Laboratory corrosion simulation method for wharf pile foundation
By simulating the corrosion environment of a high-pile wharf in the laboratory, and using scaled-down models and electrochemical monitoring technology, the problem of the difficulty in simulating the corrosion process in existing technologies has been solved, providing reliable data support and optimizing durability design and protection strategies.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- QINGDAO UNIV OF TECH
- Filing Date
- 2026-02-27
- Publication Date
- 2026-05-12
AI Technical Summary
Existing technologies make it difficult to quickly and controllably simulate the corrosion process of high-pile wharves in marine corrosive environments in the laboratory, resulting in difficulties in data acquisition and high costs, and making it difficult to provide effective theoretical support for durability design.
By designing a scaled-down model and precisely controlling chloride ion concentration, humidity, temperature, and wet-dry cycle, combined with electrochemical monitoring technology, the corrosion environment of wharf pile foundations was simulated, and the steel reinforcement corrosion rate and mechanical properties were measured to establish a corrosion damage evolution model.
This enabled the accelerated corrosion process in the laboratory, providing a reliable data foundation and theoretical support for the durability design and protection strategy optimization of high-pile wharves, while reducing costs and risks.
Smart Images
Figure CN122016630A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of port engineering technology, and specifically relates to a laboratory corrosion simulation method for wharf pile foundations. Background Technology
[0002] The main structure of the high-pile wharf consists of a large number of prestressed concrete pipe piles and steel pipe piles driven underwater, operating in an extremely harsh marine corrosive environment. The seawater contains high concentrations of Cl... - These substances can penetrate the concrete protective layer, damage the passivation film on the surface of the reinforcing steel, and initiate and accelerate electrochemical corrosion. Alternating wet and dry conditions and differences in oxygen supply exacerbate localized corrosion, which is most severe in the splash zone and tidal zone. The concrete is in a cyclical process of immersion (oxygen deficiency) and exposure (oxygen enrichment), forming a perfect oxygen concentration cell. The structural characteristics make repair extremely difficult and expensive: its concealed nature, irreplaceable nature, and high cost of repair. Therefore, pile foundation corrosion directly threatens the safety and durability of the wharf. Once the pile foundation fails, it may cause the entire structure to collapse, resulting in catastrophic consequences and huge economic losses.
[0003] Although field exposure experiments realistically reflect the actual environment, they still have certain limitations. For example, corrosion time is extremely long, measured in years or even decades; complete structural dimensions, true protective layer thickness, macroscopic crack systems, etc., with no boundary effects; corrosion is the result of long-term collaborative competition among multiple mechanisms; data acquisition and control are difficult, expensive, and time-consuming; and the costs are extremely high with huge risks.
[0004] In order to decompose, purify, and accelerate complex natural processes and understand how key variables (such as chloride ion concentration and water-cement ratio) affect the results within an acceptable timeframe, it is necessary to study a laboratory corrosion simulation method for wharf pile foundations. Summary of the Invention
[0005] This invention discloses a laboratory corrosion simulation method for wharf pile foundations. The aim is to scientifically, controllably, and rapidly reproduce and explore the corrosion damage process that takes decades to occur in the natural environment. The method is then compared and verified with field exposure experiments to ensure the reliability and engineering applicability of the experimental results. By precisely controlling key parameters such as chloride ion concentration, humidity, temperature, and wet-dry cycle periods, the method simulates the corrosion environment at different service stages. Electrochemical monitoring technology is introduced to track the steel reinforcement corrosion process in real time. A corrosion damage evolution model is established by combining microscopic morphology analysis and macroscopic mechanical property testing. Ultimately, this provides theoretical support and a data foundation for the durability design, life prediction, and protection strategy optimization of high-pile wharf structures.
[0006] To achieve the above objectives, the technical solution of the present invention is as follows: A laboratory corrosion simulation method for wharf pile foundations includes the following steps: Step 1: Specimen design and preparation; Step 2, accelerated corrosion test, includes the following specific steps: S21. Design and manufacture the water tank: Design the water tank according to the scale model, with reserved drain and inlet ports; S22. Design an acceleration regime based on the marine environmental report of the wharf; S23. Before corrosion, the specimens are immersed in a water tank for 60 days to ensure that chloride ions in the seawater solution penetrate into the concrete. S24. Calculate the energizing time and corrosion efficiency; S25. Determination of steel reinforcement corrosion rate; S26. Data collection, processing, and analysis; S27. Inspect the degree of corrosion and external characteristics of concrete; S28. Mechanical property test.
[0007] Preferably, step 1 includes the following: S11. Specimen type design: Specimen types include: Type A: Material-grade specimen, Φ100×200mm cylinder, used for testing chloride ion permeation, electrochemical parameters, and microscopic analysis; Type B: Component-level specimens, scaled-down models of actual high-pile wharves, reinforced according to the reinforcement ratio, used to simulate the degradation of the pile's bending and crack resistance performance; The design steps for the scaled-down model are as follows: draw the cross-sectional view of the high-pile wharf, calculate the embedment depth of the elastic long pile according to the specifications, and obtain the calculated length of the pile; scale it down to 1:5 or 1:6, reinforce it according to the scaled-down ratio and meet the reinforcement ratio, and add a pile pier at the bottom of the pile to obtain the scaled-down model. S12. Divide the experiments into groups: Based on differences in service environment and load conditions, the specimens were divided into 8 groups, A1 to A4 and B1 to B4, with each group containing parallel specimens; Group A was used to study the chloride corrosion path and time effect, and Group B was used to study the mechanical-environment coupling effect. Each group had a control group and an accelerated corrosion group. S13. When preparing the specimens, the concrete raw materials, mix proportions, and curing regime should be consistent with the actual project. When preparing the specimens, pre-embed the connecting sensors, strain gauges, and wires, and check whether the sensors, strain gauges, and wires can work normally after pouring. All specimens need to be cured for 28 days according to standard before the corrosion test is carried out.
[0008] Preferably, in S22, the acceleration mechanism includes: Corrosion methods: based on electro-accelerated wet-dry cycle and seawater corrosion; Simulated areas: targeting the splash zone and tidal range zone; Solution: Use sea water; Wet-dry cycle: Seawater is added to the splash zone, and water level changes are achieved by periodically pumping water in and out, thus simulating the tidal range and splash of the ocean.
[0009] Preferably, S24 includes the following: The energizing time was calculated using type A specimens to correct the energizing time for type B specimens. Based on the experimental design, the steel corrosion rates were set at 5%, 10%, 15%, and 20%, respectively. The current carrying density of the reinforcing steel during the experiment is calculated using the following formula: ; In the formula: i is the corrosion current density; I is the current intensity; l is the length of the reinforcing bar; d is the diameter of the reinforcing bar; Then, use the following formula to calculate the energizing time: ; in, = t; where: k—electrochemical equivalent of the metal, in g / (A·s); I—current magnitude, in A; t — time, in seconds; After the predetermined energizing time for the specimen has elapsed, the concrete specimen is removed, destroyed, and the corroded reinforcing steel is extracted. The surface of the steel is cleaned of any remaining concrete, then pickled in hydrochloric acid to remove rust. The remaining hydrochloric acid is then neutralized with saturated lime water, and finally rinsed thoroughly with clean water. The steel is dried and placed in a drying oven. Once its mass has stabilized, it is weighed to obtain the mass of the corroded steel. The actual amount of corrosion of the steel bar is obtained by comparing it with its initial mass. The steel reinforcement corrosion efficiency is calculated as shown in the following formula: .
[0010] Preferably, S25 includes the following: After the Type A specimen reaches the expected energizing time, the concrete is broken to obtain the corroded steel bar samples. After removing the concrete residue adhering to the steel bar surface, dilute hydrochloric acid is used to remove the rust. Then, alkaline lime water solution is used to neutralize the acid-washed steel bar, and the cleaned steel bar is placed in a drying oven. After drying is completed and the steel bar quality is stable, the weight of the steel bar is measured using an electronic scale, and the actual degree of corrosion of the steel bar is calculated according to the mass corrosion rate formula.
[0011] Preferably, S26 includes the following: The electrical equipment was subjected to corrosion testing using a DC regulated power supply. The reinforcing steel was connected to the positive terminal of the power supply via a wire, while a copper sheet was connected to the negative terminal. This configured the reinforcing steel as the anode and the copper sheet as the cathode in the electrolytic cell. To ensure insulation at the connection between the reinforcing steel and the wire, insulating tape was tightly wrapped around the connection point, and silicone rubber was applied to seal it. An accelerated corrosion experiment was conducted using a constant-voltage DC power supply, and the degree of corrosion was controlled by adjusting the duration of the energization and maintaining a constant current. Connect the pre-embedded sensors and strain gauges to the data acquisition instrument using a four-core cable, check whether each instrument is working properly, and repeatedly debug the data acquisition instrument. Proceed with the experiment according to the experimental plan to collect data, and then statistically analyze, organize, and process the obtained experimental data.
[0012] Preferably, S27 includes the following: after the energization time of the specimen reaches the expected calculated value, observe and record the rust and rust expansion cracks on the specimen surface, and analyze the relationship between its external characteristics and the distribution of chloride ions.
[0013] Preferably, S28 includes the following: after the corrosion experiment is completed, a mechanical property experiment is performed on the specimen, and the obtained experimental data is compared with that of the uncorroded specimen.
[0014] The beneficial effects of the laboratory corrosion simulation method for wharf pile foundations of the present invention are as follows: This invention realizes a complete corrosion simulation experiment from specimen design, environmental simulation, process acceleration, damage quantification to performance evaluation, forming a complete closed loop. Taking actual engineering materials and problems as the starting point and precise quantification of mechanical property degradation as the focus, it provides a theoretical basis and data foundation for the durability design and life cycle management of high-pile wharves. Attached Figure Description
[0015] Figure 1 This is the core working path of the solution described in the embodiments of the present invention.
[0016] Figure 2 This is a schematic diagram of the basic construction of the experiment in an embodiment of the present invention.
[0017] Figure 3 This describes the process flow and ultimate goal of the electrolytically accelerated corrosion scheme in this embodiment of the invention. Detailed Implementation
[0018] The following description is merely a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.
[0019] The following embodiments can be understood as illustrating a part of the structure or method of the present invention individually, or as combining the embodiments to explain the broader structure or method of the present invention.
[0020] Example 1: A laboratory corrosion simulation method for wharf pile foundations, such as Figure 1-3 As shown, it includes the following steps: Step 1: Specimen design and preparation; Step 2, accelerated corrosion test, includes the following specific steps: S21. Design and manufacture the water tank: Design the water tank according to the scale model, with reserved drain and inlet ports; S22. Design an acceleration regime based on the marine environmental report of the wharf; S23. Before corrosion, the specimens are immersed in a water tank for 60 days to ensure that chloride ions in the seawater solution penetrate into the concrete. S24. Calculate the energizing time and corrosion efficiency; S25. Determination of steel reinforcement corrosion rate; S26. Data collection, processing, and analysis; S27. Inspect the degree of corrosion and external characteristics of concrete; S28. Mechanical property test.
[0021] Example 2: Based on Embodiment 1, step 1 includes the following: S11. Specimen type design: Specimen types include: Type A: Material-grade specimen, Φ100×200mm cylinder, used for testing chloride ion permeation, electrochemical parameters, and microscopic analysis; Type B: Component-level specimens, scaled-down models of actual high-pile wharves, reinforced according to the reinforcement ratio, used to simulate the degradation of the pile's bending and crack resistance performance; The design steps of the scaled-down model are as follows: draw the cross-sectional view of the high-pile wharf, calculate the embedment depth of the elastic long pile according to the specifications, and obtain the calculated length of the pile; scale it down to 1:5 or 1:6, reinforce it according to the scaled-down ratio and meet the reinforcement ratio, and add a pile pier at the bottom of the pile to facilitate subsequent experiments, thus obtaining the scaled-down model. S12. Divide the experiments into groups: Based on differences in service environment and load conditions, the specimens were divided into 8 groups, A1 to A4 and B1 to B4, with each group containing parallel specimens; Group A was used to study the chloride corrosion path and time effect, and Group B was used to study the mechanical-environment coupling effect. Each group had a control group and an accelerated corrosion group to ensure data comparability and traceability. S13. When preparing the specimens, the concrete raw materials, mix proportions, and curing regime should be consistent with the actual project. When preparing the specimens, pre-embed the connecting sensors, strain gauges, and wires, and check whether the sensors, strain gauges, and wires can work normally after pouring. All specimens need to be cured for 28 days according to standard before the corrosion test is carried out.
[0022] Example 3: Based on Example 2, the acceleration mechanism in S22 includes: Corrosion methods: based on electro-accelerated wet-dry cycle and seawater corrosion; Simulated area: This refers to the splash zone and tidal zone, which are the areas most severely corroded. This area also needs to be scaled down when conducting corrosion experiments in the laboratory.
[0023] Solution: Using seawater can better recreate the real marine environment.
[0024] Wet-dry cycle: Seawater is added to the splash zone, and water level changes are achieved by periodically pumping water in and out, thus simulating the tidal range and splash of the ocean.
[0025] Example 4: Based on Embodiment 3, S24 includes the following: The energizing time was calculated using type A specimens to correct the energizing time for type B specimens. Based on the experimental design, the steel corrosion rates were set at 5%, 10%, 15%, and 20%, respectively. The current carrying density of the reinforcing steel during the experiment is calculated using the following formula: ; In the formula: i is the corrosion current density; I is the current intensity; l is the length of the reinforcing bar; d is the diameter of the reinforcing bar; Then, use the following formula to calculate the energizing time: ; in, = t; where: k—electrochemical equivalent of the metal, in g / (A·s); I—current magnitude, in A; t — time, in seconds; After the predetermined energizing time for the specimen has elapsed, the concrete specimen is removed, destroyed, and the corroded reinforcing steel is extracted. The surface of the steel is cleaned of any remaining concrete, then pickled in hydrochloric acid to remove rust. The remaining hydrochloric acid is then neutralized with saturated lime water, and finally rinsed thoroughly with clean water. The steel is dried and placed in a drying oven. Once its mass has stabilized, it is weighed to obtain the mass of the corroded steel. The actual amount of corrosion of the steel bar is obtained by comparing it with its initial mass. The steel reinforcement corrosion efficiency is calculated as shown in the following formula: .
[0026] Example 5: Based on Embodiment 4, S25 includes the following: According to Faraday's law: (1) The maximum cross-sectional corrosion rate refers to the ratio of the maximum corrosion depth on the cross-section of the steel bar to the diameter of the steel bar, usually expressed as a percentage. This evaluation method is used to assess the surface corrosion of the steel bar and has certain reference value for steel bars with more severe surface corrosion. (2) The steel reinforcement corrosion rate refers to the ratio of the amount of steel reinforcement corrosion to the steel reinforcement mass, usually expressed as a percentage. This evaluation method is mainly used to assess the overall corrosion of the steel reinforcement and has a good reflection of the overall damage to the steel reinforcement. (3) The actual cross-sectional corrosion rate refers to the ratio of the actual corrosion depth on the cross-section of the steel bar to the cross-sectional area of the steel bar, usually expressed as a percentage. This evaluation method is mainly used to assess the actual corrosion of the steel bars and has important reference value for the safety of the structure. The choice of these three assessment methods depends on the specific condition of the steel reinforcement corrosion and the purpose of the assessment. The calculation method is shown in the following formula: ; ; ; In the formula: S AO S represents the actual cross-sectional area of the specimen at the point of failure before the steel reinforcement corrodes; AC m0 represents the actual cross-sectional area of the specimen at the point of failure after the steel reinforcement has corroded; m1 represents the mass of the steel reinforcement before corrosion; m2 represents the mass of the steel reinforcement after corrosion; S represents the mass of the steel reinforcement after corrosion. A1 S represents the average cross-sectional area of the reinforcing steel before corrosion. A2 This represents the actual cross-sectional area of the damaged section of the specimen after corrosion. After the Type A specimen reached the expected energizing time, the concrete was broken down to obtain the corroded steel reinforcement samples. After removing the concrete residue adhering to the steel reinforcement surface, dilute hydrochloric acid was used to remove the rust, effectively dissolving any remaining rust. Subsequently, the acid-washed steel reinforcement was neutralized with an alkaline lime solution, and then placed in a drying oven. Once drying was complete and the quality stabilized, the weight of the steel reinforcement was measured using an electronic scale, and the actual degree of corrosion was calculated according to the mass corrosion rate formula.
[0027] Example 6: Based on Embodiment 5, S26 includes the following: The electrolytic corrosion test utilizes a DC regulated power supply. The reinforcing steel is connected to the positive terminal of the power supply via a wire, while a copper sheet is connected to the negative terminal. This creates a configuration in the electrolytic cell where the reinforcing steel acts as the anode and the copper sheet as the cathode. To ensure insulation at the connection between the reinforcing steel and the wire, insulating tape is tightly wrapped around the connection point, and silicone rubber is applied for a seal. A constant-voltage DC power supply is used for accelerated corrosion experiments. The degree of corrosion is controlled by adjusting the energizing time and maintaining a constant current. Voltage and current are monitored daily, and a smart test pen is used to check the consistency of voltage at various points to minimize errors in the electrochemical corrosion experiment. Adjustments are made promptly according to the set values to maintain stable energizing conditions and ensure the accuracy and comparability of the experimental results.
[0028] Connect the pre-embedded sensors and strain gauges to the data acquisition instrument using a four-core cable, check whether each instrument is working properly, and repeatedly debug the data acquisition instrument. Proceed with the experiment according to the experimental plan to collect data, and then statistically analyze, organize, and process the obtained experimental data.
[0029] S27 includes the following: after the energization time of the test piece reaches the expected calculated value, observe and record the rust and rust expansion cracks on the surface of the test piece, and analyze the relationship between its external characteristics and the distribution of chloride ions.
[0030] S28 includes the following: after the corrosion experiment is completed, a mechanical property experiment is performed on the specimen, and the obtained experimental data is compared with that of the uncorroded specimen.
Claims
1. A laboratory corrosion simulation method for wharf pile foundations, characterized in that, Includes the following steps: Step 1: Specimen design and preparation; Step 2, accelerated corrosion test, includes the following specific steps: S21. Design and manufacture the water tank: Design the water tank according to the scale model, with reserved drain and inlet ports; S22. Design an acceleration regime based on the marine environmental report of the wharf; S23. Before corrosion, the specimens are immersed in a water tank for 60 days to ensure that chloride ions in the seawater solution penetrate into the concrete. S24. Calculate the energizing time and corrosion efficiency; S25. Determination of steel reinforcement corrosion rate; S26. Data collection, processing, and analysis; S27. Inspect the degree of corrosion and external characteristics of concrete; S28. Mechanical property test.
2. The laboratory corrosion simulation method for wharf pile foundations as described in claim 1, characterized in that, Step 1 includes the following: S11. Specimen type design: Specimen types include: Type A: Material-grade specimen, Φ100×200mm cylinder, used for testing chloride ion permeation, electrochemical parameters, and microscopic analysis; Type B: Component-level specimens, scaled-down models of actual high-pile wharves, reinforced according to the reinforcement ratio, used to simulate the degradation of the pile's bending and crack resistance performance; The design steps for the scaled-down model are as follows: draw the cross-sectional view of the high-pile wharf, calculate the embedment depth of the elastic long pile according to the specifications, and obtain the calculated length of the pile; scale it down to 1:5 or 1:6, reinforce it according to the scaled-down ratio and meet the reinforcement ratio, and add a pile pier at the bottom of the pile to obtain the scaled-down model. S12. Divide the experiments into groups: Based on differences in service environment and load conditions, the specimens were divided into 8 groups, A1 to A4 and B1 to B4, with each group containing parallel specimens; Group A was used to study the chloride corrosion path and time effect, and Group B was used to study the mechanical-environment coupling effect. Each group had a control group and an accelerated corrosion group. S13. When preparing the specimens, the concrete raw materials, mix proportions, and curing regime should be consistent with the actual project. When preparing the specimens, pre-embed the connecting sensors, strain gauges, and wires, and check whether the sensors, strain gauges, and wires can work normally after pouring. All specimens need to be cured for 28 days according to standard before the corrosion test is carried out.
3. The laboratory corrosion simulation method for wharf pile foundations as described in claim 2, characterized in that, In S22, the acceleration mechanism includes: Corrosion methods: based on electro-accelerated wet-dry cycle and seawater corrosion; Simulated areas: targeting the splash zone and tidal range zone; Solution: Use sea water; Wet-dry cycle: Seawater is added to the splash zone, and water level changes are achieved by periodically pumping water in and out, thus simulating the tidal range and splash of the ocean.
4. The laboratory corrosion simulation method for wharf pile foundations as described in claim 3, characterized in that step S24 includes the following: The energizing time was calculated using type A specimens to correct the energizing time for type B specimens. Based on the experimental design, the steel corrosion rates were set at 5%, 10%, 15%, and 20%, respectively. The current carrying density of the reinforcing steel during the experiment is calculated using the following formula: ； In the formula: i is the corrosion current density; I is the current intensity; l is the length of the reinforcing bar; d is the diameter of the reinforcing bar; Then, use the following formula to calculate the energizing time: ； in, = t; where: k—electrochemical equivalent of the metal, in g / (A·s); I—current magnitude, in A; t — time, in seconds; After the predetermined energizing time for the specimen has elapsed, the concrete specimen is removed, destroyed, and the corroded reinforcing steel is extracted. The surface of the steel is cleaned of any remaining concrete, then pickled in hydrochloric acid to remove rust. The remaining hydrochloric acid is then neutralized with saturated lime water, and finally rinsed thoroughly with clean water. The steel is dried and placed in a drying oven. Once its mass has stabilized, it is weighed to obtain the mass of the corroded steel. The actual amount of corrosion of the steel bar is obtained by comparing it with its initial mass. The steel reinforcement corrosion efficiency is calculated as shown in the following formula: 。 5. The laboratory corrosion simulation method for wharf pile foundations as described in claim 4, characterized in that, S25 includes the following: After the Type A specimen reaches the expected energizing time, the concrete is broken to obtain the corroded steel bar samples. After removing the concrete residue adhering to the steel bar surface, dilute hydrochloric acid is used to remove the rust. Then, alkaline lime water solution is used to neutralize the acid-washed steel bar, and the cleaned steel bar is placed in a drying oven. After drying is completed and the steel bar quality is stable, the weight of the steel bar is measured using an electronic scale, and the actual degree of corrosion of the steel bar is calculated according to the mass corrosion rate formula.
6. The laboratory corrosion simulation method for wharf pile foundations as described in claim 5, characterized in that step S26 includes the following: The electrical equipment was subjected to corrosion testing using a DC regulated power supply. The reinforcing steel was connected to the positive terminal of the power supply via a wire, while a copper sheet was connected to the negative terminal. This configured the reinforcing steel as the anode and the copper sheet as the cathode in the electrolytic cell. To ensure insulation at the connection between the reinforcing steel and the wire, insulating tape was tightly wrapped around the connection point, and silicone rubber was applied to seal it. An accelerated corrosion experiment was conducted using a constant-voltage DC power supply, and the degree of corrosion was controlled by adjusting the duration of the energization and maintaining a constant current. Connect the pre-embedded sensors and strain gauges to the data acquisition instrument using a four-core cable, check whether each instrument is working properly, and repeatedly debug the data acquisition instrument. Proceed with the experiment according to the experimental plan to collect data, and then statistically analyze, organize, and process the obtained experimental data.
7. The laboratory corrosion simulation method for wharf pile foundations as described in claim 6, characterized in that, S27 includes the following: after the energization time of the test piece reaches the expected calculated value, observe and record the rust stains and rust expansion cracks on the surface of the test piece, and analyze the relationship between its external characteristics and the distribution of chloride ions.
8. The laboratory corrosion simulation method for wharf pile foundation as described in claim 7, characterized in that S28 includes the following: after the corrosion experiment is completed, mechanical property experiments are conducted on the specimen, and the obtained experimental data are compared with those of uncorroded specimens.