen that, with a fixed target location and coupling distance, the probe spacing is directly proportional to the theoretical sensitivity. This is understandable; with a fixed coupling distance, increasing the probe spacing means increasing the diameter of the rebar being measured. With a larger diameter, the magnetic permeability at the target location of the rebar increases, thus increasing the theoretical sensitivity.

[0097] In some embodiments, the sensitivity correction coefficient can be obtained through the following fitting steps: Multiple steel bars of different diameters are used as a fitting steel bar group; Determine the correlation between the actual sensitivity of each rebar in the rebar group and the rebar spacing under the condition of interference from adjacent rebars; Determine the theoretical sensitivity of each steel bar in the steel bar group without interference from adjacent steel bars; Based on the correlation between actual sensitivity and rebar spacing, and theoretical sensitivity, a correction logic corresponding to different rebar diameters is obtained through fitting.

[0098] For details on the method for determining theoretical sensitivity, please refer to the above description, which will not be repeated here.

[0099] When fitting the correlation between the actual sensitivity of each rebar in a rebar group and the rebar spacing, with the target position and coupling distance fixed, for any diameter rebar, the actual sensitivity of each rebar can be detected by adjusting the rebar spacing between the rebar to be tested and adjacent rebars. In this way, the correlation between the actual sensitivity of each rebar and the rebar spacing can be fitted. It is understandable that, similar to the theoretical sensitivity mentioned above, different rebar diameters can have their own corresponding correlations. For example, taking a rebar diameter of 25mm as an example, the fitted correlation between the rebar spacing and the actual sensitivity can be as follows: Figure 19 As shown, and Figure 19 The functional relationship in the expression (10) can be shown.

[0100] (10) in, denoted as the actual sensitivity, and n is the spacing between the reinforcing bar to be tested and the interfering reinforcing bars.

[0101] from Figure 19 It can be seen that when the distance between the interfering rebar and the rebar to be tested is greater than 35mm, the actual sensitivity changes very little. This indicates that when the distance between the interfering rebar and the rebar to be tested is greater than 35mm, the influence of the interfering rebar on the monitoring results is weakened. At this time, the actual sensitivity monitored is close to the theoretical sensitivity.

[0102] Furthermore, based on Figure 19 And expression (10), can be fitted to obtain as follows Figure 20 The correlation between rebar spacing and monitoring error is shown. From... Figure 20 It can also be seen that when the spacing between the reinforcing bar to be tested and the interfering reinforcing bars is greater than 35mm, the monitoring error gradually decreases, thus proving that... Figure 19 The correctness of the statement.

[0103] In some embodiments, with the target location and coupling distance fixed, a sensitivity correction coefficient for each rebar diameter can be obtained based on the correlation between the actual sensitivity and rebar spacing for each rebar diameter, and the theoretical sensitivity for each rebar diameter. For example, taking a steel bar diameter of 25mm as an example, the sensitivity correction coefficient corresponding to a steel bar diameter of 25mm can be obtained through expression (11). .

[0104] (25) Since k is known, therefore, It is a function related to the spacing n of the reinforcing bars.

[0105] Furthermore, since different rebar diameters all have functions similar to expression (25), the sensitivity correction coefficient... It is a function related to the diameter of the steel bar and the spacing n of the steel bar, as shown in expression (26).

[0106] (26) in, It refers to a function related to the diameter d of the reinforcing bar and the spacing n of the reinforcing bars. This refers to the correction logic corresponding to the diameter of each steel bar.

[0107] Based on the above description, the determination of the sensitivity correction coefficient in step S132, based on the spacing between the reinforcing bars to be tested and the interfering reinforcing bars, includes: Among multiple preset correction logics, the target correction logic corresponding to the diameter of the steel bar to be measured is found. The correction logic represents the mapping relationship between the steel bar spacing and the sensitivity correction coefficient. At least some steel bar diameters have different correction logics. Based on the target correction logic, the spacing between the reinforcing bars to be tested and the interfering reinforcing bars is mapped to obtain the sensitivity correction coefficient.

[0108] In the above embodiments, by establishing the correlation between the diameter of the reinforcing bars, the spacing of the reinforcing bars and the sensitivity correction coefficient, the sensitivity correction coefficient can be obtained by detecting the diameter of the reinforcing bars and the spacing of the reinforcing bars in practical applications, thereby improving the convenience of corrosion monitoring.

[0109] Furthermore, in some embodiments, substituting expressions (26) and (8) into expression (3) yields expression (27).

[0110] (27) Based on expression (27), the rate of change of magnetic field strength on both sides of the target location can be monitored. Then, the corrosion rate is obtained directly. It is quite convenient.

[0111] In some embodiments, the method of this application further includes: If there is a next monitoring position for the reinforcing bar to be tested, and the distance between the next monitoring position and the target position is less than the preset distance in the axial direction of the reinforcing bar to be tested, then the corrosion rate monitored at the target position will be used as the corrosion rate monitored at the next monitoring position.

[0112] Specifically, the preset distance represents the distance between locations where the corrosion rate changes relatively little. That is, when the distance between the next monitoring location and the target location is less than the preset distance, the corrosion rate at the next monitoring location can be considered to be the same as or close to the corrosion rate at the target location. This preset distance can be obtained through fitting.

[0113] For example, with the fitting position and coupling distance fixed, the following operations are performed respectively: At the fitting position corresponding to a 20mm diameter rebar, moving the probe upwards (positive Y direction) by 1mm, 2mm, 3mm, 4mm, and 5mm relative to the rebar's centerline yields the following results. Figure 21 The multiple corrosion rate-magnetic field strength change rate curves shown, along with downward (negative Y-axis) shifts of 1mm, 2mm, 3mm, 4mm, and 5mm, yield the following results: Figure 22 The multiple corrosion rate-magnetic field strength change rate curves are shown.

[0114] Similarly, at the fitting position corresponding to a 22mm diameter rebar, moving the probe upwards (positive Y direction) by 1mm, 2mm, 3mm, 4mm, and 5mm relative to the rebar's centerline yields the following results. Figure 23 The multiple corrosion rate-magnetic field strength change rate curves shown, along with downward (negative Y-axis) shifts of 1mm, 2mm, 3mm, 4mm, and 5mm, yield the following results: Figure 24 The multiple corrosion rate-magnetic field strength change rate curves are shown.

[0115] At the fitting position corresponding to the 25mm diameter rebar, moving the probe upwards (positive Y direction) by 1mm, 2mm, 3mm, 4mm, and 5mm relative to the rebar's centerline yields the following results. Figure 25The multiple corrosion rate-magnetic field strength change rate curves shown, along with downward (negative Y-axis) shifts of 1mm, 2mm, 3mm, 4mm, and 5mm, yield the following results: Figure 26 The multiple corrosion rate-magnetic field strength change rate curves are shown.

[0116] based on Figures 21 to 26 The slope of the curve (i.e., theoretical sensitivity) and the upward (Y-direction) movement distance of the probe relative to the center of the rebar can be used to establish... Figure 27 The theoretical sensitivity-Y-direction movement distance curve is shown. Figure 27 In this context, a negative axial movement distance indicates downward movement, while a positive axial movement distance indicates upward movement. From... Figure 27 It can be seen that within the range of -1 to 1, the theoretical sensitivity changes are relatively close, meaning the correspondence between the corrosion rate and the rate of change of magnetic field strength is consistent. Furthermore, since the range is small, the difference in the rate of change of magnetic field strength is small. Therefore, based on the above expression (1), it can be known that the corrosion rate at the next monitoring location is the same as or close to the corrosion rate at the target location. Thus, the corrosion rate at the target location can be used as the corrosion rate at the next monitoring location. This reduces the amount of monitoring required.

[0117] The above description is merely an embodiment of this application and is not intended to limit the scope of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of the claims of this application.

Claims

1. A quantitative monitoring method for steel reinforcement corrosion based on electromagnetic fields, characterized in that, The electromagnetic field is generated by a first probe and a second probe in a probe-type monitoring device, the first probe and the second probe being deployed on both sides of the target location of the rebar to be tested; the method includes: The current magnetic field strength on both sides of the target position is detected by the first probe and the second probe, and the rate of change of the current magnetic field strength relative to the preset reference magnetic field strength is determined. Based on the spacing between the reinforcing bars to be tested and the interfering reinforcing bars, a sensitivity correction coefficient is determined, and based on the sensitivity correction coefficient, the theoretical sensitivity is corrected. The theoretical sensitivity refers to the sensitivity of the change in magnetic field strength on both sides of the target position to the corrosion of the reinforcing bars when there is no interference from the interfering reinforcing bars. The sensitivity refers to the correlation between the rate of change of magnetic field strength on both sides of the target position and the rate of corrosion of the reinforcing bars. The interfering reinforcing bars refer to the reinforcing bars adjacent to the reinforcing bars to be tested. Adjacent means that the distance between the interfering reinforcing bars and the reinforcing bars to be tested does not exceed the distance threshold. Based on the rate of change of the magnetic field strength and the corrected sensitivity, the corrosion rate at the target location is determined; The determination of the sensitivity correction coefficient based on the spacing between the reinforcing bars to be tested and the interfering reinforcing bars includes: Among multiple preset correction logics, a target correction logic corresponding to the diameter of the steel bar to be measured is found. The correction logic represents the mapping relationship between the steel bar spacing and the sensitivity correction coefficient. At least some steel bar diameters have different correction logics. Based on the target correction logic, the spacing between the reinforcing bars to be tested and the interfering reinforcing bars is mapped to obtain the sensitivity correction coefficient; Furthermore, before modifying the aforementioned theoretical sensitivity, it also includes: Multiple steel bars of different diameters are used as a fitting steel bar group; Determine the correlation between the actual sensitivity of each rebar in the fitted rebar group and the rebar spacing under the condition of interference from adjacent rebars; Determine the theoretical sensitivity of each steel bar in the fitted steel bar group without interference from adjacent steel bars; Based on the correlation between the actual sensitivity and the spacing of the reinforcing bars, and the theoretical sensitivity, the correction logic corresponding to different reinforcing bar diameters is fitted.

2. The method according to claim 1, characterized in that, Before correcting the theoretical sensitivity, the method further includes: Obtain the probe spacing between the first probe and the second probe, and the coupling spacing between the target position and the probe; The theoretical sensitivity is determined based on the probe spacing and the coupling spacing, wherein, when the coupling spacing is fixed, the probe spacing is directly proportional to the theoretical sensitivity, and when the probe spacing is fixed, the coupling spacing is inversely proportional to the theoretical sensitivity.

3. The method according to claim 2, characterized in that, The determination of the theoretical sensitivity based on the probe spacing and the coupling spacing includes: Among multiple preset parameter sets, find the target parameter set that corresponds to the target position and the coupling distance; The probe spacing is converted using the parameters in the target parameter set as linear conversion coefficients to obtain the theoretical sensitivity.

4. The method according to claim 3, characterized in that, Before determining the theoretical sensitivity, the method further includes: Among multiple steel bars of different diameters, the same position of each steel bar is taken as the fitting position; The coupling distance between the fitted position and the probe is set as the target coupling distance, and a parameter set corresponding to the fitted position and the target coupling distance is obtained based on the correspondence between the rate of change of magnetic field strength and the corrosion rate of each steel bar.

5. The method according to claim 4, characterized in that, The method further includes: If there is a next monitoring position for the reinforcing bar to be tested, and the distance between the next monitoring position and the target position in the axial direction of the reinforcing bar to be tested is less than a preset distance, then the corrosion rate monitored at the target position will be used as the corrosion rate monitored at the next monitoring position.

6. A probe-type monitoring device, characterized in that, The device includes: The first and second probes are used to generate an electromagnetic field; A controller for executing the electromagnetic field-based quantitative monitoring method for steel corrosion as described in any one of claims 1 to 5.

7. The device according to claim 6, characterized in that, For either the first probe or the second probe, the probe includes a magnetic component and a magnetically conductive component, wherein the magnetic component is used to generate an electromagnetic field, and the magnetically conductive component is used to transmit the electromagnetic field.

8. The device according to claim 7, characterized in that, The probe also includes a magnetic sensing device, which is connected to the controller. When the first probe and the second probe are located on both sides of the target position of the steel bar to be tested, the controller detects the magnetic field strength on both sides of the target position through the magnetic sensing device.

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