A testing method and system for critical chloride ion concentration of port reinforced concrete

Abstract

The present invention relates to the technical field of chloride ion concentration testing, and particularly to a testing method and system for the critical chloride ion concentration of port reinforced concrete. In the passivation stage, an alkaline solution is used to replace the concrete passivation environment, thereby reducing the passivation time of the steel bar specimen. In the depassivation stage, the steel bar specimen is made into a reinforced concrete specimen to simulate the environment of real port reinforced concrete, so as to improve the testing accuracy of the critical chloride ion concentration of reinforced concrete. At the same time, a method for determining the energization voltage in the chloride ion electromigration acceleration test and a method for determining the data set using the test parameters and the change rate parameters of the experiment as the data source in the data set are proposed. After obtaining the model prediction result, the model prediction result is further corrected according to the change rate using a formula, making the determination result of the energization voltage more accurate, improving the accuracy of determining the electrical parameters of the depassivation test, and thus providing an accurate data basis for determining the depassivation timing.

Description

Technical Field

[0001] The present invention relates to the technical field of chloride ion concentration testing, and particularly to a method and system for testing the critical chloride ion concentration of port reinforced concrete. Background Art

[0002] Reinforced concrete structures are one of the most widely used structural forms in current port construction in the world. The combination of the high compressive strength of concrete and the high tensile performance of steel bars endows reinforced concrete structures with various advantages; Reinforced concrete structures in the port environment are long-term exposed to chloride salt erosion. If the durability design, detection, and protection of the structure are not paid attention to, its service life will be difficult to meet the design requirements, which will bring economic losses and safety hazards to the national infrastructure construction; Therefore, the durability research of reinforced concrete structures in the marine environment has become one of the important topics, and an important parameter in durability life prediction, detection, and protection is the critical chloride ion concentration for steel bar corrosion. For the reinforced concrete in the splash zone and tidal zone of the port, since the chloride ion transport mode therein includes not only diffusion but also capillary absorption and penetration, resulting in a relatively large intrusion rate, and at the same time, it is also affected by the actions such as wet-dry alternation, wind-wave load, and microbial corrosion, therefore, the steel bars in the concrete in these areas are corroded most severely. Therefore, it is necessary to test the critical chloride ion concentration of port reinforced concrete to explore the corrosion situation and mechanism of the steel bars in the concrete.

[0003] In the prior art, there are solutions for testing the critical chloride ion concentration. For example, Chinese Invention Patent (CN108254302A) discloses an experimental device and method for studying the critical chloride ion concentration in the tidal zone and splash zone of bridge piers, including the following steps: 1) Preparation of test specimens. The test specimens include a specimen body and test steel bars. The specimen body is cast from cement, fly ash, water, and standard sand according to a certain mix ratio. The test steel bars include a test embedded section and a test connection section. The test embedded section is embedded in the specimen body, and the test connection section is exposed outside the specimen body; 2) After the test specimens are prepared, the test specimens are placed in the first water tank in the test device, and the other end of the connection resistance is connected to the test connection section. The test specimens and the polarized steel bars are connected through the connection resistance. After the test specimens are placed and connected, seawater or sodium chloride solution is added to the first water tank; 3) Simulation of the tidal zone and splash zone. The simulation tidal device controls the elevation of the solution contained in the first water tank to perform periodic changes in the tidal zone. The tidal zone period is 6h or 12h; the simulation splash device performs periodic spraying on the test specimens in the splash zone. The splash zone period is 6 - 12h; 4) During the simulation of the tidal zone and splash zone, corrosion monitoring is performed on the test specimens; 5) After corrosion monitoring detects that the test specimens are corroded, the simulation of the tidal zone and splash zone is stopped, the connection resistance provided on the test steel bars is removed, and the test specimens are taken out of the first water tank; 6) After the test specimens are taken out, the surface of the specimen body is wiped dry, and the specimen body is damaged to expose the test embedded section; 7) Observe the test embedded section, take samples from the test body above the test embedded section that has not been corroded and is close to corrosion, and measure the chloride ion content. This chloride ion content is the critical chloride ion concentration value.

[0004] However, in the process of testing the critical chloride ion concentration in the above solution, there are technical problems such as long testing time, relatively rough testing process, and low testing accuracy. Summary of the Invention

[0005] To solve the above technical problems, the present invention provides a method and system for testing the critical chloride ion concentration of port reinforced concrete to solve the problems existing in the prior art.

[0006] The present invention provides a method for testing the critical chloride ion concentration of port reinforced concrete, including the following steps:

[0007] S1: Prepare a plurality of steel bar specimens;

[0008] S2: Perform passivation operation on the steel bar specimens;

[0009] S3: Place the steel bar specimens in concrete to obtain reinforced concrete specimens;

[0010] S4: Conduct a depassivation test on the reinforced concrete specimen;

[0011] Specifically, S4 is as follows:

[0012] S4.1: Prepare a solution for the depassivation test;

[0013] S4.2: Immerse the reinforced concrete specimen in the solution for the depassivation test and perform depassivation by accelerating chloride ion electro-migration treatment according to the energization parameters.

[0014] The energization parameters include the energization voltage; the process of determining the energization voltage V f for accelerating chloride ion electro-migration treatment is as follows:

[0015] Sa: Set the initial energization voltage V 0 for accelerating chloride ion electro-migration treatment for 6 h;

[0016] Sb: Let the reinforced concrete specimen stand for 24 h, and then collect the open-circuit voltage of the reinforced concrete specimen at different times;

[0017] Sc: Calculate the change rate of the open-circuit voltage at two adjacent sampling times;

[0018] Sd: Establish a data set for predicting the energization voltage V f ;

[0019] Se: Input the data set into an artificial neural network model to obtain the energization voltage V f1 predicted by the model;

[0020] Sf: Use the energization voltage V f1 predicted by the model for accelerating chloride ion electro-migration treatment for 6 h, then let the reinforced concrete specimen stand for 24 h, and then collect the open-circuit voltage V 13 of the reinforced concrete specimen after standing and the open-circuit voltage V 14 of the reinforced concrete specimen after standing for 0.5 h;

[0021] Sg: Calculate the change rate n 13 of the open-circuit voltage V 14 of the reinforced concrete specimen after standing and the open-circuit voltage V 12 of the reinforced concrete specimen after standing for 0.5 h;

[0022] Sh: According to the energization voltage V f1 predicted by the model and the change rate n 12 , obtain the energization voltage V f for accelerating chloride ion electro-migration treatment;

[0023] S5: Monitor the real-time electrochemical parameters of the reinforced concrete specimen. After detecting the depassivation of the reinforced concrete specimen, test the critical chloride ion concentration of the reinforced concrete specimen.

[0024] Preferably, in Sd, the chloride ion concentration in the solution for the depassivation test, the initial energization voltage, the open-circuit voltage of the reinforced concrete specimen at different times, and the change rate of the open-circuit voltage between two adjacent sampling times are used as the data set for predicting the energization voltage V f of.

[0025] Preferably, in Se, before the artificial neural network model makes a prediction, it further includes the step of model training;

[0026] The specific steps of the model training are as follows: Set different chloride ion concentrations and different initial energization voltages. Obtain multiple data sets according to the steps of Sa-Sd. Then, have experts label and process the data sets to obtain the training set and validation set for the training and validation of the artificial neural network model. Then, use a loss function to constrain the training process of the artificial neural network model to obtain the final artificial neural network model.

[0027] Preferably, in Sh, based on the predicted energization voltage V f1 and the change rate n 12 , the formula for obtaining the energization voltage V for accelerating chloride ion electromigration treatment is: f Specifically:

[0028]

[0029] In the formula, n i is the i-th change rate, and a is a constant.

[0030] Preferably, in S2, the passivation operation is specifically as follows:

[0031] S2.1: Place the steel bar specimen in a saturated calcium hydroxide solution;

[0032] S2.2: Real-time collect the open-circuit voltage on the surface of the steel bar specimen;

[0033] S2.3: When the open-circuit voltage is stable, end the passivation operation.

[0034] Preferably, S1 specifically includes: cutting steel bars with a diameter of 10 mm into steel bar segments with a length of 4 cm, then performing a grinding operation on the steel bar segments, grinding the steel bar segments with 60-mesh, 80-mesh, and 120-mesh sandpapers respectively to remove the oxide layer on the surface of the steel bar segments; then placing them in deionized water for ultrasonic cleaning; then welding copper wires to the cleaned steel bar segments and placing them in epoxy resin to form the steel bar specimens.

[0035] Preferably, the epoxy resin is a second-generation bisphenol A epoxy resin.

[0036] Preferably, in S2.2, a silver-silver chloride electrode is used as the reference electrode for the steel bar specimen, and the steel bar specimen and the reference electrode are connected to an electrochemical workstation to realize real-time acquisition of the open-circuit voltage on the surface of the steel bar specimen.

[0037] Preferably, in S2.3, the stable open-circuit voltage of the steel bar specimen is -254 mV.

[0038] According to another aspect of the present invention, there is provided a testing system for the critical chloride ion concentration of port reinforced concrete. The system adopts the above-mentioned testing method for the critical chloride ion concentration of port reinforced concrete, and the system includes:

[0039] A steel bar specimen preparation unit for preparing a plurality of steel bar specimens;

[0040] A passivation operation unit for performing a passivation operation on the steel bar specimens;

[0041] A reinforced concrete specimen preparation unit for placing the steel bar specimens in concrete to obtain reinforced concrete specimens;

[0042] A de-passivation unit for performing a de-passivation test on the reinforced concrete specimens;

[0043] A critical chloride ion concentration determination unit for monitoring the real-time electrochemical parameters of the reinforced concrete specimens, and testing the critical chloride ion concentration of the reinforced concrete specimens after monitoring that the reinforced concrete specimens are de-passivated.

[0044] The embodiments of the present invention have the following technical effects:

[0045] In the passivation stage of the present invention, an alkaline solution is used instead of the concrete passivation environment, thereby reducing the passivation time of the steel bar specimens; and in the de-passivation link, the steel bar specimens are made into reinforced concrete specimens in order to simulate the environment of real port reinforced concrete, so as to improve the test accuracy of the critical chloride ion concentration of reinforced concrete.

[0046] The present invention provides a method for determining the energization voltage in the chloride ion electro-migration acceleration test. In this method, an initial energization voltage is first set for the electro-migration acceleration test, and then parameters for predicting the energization voltage are obtained. Moreover, compared with the prior art, in this embodiment, a method is proposed in which the test parameters and the change rate parameters of the experiment are used as the data sources in the dataset, making the prediction effect of the model more accurate. At the same time, after obtaining the model prediction result, the model prediction result is used as the energization voltage, and then the change rate of the open-circuit voltage is further obtained. Then, the model prediction result is further corrected according to the change rate using a formula, making the determination result of the energization voltage more accurate, thereby improving the accuracy of determining the electro-parameters of the depassivation test and providing an accurate data basis for determining the depassivation timing. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for use in the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0048] Figure 1 is a schematic diagram of the electrochemical reaction of reinforced concrete corrosion in the prior art;

[0049] Figure 2 is a flowchart of a method for testing the critical chloride ion concentration of port reinforced concrete provided by an embodiment of the present invention;

[0050] Figure 3 is a flowchart of the passivation operation for the steel bar specimen provided by an embodiment of the present invention;

[0051] Figure 4 is a flowchart of the depassivation test for the reinforced concrete specimen provided by an embodiment of the present invention;

[0052] Figure 5 is a flowchart of determining the energization voltage for accelerating chloride ion electro-migration treatment provided by an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0053] To make the objectives, technical solutions, and advantages of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art without creative efforts based on the embodiments of the present invention belong to the scope protected by the present invention.

[0054] Concrete has a porous structure, so oxygen often exists in the pores of actual reinforced concrete structures. Figure 1 Figure Figure 1 shows a schematic diagram of the electrochemical reaction of reinforced concrete corrosion, as shown in the appendix Figure 1 As shown, the reaction of steel corrosion in reinforced concrete structures is mainly oxygen absorption corrosion, and the reaction process is as follows:

[0055] Anodic reaction: ;

[0056] Cathodic reaction: ;

[0057] When the hydroxide ions at the cathode transfer to the anode, they continue to react with the divalent iron ions at the anode, and the reaction formula is as follows:

[0058] ;

[0059] However, for the port environment, the pH value of the pore liquid inside the concrete is very high, up to about 13. Under high alkaline conditions, Fe(OH) generated by steel corrosion 2 is relatively stable and continues to undergo oxidation reaction in the presence of sufficient oxygen:

[0060] ;

[0061] The generated corrosion products Fe(OH) 2 and Fe(OH) 3 finally generate compounds such as FeO, Fe 2 0 3 and Fe 3 0 4 etc. attached to the surface of the steel bar. These products are the passivation films formed on the surface of the steel bar. Whether it is the passivation process or the depassivation process of the steel bar, the above anodic reaction will occur. The metal matrix of the steel bar loses electrons and becomes the raw material for the formation of the steel bar passivation film. During the passivation process, as the passivation film gradually forms, the corrosion rate of the steel bar becomes slower and slower, and the growth rate of the passivation film continuously decreases until it finally stops growing and reaches a relatively stable state.

[0062] The passivation film formed on the surface of the steel bar in the concrete structure can protect the steel bar from corrosion. However, for concrete structures in chloride environments such as ports, chloride ions will enter the concrete pore liquid through capillary action, diffusion, and penetration, and then gradually migrate to the steel bar / concrete interface and contact the passivation film on the surface of the steel bar; when the chloride ions on the surface of the steel bar accumulate to the threshold value that causes the steel bar to depassivate, that is, reach the critical chloride ion concentration, even if the steel bar is still in a high alkaline condition, the passivation film on its surface will also be damaged, resulting in steel bar corrosion; this embodiment is to test the critical chloride ion concentration of reinforced concrete in ports.

[0063] Example 1 Figure 2 is a flowchart of a method for testing the critical chloride ion concentration of port reinforced concrete provided in Example 1 of the present invention. Referring to Figure 2 , a method for testing the critical chloride ion concentration of port reinforced concrete specifically includes the following steps:

[0064] S1: Prepare a number of steel bar specimens;

[0065] Cut the steel bar with a diameter of 10 mm into steel bar segments with a length of 4 cm, and then perform a grinding operation on the steel bar segments. Grind the steel bar segments with 60-mesh, 80-mesh, and 120-mesh sandpapers respectively to remove the oxide layer on the surface of the steel bar segments and make the surface of the steel bar segments show the natural color of the steel bar. Then place them in deionized water for ultrasonic cleaning; then weld copper wires to the cleaned steel bar segments and place them in epoxy resin to form the steel bar specimens;

[0066] Specifically, the epoxy resin is a second-generation bisphenol A epoxy resin, which has the advantages of good stability, fast curing speed, and small shrinkage rate, and has little influence on the subsequent testing process;

[0067] It should be emphasized that the steel bar specimen includes a copper wire, a steel bar segment, and epoxy resin. Among them, the upper cross-section of the steel bar segment is welded and connected to the copper wire, the epoxy resin surrounds the side surface of the steel bar segment, and the lower cross-section of the steel bar specimen is the working surface for testing the critical chloride ion concentration of reinforced concrete.

[0068] S2: Perform a passivation operation on the steel bar specimens;

[0069] As can be seen from the above introduction, the steel bars in the concrete structure will form a passivation film on the surface. As time goes by, the steel bars will corrode only after the passivation film is gradually damaged. Therefore, when exploring the critical chloride ion concentration of the steel bars in the concrete, it is first necessary to perform a passivation operation on the steel bar specimens;

[0070] Specifically, Attached Figure 3 shows a flowchart of performing a passivation operation on the steel bar specimens. As shown in Attached Figure 3 shown, the passivation operation is specifically as follows:

[0071] S2.1: Place the steel bar specimens in a saturated calcium hydroxide solution;

[0072] Since the main component of the pore fluid of concrete is calcium hydroxide solution before carbonization, in order to achieve a better simulation effect in this embodiment, the saturated calcium hydroxide solution is used as the carbonization solution for the steel bar specimens;

[0073] S2.2: Real-time collect the open-circuit voltage on the surface of the steel bar specimens;

[0074] In this step, since the silver-silver chloride electrode has good stability and reproducibility and does not contain toxic mercury elements, the silver-silver chloride electrode is used as the reference electrode for the steel bar specimen. After determining the reference electrode, the steel bar specimen and the reference electrode are connected to an electrochemical workstation, so as to realize real-time collection of the open-circuit voltage on the surface of the steel bar specimen.

[0075] S2.3: When the open-circuit voltage is stable, end the passivation operation.

[0076] When passivating the steel bar specimen, in the initial time period, the open-circuit voltage of the steel bar specimen has a rapid rising process. Then, as time goes by, the open-circuit voltage of the steel bar specimen gradually stabilizes, indicating that a passivation film has been formed on the surface of the steel bar specimen at this time.

[0077] Specifically, the stable open-circuit voltage of the steel bar specimen is -254 mV.

[0078] S3: Place the steel bar specimen in concrete to obtain a reinforced concrete specimen.

[0079] In the prior art, generally, a reinforced concrete specimen is made before passivation, and then passivation tests and depassivation tests are carried out. However, the above process takes a long time to achieve passivation and depassivation, resulting in a long test time for the critical chloride ion concentration of reinforced concrete. According to the above defects, in this embodiment, an alkaline solution is used to replace the concrete passivation environment in the passivation stage, so as to reduce the passivation time of the steel bar specimen; and in the depassivation link, the steel bar specimen is made into a reinforced concrete specimen again, in order to simulate the environment of real port reinforced concrete and improve the test accuracy of the critical chloride ion concentration of reinforced concrete.

[0080] Specifically, S3 is as follows: Place the steel bar specimen in a mold so that the working surface of the steel bar specimen contacts the mold. Then, select concrete with the same specifications as the facilities in the port and pour it into the mold, and place it on a vibrating mixer for uniform vibration stirring. After uniform stirring, let it stand for 24 hours and then demold to obtain the reinforced concrete specimen.

[0081] S4: Conduct a depassivation test on the reinforced concrete specimen.

[0082] In this step, a chloride ion electromigration system is used to accelerate the transport of chloride ions in the reinforced concrete specimen by electromigration, so as to achieve the effect of reducing the test time.

[0083] Specifically, Figure 4 is a flowchart showing the depassivation test of the reinforced concrete specimen. As shown in Figure 4 shown, S4 is specifically as follows:

[0084] S4.1: Configure the solution for the activation test;

[0085] In this step, S4.1 is specifically as follows: Inject 500 ml of sodium hydroxide solution with a concentration of 0.5 mol / L into a water tank, and then inject 10 L of sodium chloride solution with a concentration of 5% into the water tank and stir evenly to obtain the solution for the activation test;

[0086] S4.2: Place the reinforced concrete specimen into the solution for the activation test and perform accelerated chloride ion electro-migration treatment according to the energization parameters for activation;

[0087] Among them, the energization parameters include the energization voltage and the energization time;

[0088] Among them, the energization time is 48 h. For the setting of the energization voltage, in the prior art, the energization voltage is generally determined according to experiments or experience to ensure the accuracy and stability of the test results of the reinforced concrete specimen; generally, the greater the energization voltage, the less time required for activation. However, at the same time, it also brings the problem of poor stability of the activation detection data; therefore, in this embodiment, in view of the above problems, a method for determining the electro-migration parameters that takes into account both the activation test time and the stability of the activation detection data is proposed;

[0089] Specifically, as shown in the appendix Figure 5 The process of determining the energization voltage V for accelerating chloride ion electro-migration treatment is as follows: f :

[0090] Sa: Set the initial energization voltage V for accelerating chloride ion electro-migration treatment for 6 h; 0 Among them, in this embodiment, the initial energization voltage V is 4 V;

[0091] Sb: Let the reinforced concrete specimen stand for 24 h, and then collect the open-circuit voltage of the reinforced concrete specimen at different times; 0 Among them, the open-circuit voltage of the reinforced concrete specimen at different times is collected starting from the end of standing, and an open-circuit voltage is collected every 0.5 h, and a total of 12 open-circuit voltages are collected, namely V

[0092] Sc: Calculate the change rate of the open-circuit voltage at two adjacent sampling times;

[0093] Among them, through this step, a total of 11 change rates n of the open-circuit voltage are obtained from 12 open-circuit voltages 1 , V 2 , … V 12 ;

[0094] Sc: Calculate the change rate of the open-circuit voltage at two adjacent sampling times;

[0095] Among them, through this step, 11 change rates n of the open-circuit voltage are obtained from 12 open-circuit voltages 1 , n2 …n 11 ;

[0096] Sd: Establish a data set for predicting the energization voltage V f ;

[0097] Wherein, the chloride ion concentration, the initial energization voltage, the open-circuit voltage of the reinforced concrete specimen at different times, and the change rate of the open-circuit voltage at two adjacent sampling times in the solution for the depassivation test are used as the data set for predicting the energization voltage V f ;

[0098] In this step, the chloride ion concentration, the initial energization voltage, the open-circuit voltage of the reinforced concrete specimen at different times, and the change rate of the open-circuit voltage at two adjacent sampling times in the solution for the depassivation test are used as the data set

[0099] Se: Input the data set into an artificial neural network model to obtain the energization voltage V predicted by the model f1 ;

[0100] Wherein, before the prediction by the artificial neural network model, it further includes the step of model training

[0101] The process of the model training is as follows: Set different chloride ion concentrations and different initial energization voltages, obtain multiple data sets according to the processes of Sa-Sd, and then label and process the data sets by experts to obtain the training set and the validation set for the training and validation of the artificial neural network model, and then constrain the training process of the artificial neural network model through a loss function to obtain the final artificial neural network model

[0102] Sf: Use the energization voltage V predicted by the model f1 for accelerating the chloride ion electromigration treatment for 6 h, then let the reinforced concrete specimen stand for 24 h, and then collect the open-circuit voltage V of the reinforced concrete specimen after standing 13 and the open-circuit voltage V of the reinforced concrete specimen after standing for 0.5 h 14 ;

[0103] Sg: Calculate the change rate n 13 of the open-circuit voltage V of the reinforced concrete specimen after standing 14 and the open-circuit voltage V of the reinforced concrete specimen after standing for 0.5 h 12 ;

[0104] Sh: According to the energization voltage V predicted by the model f1 and the change rate n 12 , obtain the energization voltage V for accelerating the chloride ion electromigration treatment f;

[0105] Among them, the energization voltage V predicted according to the model f1 and the change rate n 12 , to obtain the energization voltage V for accelerating chloride ion electromigration treatment f The specific formula is:

[0106] ;

[0107] In the formula, n i is the i-th change rate, and a is a constant;

[0108] In this embodiment, compared with the prior art, a method for determining the energization voltage in the chloride ion electromigration acceleration test is proposed. In this method, first, an initial energization voltage is set for the electromigration acceleration test, and then the parameters for energization voltage prediction are obtained. Moreover, compared with the prior art, this embodiment proposes using the test parameters and the change rate parameters of the experiment as the data sources in the dataset, making the prediction effect of the model more accurate; at the same time, after obtaining the model prediction result, taking the model prediction result as the energization voltage, further obtaining the change rate of the open-circuit voltage, and then further correcting the model prediction result according to the change rate using the formula; making the determination result of the energization voltage more accurate; thereby improving the accuracy of determining the electrical parameters of the depassivation test.

[0109] S5: Perform real-time electrochemical parameter monitoring on the reinforced concrete specimen. After detecting that the reinforced concrete specimen is depassivated, test the critical chloride ion concentration of the reinforced concrete specimen.

[0110] Among them, the electrochemical parameters include the planned resistance and current density of the reinforced concrete specimen.

[0111] In this step, thanks to the above-determined energization voltage, the determination of the depassivation timing is more accurate in the chloride ion electromigration acceleration test.

[0112] Embodiment 2, the present invention also provides a port reinforced concrete critical chloride ion concentration test system. The system adopts the port reinforced concrete critical chloride ion concentration test method of Embodiment 1. The system includes:

[0113] A steel bar specimen preparation unit for preparing a plurality of steel bar specimens;

[0114] A passivation operation unit for performing passivation operations on the steel bar specimens;

[0115] A reinforced concrete specimen preparation unit for placing the steel bar specimens in concrete to obtain reinforced concrete specimens;

[0116] A passivation-breaking unit for performing a passivation-breaking test on the reinforced concrete specimen;

[0117] A critical chloride ion concentration determination unit for real-time monitoring of the electrochemical parameters of the reinforced concrete specimen, and for testing the critical chloride ion concentration of the reinforced concrete specimen after detecting the passivation-breaking of the reinforced concrete specimen.

[0118] Example 3. The present invention also provides an electronic device, including one or more processors and a memory.

[0119] The processor may be a central processing unit (CPU) or other form of processing unit with data processing capabilities and / or instruction execution capabilities, and may control other components in the electronic device to perform desired functions.

[0120] The memory may include one or more computer program products, and the computer program products may include various forms of computer-readable storage media, such as volatile memory and / or non-volatile memory. The volatile memory may include, for example, random access memory (RAM) and / or cache memory, etc. The non-volatile memory may include, for example, read-only memory (ROM), hard disk, flash memory, etc. One or more computer program instructions may be stored on the computer-readable storage media, and the processor may run the program instructions to implement the port reinforced concrete critical chloride ion concentration testing method of any embodiment of the present application as described above and / or other desired functions. Various contents such as initial external parameters and thresholds may also be stored in the computer-readable storage media.

[0121] In one example, the electronic device may further include: an input device and an output device, and these components are interconnected through a bus system and / or other forms of connection mechanisms. The input device may include, for example, a keyboard, a mouse, etc. The output device may output various information to the outside, including early warning prompt information, braking force, etc. The output device may include, for example, a display, a speaker, a printer, and a communication network and its connected remote output devices, etc.

[0122] Of course, for simplicity, components such as buses, input / output interfaces, etc. are omitted. In addition, according to specific application scenarios, the electronic device may further include any other appropriate components.

[0123] In addition to the above methods and devices, an embodiment of the present application may also be a computer program product, which includes computer program instructions, and the computer program instructions, when run by the processor, cause the processor to implement the functions of the port reinforced concrete critical chloride ion concentration testing method provided by any embodiment of the present application.

[0124] The computer program product may be written in any combination of one or more programming languages for programming code to perform the operations of the embodiments of the present application. The programming languages include object-oriented programming languages such as Java, C++, etc., and also include conventional procedural programming languages such as the "C" language or similar programming languages. The programming code may be executed entirely on the user computing device, partially on the user device, executed as a stand-alone software package, partially on the user computing device and partially on a remote computing device, or entirely on a remote computing device or server.

[0125] In addition, an embodiment of the present application may also be a computer-readable storage medium having computer program instructions stored thereon, and when the computer program instructions are run by a processor, the processor implements a method for testing the critical chloride ion concentration of port reinforced concrete provided by any embodiment of the present application.

[0126] The computer-readable storage medium may employ any combination of one or more readable media. The readable medium may be a readable signal medium or a readable storage medium. The readable storage medium may, for example, include but is not limited to an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination of the above. More specific examples (non-exhaustive list) of the readable storage medium include: an electrical connection having one or more wires, a portable disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above.

[0127] It should be noted that the terms used in the present invention are only for describing specific embodiments and do not limit the scope of the present application. As shown in the specification of the present invention, unless the context clearly indicates an exception, words such as "a", "an", "one", and / or "the" are not specifically singular and may also include plural. The term "comprising", "including" or any other variant thereof is intended to cover a non-exclusive inclusion, such that a process, method or device comprising a series of elements not only includes those elements but also includes other elements not expressly listed, or further includes elements inherent to such process, method or device. Without further limitation, an element defined by the statement "comprising an..." does not exclude the presence of additional identical elements in the process, method or device comprising the element.

[0128] It should also be noted that the orientation or positional relationship indicated by terms such as "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to the present invention. Unless otherwise clearly specified and defined, terms such as "installed", "connected", "coupled" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0129] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the technical solutions of the embodiments of the present invention.

Claims

1. A method for testing critical chloride ion concentration of reinforced concrete in a port, characterized in that: The following steps are involved: S1: Prepare several steel bar specimens; S2: performing a passivation operation on the steel bar sample; S3: placing the passivated steel bar sample in concrete to obtain a reinforced concrete sample; S4: performing a depassivation test on the reinforced concrete specimen; The S4 is specifically: S4.1: Prepare the solution for the depassivation test; S4.2: placing the reinforced concrete sample in the solution for the depassivation test, and performing accelerated chloride ion electromigration treatment according to the power-on parameters for depassivation, wherein the power-on parameters include a power-on voltage, and determining a power-on voltage V for accelerating chloride ion electromigration treatment. f The process is: Sa: setting an initial power-on voltage V0, accelerating the chloride ion electromigration treatment at the initial power-on voltage V0, and the treatment time is 6 hours; Sb: The treated reinforced concrete sample is left to stand for 24 hours, and then the open circuit voltage of the reinforced concrete sample is collected at different times; Sc: Calculate the change rate of the open circuit voltage between two adjacent sampling moments; Sd: Established to predict the power-on voltage V f Datasets; Se: Input the data set into the first artificial neural network model to obtain the model predicted power-on voltage V f1 ; Sf: The model predicts the power-on voltage V f1 It is used to accelerate the electromigration of chloride ions for 6 hours, and then the reinforced concrete sample is left to stand for 24 hours, and then the open circuit voltage V of the reinforced concrete sample after standing is collected. 13 and the open circuit voltage V of the reinforced concrete sample after standing for 0.5 h 14 ; Sg: Calculate the open circuit voltage V of the reinforced concrete sample after standing 13 and the open circuit voltage V of the reinforced concrete sample after standing for 0.5 h 14 The rate of change n 12 ; Sh: The power-on voltage V predicted according to the model f1 And the rate of change n 12 , and the power-on voltage V for accelerating chloride ion electromigration treatment is obtained f ; S5: monitoring the electrochemical parameters of the reinforced concrete sample in real time, and after monitoring that the reinforced concrete sample is depassivated, testing the critical chloride ion concentration of the reinforced concrete sample.

2. A method for testing critical chloride ion concentration of reinforced concrete in a port according to claim 1, characterized in that: In the Sd, the chloride ion concentration in the solution for the depassivation test, the initial power-on voltage, the open circuit voltage of the reinforced concrete sample at different times, and the change rate of the open circuit voltage at two adjacent sampling times are used as the parameters for predicting the power-on voltage V f of the dataset.

3. A method for testing critical chloride ion concentration of port reinforced concrete according to claim 1, characterized in that: In the Se, the artificial neural network model further includes a model training step before prediction; The steps of model training are specifically as follows: setting different chloride ion concentrations and different initial power-on voltages, obtaining multiple data sets according to the Sa-Sd steps, and then annotating the data sets to obtain training sets and verification sets for training and verification of the artificial neural network model, and then constraining the training process of the artificial neural network model through a loss function to obtain the final artificial neural network model.

4. A method for testing critical chloride ion concentration of reinforced concrete in a port according to claim 1, characterized in that: In the Sh, the power-on voltage V predicted by the model f1 And the rate of change n 12 , and the power-on voltage V for accelerating chloride ion electromigration treatment is obtained f The specific formula is: ； Where n i is the i-th rate of change, and a is a constant.

5. A method for testing critical chloride ion concentration of port reinforced concrete according to claim 1, characterized in that: In S2, the passivation operation is specifically as follows: S2.1: placing the steel bar sample into a saturated calcium hydroxide solution; S2.2: collecting the open circuit voltage on the surface of the steel bar sample in real time; S2.3: When the open circuit is stable, the passivation operation is terminated.

6. A method for testing critical chloride ion concentration of port reinforced concrete according to claim 1, characterized in that: In S1, the preparation of several steel bar samples is specifically as follows: a steel bar with a diameter of 10 mm is cut into steel bar bars with a length of 4 cm, and then the steel bar bars are polished by sandpaper of 60 mesh, 80 mesh, and 120 mesh respectively to remove the oxide layer on the surface of the steel bar bars; then the steel bar bars are placed in deionized water for ultrasonic cleaning; then copper wires are welded in the cleaned steel bar bars, and placed in epoxy resin to form the steel bar samples.

7. A method for testing critical chloride ion concentration of port reinforced concrete according to claim 6, characterized in that: The epoxy resin is a second-generation bisphenol A epoxy resin.

8. A method for testing critical chloride ion concentration of reinforced concrete in a port according to claim 5, characterized in that: In S2.2, a silver-silver chloride electrode is used as a reference electrode of the steel bar sample, and the steel bar sample and the reference electrode are connected to an electrochemical workstation to achieve real-time collection of the open circuit voltage on the surface of the steel bar sample.

9. A method for testing critical chloride ion concentration of reinforced concrete in a port according to claim 5, characterized in that: In S2.3, the stable open circuit voltage of the steel bar sample is -254mV.

10. A critical chloride ion concentration test system for reinforced concrete in a port, characterized in that: The system adopts the critical chloride ion concentration test method for reinforced concrete in a port according to any one of claims 1 to 9, and the system comprises: A steel bar sample preparation unit, used to prepare a number of steel bar samples; A passivation operation unit, connected to the steel bar sample preparation unit, and used to perform a passivation operation on the steel bar sample; A reinforced concrete sample preparation unit is connected to the passivation operation unit and is used to place the steel sample after the passivation operation in concrete to obtain a reinforced concrete sample; a depassivation unit, connected to the reinforced concrete sample preparation unit, and used for performing a depassivation test on the reinforced concrete sample; The critical chloride ion concentration determination unit is connected to the depassivation unit and is used to monitor the electrochemical parameters of the reinforced concrete sample in real time, and after monitoring the depassivation of the reinforced concrete sample, test the critical chloride ion concentration of the reinforced concrete sample.

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