A protective rust monitoring system

Abstract

A protective rust monitoring system includes a first sensor and a second sensor; the first sensor includes an insulating layer, a ring-shaped PVDF sensor, a steel sheet, and a shielded wire. The first sensor is sleeved on the outer wall of the steel bar. The steel sheet includes an inner steel sheet and an outer steel sheet, both of which are ring-shaped. The PVDF sensor is wrapped by the insulating layer. The inner wall of the insulating layer is connected to the inner steel sheet, and the outer wall of the insulating layer is connected to the outer steel sheet. The shielded wire extends from the PVDF sensor, passes through the insulating layer and extends out of the first sensor, and then is introduced into the wire conduit; the first sensor is a circular ring structure with a notch; the PVDF sensor is a PVDF piezoelectric film sensor.

Description

Technical Field

[0001] The present invention relates to the field of the safety of reinforced concrete structures, and particularly relates to a protective rust monitoring system. Background Art

[0002] The rust of steel bars has a great impact on the durability and safety of concrete structures. Under the action of factors such as carbonation and chloride ion erosion, the pH value of the internal medium of concrete gradually decreases, and the passivation film formed on the surface of the steel bars in the alkaline medium will gradually be damaged and lose its protective effect, causing the rust of the steel bars. The rust of steel bars will not only affect the bonding performance between the steel bars and the concrete, but also cause the concrete cover to crack due to tension. Once the cracks occur, harmful substances will more easily enter the surface of the steel bars, thereby accelerating their rust. Rust will not only affect the service performance of the structure, but may even threaten the structural safety in severe cases. Therefore, it is necessary to monitor the rust of steel bars in concrete structures, discover problems in time and reduce the occurrence of accidents.

[0003] Especially for the reinforced concrete structure of the pier of a sea bridge, the rust phenomenon of the steel bars at the interface of water and air is more serious than that in pure water, pure air or underground. Therefore, it is essential to detect the rust safety of the steel bars in the reinforced concrete structure of the pier of a sea bridge.

[0004] In actual engineering practice, the following problems exist:

[0005] 1. For the detection of the rust of steel bars in the concrete structure in the prior art, generally a special laboratory or site is established, an outer shell or outer box is set outside the reinforced concrete structure, water is added to the outer box and other conditions are controlled to simulate the rust of the reinforced concrete structure caused by the water environment mentioned above. However, this kind of test requires a special site, water tank, installation cost and transportation cost.

[0006] 2. For the detection of the rust of steel bars in the reinforced concrete structure in the prior art, there are a large number of transportation links in the middle. Usually, the reinforced concrete structure taken from other places is transported to the laboratory. If the quality of the concrete is poor and there are cracks, the change of the environment during transportation is likely to cause the rust of the steel bars. When it is tested in the laboratory, the rust detection is actually inaccurate because it has already rusted before, and if it is taken out after being stored in the warehouse for a long time, the possibility of premature rust is even greater.

[0007] 3. For the existing technology of steel bar concrete pouring piles, there may be a casing around after the concrete pouring is completed, which is actually no problem. However, in the rust test of steel bars, the reinforced concrete structure needs to be in contact with water. Therefore, the casing must be removed. In order to be stable, some casings have penetrated deep into the ground and are not easy to remove. There is no effective method to balance stability and the test yet.

[0008] 4. The detachable structures in the prior art have a more flexible function, but are not as stable and strong as the integral structure. Specifically in the field of reinforced concrete cast-in-place piles, for the perfusion casing, its detachable structure will result in insufficient stability.

[0009] 5. When pouring reinforced concrete in the prior art, in the face of the falling concrete slurry, there is no good solution for how to keep the positions of the steel bars and some fittings.

[0010] 6. Most fiber Bragg grating sensors in the prior art are directly wound or pasted on the surface of the steel bars to be measured. Since the fiber Bragg grating sensors are in direct contact with the steel bars to be measured, the fiber Bragg grating sensors will inhibit or accelerate the corrosion of the steel bars in local areas. After the steel bars are corroded, it may also cause the sensors to fall off, both of which will affect the test accuracy. Moreover, civil engineering construction is rough, and the fiber Bragg grating sensors are fragile components, and it is easy to cause the bending radius of the embedded optical fiber to be too small during the concrete pouring process, resulting in sensor failure. In addition, the instrument equipment required for the fiber Bragg grating sensors is expensive and the cost is high. These factors all affect the wide application of the fiber Bragg grating sensors in the field of steel bar corrosion monitoring. Summary of the Invention

[0011] In order to overcome the above problems, the present invention proposes a solution to simultaneously solve the above-mentioned multiple problems.

[0012] The technical solution adopted by the present invention to solve its technical problems is: a protective corrosion monitoring system, including an outer pile hole, an inner pile hole, an outer casing, an inner casing, a sleeve, an arm, a wire conduit, a steel bar, a concrete column, a second sensor, a first sensor, a fixing ring, an electronic device, and a clamping jaw; the inner casing includes a lower casing and an upper casing; the outer casing includes an outer wall, a bottom wall, and a collar; wherein, the first sensor includes an insulating layer, a ring-shaped PVDF sensor, a steel sheet, and a shielded wire. The first sensor is sleeved on the outer wall of the steel bar. The steel sheet includes an inner steel sheet and an outer steel sheet. The inner steel sheet and the outer steel sheet are ring-shaped. The PVDF sensor is wrapped with the insulating layer. The inner wall of the insulating layer is connected to the inner steel sheet, and the outer wall of the insulating layer is connected to the outer steel sheet. The shielded wire extends from the PVDF sensor, passes through the insulating layer, extends out of the first sensor, and then is introduced into the wire conduit; the first sensor is a circular ring-shaped structure with a notch; the PVDF sensor is a PVDF piezoelectric film sensor.

[0013] Wherein, the outer pile hole is dug on the ground, and the inner pile hole is dug downward at the bottom of the outer pile hole. The lower casing is fixed in the inner pile hole. An upper convex ring is integrally provided above the lower casing, and a lower convex ring is integrally provided below the upper casing. The upper convex ring and the lower convex ring are detachably connected through a connecting member; the outer wall, the bottom wall, and the collar are integrally formed, and the collar is arranged above the bottom wall.

[0014] During the pouring stage, the outer casing is arranged in the outer pile hole, a through hole is arranged on the bottom wall for the inner casing to pass through, the upper casing and the lower casing are in a connected state, the sleeve is sleeved between the collar and the inner casing, the outer wall of the sleeve abuts against the inner wall of the collar, and the inner wall of the sleeve abuts against the upper casing and the lower casing at the same time; the inner wall of the upper casing is provided with an arm extending inward, and the end of the arm is provided with a clamping claw; the wire pipe is clamped by the clamping claw, and the outer wall of the steel bar is sleeved with a fixing ring, and the fixing ring and the wire pipe are fixedly connected by a connecting rod; after the concrete is poured, the clamped part of the wire pipe is exposed outside the concrete column, and the steel bar is completely buried in the concrete column;

[0015] During the testing phase, the upper casing and the sleeve are removed, water is injected between the outer casing and the concrete column, and a second sensor is also sleeved on the outer wall of the steel bar; the first sensor and the second sensor are connected to external electronic equipment via shielded wires inserted in the wire tube.

[0016] Preferably, the electronic device is a display device.

[0017] Preferably, a connecting tube is provided between the first sensor and the wire tube to accommodate the shielding wire.

[0018] Preferably, the second sensor is an annular resistance strain sensor.

[0019] Preferably, during the pouring stage, the upper end of the steel bar is lower than the upper end of the inner casing.

[0020] Preferably, during the pouring stage, the upper end of the wire tube is higher than the upper end of the inner casing.

[0021] Preferably, after pouring is completed, the arm and the clamping claw are exposed above the concrete column.

[0022] Preferably, the number of the first sensors is three, and the number of the fixing rings is two.

[0023] Preferably, the number of the second sensors is two.

[0024] Preferably, during the testing phase, the lower end of the wire tube is higher than the lower end of the steel bar.

[0025] The beneficial effects of the present invention are:

[0026] 1. Regarding the first point proposed in the background art, to solve the problem by using the existing site. When constructing the piers of a water bridge, reinforced concrete needs to be poured for each pier. The piers at both ends of the bridge are directly placed on the ground, and only the middle piers are placed underwater. For the piers on the ground, pile holes need to be drilled and the holes need to be cleared using a mud pit. The present invention utilizes the existing pile holes (or the positions where the pile holes are located) and mud pits. The existing pile holes (or the holes where the pile holes are located, with different diameters) are used to conduct corrosion tests on a small section of the reinforced concrete structure. The emptied mud pit is used as a water tank to realize water circulation, so that there is no need to specially set up a test site, a test outer box, and a test water storage tank. Based on the test holes, pile holes can be continuously drilled.

[0027] 2. Regarding the second point proposed in the background art, on-site pouring and testing are realized through the cooperation of the inner and outer casings. The inner casing can be used to realize on-site concrete pouring. After the pouring is completed, it can be removed. The poured concrete structure is fixed in the inner pile hole. There are steel bars in the concrete structure, and sensors are arranged on the outer surface of the steel bars. The outer casing can hold seawater to simulate the seawater environment. Therefore, after the pouring is completed, steel bar corrosion detection can be carried out to realize immediate detection and avoid premature corrosion of the steel bars due to a large number of transportation and storage links in the middle.

[0028] 3. Regarding the third point proposed in the background art, in order to remove the casing after the pouring is completed, the inner casing is set as an upper and lower casing, and the upper and lower casings are detachably connected. When the upper and lower casings are integrated, pile driving can be realized. After the pouring is completed, the connecting piece is disassembled, and the upper casing can be removed to expose the reinforced concrete structure to the water environment.

[0029] 4. Regarding the fourth point proposed in the background art, during the pouring operation, a sleeve is sleeved at the connection position of the upper and lower casings. A collar integrated with the outer casing is arranged on the outer periphery of the sleeve. Since the outer casing is stable, the collar is stable. The upper and lower casings are in contact with the collar through the sleeve, so stability can be achieved. During the test, the upper casing and the sleeve can be removed.

[0030] 5. Regarding the fifth point in the background art, clamping claws are arranged on the inner wall of the upper casing. The wire conduit is clamped by the clamping claws. A connecting rod is arranged between the wire conduit and the steel bar. The fixing ring on the connecting rod is fixed on the outer wall of the steel bar, so as to initially fix the positions of the steel bar and the wire conduit. After a certain amount of concrete is poured, the position of the steel bar is stable, and the clamping claws do not need to be stressed all the time. At this time, they only play a positioning role. After the pouring is completed, the steel bar is completely buried in the concrete, and only the clamped part of the wire conduit is exposed outside the concrete. The exposure of the wire conduit will not affect the corrosion degree of the steel bar.

[0031] 6. Regarding the 6th point of the background art, the flexible embedded steel bar corrosion sensor is made of polyvinylidene fluoride piezoelectric thin film material. The piezoelectric thin film is encapsulated between two annular steel sheets, and insulation treatment is carried out between the piezoelectric thin film and the steel plate. The shapes of the two steel sheets are circular rings, which can well surround the steel bar. Since the piezoelectric thin film material is flexible, it can well adapt to the shape of the annular steel sheet, thereby improving the strength of the sensor and ensuring its good working performance in harsh environments. The encapsulated piezoelectric thin film material is led out through a shielded wire. The encapsulated flexible embedded steel bar corrosion sensor is sleeved on the steel bar, and concrete is poured. The sensor is pre-embedded in the concrete structure and monitors the internal stress of the concrete.

[0032] Note: The above designs are not in any order, and each one makes the present invention have differences and significant improvements compared with the prior art. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The present invention will be further described below in conjunction with the drawings and embodiments.

[0034] Figure 1 is a schematic diagram of the real-time pouring state of the present invention

[0035] Figure 2 is a schematic diagram of the test and measurement state after pouring and disassembly of the present invention

[0036] Figure 3 is the present invention Figure 1 is an enlarged schematic diagram of the structure at A in the present invention

[0037] Figure 4 is a three-dimensional perspective view of the reinforced concrete structure of the present invention (Note: The concrete column is generally cylindrical, and in special cases, it can be a square column. Here, the perspective view shows the internal structure, and the unique shape of the concrete column is not limited)

[0038] Figure 5 is a top view schematic diagram of the clamping structure of the present invention

[0039] Figure 6 is a three-dimensional schematic diagram of the first sensor of the present invention

[0040] Figure 7 is a cross-sectional schematic diagram of the first sensor of the present invention

[0041] In the figure, the reference numerals are as follows:

[0042] 1. Outer pile hole 2. Inner pile hole 3. Outer wall 4. Bottom wall 5. Collar 6. Sleeve 7. Lower casing 8. Upper casing 9. Arm 10. Claw 11. Conduit 12. Steel bar 13. Concrete column 14. Lower convex ring 15. Upper convex ring 16. Second sensor 17. First sensor 18. Fixed ring 19. Electronic device. 20. Insulation layer 21. PVDF sensor 22. Steel sheet 23. Shielded wire DETAILED DESCRIPTION

[0043] As shown in the figure: a protective corrosion monitoring system, including an outer pile hole, an inner pile hole, an outer casing, an inner casing, a sleeve, an arm, a wire tube, a steel bar, a concrete column, a second sensor, a first sensor, a fixing ring, an electronic device, and a clamp; the inner casing includes a lower casing and an upper casing; the outer casing includes an outer wall, a bottom wall, and a collar; wherein the first sensor includes an insulating layer, an annular PVDF sensor, a steel sheet, and a shielding wire, the first sensor is sleeved on the outer wall of the steel bar, the steel sheet includes an inner steel sheet and an outer steel sheet, the inner steel sheet and the outer steel sheet are annular, the outer periphery of the PVDF sensor is wrapped with the insulating layer, the inner wall of the insulating layer is connected to the inner steel sheet, the outer wall of the insulating layer is connected to the outer steel sheet, the shielding wire extends from the PVDF sensor and passes through the insulating layer to extend out of the first sensor, and then is introduced into the wire tube; the first sensor is a circular ring structure with a notch; the PVDF sensor is a PVDF piezoelectric film sensor;

[0044] The outer pile hole is dug on the ground, the inner pile hole is dug downward from the bottom of the outer pile hole, the lower casing is fixed in the inner pile hole, an upper convex ring is integrally arranged above the lower casing, a lower convex ring is integrally arranged below the upper casing, and the upper convex ring and the lower convex ring are detachably connected via a connecting piece; the outer wall, the bottom wall and the sleeve ring are integrally formed, and the sleeve ring is arranged above the bottom wall;

[0045] During the pouring stage, the outer casing is arranged in the outer pile hole, a through hole is arranged on the bottom wall for the inner casing to pass through, the upper casing and the lower casing are in a connected state, the sleeve is sleeved between the collar and the inner casing, the outer wall of the sleeve abuts against the inner wall of the collar, and the inner wall of the sleeve abuts against the upper casing and the lower casing at the same time; the inner wall of the upper casing is provided with an arm extending inward, and the end of the arm is provided with a clamping claw; the wire pipe is clamped by the clamping claw, and the outer wall of the steel bar is sleeved with a fixing ring, and the fixing ring and the wire pipe are fixedly connected by a connecting rod; after the concrete is poured, the clamped part of the wire pipe is exposed outside the concrete column, and the steel bar is completely buried in the concrete column;

[0046] During the testing phase, the upper casing and the sleeve are removed, water is injected between the outer casing and the concrete column, and a second sensor is also sleeved on the outer wall of the steel bar; the first sensor and the second sensor are connected to external electronic equipment via shielded wires inserted in the wire tube.

[0047] As shown in the figure: The electronic device is a display setting. A connecting pipe is provided between the first sensor and the conduit to accommodate the shielded wire. The second sensor is an annular resistance strain sensor. During the pouring stage, the upper end of the steel bar is lower than the upper end of the inner casing. During the pouring stage, the upper end of the conduit is higher than the upper end of the inner casing. After pouring is completed, the arm and the jaws are exposed above the concrete column. The number of the first sensors is three, and the number of the fixing rings is two. The number of the second sensors is two. During the testing stage, the lower end of the conduit is higher than the lower end of the steel bar.

[0048] The above detailed description is a specific description of the feasible embodiments of the present invention, and this embodiment is not intended to limit the patent scope of the present invention. Any equivalent implementation or change without departing from the present invention shall be included in the patent scope of this case.

Claims

1. A protective rust monitoring system, characterized in that: It includes an outer pile hole, an inner pile hole, an outer casing, an inner casing, a sleeve, an arm, a wire tube, a steel bar, a concrete column, a second sensor, a first sensor, a fixing ring, an electronic device, and a clamp; the inner casing includes a lower casing and an upper casing; the outer casing includes an outer wall, a bottom wall, and a collar; wherein the first sensor includes an insulating layer, an annular PVDF sensor, a steel sheet, and a shielding wire, the first sensor is sleeved on the outer wall of the steel bar, the steel sheet includes an inner steel sheet and an outer steel sheet, the inner steel sheet and the outer steel sheet are annular, the outer periphery of the PVDF sensor is wrapped with the insulating layer, the inner wall of the insulating layer is connected to the inner steel sheet, the outer wall of the insulating layer is connected to the outer steel sheet, the shielding wire extends from the PVDF sensor and passes through the insulating layer to extend out of the first sensor, and then is introduced into the wire tube; the first sensor is a circular ring structure with a notch; the PVDF sensor is a PVDF piezoelectric film sensor; the second sensor is an annular resistance strain sensor; The outer pile hole is dug on the ground, the inner pile hole is dug downward from the bottom of the outer pile hole, the lower casing is fixed in the inner pile hole, an upper convex ring is integrally arranged above the lower casing, a lower convex ring is integrally arranged below the upper casing, and the upper convex ring and the lower convex ring are detachably connected via a connecting piece; the outer wall, the bottom wall and the sleeve ring are integrally formed, and the sleeve ring is arranged above the bottom wall; During the pouring stage, the outer casing is arranged in the outer pile hole, a through hole is arranged on the bottom wall for the inner casing to pass through, the upper casing and the lower casing are in a connected state, the sleeve is sleeved between the collar and the inner casing, the outer wall of the sleeve abuts against the inner wall of the collar, and the inner wall of the sleeve abuts against the upper casing and the lower casing at the same time; the inner wall of the upper casing is provided with an arm extending inward, and the end of the arm is provided with a clamping claw; the wire pipe is clamped by the clamping claw, and the outer wall of the steel bar is sleeved with a fixing ring, and the fixing ring and the wire pipe are fixedly connected by a connecting rod; after the concrete is poured, the clamped part of the wire pipe is exposed outside the concrete column, and the steel bar is completely buried in the concrete column; During the testing phase, the upper casing and the sleeve are removed, water is injected between the outer casing and the concrete column, and a second sensor is also sleeved on the outer wall of the steel bar; the first sensor and the second sensor are connected to external electronic equipment via shielded wires inserted in the wire tube.

2. The protective rust monitoring system according to claim 1, characterized in that: The electronic device is a display device.

3. The protective rust monitoring system according to claim 1, characterized in that: A connecting tube is provided between the first sensor and the wire tube to accommodate the shielding wire.

4. The protective rust monitoring system according to claim 1, characterized in that: During the pouring stage, the upper end of the steel bar is lower than the upper end of the inner casing.

5. The protective rust monitoring system according to claim 4, characterized in that: During the pouring stage, the upper end of the wire tube is higher than the upper end of the inner casing.

6. The protective rust monitoring system according to claim 5, characterized in that: After pouring is completed, the arm and the clamping jaws are exposed above the concrete column.

7. The protective rust monitoring system according to claim 1, wherein: The number of the first sensors is three, and the number of the fixing rings is two.

8. A protective rust monitoring system according to claim 1, characterized in that: The number of the second sensors is two.

9. The protective rust monitoring system according to claim 1, characterized in that: During the testing phase, the lower end of the wire tube is higher than the lower end of the steel bar.

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