Simulation test device and method for non-uniform corrosion of steel bars in complex marine environment

Abstract

The present invention proposes a simulation test device and method for non-uniform corrosion of steel bars in a complex marine environment, and relates to the technical field. It comprises a closed environmental box, wherein a test water tank and a water level supplementary water tank are arranged in the closed environmental box, wherein a test piece, a high water level mark, a low water level mark and a low water level water pump are arranged in the test water tank, and a high water level water pump and a simulated seawater medium are arranged in the water level supplementary water tank; the high water level water pump extracts the simulated seawater medium into the test water tank through a first pipeline, so that the water level in the test water tank reaches the high water level mark position; the low water level water pump extracts the simulated seawater medium into the water level supplementary water tank through a second pipeline, so that the water level in the test water tank drops to the low water level mark position; the upper, middle and lower parts of the test piece are respectively located above the high water level mark, between the high water level mark and the low water level mark, and below the low water level mark. The present invention can simulate multiple exposure conditions at the same time, and truly simulate the non-uniform corrosion behavior of steel bars in a complex marine environment.

Description

Technical Field

[0001] The invention belongs to the technical field of steel bar corrosion simulation, and in particular relates to a simulation test device and method for non-uniform steel bar corrosion in a complex marine environment. Background Art

[0002] Chloride ions in the marine environment can easily cause steel corrosion, which is considered to be the main problem facing the durability of cross-sea projects. Steel corrosion reduces the cross-sectional area of ​​steel bars and causes cracking, even peeling and delamination of concrete, which is the main factor leading to reduced structural durability and overall service performance. In addition, due to the different exposure conditions of the structure along the height direction in the marine environment, it is divided into the atmospheric zone, splash zone, tidal zone and underwater zone, and the steel corrosion in different areas is spatially non-uniformly distributed.

[0003] The inventors found that the existing test methods usually use dry-wet cycle or power acceleration method to simulate steel corrosion:

[0004] It is generally difficult to simulate the corrosion behavior of steel bars under multiple exposure conditions simultaneously using dry-wet cycles;

[0005] Electrical acceleration is often used to simulate uniform corrosion of steel bars, but its similarity to the corrosion behavior of steel bars in natural environments is difficult to estimate. Summary of the invention

[0006] In order to overcome the deficiencies of the above-mentioned prior art, the present invention provides a simulation test device and method for non-uniform corrosion of steel bars in a complex marine environment, which can simulate multiple exposure conditions at the same time, and proposes corresponding test methods, which can truly simulate the non-uniform corrosion behavior of steel bars in a complex marine environment and conduct experimental observations.

[0007] To achieve the above objectives, one or more embodiments of the present invention provide the following technical solutions:

[0008] The first aspect of the present invention provides a simulation test device for non-uniform corrosion of steel bars in a complex marine environment.

[0009] A simulation test device for non-uniform corrosion of steel bars in a complex marine environment comprises a closed environmental box, wherein a test water tank and a water level supplementary water tank are arranged in the closed environmental box, wherein a test piece, a high water level mark, a low water level mark and a low water level water pump are arranged in the test water tank, wherein a high water level water pump and a simulated seawater medium are arranged in the water level supplementary water tank; wherein the high water level water pump draws the simulated seawater medium into the test water tank through a first pipeline, so that the water level in the test water tank reaches the position of the high water level mark; wherein the low water level water pump draws the simulated seawater medium into the water level supplementary water tank through a second pipeline, so that the water level in the test water tank drops to the position of the low water level mark; wherein the upper part, the middle part and the lower part of the test piece are respectively located above the high water level mark, between the high water level mark and the low water level mark, and below the low water level mark.

[0010] Optionally, a high water level stop valve and a low water level stop valve are further provided in the test water tank, and a water replenishment pump is also provided in the water level replenishment tank. The water replenishment pump is connected to the low water level stop valve through a third pipeline, and the first pipeline is connected to the high water level stop valve.

[0011] Optionally, the high water level stop valve corresponds to the height of the high water level mark, and the low water level stop valve corresponds to the height of the low water level mark.

[0012] Optionally, it also includes a control system, which is electrically connected to the high water level pump and the low water level pump, and is used to control the running time of the high water level pump and the low water level pump, and dynamically adjust the water level of the test water tank so that the water level in the test water tank cycles back and forth between the high water level mark and the low water level mark.

[0013] Optionally, the control system is electrically connected to a water replenishment pump to control the running time of the water replenishment pump, and when the water level in the test water tank drops below a low water level mark, automatic water level replenishment is performed.

[0014] Optionally, the specimen includes a plurality of small segments of steel bars that are fixedly connected, each of the small segments of steel bars is provided with holes at both ends, a wire is provided in the hole, a material is filled between the wire and the hole wall, and each wire extends to the surface of the small segment of steel bars.

[0015] Optionally, switches are provided between adjacent wires, and a reference electrode and a multimeter are electrically connected between the head and tail wires to form a measurement circuit;

[0016] Alternatively, a multimeter is provided between at least one group of adjacent wires, and switches are provided between the remaining wires.

[0017] Optionally, a heating device, a humidifying device and a temperature and humidity control device are provided in the closed environment box, and the heating device, the humidifying device and the temperature and humidity control device are electrically connected to the control system respectively.

[0018] Optionally, the closed environment box includes a light steel inner frame and a light steel outer frame, the space between the light steel inner frame and the light steel outer frame is filled with insulation material, and the outer sides of the light steel inner frame and the light steel outer frame are provided with plastic film; the splicing gaps of the insulation material are connected by sealant.

[0019] The second aspect of the present invention provides a simulation test method for non-uniform corrosion of steel bars in a complex marine environment.

[0020] A test method based on the complex marine environment steel bar non-uniform corrosion simulation test device according to the first aspect, comprising the following steps:

[0021] Step 1: Build the test device and place the cast specimens into the test water tank after curing;

[0022] Step 2: Use the position above the high water mark, the position between the high water mark and the low water mark, and the position below the low water mark to simulate the atmospheric zone, the tidal splash zone, and the underwater zone, and set the heights of the high water stop valve and the low water stop valve;

[0023] Step 3: Control the running time of the high water level pump to make the water level in the test water tank reach the high water level mark position;

[0024] Step 4: Control the running time of the low water level pump to make the water level in the test water tank drop to the low water level mark position;

[0025] Step 5: Cycle steps 3 to 4 to automatically cycle high and low water levels;

[0026] Step 6: Control the running time of the water replenishment pump, and automatically replenish the water level when the water level in the test water tank drops below the low water level mark;

[0027] Step 7: Perform half-cell potential measurement and macro current measurement based on the set conductors, and record the measurement data.

[0028] One or more of the above technical solutions have the following beneficial effects:

[0029] The present invention provides a simulation test device and method for non-uniform corrosion of steel bars in a complex marine environment. By arranging a high-water level pump, a low-water level pump and a water replenishment pump, multiple marine environment exposure conditions can be simulated at the same time, and the water level changes of seawater high tide and low tide can be simulated. The upper, middle and lower parts of the test piece are respectively located above the high water level mark, between the high water level mark and the low water level mark, and below the low water level mark, corresponding to the simulation of the atmospheric zone, the tidal and splashing zone, and the underwater zone, so as to truly simulate the non-uniform corrosion behavior of steel bars in a complex marine environment.

[0030] The present invention proposes a corresponding test method, including a specific test piece preparation method and test data observation steps, which can measure the macroscopic corrosion current and corrosion potential of steel bars between different areas, effectively explore the non-uniform corrosion characteristics and time-varying laws of steel bars, and provide a scientific method for revealing its corrosion mechanism.

[0031] Advantages of additional aspects of the present invention will be given in part in the following description, and in part will become obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The accompanying drawings in the specification, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0033] Figure 1Schematic diagram of a closed environment box with a flat top structure in Example 1.

[0034] Figure 2 This is a schematic diagram of a closed environmental box with a sloped roof structure in Example 1.

[0035] Figure 3 It is a schematic cross-sectional view of the wall thickness direction of the closed environment box of Example 1.

[0036] Figure 4 It is a schematic cross-sectional view of the overall structure of the closed environment box of Example 1.

[0037] Figure 5 This is a schematic diagram of the internal structure of the closed environment box in Example 1.

[0038] Figure 6 This is a schematic diagram of half-cell potential measurement in Example 2.

[0039] Figure 7 This is a schematic diagram of macro current measurement in Example 2.

[0040] In the accompanying drawings, the components represented by the reference numerals are listed as follows:

[0041] 1 closed environment chamber, 2 test water tank, 3 water level replenishment water tank, 4 test piece, 5 high water level stop valve, 6 low water level stop valve, 7 high water level pump, 8 low water level pump, 9 high water level mark, 10 low water level mark, 11 replenishment water pump, 12 small section of steel bar, 13 wire, 14 switch, 15 reference electrode, 16 multimeter, 17 light steel inner frame, 18 light steel outer frame, 19 insulation material, 20 plastic film, 21 sealant, 22 door, 23 spherical bearing, 24 simulated seawater medium, 25 atmospheric zone, 26 tidal and splash zone, 27 underwater zone, 28 sponge, 29 first pipeline, 30 second pipeline, 31 third pipeline. DETAILED DESCRIPTION

[0042] It should be noted that the following detailed descriptions are exemplary and are intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0043] It should be noted that the terms used herein are for describing specific embodiments only and are not intended to be limiting of exemplary embodiments according to the present invention.

[0044] In the absence of conflict, the embodiments of the present invention and the features of the embodiments may be combined with each other.

[0045] Embodiment 1

[0046] This embodiment discloses a simulation test device for non-uniform corrosion of steel bars in a complex marine environment.

[0047] like Figure 1 , Figure 2 , Figure 5 As shown, a simulation test device for non-uniform corrosion of steel bars in a complex marine environment comprises a closed environment box 1, wherein a test water tank 2 and a water level replenishment water tank 3 are arranged in the closed environment box 1, wherein a test specimen 4, a high water level mark 9, a low water level mark 10 and a low water level water pump 8 are arranged in the test water tank 2, and a high water level water pump 7 and a simulated seawater medium 24 are arranged in the water level replenishment water tank 3; the high water level water pump 7 draws the simulated seawater medium 24 into the test water tank 2 through a first pipeline 29, so that the water level in the test water tank 2 reaches the position of the high water level mark 9; the low water level water pump 8 draws the simulated seawater medium 24 into the water level replenishment water tank 3 through a second pipeline 30, so that the water level in the test water tank 2 drops to the position of the low water level mark 10; the upper part, the middle part and the lower part of the test specimen 4 are respectively located above the high water level mark 9, between the high water level mark 9 and the low water level mark 10, and below the low water level mark 10.

[0048] In this embodiment, the upper part of the specimen 4 is higher than the high water level stop valve 5. The position of the specimen 4 above the high water level mark 9 is used to simulate the atmospheric zone 25, the position of the specimen 4 between the high water level mark 9 and the low water level mark 10 is used to simulate the tide and splash zone 26, and the position of the specimen 4 below the low water level mark 10 is used to simulate the underwater zone 27. Multiple exposure conditions are simulated at the same time to achieve simulation of multiple exposure situations.

[0049] The test water tank 2 is also provided with a high water level stop valve 5 and a low water level stop valve 6. To facilitate determination of the water level, the high water level stop valve 5 corresponds to the height of the high water level mark 9, and the low water level stop valve 6 corresponds to the height of the low water level mark 10. The high water level pump 7 is connected to the test water tank 2 through a first pipeline 29, and the low water level pump 8 is connected to the water level replenishment tank 3 through a second pipeline 30. The first pipeline 29 is connected to the high water level stop valve 5.

[0050] A water replenishment pump 11 is also provided in the water level replenishment water tank 3 . The water replenishment pump 11 is connected to the test water tank 2 through a third pipeline 31 and is connected to the low water level stop valve 6 .

[0051] The high water level pump 7, low water level pump 8 and water supply pump 11, as well as the high water level stop valve 5 and low water level stop valve 6 are provided to control the real-time water level of the test water tank 2 to meet the simulation of seawater tide, high tide and low tide, and to perform circulation. Specifically:

[0052] The simulated seawater medium 24 is pumped from the water level replenishment tank 3 to the test water tank 2 by using the high water level pump 7. When the real-time water level in the test water tank 2 reaches the position of the high water level mark 9, the operation is stopped;

[0053] Then, the simulated seawater medium 24 in the test water tank 2 is pumped into the water level replenishment tank 3 by using the low water level pump 8, until the real-time water level of the test water tank 2 reaches the position of the low water level mark 10, at which time the low water level pump 8 stops running;

[0054] When the water level in the test water tank 2 drops below the low water level mark 10, the water level is automatically replenished by the water replenishment pump 11;

[0055] The above process is repeated to make the water level in the test water tank 2 cycle between the high water level mark 9 and the low water level mark 10, thereby simulating the tidal fluctuation.

[0056] In order to realize the control of the high water level pump 7, the low water level pump 8 and the water replenishment pump 11, it can be understood that the present embodiment also includes a control system, which is used to control the running time of the high water level pump 7 and the low water level pump 8, and dynamically adjust the water level of the test water tank 2, so that the water level in the test water tank 2 reciprocates between the position of the high water level mark 9 and the position of the low water level mark 10. The control system is also used to control the running time of the water replenishment pump 11, and when the water level of the test water tank 2 drops below the low water level mark 10, the water level is automatically replenished. The control system can control the water pump through a relay, and realize the on-off of the circuit by the on-off of the relay.

[0057] The test device of this embodiment mainly includes:

[0058] 1) Sealed environment box 1: Figure 1 , Figure 2 As shown, the closed environment box 1 of this embodiment can adopt two forms: flat roof and slope roof.

[0059] like Figure 3 , Figure 4 As shown, the closed environment box 1 includes a light steel inner frame 17 and a light steel outer frame 18, and the light steel inner frame 17 and the light steel outer frame 18 are filled with insulation material 19, and the outer sides of the light steel inner frame 17 and the light steel outer frame 18 are provided with plastic film 20; the splicing gaps of the insulation material 19 are connected by sealant 21.

[0060] More specifically, the insulation material 19 can be inorganic microporous plasticized insulation board or other high-efficiency insulation material 19, and the joints of the insulation material 19 are sealed with weather-resistant silicone sealant 21. A door 22 is also provided on the side wall of the sealed environment box; a spherical support 23 is provided at the bottom of the sealed environment box for easy movement. A light steel structure frame is used, and the enclosure material is inorganic plasticized microporous insulation board (combustibility grade A non-combustible), and the on-site assembly construction and installation are carried out. The joint gaps are caulked with weather-resistant silicone sealant 21 to reduce the humidity and temperature exchange inside and outside the environment box, while maintaining the stability of the salinity in the box air.

[0061] 2) Self-compensating circulating water level control system:

[0062] It includes test water tank 2 and water level compensation water tank, relay, water pump, water stop valve and water pipe. The working principle of test water tank 2 and compensation water tank is as follows: Figure 5 shown.

[0063] 3) Complex marine environment simulation system:

[0064] It includes a heating device, a humidifying device, a temperature and humidity control device, a salt spray plate, and a simulated seawater medium 24 in a water tank to achieve a temperature of 15-35°C and a humidity of 40%-90%.

[0065] Among them, the heating device, humidifying device and temperature and humidity control device are electrically connected to the control system respectively, so as to simulate various environmental indicators more realistically.

[0066] In order to facilitate the measurement of test data, the test piece 4 includes a plurality of small segments of steel bars 12 that are fixedly connected, each of which is provided with holes at both ends, a wire 13 is provided in the hole, a material is filled between the wire 13 and the hole wall, and each wire 13 extends to the surface of the small segment of steel bars 12.

[0067] During the specific production of the test piece 4, a plurality of small sections of steel bars 12 with a diameter of 70 to 180 mm were used. The two ends of adjacent small sections of steel bars 12 were fixed with plastic rings and epoxy resin. Holes were drilled at both ends of each small section of steel bars 12 to insert wires and fixed with pins. The gaps in the middle were filled with cement mortar. When pouring concrete, all wires were extended out of the surface of the test piece 4.

[0068] In order to achieve data measurement, in this embodiment, a switch 14 is provided between adjacent wires 13, and a reference electrode 15 and a multimeter 16 are electrically connected between the head and tail wires 13 to form a measurement circuit, which is convenient for half-cell potential measurement; a sponge 28 is provided between the test piece 4 and the reference electrode 15 for easy connection.

[0069] Alternatively, a multimeter 16 is provided between at least one group of adjacent conductors 13, and switches 14 are provided between the remaining conductors 13, so as to facilitate macro current measurement.

[0070] Embodiment 2

[0071] This embodiment discloses a simulation test method for non-uniform corrosion of steel bars in a complex marine environment.

[0072] A test method based on the complex marine environment steel bar non-uniform corrosion simulation test device described in Example 1 comprises the following steps:

[0073] Step 1: Build the test device, and place the cast test piece 4 into the test water tank 2 after curing;

[0074] Step 2: Use the position above the high water mark 9, the position between the high water mark 9 and the low water mark 10, and the position below the low water mark 10 to simulate the atmospheric zone 25, the tidal wave splash zone, and the underwater zone 27, respectively, and set the heights of the high water level stop valve 5 and the low water level stop valve 6;

[0075] Step 3: Control the running time of the high water level pump 7 so that the water level of the test water tank 2 reaches the position of the high water level mark 9;

[0076] Step 4: Control the running time of the low water level pump 8 to make the water level of the test water tank 2 drop to the position of the low water level mark 10;

[0077] Step 5: Cycle steps 3 to 4 to automatically cycle high and low water levels;

[0078] Step 6: Control the running time of the water replenishment pump 11, and automatically replenish the water level when the water level in the test water tank 2 drops below the low water level mark 10;

[0079] Step 7: Perform half-cell potential measurement and macro current measurement based on the set conductor 13, and record the measurement data.

[0080] For details on half-cell potential measurement, please refer to Figure 6 As shown, a sponge 28 is provided at the upper end of the test piece 4, and the sponge 28 is connected to the reference electrode 15, and then each switch 14 is closed to form a closed loop as a whole, and the voltage is measured using a multimeter 16.

[0081] Specifically when measuring test data:

[0082] When measuring the half-cell potential of steel bars, keep all sections of steel bars in different areas connected;

[0083] When measuring macro current, you can refer to Figure 7 (a) Figure 7 As shown in (b), all steel bars are disconnected first, and then the difference in current readings between two adjacent steel bars is measured from one side of the specimen 4.

[0084] Although the above describes the specific implementation mode of the present invention in conjunction with the accompanying drawings, it is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art on the basis of the technical solution of the present invention without creative work are still within the scope of protection of the present invention.

Claims

1. A simulation test device for non-uniform corrosion of steel bars in complex marine environments, characterized in that: It comprises a closed environment box, wherein a test water tank and a water level supplementary water tank are arranged in the closed environment box, wherein a test piece, a high water level mark, a low water level mark and a low water level water pump are arranged in the test water tank, wherein a high water level water pump and a simulated seawater medium are arranged in the water level supplementary water tank; wherein the high water level water pump draws the simulated seawater medium into the test water tank through a first pipeline, so that the water level in the test water tank reaches the position of the high water level mark; wherein the low water level water pump draws the simulated seawater medium into the water level supplementary water tank through a second pipeline, so that the water level in the test water tank drops to the position of the low water level mark; wherein the upper part, the middle part and the lower part of the test piece are respectively located above the high water level mark, between the high water level mark and the low water level mark, and below the low water level mark; The position above the high water mark of the specimen is used to simulate the atmospheric zone, the position between the high water mark and the low water mark is used to simulate the tidal and splash zone, and the position below the low water mark is used to simulate the underwater zone. The test piece includes a plurality of small segments of steel bars that are fixedly connected, each of which is provided with holes at both ends, and a wire is provided in the hole, a material is filled between the wire and the hole wall, and each wire extends to the surface of the small segment of steel bars; a switch is provided between adjacent wires, and a reference electrode and a multimeter are electrically connected between the head and tail wires to form a measurement circuit; or, a multimeter is provided between at least one group of adjacent wires, and switches are provided between the remaining wires; the macroscopic corrosion current and corrosion potential of steel bars between different regions can be measured, the non-uniform corrosion characteristics and time-varying laws of steel bars can be effectively explored, and a scientific method is provided for revealing their corrosion mechanism; A water replenishment pump is also provided in the water level replenishment water tank, and the water replenishment pump is connected to the low water level stop valve through a third pipeline, and the first pipeline is connected to the high water level stop valve; Use a high water level pump to pump simulated seawater from the water level supplement tank to the test water tank. When the real-time water level in the test water tank reaches the high water level mark, stop running; Afterwards, the simulated seawater medium in the test water tank is pumped into the water level supplement tank using a low water level pump until the real-time water level of the test water tank reaches the low water level mark position, at which time the low water level pump stops running; When the water level in the test water tank drops below the low water level mark, the water level will be automatically replenished using a water replenishment pump; The above process is repeated to realize that the water level in the test water tank cycles between the high water level mark and the low water level mark, thereby simulating the tidal fluctuation; Perform half-cell potential measurement and macro current measurement based on the set conductors, and record the measurement data; Specifically when measuring test data: When measuring the half-cell potential of steel bars, keep all sections of steel bars in different areas connected; When measuring the macro current, first disconnect all the steel bars, and then measure the difference in current readings between two adjacent steel bars from one side of the specimen.

2. The complex marine environment steel bar non-uniform corrosion simulation test device according to claim 1 is characterized in that: A high water level stop valve and a low water level stop valve are also provided in the test water tank.

3. The complex marine environment steel bar non-uniform corrosion simulation test device according to claim 2 is characterized in that: The high water level stop valve corresponds to the height of the high water level mark, and the low water level stop valve corresponds to the height of the low water level mark.

4. The complex marine environment steel bar non-uniform corrosion simulation test device according to claim 3 is characterized in that: It also includes a control system, which is electrically connected to the high water level pump and the low water level pump, and is used to control the running time of the high water level pump and the low water level pump, and dynamically adjust the water level of the test water tank so that the water level in the test water tank cycles back and forth between the high water level mark and the low water level mark.

5. The complex marine environment steel bar non-uniform corrosion simulation test device according to claim 4, characterized in that: The control system is electrically connected to the water replenishment pump and is used to control the running time of the water replenishment pump. When the water level in the test water tank drops below the low water level mark, the water level is automatically replenished.

6. The complex marine environment steel bar non-uniform corrosion simulation test device according to claim 4, characterized in that: A heating device, a humidifying device and a temperature and humidity control device are arranged in the closed environment box, and the heating device, the humidifying device and the temperature and humidity control device are electrically connected to the control system respectively.

7. The complex marine environment steel bar non-uniform corrosion simulation test device according to claim 1 is characterized in that: The closed environment box includes a light steel inner frame and a light steel outer frame, the space between the light steel inner frame and the light steel outer frame is filled with insulation material, and the outer sides of the light steel inner frame and the light steel outer frame are both provided with plastic films; the splicing gaps of the insulation materials are connected by sealant.

8. A test method based on the complex marine environment steel bar non-uniform corrosion simulation test device according to any one of claims 1 to 7, characterized in that: The following steps are involved: Step 1: Build the test device and place the cast specimens into the test water tank after curing; Step 2: Use the position above the high water mark, the position between the high water mark and the low water mark, and the position below the low water mark to simulate the atmospheric zone, the tidal splash zone, and the underwater zone, and set the heights of the high water stop valve and the low water stop valve; Step 3: Control the running time of the high water level pump to make the water level in the test water tank reach the high water level mark position; Step 4: Control the running time of the low water level pump to make the water level in the test water tank drop to the low water level mark position; Step 5: Cycle steps 3 to 4 to automatically cycle high and low water levels; Step 6: Control the running time of the water replenishment pump, and automatically replenish the water level when the water level in the test water tank drops below the low water level mark; Step 7: Perform half-cell potential measurement and macro current measurement based on the set conductors, and record the measurement data.

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