Electrochemical noise signal experiment system for steel-concrete structure corroded by stray current
By designing an electrochemical noise signal experimental system that simulates the stray current and chloride ion environment of reinforced concrete structures in subway tunnels, the corrosion problem of stray current on reinforced concrete structures in subway operations is solved, and a scientific and reliable assessment of corrosion behavior is achieved.
Patent Information
- Application Number
- CN202421162463.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-05-27
- Publication Date
- 2025-04-25
- Estimated Expiration
- 2034-05-27
AI Technical Summary
During subway operations, stray currents cause corrosion to reinforced concrete structures, resulting in the impact of structural safety and durability. It is difficult for the prior art to effectively simulate and measure such corrosion conditions.
Design an experimental system for electrochemical noise signal of steel-mixed structures corroded by stray current, including test chambers and electrochemical workstations, to simulate the corrosion of reinforced concrete structures in subway tunnels under the action of stray currents, and to evaluate the corrosion behavior through electrochemical noise signal measurement.
The system can effectively simulate and measure the corrosion conditions of reinforced concrete structures in stray currents and chloride ion environments, and provides a scientific and reliable experimental platform to help prevent and control such corrosion problems.
Smart Images
Figure CN222800578U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of electrochemical noise detection, in particular to an electrochemical noise signal experimental system for a steel-concrete structure corroded by stray current. Background Art
[0002] In modern urban rail transit systems, especially in subway operations, stray currents have long been a key factor affecting the safety and durability of reinforced concrete structures. During train operation, the return rail's inherent resistance causes a voltage drop, particularly in areas close to the train, where the potential increases significantly, creating an anode area with significant energy loss. Furthermore, the insulation layer between the return rail and the ground is susceptible to wear, aging, or physical damage, making it impossible to maintain absolute insulation. This causes some current to leak directly into the ground, generating so-called secondary stray currents.
[0003] This stray current leaks into the ground along the subway trackbed and ultimately returns to the rail return point through the earth's medium. Along the way, it inevitably passes through the reinforced concrete structures surrounding the subway. The network of steel bars within the reinforced concrete structure forms a potential closed circuit with the return rails and the earth, providing a suitable medium for electrochemical corrosion. The injection of stray current activates redox reactions on the steel surface, accelerating the corrosion rate. The corrosive effects of stray current are even more pronounced in chloride-rich groundwater. Chloride ions, as a highly active corrosive agent, easily penetrate the concrete protective layer and directly act on the steel surface, accelerating the corrosion process. Utility Model Content
[0004] The utility model discloses an electrochemical noise signal experimental system for steel-concrete structures corroded by stray currents. The system can effectively simulate the corrosion of reinforced concrete in iron tunnels under the combined effects of an aggressive ion environment and stray currents, and accurately measure the electrochemical noise signal to deeply study and evaluate such corrosion behavior.
[0005] To achieve the above, the utility model discloses an electrochemical noise signal experimental system for steel-concrete structures corroded by stray current, comprising a test box and an electrochemical workstation. A sodium chloride solution is provided in the test box, a reinforced concrete test block for simulation testing is immersed in the sodium chloride solution, and a filling liquid for simulating corrosive ion conditions is filled between the test box and the reinforced concrete test block.
[0006] The reinforced concrete test block includes a threaded steel bar wrapped in a concrete layer and wound with a copper wire. The threaded steel bar is horizontally arranged at a central position in the reinforced concrete test block. A high-purity graphite electrode rod is provided at one end of the threaded steel bar and is arranged in the concrete without contacting the threaded steel bar. The high-purity graphite electrode rod extends out of the concrete layer through an auxiliary electrode. The other end of the threaded steel bar extends out of the concrete layer through a working electrode formed by the wound copper wire. A ruthenium-iridium-titanium mesh and a pure titanium mesh are respectively provided in the concrete layer on both sides of the threaded steel bar to simulate stray currents near the reinforced concrete main structure of a subway. The ruthenium-iridium-titanium mesh and the pure titanium mesh are respectively connected to a positive conductor of a direct current power supply and a negative conductor of a direct current power supply extending out of the concrete layer.
[0007] The electrochemical workstation is equipped with a reference electrode interface, an auxiliary electrode interface and a working electrode interface. The reference electrode interface is connected to a saturated calomel electrode with its end set in a sodium chloride solution through a wire, the auxiliary electrode interface is connected to the auxiliary electrode, and the working electrode interface is connected to the working electrode.
[0008] Furthermore, the test box is a HDPE polyethylene plastic turnover box.
[0009] Furthermore, the filling liquid in the experimental box is a sodium chloride solution, and the sodium chloride solution is immersed to two-thirds of the height of the reinforced concrete test block.
[0010] Furthermore, the electrochemical workstation is a CHI660E electrochemical workstation.
[0011] Furthermore, the reference electrode is a 232-01 type saturated calomel electrode, and the internal structure is a calomel single salt bridge type.
[0012] Furthermore, during the test, the positive conductor of the DC power supply and the negative conductor of the DC power supply were respectively connected to a DC voltage source for simulating stray current.
[0013] Furthermore, a high-purity graphite electrode rod is vertically set in a reinforced concrete test block, and the distance between the high-purity graphite electrode rod and the end of the threaded steel bar is 50 mm.
[0014] Beneficial effects:
[0015] The utility model utilizes reinforced concrete test blocks combined with electrochemical corrosion experimental measurement methods to ensure the effectiveness and representativeness of reinforced concrete structure test blocks; the reinforced concrete test blocks contain threaded steel bars as working electrodes for electrochemical testing, ruthenium-iridium-titanium mesh and pure titanium mesh for simulating stray currents around the reinforced concrete main structure of subways, and high-purity graphite electrode rods as auxiliary electrodes for electrochemical testing.
[0016] The experimental environment simulation is carried out based on the characteristics that the reinforced concrete main structure of the subway tunnel will be corroded by groundwater rich in chloride ions, and there is stray current leaked around the reinforced concrete main structure when the subway train is running.
[0017] This utility model provides a scientific and reliable experimental platform for studying the corrosion behavior of reinforced concrete structures under stray current environments through a carefully designed reinforced concrete test block preparation scheme, simulation of actual stray current environments, and precise electrochemical noise signal measurement. This is of great significance for preventing and controlling such corrosion problems. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] Figure 1 This is a schematic diagram of the main body of the reinforced concrete test block of the present utility model;
[0019] Figure 2 This is a schematic diagram of the electrochemical noise experimental measurement system of the present utility model;
[0020] In the figure: 1. Auxiliary electrode; 2. Negative lead of DC power supply; 3. Positive lead of DC power supply; 4. High-purity graphite electrode rod; 5. Ruthenium-iridium-titanium mesh; 6. Threaded steel bar; 7. Pure titanium mesh; 8. Working electrode; 9. Electrochemical workstation; 10. Reference electrode interface; 11. Auxiliary electrode interface; 12. Working electrode interface; 13. Saturated calomel electrode; 14. Reinforced concrete test block; 15. Sodium chloride solution; 16. Computer testing software. DETAILED DESCRIPTION
[0021] The following describes the implementation examples of the present invention in conjunction with the accompanying drawings:
[0022] The present utility model discloses an electrochemical noise signal experimental system for a steel-concrete structure corroded by stray current, which specifically includes the preparation of reinforced concrete test blocks 14, the construction of an experimental environment, and an electrochemical measurement electrode system.
[0023] The preparation of the reinforced concrete test block 14 includes material proportioning, processing of the threaded steel bars 6, and mold and pouring.
[0024] Material ratio: Use P.O42.5 type silicate cement, natural river sand for construction and daily tap water, and mix them in the ratio of water: cement: sand = 1:2:6.
[0025] Treatment of rebar 6: 10mm diameter, national standard rebar was used for casting, with a length of 260mm. Before casting, the rusted portion of the rebar and the coating on one side were polished. A 2mm diameter, 200mm long copper wire was wrapped around the polished end and secured with PVC electrical insulation tape. A 20mm bare copper conductor was left at the other end for electrochemical parameter measurement.
[0026] Mold and pouring: Select PVC material with a size of 100mm×100mm×300mm as the pouring mold. During the pouring process, first fill the concrete to a depth of 50mm in the mold, put in the polished steel bars, ensure that the threaded steel bars are placed horizontally and the wrapped copper wires are led out of the mold, and insert a high-purity graphite electrode rod with a diameter of 6mm and a length of 100mm at the other end of the threaded steel bars as an auxiliary electrode. Continue pouring concrete, and at the same time, insert a ruthenium-iridium-titanium mesh 5 and a pure titanium mesh 7 with a mesh size of 5mm×10mm and a size of 50mm×200mm on both sides of the threaded steel bar 6. After the pouring is completed, ensure that the wiring handles of the ruthenium-iridium-titanium mesh 5 and the pure titanium mesh 7 are exposed outside the mold, and connect copper wires with a diameter of 2mm and a length of 150mm to connect to the positive and negative poles of the DC power supply, simulating the stray current existing near the main reinforced concrete structure of the subway. The structure of the prepared cement test block 14 is as shown Figure 1 shown.
[0027] Experimental environment simulation includes the construction of corrosion ion environment and stray current simulation.
[0028] Corrosive Ion Environment Construction: A plastic turnover box made of HDPE polyethylene was selected as the corrosion environment for a single reinforced concrete specimen 14. The internal solution was a sodium chloride solution 15 with varying chloride ion concentrations, which was immersed to two-thirds of the reinforced concrete specimen 14. Before the electrical corrosion test, the reinforced concrete specimen 14 was immersed in the sodium chloride solution 15 for one day to fully fill the pores of the reinforced concrete specimen 14, simulating the environment in which the reinforced concrete is corroded by chloride-rich groundwater in a subway tunnel.
[0029] Stray current simulation: A DC voltage source was used to simulate stray current leakage from the traction substation. The positive terminal of the voltage source was connected to the terminal 5 of the ruthenium-iridium-titanium mesh in reinforced concrete specimen 14, and the negative terminal was connected to the terminal 7 of the pure titanium mesh.
[0030] Electrochemical noise signal measurement includes electrode configuration and measurement equipment and parameters.
[0031] Electrode configuration: Figure 1 and Figure 2 As shown, the working electrode 8 is connected to the threaded steel bar 6 embedded in the reinforced concrete through a copper wire; the auxiliary electrode 1 is connected to the embedded high-purity graphite electrode rod 4 through a copper wire; the reference electrode 13 is a 232-01 saturated calomel electrode produced by Shanghai Leici Company, with an internal structure of calomel single salt bridge type and a saturated potassium chloride solution as the filling liquid. The positive and negative poles of the DC constant voltage and constant current power supply are connected to the ruthenium iridium titanium mesh 5 and the pure titanium mesh 7 respectively. The embedding and connection of the ruthenium iridium titanium mesh and the pure titanium mesh are the same as those in the figure. Figure 1 The same as shown.
[0032] Measurement equipment and parameters: Electrochemical noise signal was measured using the CHI660E electrochemical workstation analyzer, and the supporting software was the CHI660E measurement software. The sampling interval was set to 0.1s (sampling frequency 10Hz), electrochemical noise time was 3600s, and the test sensitivity was 1×10 -6 , and simultaneously measure the electrochemical current and potential noise.
Claims
1. An electrochemical noise signal experimental system for steel-concrete structures corroded by stray current, characterized by: The invention comprises a test box and an electrochemical workstation (9), wherein a sodium chloride solution (15) is arranged in the test box, a reinforced concrete test block (14) for simulating detection is immersed in the sodium chloride solution (15), and a filling liquid for simulating corrosive ion conditions is filled between the test box and the reinforced concrete test block (14); The reinforced concrete test block (14) comprises a threaded steel bar (6) wrapped in a concrete layer and wound with a copper wire, the threaded steel bar (6) being horizontally arranged at a central position in the reinforced concrete test block (14), one end of the threaded steel bar (6) being provided with a high-purity graphite electrode rod (4) arranged in the concrete and not in contact with the end of the threaded steel bar (6), the high-purity graphite electrode rod (4) extending out of the concrete layer through an auxiliary electrode (1), the other end of the threaded steel bar (6) being provided with a working electrode (8) formed by the wound copper wire extending out of the concrete layer, a ruthenium-iridium-titanium mesh (5) and a pure titanium mesh (7) for simulating stray current near a reinforced concrete main structure of a subway being arranged in the concrete layer on both sides of the threaded steel bar (6), the ruthenium-iridium-titanium mesh (5) and the pure titanium mesh (7) being connected to a positive conductor (3) of a direct current power source and a negative conductor (2) of a direct current power source extending out of the concrete layer respectively; The electrochemical workstation (9) is provided with a reference electrode interface (10), an auxiliary electrode interface (11) and a working electrode interface (12), wherein the reference electrode interface (10) is connected to a saturated calomel electrode (13) whose end is disposed in a sodium chloride solution via a wire, the auxiliary electrode interface (11) is connected to the auxiliary electrode (1), and the working electrode interface (12) is connected to the working electrode (8).
2. The electrochemical noise signal experimental system for steel-concrete structure corroded by stray current according to claim 1 is characterized by: The test box is a HDPE polyethylene plastic turnover box.
3. The electrochemical noise signal experimental system for steel-concrete structure corroded by stray current according to claim 2 is characterized by: The filling liquid in the test box is a sodium chloride solution (15), and the sodium chloride solution is immersed to two-thirds of the height of the reinforced concrete test block (14).
4. The electrochemical noise signal experimental system for steel-concrete structure corroded by stray current according to claim 1 is characterized by: The electrochemical workstation (9) is a CHI660E electrochemical workstation.
5. The electrochemical noise signal experimental system for steel-concrete structure corroded by stray current according to claim 1 is characterized by: The saturated calomel electrode (13) is a 232-01 type saturated calomel electrode, and its internal structure is a calomel single salt bridge type.
6. The electrochemical noise signal experimental system for steel-concrete structure corroded by stray current according to claim 1 is characterized by: The DC power supply positive wire (3) and the DC power supply negative wire (2) are respectively connected to a DC voltage source for simulating stray current.
7. The electrochemical noise signal experimental system for steel-concrete structure corroded by stray current according to claim 1 is characterized by: The high-purity graphite electrode rod (4) is vertically arranged in the reinforced concrete test block (14), and the distance between the high-purity graphite electrode rod (4) and the end of the threaded steel bar (6) is 50 mm.