阅读说明：本技术 基于电磁场原理的外置式钢筋锈蚀原位无损监测试验装置及测试方法 (External steel bar corrosion in-situ nondestructive monitoring test device and test method based on electromagnetic field principle ) 是由 付传清 黄家辉 金南国 李宗津 于 2019-10-18 设计创作，主要内容包括：一种基于电磁场原理的外置式钢筋锈蚀原位无损监测试验装置,包括传感器系统和三维精准定位及移动系统；传感器系统包括磁感应强度监测单元和数据处理单元,磁感应强度监测单元包括磁芯、线圈、封装外壳、霍尔传感器和信号发生器；数据处理单元包括信号处理器和中央处理器,三维精准定位及移动系统包括左右移动与固定单元、上下移动与固定单元、前后移动与固定单元和夹紧爪单元。以及提供一种基于电磁场原理的外置式钢筋锈蚀原位无损监测试验装置测试方法,包括待测试件预处理、测定磁感应强度、三维精准定位及移动、标定试验、根据标定拟合方程计算得到钢筋锈蚀率。本发明实现对钢筋锈蚀的精准监测；既适用于砂浆试件也适用于混凝土试件。(An external steel bar corrosion in-situ nondestructive monitoring test device based on an electromagnetic field principle comprises a sensor system and a three-dimensional accurate positioning and moving system; the sensor system comprises a magnetic induction intensity monitoring unit and a data processing unit, wherein the magnetic induction intensity monitoring unit comprises a magnetic core, a coil, a packaging shell, a Hall sensor and a signal generator; the data processing unit comprises a signal processor and a central processing unit, and the three-dimensional accurate positioning and moving system comprises a left-right moving and fixing unit, an up-down moving and fixing unit, a front-back moving and fixing unit and a clamping claw unit. The testing method of the external steel bar corrosion in-situ nondestructive monitoring testing device based on the electromagnetic field principle comprises the steps of pretreatment of a piece to be tested, determination of magnetic induction intensity, three-dimensional accurate positioning and movement, calibration test and calculation according to a calibration fitting equation to obtain the steel bar corrosion rate. The invention realizes the accurate monitoring of the corrosion of the steel bar; the test piece is suitable for both mortar test pieces and concrete test pieces.)

1. An external steel bar corrosion in-situ nondestructive monitoring test device based on an electromagnetic field principle is characterized by comprising a sensor system and a three-dimensional precise positioning and moving system;

the sensor system comprises a magnetic induction intensity detection unit and a data processing unit; the magnetic induction intensity detection unit comprises a signal generator, a coil, a magnetic core, a packaging shell, a first Hall sensor and a second Hall sensor, wherein the coil is uniformly wound on the magnetic core, and two ends of the coil are electrically connected with a signal input end of the signal generator; the middle position of the reinforced concrete test piece clamped by the fixing unit corresponds to the middle position of the bayonet of the magnetic core; the packaging shell comprises a first Hall sensor placing groove, a second Hall sensor placing groove and a sealing cover; the first Hall sensor and the second Hall sensor are symmetrically arranged by taking a bayonet center line as an axis and are respectively arranged in a first Hall sensor placing groove and a second Hall sensor placing groove of the packaging shell; the data processing unit comprises a signal collector, a signal processor and a central controller, wherein the input end of the signal collector is electrically connected with the signal output ends of the first Hall sensor and the second Hall sensor, the signal output end of the signal generator and the output end of the signal collector are respectively electrically connected with the signal input end of the signal processor, and the signal output end of the signal processor is electrically connected with a port of the central controller;

the three-dimensional accurate positioning and moving system comprises a left-right moving and fixing unit, an up-down moving and fixing unit, a front-back moving and fixing unit and a clamping claw unit; the left-right moving and fixing unit comprises a left-right precession handle, a left-right precession bearing, an I-shaped sliding block, a bottom base and an upper polish rod and a lower polish rod; the screw-in handle is provided with a threaded hole, and the threaded hole is in threaded connection with the left screw-in bearing and the right screw-in bearing; the bottom base is provided with a dial scale for a tester to observe the left-right movement length of the reinforced concrete test piece, the bottom base is provided with an inverted T-shaped hole for an I-shaped sliding block to slide left and right in the bottom base, and the I-shaped sliding block is fixedly connected with a left-right precession bearing, an upper polish rod and a lower polish rod; the up-down moving and fixing unit comprises a first arc-shaped fixing clamp, an upper polish rod, a lower polish rod, a first screw rod and a first locking nut; the left side and the right side of the first arc-shaped fixing clamp are respectively provided with a fixing surface and a threaded hole, the first screw rod is connected with the first locking nut bolt through the threaded hole, and the fixing surface of the first arc-shaped fixing clamp and the first screw rod are in close contact with the left surface and the right surface of the upper polish rod and the lower polish rod; the front-back moving and fixing unit comprises a second arc-shaped fixing clamp, a second screw rod, a second locking nut and a front polish rod and a rear polish rod; the right side and the left side of the second arc-shaped fixing clamp are respectively provided with a fixing surface and a threaded hole, the second screw rod and the second locking nut are connected through the threaded hole by bolts, and the fixing surface of the second arc-shaped clamp and the second screw rod are in close contact with the left surface and the right surface of the front polished rod and the rear polished rod; the clamping jaw unit comprises a third screw rod, a third locking nut, a first dome screw rod, a second dome screw rod, a fourth locking nut, a fifth locking nut, a square rotating block, a jaw shell and a jaw accessory; the claw fittings comprise a left claw, a right claw, a rotary key and a connecting block, and the left claw and the right claw are fixedly connected with the claw shell.

2. The external steel bar corrosion in-situ nondestructive monitoring test device based on the electromagnetic field principle as claimed in claim 1, wherein in the magnetic induction intensity detection unit, the first hall sensor and the second hall sensor are symmetrically arranged, and the position of the steel bar is accurately detected through different magnetic induction intensities.

3. The external steel bar corrosion in-situ nondestructive monitoring test device based on the electromagnetic field principle as claimed in claim 1 or 2, wherein in the magnetic induction intensity detection unit, the magnetic core is made of silicon steel, and the packaging shell is made of plastic; the magnetic core bayonet socket be trapezoidal shape, can firmly block in the edge of reinforced concrete square column, accomplish the monitoring of single detection reinforcing bar corrosion, and can block not unidimensional reinforced concrete column according to the embedding degree of depth or change magnetic core bayonet socket distance.

4. The external steel bar corrosion in-situ nondestructive monitoring test device based on the electromagnetic field principle as claimed in claim 1 or 2, wherein in the magnetic induction intensity detection unit, the signal generator can stably control the current of the coil; the signal collector and the signal generator are respectively provided with a first indicator light and a second indicator light of a circuit, and the first indicator light and the second indicator light respectively prompt whether the signal collector and the signal generator work normally or not.

5. The external steel bar corrosion in-situ nondestructive monitoring test device based on the electromagnetic field principle as claimed in claim 1 or 2, wherein in the magnetic induction detection unit, a uniform electromagnetic field generated by a magnetic core of the magnetic induction detection unit and a uniformly wound coil depends on the coil current and the number of turns of the coil, so that demagnetization caused by time change is avoided, and the detection result is accurate; the electromagnet composed of the magnetic core, the coil with uniform winding and the signal generator can change the magnetic field intensity by controlling the current of the coil and the number of turns of the coil, and the inventor tests the result that the change of the magnetic field intensity can effectively reduce the influence of air domain magnetic leakage caused by the change of the bayonet distance of the magnetic core, and improve the detection precision of the magnetic induction intensity of the sensor.

6. The external steel bar corrosion in-situ nondestructive monitoring test device based on the electromagnetic field principle as claimed in claim 1 or 2, wherein the magnetic induction intensity detection unit is externally arranged on the reinforced concrete column so as to realize recycling and dynamic monitoring.

7. The external steel bar corrosion in-situ nondestructive monitoring test device based on the electromagnetic field principle as claimed in claim 1 or 2, wherein the data processing unit comprises a control coil working current, and magnetic induction intensity values of the first hall sensor and the second hall sensor are measured so as to calculate the corrosion rate, and the magnetic induction intensity measuring system and the data processing system complete data storage, post-processing and real-time display through a signal processor and a central controller.

8. The external steel bar corrosion in-situ nondestructive monitoring test device based on the electromagnetic field principle as claimed in claim 1 or 2, wherein in the three-dimensional precise positioning and moving system, the bottom base is provided with a dial scale for testers to visually and accurately measure the coordinate values of the left and right directions of the reinforced concrete test piece; scales are arranged on the upper and lower polish rods, so that a tester can visually and accurately measure coordinate values of the reinforced concrete test piece in the upper and lower directions; the front and rear polished rods are provided with scales for testing personnel to visually and accurately measure the coordinate values of the reinforced concrete test piece in the front and rear directions.

9. The external steel bar corrosion in-situ nondestructive monitoring test device based on the electromagnetic field principle as claimed in claim 1 or 2, wherein in the three-dimensional precise positioning and moving system, an arc-shaped space is reserved on the left side of the connecting block to allow the left part of the claw shell and the rotary key to move when extending and retracting, the connecting block is fixedly connected with the claw shell, the left part of the claw shell is fixedly connected with the rotary key, the claw shell is provided with a left through hole and a right through hole, wherein the left part and the right part of the claw shell are connected with a fifth locking nut through a second dome screw rod and a bolt, and the extension and retraction length of the clamping claw is controlled by controlling the screwing depth of the fifth locking nut; the effective clamping area of the clamping claw unit has a circular section with the diameter of 6-25 mm, so that reinforcing steel bars with different diameters can be firmly clamped; the left and right sides of the I-shaped sliding block are provided with threaded through holes; the bottom base is made of pig iron or other high-density materials, so that the whole device is prevented from tilting forward due to overweight of a large reinforced concrete test piece; the rear part of the connecting block is provided with a threaded hole and is connected with the square rotating block and the front-back and fixing unit through a third screw and a third locking nut; the claw shell and the rotary key are provided with upper and lower thread through holes, and the rotary key and the claw shell are connected through a first round top screw and a fourth locking nut bolt; the third locking nut locks the rotating block connected with the front rotatable threaded rod to drive the clamping claw unit and the reinforced concrete test piece to rotate so as to ensure that the edge of the reinforced concrete test piece is embedded into the sensor bayonet; the left and right precession bearings can control the precession depth through the left and right precession handles, so that the operation of a tester is facilitated; the two sides of the arc-shaped fixing clamp are respectively provided with a fixing surface and a threaded hole, and the fixing surface, the first screw rod and the second screw rod are in close contact with the upper and lower polish rods and the front and rear polish rods through the threaded holes so that the arc-shaped fixing clamp is fixed with the upper and lower polish rods and the front and rear polish rods; after the first screw rod and the second screw rod are screwed out, the arc-shaped fixing clamp can move up and down along the upper polish rod and the lower polish rod, and the front polish rod and the rear polish rod can move back and forth along the first arc-shaped fixing clamp; the arc-shaped fixing clamp is fixedly connected with the first arc-shaped fixing clamp and the second arc-shaped fixing clamp in a mutually perpendicular mode, and a space is reserved for the first arc-shaped fixing clamp, the second arc-shaped fixing clamp and the front and rear polished rods to move.

10. The testing method of the external steel bar corrosion in-situ nondestructive testing device based on the electromagnetic field principle as claimed in claim 1, characterized by comprising the following steps:

firstly, preparing a reinforced concrete test piece before testing, wherein the process is as follows:

1.1 taking the smooth round steel bar with set length and diameter as a calibration steel bar and a steel bar to be measured, weighing the mass m of the steel bar to be measured_1I，m_2I，m_3I，m_4I，m_5I，m_6I，m_7IAnd calibrating the steel bar mass m₀And record；

1.2 coating epoxy resin on the positions 5cm away from the two ends of the calibration steel bar and the steel bar to be detected, placing the epoxy resin in a mold, casting and molding, and soaking the cast and molded reinforced concrete test piece and the reinforced concrete test piece to be detected in a standard salt concentration solution until the samples are saturated with salt, wherein the concentration of the standard sodium chloride solution is 0.1-2 mol/L;

second, preparation before measurement, as follows:

2.1 uniformly winding an enameled copper wire in the same direction around a magnetic core to form a coil, mounting a first Hall sensor and a second Hall sensor in a first Hall sensor placing groove and a second Hall sensor placing groove of a packaging shell, then electrifying to form a uniform electromagnetic field, and covering a sealing cover for packaging;

2.2 after installing the left-right moving and fixing unit, the up-down moving and fixing unit, the front-back moving and fixing unit and the clamping claw unit, screwing in a fifth locking nut, reserving a space on the left side of the connecting block to allow the left part of the claw shell and the rotary key to rotate when being stretched, and allowing the left part of the claw shell and the rotary key to simultaneously rotate when the fifth locking nut is screwed in, so that the left part of the claw shell is stretched, and the stretching effect of the clamping claw is achieved, and the reinforced concrete test piece is clamped;

2.3, screwing out the first screw rod, wherein the arc-shaped fixing clamp can move up and down along the upper and lower polish rods, so that the reinforced concrete test piece can move up and down; the second screw rod is screwed out, and the front and rear polish rods can move back and forth along the first arc-shaped fixing clamp, so that the reinforced concrete test piece can move back and forth; the bottom base is provided with an inverted T-shaped hole for the I-shaped sliding block to slide left and right in the bottom base, the I-shaped sliding block is in threaded connection with the left and right precession bearings, and the left and right precession bearings are controlled by operating the left and right precession handles to drive the I-shaped sliding block to move left and right, so that the reinforced concrete test piece moves left and right; moving the reinforced concrete test piece to the center of a bayonet of a magnetic core of the sensor by moving left and right, moving up and down and moving back and forth, establishing an x axis in the front and back directions, establishing a y axis in the left and right directions, establishing a z axis in the up and down directions, and respectively arranging scales on the bottom base, the upper and lower polish rods and the front and back polish rods so as to allow a tester to visually and accurately measure three-dimensional coordinate values (x, y and z) of the reinforced concrete test piece, and keeping the x, y and z coordinates unchanged when the replacement test piece is taken down in a later test, thereby realizing in-situ corrosion monitoring of the reinforced;

2.4 controlling the collection frequency of the signal collector and the current of the signal generator through the central controller, and electrifying the test magnetic field to ensure that the gauss values of the magnetic induction intensity of the first Hall sensor are the same as that of the second Hall sensor;

thirdly, a calibration test is carried out, and the process is as follows:

3.1 recording mass m_1I，m_2I，m_3I，m_4I，m_5I，m_6I，m_7ICorresponding magnetic induction intensity data B of calibration reinforcing steel bar before corrosion of reinforced concrete test piece_1I，B_2I，B_3I，B_4I，B_5I，B_6I，B_7I；

3.2 realize the simulation experiment of reinforcing bar corrosion with the mode of corrosion is accelerated to the electric current, and control current density is the same, and the quality is m_1I，m_2I，m_3I，m_4I，m_5I，m_6I，m_7IThe corresponding reinforced concrete test pieces are electrified at equal intervals t₁，t₂，t₃，t₄，t₅，t₆，t₇Day;

3.3 recording the magnetic induction intensity data B of the calibration steel bar after the reinforced concrete test piece is corroded_1II，B_2II，B_3II，B_4II，B_5II，B_6II，B_7IIAnd steel bar quality data m_1II，m_2II，m_3II，m_4II，m_5II，m_6II，m_7II；

3.4 respectively calculating and calibrating the change rate Delta m of the steel bar quality₁，△m₂，△m₃，△m₄，△m₅，△m₆，△m₇The calculation formulas are respectively formulas (1) to (7);

3.5 respectively calculating and calibrating the magnetic induction intensity change rate Delta B of the steel bars₁，△B₂，△B₃，△B₄，△B₅，△B₆，△B₇The calculation formulas are respectively the formulas (8) to (14)

3.6, carrying out linear fitting on the relationship between the change rate of the steel bar mass and the change rate of the magnetic induction intensity of the Hall sensor to obtain a linear relationship coefficient alpha;

step four, measuring the test, the process is as follows:

4.1 recording the magnetic induction intensity B before the piece to be tested is rusted_0I；

4.2 placing the reinforced concrete to be tested in an environment which is easy to cause the reinforcing steel bars to be corroded so as to promote the reinforcing steel bars to be corroded;

4.3 the corroded test piece to be tested is put back to the original position, and the magnetic induction intensity B after the steel bar is corroded is recorded_0II；

4.4 Corrosion Rate p of Steel bars_IIThe calculation formula is formula (15)

P_II＝α(B_0II-B_0I) (15)。

Technical Field

The invention relates to a steel bar corrosion monitoring technology in building engineering, in particular to an external steel bar corrosion in-situ nondestructive monitoring test device and a test method based on an electromagnetic field principle.

Background

The reinforced concrete structure combines the characteristics of tensile strength and compression strength of the reinforced steel bar, and has become the most widely applied structural form in the world due to the characteristics of low cost, wide material sources, convenience in construction and the like since the reinforced concrete structure is applied to the field of civil engineering in the middle of 19 th century. The damage caused by the failure of the durability of the concrete is huge for a long time and far exceeds the expectation of people, and the damage becomes a worldwide problem. The steel bar corrosion is the most serious in the cause of the durability damage of the concrete, and the method has attracted wide attention at home and abroad. A great deal of research is also made by the predecessors aiming at the research of the detection of the corrosion of the steel bar in the construction engineering.

At present, the monitoring method of the steel bar corrosion is divided into damage detection and nondestructive detection. The damage detection measurement result is more accurate, but need to carry out the broken type to reinforced concrete and take out the reinforcing bar, the harm that causes the concrete structure is irreversible, is just being not suitable for the reinforced concrete structure in service period. The nondestructive testing method is a hotspot of current research, and mainly comprises a half-cell potential method, an acoustic emission technology and a built-in monitoring technology. The half-cell potential method utilizes the potential change caused by the electrochemical reaction of the steel bar corrosion to determine the steel bar corrosion state, but the accuracy is lower, the probability of the steel bar corrosion can be only determined qualitatively, and no unified determination standard exists; the acoustic emission technology can only qualitatively judge the corrosion occurrence probability according to parameters such as accumulated impact number and the like, and can not quantitatively measure the corrosion rate of the steel bar; a steel bar corrosion monitoring method based on a magnetic field principle is disclosed in Chinese patent grant No. CN109374726A, wherein the grant date is 2019, 2 and 22 days, and the name is 'a steel bar corrosion nondestructive dynamic monitoring sensor and system in concrete based on a magnetic field'; the two patents provide a steel bar corrosion monitoring sensor applied to built-in concrete and used for monitoring the steel bar corrosion condition of the built-in concrete, but the built-in monitoring sensor can seriously influence the mechanical property of the reinforced concrete and the natural corrosion rule of the steel bar; and the sensor is arranged in the concrete and can only be used once, so that the cost is higher. The Chinese patent is entitled "monitoring equipment and method for steel bar corrosion behavior in concrete" with an authorization publication number CN108469514A, the publication date is 2018, 8 and 31, and the sensor related to the patent has the following defects: firstly, although the sensor can measure the corrosion condition of the steel bar, the sensor can only qualitatively judge the corrosion condition of the whole steel bar in the concrete and cannot judge the corrosion condition of a single steel bar, and the corrosion conditions of the steel bar in the concrete in actual engineering are different, so that the corrosion condition of the single steel bar needs to be measured; secondly, the test results of the inventor prove that the influence of different positions of the steel bars on the response condition of the Hall sensor is far larger than the influence of corrosion of the steel bars, so that the error is larger under the condition that the steel bars cannot ensure in-situ monitoring; thirdly, the Hall sensors are arranged in a single linear direction, and the method cannot effectively monitor the change rule of the position of the steel bar; fourthly, the actual concrete column is large in size, the whole reinforced concrete column needs to be clamped effectively in the patent test, the required magnetic core bayonet is large, and the increase of the bayonet can cause the detection sensitivity of the Hall sensor to be reduced through the test result of the inventor; meanwhile, the steel bar corrosion monitoring systems related to the three patents lack effective three-dimensional positioning and moving devices, and can not realize steel bar in-situ corrosion monitoring, and the inventor tests prove that the relative position movement of a steel bar and a sensor bayonet can cause the change of magnetic induction intensity, and the monitoring of the steel bar corrosion also takes the change value of the magnetic induction intensity as a basis, so that the steel bar has larger error under the condition that the in-situ monitoring can not be ensured; in summary, the measurement results of the sensors in the above three patents cannot reflect the real corrosion situation of the steel bar, and accurate and reliable data cannot be obtained to predict the corrosion degree of the steel bar under different situations.

In the actual building engineering, an external in-situ monitoring test device and a test method for accurately measuring the corrosion rate of the steel bars still do not exist.

Therefore, the external nondestructive dynamic steel bar corrosion monitoring test device and the test method which have the advantages of clear principle, simple and convenient method, high determination speed, repeated use, strong engineering applicability, good stability and the like are found, and the improvement has important significance for continuously and deeply evaluating and predicting the steel bar corrosion degree.

Disclosure of Invention

In order to overcome the defects of the existing nondestructive monitoring technology for the corrosion of the steel bar in the constructional engineering, the invention provides a monitoring technology which has high stability and simple and convenient operation and can realize the external steel bar corrosion in-situ monitoring, in particular to the steel bar corrosion in-situ monitoring technology based on the electromagnetic field principle: externally arranged outside the reinforced concrete structure; the bayonet of the magnetic core is designed into a trapezoidal bayonet, so that the reinforced concrete square column can be effectively clamped, and the corrosion condition of a single detection reinforcing steel bar at the corner of the reinforced concrete square column can be effectively detected; the electromagnetic field intensity is changed by controlling the current of the coil and the number of turns of the coil, so that the air field magnetic leakage influence caused by the change of the bayonet distance of the magnetic core is reduced, and the detection precision of the magnetic induction intensity of the Hall sensor is improved so as to adapt to reinforced concrete square columns with different sizes; the position of the steel bar is accurately detected through the symmetrical arrangement of the Hall sensors; the three-dimensional accurate positioning and moving of the reinforcing steel bar can be realized.

In order to solve the technical problems, the invention provides the following technical scheme:

an external steel bar corrosion in-situ nondestructive monitoring test device based on an electromagnetic field principle comprises a sensor system and a three-dimensional accurate positioning and moving system.

The sensor system comprises a magnetic induction intensity detection unit and a data processing unit; the magnetic induction intensity detection unit comprises a signal generator, a coil, a magnetic core, a packaging shell, a first Hall sensor and a second Hall sensor, wherein the coil is uniformly wound on the magnetic core, and two ends of the coil are electrically connected with a signal input end of the signal generator; the middle position of the reinforced concrete test piece clamped by the fixing unit corresponds to the middle position of the bayonet of the magnetic core; the packaging shell comprises a first Hall sensor placing groove, a second Hall sensor placing groove and a sealing cover; the first Hall sensor and the second Hall sensor are symmetrically arranged by taking a bayonet center line as an axis and are respectively arranged in a first Hall sensor placing groove and a second Hall sensor placing groove of the packaging shell; the data processing unit comprises a signal collector, a signal processor and a central controller, wherein the input end of the signal collector is electrically connected with the signal output ends of the first Hall sensor and the second Hall sensor, the signal output end of the signal generator and the output end of the signal collector are respectively electrically connected with the signal input end of the signal processor, and the signal output end of the signal processor is electrically connected with a port of the central controller.

The three-dimensional accurate positioning and moving system comprises a left-right moving and fixing unit, an up-down moving and fixing unit, a front-back moving and fixing unit and a clamping claw unit; the left-right moving and fixing unit comprises a left-right precession handle, a left-right precession bearing, an I-shaped sliding block, a bottom base and an upper polish rod and a lower polish rod; the screw-in handle is provided with a threaded hole, and the threaded hole is in threaded connection with the left screw-in bearing and the right screw-in bearing; the bottom base is provided with a dial scale for a tester to observe the left-right movement length of the reinforced concrete test piece, the bottom base is provided with an inverted T-shaped hole for an I-shaped sliding block to slide left and right in the bottom base, and the I-shaped sliding block is fixedly connected with a left-right precession bearing, an upper polish rod and a lower polish rod; the up-down moving and fixing unit comprises a first arc-shaped fixing clamp, an upper polish rod, a lower polish rod, a first screw rod and a first locking nut; the left side and the right side of the first arc-shaped fixing clamp are respectively provided with a fixing surface and a threaded hole, the first screw rod is connected with the first locking nut bolt through the threaded hole, and the fixing surface of the first arc-shaped fixing clamp and the first screw rod are in close contact with the left surface and the right surface of the upper polish rod and the lower polish rod; the front-back moving and fixing unit comprises a second arc-shaped fixing clamp, a second screw rod, a second locking nut and a front polish rod and a rear polish rod; the right side and the left side of the second arc-shaped fixing clamp are respectively provided with a fixing surface and a threaded hole, the second screw rod and the second locking nut are connected through the threaded hole by bolts, and the fixing surface of the second arc-shaped clamp and the second screw rod are in close contact with the left surface and the right surface of the front polished rod and the rear polished rod; the clamping jaw unit comprises a third screw rod, a third locking nut, a first dome screw rod, a second dome screw rod, a fourth locking nut, a fifth locking nut, a square rotating block, a jaw shell and a jaw accessory; the claw fittings comprise a left claw, a right claw, a rotary key and a connecting block, and the left claw and the right claw are fixedly connected with the claw shell.

Further, the first Hall sensor and the second Hall sensor are symmetrically arranged.

Still further, the magnetic core is a trapezoidal bayonet.

Furthermore, the signal generator can stably control the current of the coil.

The magnetic core is made of silicon steel.

The packaging shell is made of plastic materials.

The signal collector and the signal generator are respectively provided with a first indicator light and a second indicator light of a circuit, and the first indicator light and the second indicator light respectively prompt whether the signal collector and the signal generator work normally or not.

The Hall sensors can be symmetrically arranged in one or more pairs according to the precision requirement and the actual engineering requirement.

The bottom base is provided with a dial for a tester to visually and accurately measure the coordinate value of the left and right directions of the reinforced concrete test piece.

The upper and lower polished rods are provided with scales for testing personnel to visually and accurately measure coordinate values of the reinforced concrete test piece in the up-down direction.

The front and rear polished rods are provided with scales for testing personnel to visually and accurately measure the coordinate values of the reinforced concrete test piece in the front and rear directions.

The claw shell is provided with a left through hole and a right through hole, wherein the left part and the right part of the claw shell are connected with a fifth locking nut through a second round top screw rod, and the telescopic length of the clamping claw is controlled by controlling the screwing depth of the fifth locking nut.

And an arc-shaped space is reserved on the left side of the connecting block so that the left part of the claw shell and the rotary key can move when stretching.

And threaded through holes are formed on the left and the right of the I-shaped sliding block.

The bottom base is made of pig iron or other high-density materials, so that the whole device is prevented from inclining forwards due to the fact that a large reinforced concrete test piece is too heavy.

The connecting block is fixedly connected with the claw shell.

And the rear part of the connecting block is provided with a threaded hole and is connected with the square rotating block, the front-back moving and fixing unit through a third screw and a third locking nut.

The claw shell and the rotary key are provided with upper and lower thread through holes, and the rotary key and the claw shell are connected through a first round top screw rod and a fourth locking nut bolt.

The left part of the claw shell is fixedly connected with the rotary key.

As an improvement, the magnetic core bayonet of the magnetic induction intensity detection unit is trapezoidal, can be firmly clamped at the corner of a reinforced concrete square column to complete the corrosion monitoring of a single detection reinforcing steel bar, and can clamp reinforced concrete columns with different sizes according to the embedding depth or the distance change of the magnetic core bayonet.

As an improvement, the uniform electromagnetic field generated by the magnetic core of the magnetic induction intensity detection unit and the uniformly wound coil depends on the coil current and the number of turns of the coil, and is not demagnetized due to time change, so that the detection result is accurate.

As an improvement, the electromagnet consisting of the magnetic core of the magnetic induction intensity detection unit, the uniformly wound coil and the signal generator can change the magnetic field intensity by controlling the current of the coil and the number of turns of the coil, and the inventor tests prove that the air domain magnetic leakage influence caused by the change of the bayonet distance of the magnetic core can be effectively reduced by changing the magnetic field intensity, and the magnetic induction intensity detection precision of the sensor is improved.

As an improvement, the magnetic induction intensity detection unit is externally arranged on the reinforced concrete column, so that the repeated utilization and dynamic monitoring are realized.

As an improvement, the first Hall sensor and the second Hall sensor of the magnetic induction intensity detection unit are symmetrically arranged by taking a bayonet center line as an axis, and the test result of the inventor proves that the position of the steel bar can be accurately detected.

As an improvement, the data processing unit and related control circuits of the data processing unit can be realized by using the existing mature technology, and the data processing unit mainly comprises a control coil, a first Hall sensor and a second Hall sensor, wherein the magnetic induction intensity values of the first Hall sensor and the second Hall sensor are measured, so that the corrosion rate is calculated. The magnetic induction intensity measuring system and the data processing system finish data storage, post-processing and real-time display through the signal processor and the central controller.

As an improvement, the clamping claw unit provided by the invention has a circular section with the effective clamping area diameter of 6-25 mm, and can firmly clamp reinforcing steel bars with different diameters.

As an improvement, the bottom base, the upper and lower polish rods and the front and rear polish rods are respectively provided with scales, so that a tester can visually and accurately measure the length values of the left, right, up, down and front and rear movement of the reinforced concrete test piece, and a three-dimensional coordinate value is established so as to monitor and position the reinforced concrete test piece in situ.

As an improvement, the left side of the connecting block is provided with a space for the left part of the claw shell and the rotary key to rotate when being stretched, and the left part of the claw shell and the rotary key can simultaneously rotate when being stressed, so that the left part of the claw shell is stretched, and the effect of stretching and retracting the clamping claw is achieved.

As an improvement, the surface of the rotating block is smooth, and the rotating block connected with the threaded rod can be rotated to drive the clamping claw unit and the reinforced concrete test piece to rotate before the third locking nut is locked, so that the edge of the reinforced concrete test piece is embedded into the sensor bayonet.

As an improvement, the left and right precession bearings can control the precession depth through the left and right precession handles, and are convenient for test personnel to operate.

As an improvement, the two sides of the arc-shaped fixing clamp are respectively provided with a fixing surface and a threaded hole, and the fixing surface, the first screw rod and the second screw rod are in close contact with the upper polish rod, the lower polish rod, the front polish rod and the rear polish rod through the threaded holes, so that the arc-shaped fixing clamp is fixed with the upper polish rod, the lower polish rod, the front polish rod and the rear polish rod.

As an improvement, after the first screw rod and the second screw rod are screwed out, the arc-shaped fixing clamp can move up and down along the upper polish rod and the lower polish rod, and the front polish rod and the rear polish rod can move back and forth along the first arc-shaped fixing clamp.

As an improvement, the arc-shaped fixing clamp is formed by fixedly connecting a first arc-shaped fixing clamp and a second arc-shaped fixing clamp in a mutually vertical mode, and a space is reserved for the first arc-shaped fixing clamp, the second arc-shaped fixing clamp and the front and rear polished rods to move.

A testing method of an external steel bar corrosion in-situ nondestructive monitoring testing device based on an electromagnetic field principle comprises the following steps:

firstly, preparing a reinforced concrete test piece before testing, wherein the process is as follows:

1.1 taking the smooth round steel bar with set length and diameter as a calibration steel bar and a steel bar to be measured, weighing the mass m of the steel bar to be measured_1I，m_2I，m_3I，m_4I，m_5I，m_6I，m_7IAnd calibrating the steel bar mass m₀And recording;

1.2 coating epoxy resin on the positions 5cm away from the two ends of the calibration steel bar and the steel bar to be detected, placing the epoxy resin in a mold, casting and molding, and soaking the cast calibration reinforced concrete test piece and the cast reinforced concrete test piece in a standard salt concentration solution until saturated salt exists, wherein the concentration of the standard sodium chloride solution is 0.1-2 mol/L;

second, preparation before measurement, as follows:

2.1 uniformly winding an enameled copper wire in the same direction around a magnetic core to form a coil, mounting a first Hall sensor and a second Hall sensor in a first Hall sensor placing groove and a second Hall sensor placing groove of a packaging shell, then electrifying to form a uniform electromagnetic field, and covering a sealing cover for packaging;

2.2 after installing the left-right moving and fixing unit, the up-down moving and fixing unit, the front-back moving and fixing unit and the clamping claw unit, screwing in a fifth locking nut, reserving a space on the left side of the connecting block to allow the left part of the claw shell and the rotary key to rotate when being stretched, and allowing the left part of the claw shell and the rotary key to simultaneously rotate when the fifth locking nut is screwed in, so that the left part of the claw shell is stretched, and the stretching effect of the clamping claw is achieved, and the reinforced concrete test piece is clamped;

2.3, screwing out the first screw rod, wherein the arc-shaped fixing clamp can move up and down along the upper and lower polish rods, so that the reinforced concrete test piece can move up and down; the second screw rod is screwed out, and the front and rear polish rods can move back and forth along the first arc-shaped fixing clamp, so that the reinforced concrete test piece can move back and forth; the bottom base is provided with an inverted T-shaped hole for the I-shaped sliding block to slide left and right in the bottom base, the I-shaped sliding block is in threaded connection with the left and right precession bearings, and the left and right precession bearings are controlled by operating the left and right precession handles to drive the I-shaped sliding block to move left and right, so that the reinforced concrete test piece moves left and right; and moving the reinforced concrete test piece to the center of the bayonet of the sensor magnetic core through left-right movement, up-down movement and front-back movement. The x-axis is established in the front-back direction, the y-axis is established in the left-right direction, and the z-axis is established in the up-down direction. The bottom base, the upper and lower polish rods and the front and rear polish rods are respectively provided with scales for a tester to visually and accurately measure three-dimensional coordinate values (x, y, z) of the reinforced concrete test piece, and the x, y and z coordinates are kept unchanged when the replacement test piece is taken down in a later test, so that in-situ corrosion monitoring of the reinforced concrete test piece is realized;

2.4 controlling the collection frequency of the signal collector and the current of the signal generator through the central controller, and electrifying the test magnetic field to ensure that the gauss values of the magnetic induction intensity of the first Hall sensor are the same as that of the second Hall sensor;

thirdly, a calibration test is carried out, and the process is as follows:

3.1 recording mass m_1I，m_2I，m_3I，m_4I，m_5I，m_6I，m_7ICorresponding magnetic induction intensity data B of calibration reinforcing steel bar before corrosion of reinforced concrete test piece_1I，B_2I，B_3I，B_4I，B_5I，B_6I，B_7I；

3.2 realize the simulation experiment of reinforcing bar corrosion with the mode of corrosion is accelerated to the electric current, and control current density is the same, and the quality is m_1I，m_2I，m_3I，m_4I，m_5I，m_6I，m_7IThe corresponding reinforced concrete test pieces are electrified at equal intervals t₁，t₂，t₃，t₄，t₅，t₆，t₇；

3.3 recording reinforcing barMagnetic induction intensity data B of calibration reinforcing steel bar after concrete sample is corroded_1II，B_2II，B_3II，B_4II，B_5II，B_6II，B_7IIAnd steel bar quality data m_1II，m_2II，m_3II，m_4II，m_5II，m_6II，m_7II；

3.4 respectively calculating and calibrating the change rate Delta m of the steel bar quality₁，△m₂，△m₃，△m₄，△m₅，△m₆，△m₇The calculation formulas are respectively formulas (1) to (7);

3.5 respectively calculating and calibrating the magnetic induction intensity change rate Delta B of the steel bars₁，△B₂，△B₃，△B₄，△B₅，△B₆，△B₇The calculation formulas are respectively the formulas (8) to (14)

3.6, carrying out linear fitting on the relationship between the change rate of the steel bar mass and the change rate of the magnetic induction intensity of the Hall sensor to obtain a linear relationship coefficient alpha;

step four, measuring the test, the process is as follows:

4.1 recording the magnetic induction intensity B before the piece to be tested is rusted_0I；

4.2 placing the reinforced concrete to be tested in an environment which is easy to cause the reinforcing steel bars to be corroded so as to promote the reinforcing steel bars to be corroded;

4.3 the corroded test piece to be tested is put back to the original position, and the magnetic induction intensity B after the steel bar is corroded is recorded_0II；

4.4 Corrosion Rate p of Steel bars_IIThe calculation formula is formula (15)

P_II＝α(B_0II-B_0I) (15)。

The working principle of the invention is as follows: the Hall sensor detects the magnetic induction intensity of the magnetic induction intensity detection unit and sends the magnetic induction intensity to the signal processor, and the current of the magnetic induction intensity detection unit is controlled by the signal generator; the signal processor collects data of the signal generator and the signal collector according to the set frequency, calculates and analyzes the data, stores the collected data and the calculation result in the central controller in real time, and displays the analysis and calculation result in real time through the display screen. When the device is used specifically, after the left-right moving and fixing unit, the up-down moving and fixing unit, the front-back moving and fixing unit and the clamping claw unit are installed, a fifth locking nut is screwed in, a space is reserved on the left side of the connecting block, so that the left part of the claw shell and the rotary key can rotate when being stretched, the left part of the claw shell and the rotary key can simultaneously rotate when the fifth locking nut is screwed in, the left part of the claw shell is stretched, and the stretching effect of the clamping claw is achieved, so that a reinforced concrete test piece is clamped; the first screw rod is screwed out, and the arc-shaped fixing clamp can move up and down along the upper and lower polish rods, so that the reinforced concrete test piece can move up and down; the second screw rod is screwed out, and the front and rear polish rods can move back and forth along the first arc-shaped fixing clamp, so that the reinforced concrete test piece can move back and forth; the bottom base is provided with an inverted T-shaped hole for the I-shaped sliding block to slide left and right in the bottom base, the I-shaped sliding block is in threaded connection with the left and right precession bearings, and the left and right precession bearings are controlled by operating the left and right precession handles to drive the I-shaped sliding block to move left and right, so that the reinforced concrete test piece moves left and right; the bottom base, the upper and lower polish rods and the front and rear polish rods are respectively provided with scales so as to allow a tester to visually and accurately measure three-dimensional coordinate values of the reinforced concrete test piece after left and right, up and down and front and rear movement, and realize in-situ corrosion monitoring of the reinforced concrete test piece.

The invention has the beneficial effects that: the invention is based on a nondestructive testing method, and realizes the nondestructive monitoring of the corrosion of the steel bar by applying an electromagnetic induction technology, thereby calculating the corrosion rate of the steel bar according to a theoretical formula. The limit of the test stability, accuracy and use times of the traditional test method is broken through, and the test of the corrosion rate of the steel bar of the reinforced concrete test piece is realized; the measured corrosion rate of the steel bars can be applied to the evaluation of the current service performance and the prediction of the durability of the reinforced concrete structure. The device can accurately position the reinforced concrete test piece in three dimensions, and realize in-situ corrosion monitoring; the test object can be suitable for reinforcing steel bars and reinforced concrete square columns with different sizes, has the advantages of clear principle, simple and convenient method, high measuring speed, accurate positioning, repeated use, good stability and the like, and can make up the defect of the prior method and equipment for measuring the corrosion rate of the reinforcing steel bars.

Drawings

FIG. 1 is a schematic view of the structure of the apparatus of the present invention.

Fig. 2 is a front view of the clamping jaw unit of the present invention.

Fig. 3 is a top view of the clamping jaw unit of the present invention.

Fig. 4 is a front view of the arcuate retaining clip of the present invention.

Fig. 5 is a right side view of the arcuate retaining clip of the present invention.

Fig. 6 is a top view of the arcuate retaining clip of the present invention.

Fig. 7 is a top view of the left-right moving and fixing unit of the present invention.

Fig. 8 is a right side view of the left-right moving and fixing unit of the present invention.

Fig. 9 is a front view of the left-right moving and fixing unit of the present invention.

Fig. 10 is a three-dimensional schematic view of a connection block of the clamping jaw unit of the present invention.

Fig. 11 is a top view of a clamping jaw unit attachment block of the present invention.

Fig. 12 is a front view of a rotary key of the clamping jaw unit of the present invention.

Fig. 13 is a right side view of the rotary key of the clamping jaw unit of the present invention.

Fig. 14 is a top view of the rotary key of the clamping jaw unit of the present invention.

FIG. 15 is a schematic diagram of a front structure of a package cover according to the present invention.

Fig. 16 is a top view of the closure of the present invention.

Fig. 17 shows the detection result of the magnetic core bayonet enlarging sensor according to the present invention.

FIG. 18 shows the magnetic field amplified sensor results of the present invention.

Fig. 19 shows the x and y direction position detection test results of the hall sensor according to the present invention.

FIG. 20 shows the z-direction position detection test results of the Hall sensor according to the present invention.

FIG. 21 shows the results of the Hall sensor steel bar corrosion detection test.

Reference numbers in the figures: 1. a left and right screw-in handle; 2. a left and right precession bearing; 3. a bottom base; 4. an I-shaped slider; 5. an upper polish rod and a lower polish rod; 6-1, a first locking nut; 6-2, a second lock nut; 6-3, a third lock nut; 6-4, a fourth lock nut; 6-5, a fifth lock nut; 7. an arc-shaped fixing clip; 7-1, a first arc-shaped fixing clamp; 7-2, a second arc-shaped fixing clamp; 8. front and rear polished rods; 9-1, a first screw; 9-2, a second screw; 9-3 third screw; 10. rotating the block; 11-1, a first dome screw; 11-2, a second dome screw, 12, a claw shell; 13. a jaw fitting; 13-1, left paw; 13-2, right claw; 13-3, a rotating key; 13-4, connecting blocks; 14. a coil; 15. a magnetic core; 16-1, a first hall sensor; 16-2, a second hall sensor; 17. a signal generator; 18. a signal collector; 19. a data processor; 20. a central controller; 21-1, a first indicator light; 21-2, a second indicator light; 22. a package housing; 22-1, a first Hall sensor placing groove; 22-2, a second Hall sensor placing groove; 22-3 and sealing the cover.

Detailed Description

The present invention will be further described with reference to the accompanying drawings, wherein the terms "upper", "lower", "front", "rear", "left", "right", "bottom", and the like, as used herein, refer to an orientation or positional relationship based on that shown in the drawings, which is for convenience of description only and does not require that the invention be constructed and operated in a particular orientation, and therefore should not be construed as limiting the invention.

Referring to fig. 1 to 21, an external steel bar corrosion in-situ nondestructive monitoring test device test method based on an electromagnetic field principle, in example 1, taking an HPB300 smooth round steel bar with a diameter of 16mm as an example, includes the following steps:

firstly, preparing a reinforced concrete test piece before testing, wherein the process is as follows:

1.1 taking HPB300 smooth round steel bars with the length of 20cm and the diameter of 16mm as calibration steel bars and steel bars to be measured, weighing the steel to be measuredMass m of rib_1I，m_2I，m_3I，m_4I，m_5I，m_6I，m_7IAnd calibrating the steel bar mass m₀And recording;

1.2 coating epoxy resin at 5cm positions at two ends of the calibration steel bar and the steel bar to be detected in a mold and pouring for molding, wherein the concrete comprises the following raw materials: the cement is P.I 525 grade Portland cement, river sand with fineness modulus of 2.6 is adopted as the sand, continuous graded broken stone (the maximum grain diameter is 25mm) is adopted as coarse aggregate, tap water is adopted as water, the effective section size of a cast test piece in a standard die is 100mm multiplied by 100mm, the length of a steel bar is 200mm, the protruding length of the steel bars on two sides is 50mm, the length of the test piece is 100mm, the standard maintenance is carried out in a maintenance room for 28d after the cast molding is carried out, the calibrated reinforced concrete test piece and the reinforced concrete test piece to be tested after the cast molding are soaked in a standard salt concentration solution until the salt is saturated, and the concentration of the standard sodium chloride solution is 0.1-2 mol/L;

second, preparation before measurement, as follows:

2.1 uniformly and equidirectionally winding an enameled copper wire on the magnetic core 15 to form a coil 14, installing a first Hall sensor 16-1 and a second Hall sensor 16-2 on a first Hall sensor placing groove 22-1 and a second Hall sensor placing groove 22-2 of a packaging shell 22, then electrifying to form a uniform strong electromagnetic field, and covering a sealing cover 22-3 for packaging.

2.2 after installing the left-right moving and fixing unit, the up-down moving and fixing unit, the front-back moving and fixing unit and the clamping jaw unit, screwing in a fifth locking nut 6-5, reserving a space on the left side of a connecting block 13-4 to allow the left part of the jaw shell 12 and the rotary key 13-3 to rotate when being stretched, and allowing the left part of the jaw shell 12 and the rotary key 13-3 to simultaneously rotate when the fifth locking nut 6-5 is screwed in, so that the left part of the jaw shell 12 is stretched, and the effect of stretching the clamping jaw is achieved, and the reinforced concrete test piece is clamped.

2.3, the first screw rod 9-1 is screwed out, and the arc-shaped fixing clamp 7 can move up and down along the upper polish rod 5 and the lower polish rod 5, so that the reinforced concrete test piece moves up and down; the second screw rod 9-2 is screwed out, and the front and rear polish rods 8 can move back and forth along the first arc-shaped fixing clamp 7-1, so that the reinforced concrete test piece can move back and forth; the bottom base 3 is provided with an inverted T-shaped hole for the I-shaped sliding block 4 to slide left and right in the bottom base 3, the I-shaped sliding block 4 is in threaded connection with the left and right precession bearings 2, and the left and right precession bearings 2 are controlled by operating the left and right precession handles 1 to drive the I-shaped sliding block 4 to move left and right, so that the reinforced concrete test piece moves left and right; the reinforced concrete test piece is moved to the center of the bayonet 15 of the magnetic core of the sensor through left-right movement, up-down movement and front-back movement. The x-axis is established in the front-back direction, the y-axis is established in the left-right direction, and the z-axis is established in the up-down direction. The bottom base 3, the upper and lower polish rods 5 and the front and rear polish rods 8 are respectively provided with scales for testing personnel to visually and accurately measure three-dimensional coordinate values (x, y, z) of the reinforced concrete test piece to be (30,41,20), and the x, y and z coordinates are kept unchanged when the replacement test piece is taken down in the later test, so that in-situ corrosion monitoring of the reinforced concrete test piece is realized.

2.4 the central controller 9 controls the collection frequency of the signal collector 6 and the current of the signal generator 7, and the magnetic field is electrified and tested, so that the magnetic induction intensity gauss values of the first Hall sensor 1-1 and the second Hall sensor 1-2 are ensured to be the same.

Thirdly, a calibration test is carried out, and the process is as follows:

3.1 recording mass m_1I，m_2I，m_3I，m_4I，m_5I，m_6I，m_7ICorresponding magnetic induction intensity data B of calibration reinforcing steel bar before corrosion of reinforced concrete test piece_1I，B_2I，B_3I，B_4I，B_5I，B_6I，B_7I；

3.2 simulation experiment of reinforcing steel bar corrosion is realized in a mode of current-accelerated corrosion, the current density is controlled to be the same as the electrifying time, and the mass is m_1I，m_2I，m_3I，m_4I，m_5I，m_6I，m_7IElectrifying the corresponding reinforced concrete test pieces for 1 day, 2 days, 3 days, 4 days, 5 days, 6 days and 7 days respectively;

3.3 recording the magnetic induction intensity data B of the calibration steel bar after the reinforced concrete test piece is corroded_1II，B_2II，B_3II，B_4II，B_5II，B_6II，B_7IIAnd steel bar quality data m_1II，m_2II，m_3II，m_4II，m_5II，m_6II，m_7II；

3.4 respectively calculating and calibrating the change rate Delta m of the steel bar quality₁，△m₂，△m₃，△m₄，△m₅，△m₆，△m₇The calculation formulas are respectively formulas (1) to (7);

3.5) respectively calculating and calibrating the magnetic induction intensity change rate Delta B of the steel bars₁，△B₂，△B₃，△B₄，△B₅，△B₆，△B₇The calculation formulas are respectively the formulas (8) to (14)

3.6, carrying out linear fitting on the relationship between the change rate of the steel bar mass and the change rate of the magnetic induction intensity of the Hall sensor to obtain a linear relationship coefficient alpha;

step four, measuring the test, the process is as follows:

4.1 recording the magnetic induction intensity B before the piece to be tested is rusted_0I；

4.2 placing the reinforced concrete to be tested in an environment which is easy to cause the reinforcing steel bars to be corroded so as to promote the reinforcing steel bars to be corroded;

4.3 the corroded test piece to be tested is put back to the original position, and the magnetic induction intensity B after the steel bar is corroded is recorded_0II；

4.4 Corrosion Rate p of Steel bars_IIThe calculation formula is formula (15)

P_II＝α(B_0II-B_0I) (15)。

An external steel bar corrosion in-situ nondestructive monitoring test device based on an electromagnetic field principle comprises a sensor system and a three-dimensional accurate positioning and moving system;

the sensor system comprises a magnetic induction intensity detection unit and a data processing unit; the magnetic induction intensity detection unit comprises a signal generator 17, a coil 14, a magnetic core 15, a packaging shell 22, a first Hall sensor 16-1 and a second Hall sensor 16-2, wherein the coil 14 is uniformly wound on the magnetic core 15, and two ends of the coil 14 are electrically connected with a signal input end of the signal generator 17; the middle position of the reinforced concrete test piece corresponds to the middle position of the bayonet of the magnetic core 15; the packaging shell 22 comprises a first Hall sensor placing groove 22-1, a second Hall sensor placing groove 22-2 and a sealing cover 22-3; the first Hall sensor 16-1 and the second Hall sensor 16-2 are symmetrically arranged by taking a bayonet central line as an axis, and are respectively arranged in a first Hall sensor placing groove 22-1 and a second Hall sensor placing groove 22-2 of the packaging shell 22; the data processing unit comprises a signal collector 18, a signal processor 19 and a central controller 20, wherein the input end of the signal collector 18 is electrically connected with the signal output ends of the first hall sensor 16-1 and the second hall sensor 16-2, the signal output end of the signal generator 17 and the output end of the signal collector 18 are respectively electrically connected with the signal input end of the signal processor 19, and the signal output end of the signal processor 19 is electrically connected with a port of the central controller 20;

the three-dimensional accurate positioning and moving system comprises a left-right moving and fixing unit, an up-down moving and fixing unit, a front-back moving and fixing unit and a clamping claw unit; the left-right moving and fixing unit comprises a left-right precession handle 1, a left-right precession bearing 2, an I-shaped sliding block 4, a bottom base 3 and an upper polish rod and a lower polish rod 5; the screw-in handle is provided with a threaded hole which is in threaded connection with the left and right screw-in bearings 2; the bottom base 3 is provided with a dial scale for a tester to observe the left-right movement length of the reinforced concrete test piece, the bottom base is provided with an inverted T-shaped hole for an I-shaped sliding block 4 to slide left and right in the bottom base, and the I-shaped sliding block 4 is fixedly connected with a left-right precession bearing 2 and an upper polish rod 5 and a lower polish rod 5; the up-down moving and fixing unit comprises a first arc-shaped fixing clamp 7-1, an upper polish rod 5, a lower polish rod 5, a first screw rod 9-1 and a first locking nut 6-1; the left side and the right side of the first arc-shaped fixing clamp 7-1 are respectively provided with a fixing surface and a threaded hole, the first screw 9-1 is in bolt connection with the first locking nut 6-1 through the threaded hole, and the fixing surface of the first arc-shaped fixing clamp 7-1 and the first screw 9-1 are in close contact with the left surface and the right surface of the upper polish rod 5 and the lower polish rod 5; the back-and-forth moving and fixing unit comprises a second arc-shaped fixing clamp 7-2, a second screw 9-2, a second locking nut 6-2 and a front and a rear polished rods 8; the right side and the left side of the second arc-shaped fixing clamp 7-2 are respectively provided with a fixing surface and a threaded hole, the second screw 9-2 and the second locking nut 6-2 are connected through the threaded hole by bolts, and the fixing surface of the second arc-shaped clamp 7-2 and the second screw 9-2 are in close contact with the left surface and the right surface of the front polished rod 8 and the rear polished rod 8; the clamping jaw unit comprises a third screw rod 9-3, a third locking nut 6-3, a first dome screw rod 11-1, a second dome screw rod 11-2, a fourth locking nut 6-4, a fifth locking nut 6-5, a square rotating block 10, a jaw shell 12 and a jaw accessory 13; the claw fittings comprise a left claw 13-1, a right claw 13-2, a rotary key 13-3 and a connecting block 13-4, and the left claw 13-1 and the right claw 13-2 are fixedly connected with a claw shell 12.

Further, the first Hall sensor 16-1 and the second Hall sensor 16-2 are symmetrically arranged.

Still further, the magnetic core 15 is a trapezoidal bayonet.

Furthermore, the signal generator 17 can stably control the current magnitude of the coil 14.

The magnetic core 15 is made of silicon steel.

The package housing 22 is made of plastic.

The signal collector and the signal generator are respectively provided with a first indicator light 21-1 and a second indicator light 21-2 of a circuit, and the first indicator light 21-1 and the second indicator light 21-2 respectively prompt whether the signal collector 18 and the signal generator 17 work normally or not.

The Hall sensors can be symmetrically arranged in one or more pairs according to the precision requirement and the actual engineering requirement.

The bottom base 3 is provided with a dial for a tester to visually and accurately measure the coordinate value of the left and right directions of the reinforced concrete test piece.

The upper and lower polish rods 5 are provided with scales for the tester to visually and accurately measure the coordinate values of the reinforced concrete test piece in the up-down direction.

The front and rear polish rods 8 are provided with scales for testing personnel to visually and accurately measure the coordinate values of the reinforced concrete test piece in the front and rear directions.

The claw shell 12 is provided with a left through hole and a right through hole, wherein the left part and the right part of the claw shell 12 are connected through a second dome screw rod 11-2 and a fifth locking nut 6-5 through bolts, and the telescopic length of the clamping claw is controlled by controlling the screwing depth of the fifth locking nut 6-5.

As an improvement, the clamping claw unit provided by the invention has a circular section with the effective clamping area diameter of 6-25 mm, and can firmly clamp reinforcing steel bars with different diameters.

An arc-shaped space is reserved on the left side of the connecting block 13-4, so that the left part of the claw shell 12 and the rotary key 13-3 can move when being stretched.

The left and right sides of the I-shaped sliding block 4 are provided with threaded through holes.

The bottom base 3 is made of pig iron or other high-density materials, so that the whole device is prevented from inclining forwards due to the fact that a large reinforced concrete test piece is too heavy.

The connecting block 13-4 is fixedly connected with the claw shell 12.

The rear part of the connecting block 13-4 is provided with a threaded hole which is connected with the square rotating block 10 and the front-back movement and fixing unit through a third screw 9-3 and a third locking nut 6-3.

The claw shell 12 and the rotary key 13-3 are provided with upper and lower thread through holes, and the rotary key 13-3 and the claw shell 12 are connected through a first dome screw 11-1 and a fourth lock nut 6-4 by bolts.

The left part of the claw shell 12 is fixedly connected with a rotary key 13-3.

As an improvement, the bayonet 15 of the magnetic core of the magnetic induction intensity detection unit is trapezoidal, can be firmly clamped at the corner of a reinforced concrete square column to complete the corrosion monitoring of a single detection reinforcing steel bar, and can clamp reinforced concrete columns with different sizes according to the embedding depth or the distance change of the bayonet of the magnetic core.

As an improvement, the uniform electromagnetic field generated by the magnetic core 15 and the uniformly wound coil 14 of the magnetic induction intensity detection unit depends on the current of the coil 14 and the number of turns of the coil, and is not demagnetized due to time change, so that the detection result is accurate.

As an improvement, the electromagnet consisting of the magnetic core 15, the uniformly wound coil 14 and the signal generator 17 of the magnetic induction intensity detection unit can change the magnetic field intensity by controlling the current of the coil 14 and the number of turns of the coil 14, and the test result of the inventor proves that the influence of air domain magnetic leakage caused by the change of the bayonet distance of the magnetic core 15 can be effectively reduced by changing the magnetic field intensity, and the magnetic induction intensity detection precision of the sensor is improved.

As an improvement, the clamping claw unit provided by the invention has a circular section with the effective clamping area diameter of 6-25 mm, and can firmly clamp reinforcing steel bars with different diameters.

As an improvement, the bottom base 3, the upper and lower polish rods 5 and the front and rear polish rods 8 are respectively provided with scales, so that a tester can visually and accurately measure the length values of the left, right, up, down and front and rear movement of the reinforced concrete test piece, and a three-dimensional coordinate value is established so as to facilitate the in-situ monitoring and positioning of the reinforced concrete test piece.

As an improvement, the left side of the connecting block 13-4 is provided with a space for the left part of the claw shell 12 and the rotary key 13-3 to rotate when stretching, and the left part of the claw shell 12 and the rotary key 13-3 can simultaneously rotate when being stressed, so that the left part of the claw shell 12 stretches, and the effect of clamping the claw to stretch is achieved.

As an improvement, the surface of the rotating block 10 is smooth, the rotating block 10 connected with a threaded rod can be rotated to drive the clamping claw unit and the reinforced concrete test piece to rotate before the third locking nut 6-3 locks, and the edge of the reinforced concrete test piece is ensured to be embedded into the sensor bayonet.

As an improvement, the left and right precession bearings 2 can control the precession depth through the left and right precession handles 1, and are convenient for a tester to operate.

As an improvement, the two sides of the arc-shaped fixing clamp 7 are respectively provided with a fixing surface and a threaded hole, and the fixing surface, the first screw 9-1 and the second screw 9-2 are tightly contacted with the upper polish rod 5, the lower polish rod 5, the front polish rod 8 and the rear polish rod 8 through the threaded holes, so that the arc-shaped fixing clamp 7 is fixed with the upper polish rod 5, the lower polish rod 5 and the front polish rod 8.

As an improvement, after the first screw rod 9-1 and the second screw rod 9-2 are screwed out, the arc-shaped fixing clamp 7 can move up and down along the upper polish rod 5 and the lower polish rod 5, and the front polish rod 8 and the rear polish rod 8 can move back and forth along the first arc-shaped fixing clamp 7-1.

As an improvement, the arc-shaped fixing clamp is formed by fixedly connecting a first arc-shaped fixing clamp 7-1 and a second arc-shaped fixing clamp 7-2 in a mutually vertical mode, and a space is reserved for the first arc-shaped fixing clamp 7-1, the second arc-shaped fixing clamp 7-2 and a front polished rod and a rear polished rod to move 8.