Power transmission and transformation project reinforced concrete corrosion evaluation method and system

Abstract

The application provides a power transmission and transformation engineering reinforced concrete corrosion evaluation method and system, and relates to the technical field of civil engineering durability evaluation. The application collects temperature data of the engineering site, total volume of reinforced concrete, water content and pore volume, and constructs a freeze-thaw damage index formula. According to the measured sulfate concentration, the product type is distinguished, and different sulfate corrosion index formulas are constructed by combining related data. The magnesium ion concentration is considered alone in the marine environment. The chloride salt corrosion index formula is constructed according to the chloride ion concentration. The carbonation corrosion index formula is constructed by extracting data from the research report. Then, the weight of each corrosion type is given to establish a comprehensive corrosion evaluation index formula, and the corrosion degree can be determined according to the result. Through this method, various corrosion factors can be considered comprehensively, and the corrosion degree can be effectively determined according to the evaluation result, which provides key basis and scientific guidance for the durability protection, protection measure development and maintenance decision of the reinforced concrete structure of the power transmission and transformation engineering.

Description

Technical Field

[0001] This invention relates to the field of civil engineering durability assessment technology, specifically to a method and system for assessing the corrosivity of reinforced concrete in power transmission and transformation projects. Background Technology

[0002] In the field of power transmission and transformation engineering, reinforced concrete structures are widely used in key components such as tower foundations and substation building foundations. Their durability directly affects the safe and stable operation of the entire power transmission and transformation system. However, during actual service, reinforced concrete inevitably suffers from various corrosive factors. For example, freeze-thaw damage is common in power transmission and transformation projects in cold regions. In power transmission and transformation projects in the cold winter regions of northern my country, tower foundations and substation building foundations are frequently subjected to freeze-thaw cycles, leading to erosion, cracking, and other defects on the surface of reinforced concrete. Sulfate corrosion damages reinforced concrete components, causing the reinforced concrete to absorb water, expand, and crack, eventually turning into a non-sticky paste. Chloride salts penetrate into the interior of reinforced concrete through penetration, diffusion, and convection, easily leading to problems such as steel corrosion and concrete spalling. Corrosion problems are becoming increasingly prominent.

[0003] Reinforced concrete structures in power transmission and transformation projects are often subjected to the combined effects of multiple corrosive factors. Currently, most assessment methods for the corrosion of reinforced concrete focus on a single corrosive factor, which cannot accurately reflect the true corrosion state of the structure and lack a systematic assessment of the combined effects of multiple corrosive factors.

[0004] In summary, this invention aims to provide a comprehensive, accurate, and practical method and system for assessing the corrosion of reinforced concrete in power transmission and transformation projects. By comprehensively considering multiple corrosion factors such as freeze-thaw damage, sulfate attack, chloride attack, and carbonation, a corresponding corrosion index formula is constructed. Furthermore, weights are assigned according to the importance of each corrosion type to the overall corrosion, establishing a comprehensive corrosion assessment index formula that can more realistically reflect the corrosion status of reinforced concrete structures in actual service environments.

[0005] The information disclosed in the background section is only intended to enhance the understanding of the background of this disclosure, and therefore may include information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0006] The purpose of this invention is to provide a method and system for assessing the corrosivity of reinforced concrete in power transmission and transformation projects, so as to solve the problems mentioned in the background art.

[0007] To achieve the above objectives, the present invention provides the following technical solution: A method for assessing the corrosivity of reinforced concrete in power transmission and transformation projects, comprising the following steps: Step 1: Collect temperature data of the location of the power transmission and transformation project, as well as the characteristic data of the reinforced concrete to be evaluated. Construct a freeze-thaw damage index formula based on the collected temperature data and characteristic data. The temperature data includes temperature cycle, variation range and temperature change time. The characteristic data includes the total volume, water content and pore volume of the reinforced concrete. Step 2: Based on the groundwater sulfate concentration data at the location of the power transmission and transformation project, determine the type of erosion products generated. Based on the type of erosion products, construct the corresponding sulfate erosion index formula using groundwater pH value, erosion time, aluminum ion concentration, and calcium ion concentration data. When in a marine environment, incorporate the magnesium ion concentration data in the ocean into the analysis system to construct a new sulfate erosion index formula. Step 3: Pre-set the chloride ion content threshold, and construct the chloride salt erosion index formula based on the groundwater chloride ion concentration, chloride ion content threshold, and reinforced concrete porosity data at the location of the power transmission and transformation project. Step 4: Extract the relative humidity data of the air at the location of the power transmission and transformation project, construct the humidity influence function, and construct the carbonation erosion index formula based on the humidity influence function, the total volume of reinforced concrete, the total pore volume of reinforced concrete, the carbon dioxide concentration in the environment at the location of the power transmission and transformation project, and the water-cement ratio of reinforced concrete. Step 5: Assign corresponding weights to the erosion types represented by each formula based on their importance to the overall corrosion, establish a comprehensive corrosion assessment index formula that can comprehensively evaluate corrosion, and determine the degree of corrosion based on the results.

[0008] Furthermore, the temperature cycle is the time span during which the ambient temperature changes from above 0℃ to below 0℃ and then rises back above 0℃, starting from the time when reinforced concrete is put into use. The temperature change range is the difference between the highest and lowest temperatures within a temperature cycle; Temperature change time is the time it takes for the temperature to change from its highest value to its lowest value, or from its lowest value to its highest value, within a temperature cycle.

[0009] Furthermore, the volume of water in the reinforced concrete is calculated based on the water content and the total volume of the reinforced concrete: ; In the formula, This represents the volume of water in reinforced concrete. This refers to the moisture content of reinforced concrete. The volume of ice is expressed as the total volume of reinforced concrete. The volume of ice is calculated based on the volume of water within the reinforced concrete. ; In the formula, Expressed as the density of water, Expressed as the density of ice, Expressed as the volume of ice, the pressure exerted by the ice on the pore walls during each freeze-thaw cycle is calculated based on the duration of the low-temperature period and the magnitude of the temperature change. ; In the formula, This represents the pressure exerted by the ice inside the pores on the pore walls during each freeze-thaw cycle. A coefficient related to the material properties of reinforced concrete. It is the pore volume. Represented as the first The temperature change range within a temperature cycle Represented as the first The time of temperature change within a temperature cycle ,in, This is expressed as the number of temperature cycles, followed by the construction of the freeze-thaw damage index formula: ; In the formula, It is expressed as the freeze-thaw damage index.

[0010] Furthermore, the erosion products generated are determined based on the sulfate concentration measured in the groundwater; When the sulfate concentration is less than When considering ettringite erosion, a sulfate erosion index formula is constructed: ; In the formula, Expressed as the sulfate erosion index, This is a coefficient relating the concentration of sulfate ions to the degree of sulfate erosion. It is a coefficient related to the effect of pH on sulfate attack. This is a coefficient relating the effect of erosion time on sulfate erosion. This is a coefficient relating the aluminum ion concentration to the effect of sulfate corrosion. It refers to sulfate concentration. It is the pH value of reinforced concrete. This is the baseline value at which ettringite begins to exhibit erosive effects. It is in the service life of reinforced concrete The duration of erosion, i.e., the erosion time; When the sulfate concentration is When considering the combined erosion by ettringite and gypsum, a sulfate erosion index formula is constructed: ; In the formula, It refers to the concentration of aluminum ions in reinforced concrete. It refers to the concentration of calcium ions in reinforced concrete. It is a coefficient related to the contribution of aluminum ions to corrosion. It is a coefficient related to the contribution of calcium ions to erosion. It is a coefficient used to adjust the combined erosive effect of ettringite and gypsum; When the sulfate concentration is greater than When considering gypsum erosion, a sulfate erosion index formula is constructed: .

[0011] Furthermore, when in a marine environment, and the sulfate concentration in the seawater is greater than... Considering magnesium salt corrosion, a formula for the sulfate corrosion index is constructed: ; In the formula, Expressed as the sulfate erosion index, It refers to the concentration of magnesium ions in seawater. It is a coefficient that adjusts the combined effect of magnesium salt and sulfate corrosion; When the sulfate concentration in seawater is less than 4000 ppm, considering ettringite erosion, the sulfate erosion index formula is as follows: ; The concentration of sulfate in seawater is When considering the combined erosion by ettringite and gypsum, the sulfate erosion index formula is: .

[0012] Furthermore, the obtained chloride ion concentration in the groundwater at the location of the power transmission and transformation project was calibrated as follows: Compared with the preset chloride ion content threshold In contrast, when At that time, it was determined that chloride ions had a corrosive effect, and a formula for the chloride salt corrosion index was constructed: ; In the formula, Expressed as the chloride erosion index, This represents a coefficient related to the degree of contribution of chloride salt erosion. It is expressed as porosity. .

[0013] Furthermore, construct the humidity effect function: ; In the formula, Represented as a humidity effect function, This represents the relative humidity of the environment at the location of the power transmission and transformation project, collected in real time. Represented as a constant; Constructing the formula for the carbonization erosion index: ; In the formula, The contribution coefficient of carbonization erosion related to the pore volume ratio. These are the coefficients related to the influence of humidity on carbonization erosion. It refers to the water-cement ratio of reinforced concrete. It refers to the carbon dioxide concentration in the environment where the power transmission and transformation project is located. This is a coefficient relating the water-cement ratio of reinforced concrete to the effect of carbonation erosion. It is a coefficient relating the concentration of carbon dioxide in the environment to the effect of carbonization erosion.

[0014] Furthermore, the weight of the freeze-thaw damage index is set as follows: The weight of the sulfate erosion index is The weight of the chloride salt corrosion index is The weight of the carbonization erosion index is Establish a comprehensive corrosion assessment index formula: ; In the formula, It is represented as a comprehensive corrosion assessment index.

[0015] Furthermore, a pre-set threshold for the degree of erosion is set as follows: ,and ,when At that time, it was determined to be a minor degree of erosion. At that time, it was determined to be of a moderate degree of erosion. At that time, it was determined to be a severe degree of erosion. At that time, it was determined to be an extremely severe degree of erosion.

[0016] The present invention also provides a system for assessing the corrosion of reinforced concrete in power transmission and transformation projects. This system is used to perform the aforementioned method for assessing the corrosion of reinforced concrete in power transmission and transformation projects, comprising: The freeze-thaw damage index construction module is used to collect temperature data of the location of the power transmission and transformation project, as well as the self-characteristic data of the reinforced concrete to be evaluated. Based on the collected temperature data and self-characteristic data, the freeze-thaw damage index formula is constructed. The temperature data covers temperature cycle, variation range and temperature change time. The self-characteristic data includes the total volume, water content and pore volume of the reinforced concrete. The sulfate erosion index construction module is used to determine the type of erosion products generated based on the sulfate concentration data of groundwater at the location of the power transmission and transformation project. Based on the type of erosion products, the module constructs the corresponding sulfate erosion index formula using groundwater pH value, erosion time, aluminum ion concentration, and calcium ion concentration data. When the project is in a marine environment, the module incorporates magnesium ion concentration data from the ocean into the analysis system to construct a new sulfate erosion index formula. The chloride erosion index construction module is used to pre-set the chloride ion content threshold and construct the chloride erosion index formula based on the groundwater chloride ion concentration, chloride ion content threshold, and reinforced concrete porosity data at the location of the power transmission and transformation project. The carbonation erosion index construction module is used to extract relative humidity data of the air at the site of the power transmission and transformation project, construct a humidity influence function, and construct a carbonation erosion index formula based on the humidity influence function, the total volume of reinforced concrete, the total pore volume of reinforced concrete, the carbon dioxide concentration in the environment at the site of the power transmission and transformation project, and the water-cement ratio of reinforced concrete. The comprehensive corrosion assessment index construction module is used to assign corresponding weights to the overall corrosion based on the importance of the corrosion type represented by each formula to the overall corrosion, establish a comprehensive corrosion assessment index formula that can comprehensively assess corrosion, and determine the degree of corrosion based on the results.

[0017] Compared with the prior art, the beneficial effects of the present invention are: By thoroughly considering core factors such as freeze-thaw damage, sulfate corrosion, chloride corrosion, and carbonation, this approach comprehensively covers all major corrosive threats faced by reinforced concrete structures in power transmission and transformation projects during actual service. This comprehensiveness avoids the biased assessment results caused by previous single-factor assessments or omissions of certain factors.

[0018] Specialized index formulas were constructed for different types of erosion. The freeze-thaw damage index formula combines key parameters such as temperature cycle, variation range, time, and the volume, water content, and pore volume of reinforced concrete itself, which can accurately reflect the degree of damage caused by freeze-thaw action to the structure. The sulfate erosion index formula under different conditions fully considers multiple factors such as sulfate concentration differences, pH value of reinforced concrete, erosion time, aluminum ion and calcium ion concentrations, and also reasonably incorporates the influence of magnesium ion concentration in the marine environment, thus accurately quantifying the degree of harm of sulfate erosion under different conditions. The chloride erosion index formula measures the corrosive effect of chloride on reinforced concrete structures based on the relationship between chloride ion concentration, a set threshold, and porosity. The carbonation erosion index formula accurately assesses the corrosive effects of carbonation by using a humidity influence function and data such as the total volume of reinforced concrete, total pore volume, environmental carbon dioxide concentration, and water-cement ratio.

[0019] Finally, the comprehensive corrosion assessment index formula in this invention constructs index formulas and assigns weights to multiple factors such as freeze-thaw damage, sulfate corrosion, chloride corrosion, and carbonization. This avoids the assessment bias caused by traditional assessment methods that only focus on one or a few types of corrosion while ignoring other factors. As a result, the assessment results are more in line with the actual situation, providing a comprehensive and reliable basis for subsequent protection and repair measures. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the overall method flow of the present invention; Figure 2 This is a schematic diagram of the system structure of the present invention. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments.

[0022] It should be noted that, unless otherwise defined, the technical or scientific terms used in this invention should have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms "first," "second," and similar terms used in this invention do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0023] Example: Please see Figure 1 The present invention provides a technical solution: A method for assessing the corrosivity of reinforced concrete in power transmission and transformation projects, comprising the following steps: Step 1: Collect temperature data of the location of the power transmission and transformation project, as well as the characteristic data of the reinforced concrete to be evaluated. Construct a freeze-thaw damage index formula based on the collected temperature data and characteristic data. The temperature data includes temperature cycle, variation range and temperature change time. The characteristic data includes the total volume, water content and pore volume of the reinforced concrete. In step 1, after the reinforced concrete is put into use, temperature sensors are installed in the surrounding environment, or meteorological data is queried to collect temperature data. The collected temperature data covers temperature cycles, temperature variation ranges, and temperature variation times. The specific temperature data collection methods are as follows: Once the start time of putting reinforced concrete into use is determined, the next nearest hour is taken as the time point for the first collection of temperature data. Then, ambient temperature data is collected at a fixed frequency of one hour. For example, if the start time is 12:03, the first collection time is 13:00, and the subsequent collection times are 14:00, 15:00 and so on until 23:00. This cycle is repeated to ensure that temperature information for different time periods can be obtained completely and systematically.

[0024] Freeze-thaw damage manifests macroscopically as the peeling of the surface layer of reinforced concrete, with a gradual decrease in quality and strength until complete loss. Essentially, water entering the capillary pores of reinforced concrete freezes into ice at low temperatures (below the freezing point of water), and the expansion of the ice volume exerts pressure on the pores, causing damage to the internal structure. When the temperature rises above the freezing point, the ice in the pores begins to melt, which generates tensile stress on the pore walls. The continuous freeze-thaw cycle causes sustained damage to the internal structure of reinforced concrete, which in severe cases manifests as a decrease in macroscopic strength and damage to reinforced concrete components.

[0025] The temperature cycle refers to the period from the time the reinforced concrete begins to be used, during which the ambient temperature drops from above 0°C to below 0°C, and then rises back above 0°C. By collecting temperature data, the time span of such a complete change process can be monitored to see if there are frequent temperature fluctuations in the environment. The situation; Temperature variation range refers to the difference between the highest and lowest temperatures within each temperature cycle. If the difference between the highest and lowest temperatures is large within a temperature cycle, the difference in the expansion and contraction of reinforced concrete and steel bars will be more obvious. Therefore, temperature variation range is a key factor for assessing the corrosivity of reinforced concrete. Temperature change time refers to the time it takes for the temperature to change from its highest value to its lowest value, or from its lowest value to its highest value, within a temperature cycle. When the temperature change time is long, the internal thermal stress changes relatively smoothly. Because the thermal expansion and contraction process caused by temperature changes has enough time to buffer, the possibility of cracks will be reduced. When the temperature change time is very short, the material does not have enough time to adapt to the rapid temperature change, and a large temperature gradient will form between the surface and the interior of the structure, causing large tensile stress on the surface, which will lead to cracks in the steel bars.

[0026] Then collect data on the total volume, water content, and pore volume of reinforced concrete at the site of the power transmission and transformation project.

[0027] First, locate the power transmission and transformation project design drawings, and calculate the total volume of reinforced concrete based on the dimensional parameters in the design drawings; The moisture content of reinforced concrete was obtained using the drying method, and a sample of mass was drilled from the reinforced concrete structure. The sample was placed in a temperature controlled at... Dry in an oven until constant weight, then weigh the dried product as follows: The moisture content of the reinforced concrete at the location of the power transmission and transformation project is calculated by using the mass of samples drilled from the reinforced concrete structure and the mass after drying. ; In the formula, This represents the moisture content of the reinforced concrete at the location of the power transmission and transformation project. A cutting saw was used to cut a volume of [unclear - possibly related to a power transmission and transformation project site]. After drying in a drying oven, the sample was placed in a vacuum container to create a vacuum in the pores. The sample was then weighed after vacuuming, and its initial mass was recorded. The sample is then placed into the sample chamber of the mercury porosimeter, and the porosimeter is started. As the pressure gradually increases, mercury will gradually fill the pores under the pressure, and a mercury porosimetry curve will be output.

[0028] Data for each pressure stage was obtained from the mercury intrusion porosimetry curve. The surface tension of mercury is a known physical constant with a value of [value missing]. Based on extensive experimental research and experience by the research team, the contact angle between mercury and the pore walls of concrete was determined. for Construct the Washburn equation: ; In the formula, This represents the pore radius corresponding to each pressure stage. This is expressed as the surface tension of mercury. Represented as pressure, the pore radius corresponding to each pressure stage is calculated using the Washburn equation. The pore volume increment within this radius Then, the pore volume increments for all pressure stages are summed to obtain the pore volume. .

[0029] Based on the collected temperature data, the formula for constructing the freeze-thaw damage index by considering the total volume, water content, and pore volume of reinforced concrete includes the following steps: Calculate the volume of water in reinforced concrete based on its moisture content and total volume: ; In the formula, This refers to the moisture content of reinforced concrete. Given the total volume of reinforced concrete, calculate the volume of ice based on the volume of water within the reinforced concrete: ; In the formula, It is the density of water. It is the density of ice. The volume of ice is used as the basis for calculation. Then, based on the duration of the low-temperature period and the magnitude of the temperature change, the pressure exerted by the ice on the pore walls during each freeze-thaw cycle is calculated. ; In the formula, This represents the pressure exerted by the ice inside the pores on the pore walls during each freeze-thaw cycle. A coefficient related to the material properties of reinforced concrete. It is the pore volume. Represented as the first The temperature change range within a temperature cycle Represented as the first The time of temperature change within a temperature cycle ,in, This involves determining the number of temperature cycles, followed by constructing the freeze-thaw damage index formula: ; In the formula, Expressed as the freeze-thaw damage index, it is determined by the number of temperature cycles. The larger the value, the more freeze-thaw cycles the reinforced concrete structure experiences. The results of each cycle are accumulated, and the impact of the results increases with the number of freeze-thaw cycles. This indicates that water expands in volume when it freezes, and this volume change exerts greater pressure on the porous structure, thus exacerbating freeze-thaw damage. This indicates that larger temperature fluctuations and shorter freeze-thaw cycles exacerbate the damage caused by freeze-thaw cycles.

[0030] Among the durability issues of reinforced concrete, freeze-thaw damage is one of the most common and destructive methods. Therefore, the quality of freeze-thaw resistance has become one of the most important indicators for evaluating the durability of reinforced concrete.

[0031] Given that the principles of freeze-thaw damage are closely related to the water and pore structure within reinforced concrete, data such as the total volume, water content, and pore volume of reinforced concrete are crucial for accurately assessing the degree of freeze-thaw damage. By collecting this data and constructing a freeze-thaw damage index formula, the potential risks and actual severity of freeze-thaw damage can be quantified. This provides a scientific basis for judging the freeze-thaw resistance of reinforced concrete under specific environments, and thus becomes one of the core indicators for evaluating the durability of reinforced concrete.

[0032] Step 2: Based on the groundwater sulfate concentration data at the location of the power transmission and transformation project, determine the type of erosion products generated. Based on the type of erosion products, construct the corresponding sulfate erosion index formula using groundwater pH value, erosion time, aluminum ion concentration, and calcium ion concentration data. When in a marine environment, incorporate the magnesium ion concentration data in the ocean into the analysis system to construct a new sulfate erosion index formula. For sodium sulfate corrosion, when the sulfate concentration is low (<1000 ppm SO4), 2- It mainly produces ettringite; when the sulfate concentration is high (>8000 ppm SO4), it can form ettringite. 2- It mainly produces gypsum; when the sulfate concentration is 1000~8000 ppm SO4 2- At that time, ettringite and gypsum coexisted.

[0033] Among these, ettringite has low solubility and a chemical structure that binds a large amount of water of crystallization. After the reaction, the solid phase volume can increase by 94%. This volume increase causes reinforced concrete to expand, crack, and form large cracks on the surface of the structure, even leading to the spalling of the reinforced concrete. When the alkalinity of the reinforced concrete is low, the formed ettringite is mostly in the form of large lamellar crystals, which is generally not harmful. However, when the alkalinity is high, ettringite is mostly in the form of needle-like or platy crystals with strong adsorption capacity, absorbing water and expanding, forming extremely high crystallization stress. Therefore, properly controlling the alkalinity of reinforced concrete can mitigate the expansive damage caused by ettringite. Gypsum formation can increase the solid phase volume by 124%, causing the reinforced concrete to expand. At the same time, the formation of gypsum consumes calcium hydroxide, leading to a decrease in the strength and durability of the reinforced concrete. Gypsum-type corrosion damage generally does not produce large cracks, but the reinforced concrete will collapse.

[0034] Calcium carbosulfonate typically forms between 0°C and 5°C. It also forms when the pH of the pore solution is above 10.5 and SO42- is present. 2- CO3 2- As calcium carbosulfanate exists, it will continuously react and generate, consuming the hydrated calcium silicate gel. Because calcium carbosulfanate lacks binding force, coupled with the consumption of the hydrated calcium silicate gel, the material loses strength, leading to structural failure. Therefore, the calcium ion concentration and the erosion time of the reinforced concrete must be considered. The erosion time refers to the period during service life... Duration.

[0035] Therefore, the erosion products generated are first determined based on the sulfate concentration measured in the groundwater; When the sulfate concentration is less than When considering ettringite erosion, a sulfate erosion index formula is constructed: ; In the formula, This is a coefficient relating the concentration of sulfate ions to the degree of sulfate erosion. It is a coefficient related to the effect of pH on sulfate attack. This is a coefficient relating the effect of erosion time on sulfate erosion. This is a coefficient relating the aluminum ion concentration to the effect of sulfate corrosion. It refers to sulfate concentration. It is the pH value of reinforced concrete. This is the baseline value at which ettringite begins to exhibit erosive effects. It refers to the erosion time, that is, the period during which reinforced concrete is in service. Duration; When the sulfate concentration is When considering the combined erosion by ettringite and gypsum, a sulfate erosion index formula is constructed: ; In the formula, It refers to the concentration of aluminum ions in reinforced concrete. It refers to the concentration of calcium ions in reinforced concrete. It is a coefficient related to the contribution of aluminum ions to corrosion. It is a coefficient related to the contribution of calcium ions to erosion. It is a coefficient used to adjust the combined erosive effect of ettringite and gypsum; When the sulfate concentration is greater than When considering gypsum erosion, a sulfate erosion index formula is constructed: ; MgSO4 corrosion is the most damaging of all sulfate corrosions to reinforced concrete because of the magnesium in it. 2+ and SO4 2- Both can corrode reinforced concrete, and the combined effect of both can cause severe corrosion, even causing the reinforced concrete to lose its binding properties. Seawater contains a large amount of magnesium... 2+ and SO4 2- For magnesium sulfate corrosion, at low concentrations (<4000 ppm SO4) 2- ), ettringite is formed; when the concentration is high (>7500 ppm SO4), ettringite is formed; 2- The main cause is magnesium salt corrosion; moderate concentrations (4000~7500 ppm SO4) 2- When ettringite and gypsum are formed simultaneously, therefore, in a marine environment with a sulfate concentration greater than [a certain value], [the concentration of sulfates can increase]. Considering magnesium salt corrosion, a formula for the sulfate corrosion index is constructed: ; In the formula, It refers to the concentration of magnesium ions in seawater. This is a coefficient relating magnesium ion concentration to the effect of sulfate corrosion. It is a coefficient that adjusts the combined effect of magnesium salt and sulfate corrosion; When the sulfate concentration in seawater is less than 4000 ppm, considering ettringite erosion, the sulfate erosion index formula is as follows: ; The concentration of sulfate in seawater is When considering the combined erosion by ettringite and gypsum, the sulfate erosion index formula is: .

[0036] Step 3: Pre-set the chloride ion content threshold, and construct the chloride salt erosion index formula based on the groundwater chloride ion concentration, chloride ion content threshold, and reinforced concrete porosity data at the location of the power transmission and transformation project. When chloride ions in the environment enter reinforced concrete through penetration, diffusion, and convection, even small amounts can react with Ca(OH)₂ in the concrete to form CaCl₂. Because CaCl₂ carries a large amount of water of crystallization, it easily expands, damaging the reinforced concrete structure. For example, in the salt lake areas of northwestern my country and in northern regions, the spraying of large amounts of de-icing salt in winter can also cause chloride erosion damage to reinforced concrete structures. When the concentration of chloride ions in reinforced concrete is too high, the oxygen and water present in the pores provide the environmental conditions for electrochemical corrosion between chloride ions and the reinforcing steel in the internal environment. Rapid electrochemical corrosion leads to the rusting of reinforced concrete components. In groundwater environments, high concentrations of chloride ions exist mostly in a free state. After penetrating the interior of reinforced concrete, they easily cause localized acidification, thereby destroying the passivation film on the surface of the reinforcing steel, initiating corrosion, and greatly reducing the durability of reinforced concrete, becoming one of the most deadly corrosive media for reinforced concrete.

[0037] First, determine the chloride ion concentration in the groundwater at the location of the power transmission and transformation project, and then accurately draw up a sample using a pipette. Add 3 drops of potassium chromate indicator to the groundwater at the site of the power transmission and transformation project, using a concentration of... Titrate with standard silver nitrate solution until the solution color changes from yellow to brick red, and record the volume of silver nitrate solution consumed. Calculate the chloride ion concentration: ; In the formula, This represents the chloride ion concentration in the groundwater at the location of the power transmission and transformation project.

[0038] The calibrated porosity is The calculation method is as follows: ; Meanwhile, there exists a critical chloride ion concentration in the reinforced concrete solution. When the chloride ion concentration on the surface of the reinforcing steel reaches this critical value, the steel begins to corrode. A survey of bridges in the UK showed that, when expressed as total chloride ion concentration, the critical chloride ion concentration is... British national standards stipulate that the chloride ion content in reinforced concrete structures must be less than [a certain value]. Therefore, a chloride ion content threshold is set. The obtained chloride ion concentration in the groundwater at the site of the power transmission and transformation project was calibrated as follows: Compared with the preset chloride ion content threshold In contrast, when At that time, it was determined that chloride ions had a corrosive effect, and a formula for the chloride salt corrosion index was constructed: ; In the formula, It is a coefficient related to the degree of chloride erosion, and the chloride ion concentration in groundwater at the site of the power transmission and transformation project. The higher the value, the greater the chloride erosion index.

[0039] Step 4: Extract the relative humidity data of the air at the location of the power transmission and transformation project, construct the humidity influence function, and construct the carbonation erosion index formula based on the humidity influence function, the total volume of reinforced concrete, the total pore volume of reinforced concrete, the carbon dioxide concentration in the environment at the location of the power transmission and transformation project, and the water-cement ratio of reinforced concrete. Carbonation of reinforced concrete is essentially the process by which CO2 from the air diffuses into the interior of the concrete and reacts with alkaline hydration products such as Ca(OH)2 to form calcium carbonate and water, causing the alkalinity of the reinforced concrete to decrease and tend towards neutrality. Calcium carbonate has extremely low solubility and, after formation, deposits on the surface of the pore walls, reducing the concentration of calcium ions in the pore solution. To replenish the calcium ions lost due to calcium carbonate formation, calcium hydroxide dissolves, increasing the calcium carbonate content. This cycle continues until all calcium hydroxide in the reinforced concrete is dissolved, lowering the pH value. The strong alkalinity of reinforced concrete is a prerequisite for the formation of a passivation film on the steel reinforcement surface, which protects the steel from corrosion. After carbonation, the internal pH value decreases, affecting the passivation film on the steel reinforcement surface and leading to corrosion.

[0040] Existing research indicates that the carbonation of reinforced concrete is correlated with water-cement ratio, CO2 concentration, and internal porosity, presenting data on relative humidity and the corresponding degree of carbonation. Therefore, a humidity influence function is constructed: ; In the formula, Represented as a humidity effect function, This represents the relative humidity of the environment at the location of the power transmission and transformation project, collected in real time. Relative humidity is expressed as a constant, and based on numerous experiments, it is... At different times, the corresponding degree of carbonization varies. Based on the carbonization effect, the humidity influence function is set to yield the following results: and Substituting the humidity effect function, we can obtain ; set up The water-cement ratio is expressed as the concrete mix design report. The value is obtained from the concrete mix design report, which will record in detail the calculation process, basis, and trial mix results of the water-cement ratio. Using a detector, after introducing a standard carbon dioxide gas of known concentration, the sampling probe of the detector is placed in the air to be tested. The detector can then output the concentration of carbon dioxide in the environment at the location of the power transmission and transformation project, and calibrate it as follows. .

[0041] Because reinforced concrete is correlated with porosity, a formula for the carbonation erosion index is constructed: ; In the formula, The contribution coefficient of carbonization erosion related to the pore volume ratio. These are the coefficients related to the influence of humidity on carbonization erosion. It refers to the water-cement ratio of reinforced concrete. It refers to the carbon dioxide concentration in the environment where the power transmission and transformation project is located. This is a coefficient relating the water-cement ratio of reinforced concrete to the effect of carbonation erosion. It is a coefficient related to the influence of carbon dioxide concentration in the environment on carbonation erosion. The water-cement ratio, humidity influence function, pore volume of reinforced concrete and carbon dioxide concentration in the environment are positively correlated with the carbonation erosion index of the building.

[0042] Step 5: Assign corresponding weights to the erosion types represented by each formula according to their importance to the overall corrosivity, establish a comprehensive corrosion assessment index formula that can comprehensively evaluate corrosion, and determine the degree of erosion based on the results; The weight of the freeze-thaw damage index is set as follows: The weight of the sulfate erosion index is The weight of the chloride salt corrosion index is The weight of the carbonization erosion index is The relative importance of the four erosion types—freeze-thaw damage, sulfate erosion, chloride erosion, and carbonization—is subjectively assessed. For example, in power transmission and transformation projects in cold regions with extensive use of de-icing salt, freeze-thaw damage and chloride erosion might be considered to have relatively high weights; while in areas near industrial pollution zones or coastal areas with high sulfate content in groundwater, sulfate erosion would be given greater weight. Each erosion type is assigned a reasonable weight value, and under general environmental conditions without special requirements, the weight is set based on the degree of impact of each erosion type on reinforced concrete structures. .

[0043] Then, a comprehensive corrosion assessment index formula was established: ; Based on long-term observation of actual engineering conditions, the erosion threshold was pre-set as follows: ,and This divides the degree of erosion into four levels, when At this point, it means that the current reinforced concrete structure is subjected to a relatively mild degree of corrosion due to the combined effects of various corrosive factors, namely freeze-thaw damage, sulfate corrosion, chloride corrosion, and carbonation, but it has not yet posed a significant threat to the overall performance and safety of the structure, and is therefore judged as a slight degree of corrosion. when The reading indicates that multiple corrosive factors have worked synergistically to cause significant damage to the reinforced concrete structure. The structure may have already exhibited some problems such as cracks and localized degradation of reinforced concrete performance, which have had a noticeable impact on some of the structure's performance and stability. However, the overall structure can still maintain basic function and safety, and is therefore classified as having a moderate degree of erosion. when When the corrosion reaches a certain level, it indicates that the reinforced concrete structure has suffered severe corrosion, and its key properties such as integrity, load-bearing capacity, and durability are greatly threatened. At this point, the structure may exhibit serious problems such as large-area cracks, reinforced concrete spalling, and steel reinforcement corrosion, which is classified as severe corrosion. when At this point, it indicates that the erosion of the reinforced concrete structure has reached an extremely severe level, the entire structure is almost on the verge of collapse, and all its performance indicators have deteriorated significantly, posing an extremely high risk to the safe operation of the power transmission and transformation project, and is judged to be of an extremely severe erosion level.

[0044] Please see Figure 2 Furthermore, a system for assessing the corrosivity of reinforced concrete in power transmission and transformation projects is provided. This system is used to perform the aforementioned method for assessing the corrosivity of reinforced concrete in power transmission and transformation projects, comprising: The freeze-thaw damage index construction module is used to collect temperature data of the location of the power transmission and transformation project, as well as the self-characteristic data of the reinforced concrete to be evaluated. Based on the collected temperature data and self-characteristic data, the freeze-thaw damage index formula is constructed. The temperature data covers temperature cycle, variation range and temperature change time. The self-characteristic data includes the total volume, water content and pore volume of the reinforced concrete. The sulfate erosion index construction module is used to determine the type of erosion products generated based on the sulfate concentration data of groundwater at the location of the power transmission and transformation project. Based on the type of erosion products, the module constructs the corresponding sulfate erosion index formula using groundwater pH value, erosion time, aluminum ion concentration, and calcium ion concentration data. When the project is in a marine environment, the module incorporates magnesium ion concentration data from the ocean into the analysis system to construct a new sulfate erosion index formula. The chloride erosion index construction module is used to pre-set the chloride ion content threshold and construct the chloride erosion index formula based on the groundwater chloride ion concentration, chloride ion content threshold, and reinforced concrete porosity data at the location of the power transmission and transformation project. The carbonation erosion index construction module is used to extract relative humidity data of the air at the site of the power transmission and transformation project, construct a humidity influence function, and construct a carbonation erosion index formula based on the humidity influence function, the total volume of reinforced concrete, the total pore volume of reinforced concrete, the carbon dioxide concentration in the environment at the site of the power transmission and transformation project, and the water-cement ratio of reinforced concrete. The comprehensive corrosion assessment index construction module is used to assign corresponding weights to the overall corrosion based on the importance of the corrosion type represented by each formula to the overall corrosion, and to establish a comprehensive corrosion assessment index formula that can comprehensively assess corrosion. The degree of corrosion is determined based on the results. All the above formulas are dimensionless and calculated by taking their numerical values. The formulas are derived from the most recent real situation by software simulation based on a large amount of collected data. The preset parameters in the formulas are set by those skilled in the art according to the actual situation.

[0045] The above embodiments can be implemented, in whole or in part, by software, hardware, firmware, or any other combination thereof. When implemented in software, the above embodiments can be implemented, in whole or in part, as a computer program product. Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented by electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution.

[0046] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment, depending on actual needs.

[0047] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application.

Claims

1. A method for assessing the corrosivity of reinforced concrete in power transmission and transformation projects, characterized in that, The specific steps include: Step 1: Collect temperature data of the location of the power transmission and transformation project, as well as the characteristic data of the reinforced concrete to be evaluated. Construct a freeze-thaw damage index formula based on the collected temperature data and characteristic data. The temperature data includes temperature cycle, variation range and temperature change time. The characteristic data includes the total volume, water content and pore volume of the reinforced concrete. Step 2: Based on the groundwater sulfate concentration data at the location of the power transmission and transformation project, determine the type of erosion products generated. Based on the type of erosion products, construct the corresponding sulfate erosion index formula using groundwater pH value, erosion time, aluminum ion concentration, and calcium ion concentration data. When in a marine environment, incorporate the magnesium ion concentration data in the ocean into the analysis system to construct a new sulfate erosion index formula. Step 3: Pre-set the chloride ion content threshold, and construct the chloride salt erosion index formula based on the groundwater chloride ion concentration, chloride ion content threshold, and reinforced concrete porosity data at the location of the power transmission and transformation project. Step 4: Extract the relative humidity data of the air at the location of the power transmission and transformation project, construct the humidity influence function, and construct the carbonation erosion index formula based on the humidity influence function, the total volume of reinforced concrete, the total pore volume of reinforced concrete, the carbon dioxide concentration in the environment at the location of the power transmission and transformation project, and the water-cement ratio of reinforced concrete. Step 5: Assign corresponding weights to the erosion types represented by each formula according to their importance to the overall corrosion, establish a comprehensive corrosion assessment index formula that can comprehensively evaluate corrosion, and determine the degree of corrosion based on the results; The erosion products generated are determined based on the sulfate concentration measured in the groundwater. When sulfate concentration is less than When considering ettringite erosion, a sulfate erosion index formula is constructed: In the formula, Expressed as the sulfate erosion index, This is a coefficient relating the concentration of sulfate ions to the degree of sulfate erosion. It is a coefficient related to the effect of pH on sulfate attack. This is a coefficient relating the effect of erosion time on sulfate erosion. This is a coefficient relating the aluminum ion concentration to the effect of sulfate corrosion. It refers to sulfate concentration. It is the pH value of reinforced concrete. This is the baseline value at which ettringite begins to exhibit erosive activity. It is in the service life of reinforced concrete The duration of erosion, i.e., the erosion time; When the sulfate concentration is When considering the combined erosion by ettringite and gypsum, a sulfate erosion index formula is constructed: In the formula, It refers to the concentration of aluminum ions in reinforced concrete. It refers to the concentration of calcium ions in reinforced concrete. It is a coefficient related to the contribution of aluminum ions to corrosion. It is a coefficient related to the contribution of calcium ions to erosion. It is a coefficient used to adjust the combined erosive effect of ettringite and gypsum; When the sulfate concentration is greater than When considering gypsum erosion, a sulfate erosion index formula is constructed: When in a marine environment, and the sulfate concentration in the seawater is greater than Considering magnesium salt corrosion, a formula for the sulfate corrosion index is constructed: In the formula, Expressed as the sulfate erosion index, It refers to the concentration of magnesium ions in seawater. It is a coefficient that adjusts the combined effect of magnesium salt and sulfate corrosion; When the sulfate concentration in seawater is less than 4000 ppm, considering ettringite erosion, the sulfate erosion index formula is as follows: The concentration of sulfate in seawater is When considering the combined erosion by ettringite and gypsum, the sulfate erosion index formula is: 。 2. The method for assessing the corrosivity of reinforced concrete in power transmission and transformation projects according to claim 1, characterized in that: In step 1, the temperature period, the amplitude of change, and the time of temperature change are as follows: The temperature cycle is the time span during which the ambient temperature changes from above 0°C to below 0°C and then rises back above 0°C, starting from the time when reinforced concrete is put into use. The temperature change range is the difference between the highest and lowest temperatures within a temperature cycle; Temperature change time is the time it takes for the temperature to change from its highest value to its lowest value, or from its lowest value to its highest value, within a temperature cycle.

3. The method for assessing the corrosivity of reinforced concrete in power transmission and transformation projects according to claim 1, characterized in that: Step 1, constructing the freeze-thaw damage index formula based on the collected temperature data and its own characteristic data, includes the following steps: Calculate the volume of water in reinforced concrete based on its moisture content and total volume: In the formula, This represents the volume of water in reinforced concrete. This refers to the moisture content of reinforced concrete. The volume of ice is expressed as the total volume of reinforced concrete. The volume of ice is calculated based on the volume of water within the reinforced concrete. In the formula, Expressed as the density of water, Expressed as the density of ice, Expressed as the volume of ice, the pressure exerted by the ice on the pore walls during each freeze-thaw cycle is calculated based on the duration of the low-temperature period and the magnitude of the temperature change. In the formula, This represents the pressure exerted by the ice inside the pores on the pore walls during each freeze-thaw cycle. A coefficient related to the material properties of reinforced concrete. It is the pore volume. Represented as the first The temperature change range within a temperature cycle Represented as the first The time of temperature change within a temperature cycle ,in, This is expressed as the number of temperature cycles, followed by the construction of the freeze-thaw damage index formula: In the formula, It is expressed as the freeze-thaw damage index.

4. The method for assessing the corrosivity of reinforced concrete in power transmission and transformation projects according to claim 1, characterized in that: Step 3, constructing the chloride erosion index formula includes the following steps: The obtained chloride ion concentration in the groundwater at the location of the power transmission and transformation project was calibrated as follows: Compared with the preset chloride ion content threshold In contrast, when At that time, it was determined that chloride ions had a corrosive effect, and a formula for the chloride salt corrosion index was constructed: In the formula, Expressed as the chloride erosion index, This represents a coefficient related to the degree of contribution of chloride salt erosion. Expressed as porosity, .

5. The method for assessing the corrosivity of reinforced concrete in power transmission and transformation projects according to claim 1, characterized in that: Step 4 involves constructing the carbonization erosion index formula, which includes the following steps: Construct the humidity effect function: In the formula, Represented as a humidity effect function, This represents the relative humidity of the environment at the location of the power transmission and transformation project, collected in real time. Represented as a constant; Construct the formula for the carbonization erosion index: In the formula, It is expressed as the carbonization erosion index. The contribution coefficient of carbonization erosion related to the pore volume ratio. These are the coefficients related to the influence of humidity on carbonization erosion. It refers to the water-cement ratio of reinforced concrete. It refers to the carbon dioxide concentration in the environment where the power transmission and transformation project is located. This is a coefficient relating the water-cement ratio of reinforced concrete to the effect of carbonation erosion. It is a coefficient relating the concentration of carbon dioxide in the environment to the effect of carbonization erosion.

6. The method for assessing the corrosivity of reinforced concrete in power transmission and transformation projects according to claim 1, characterized in that: In step 5, the method for establishing a comprehensive corrosion assessment index formula that can fully evaluate corrosion is as follows: The weight of the freeze-thaw damage index is set as follows: The weight of the sulfate erosion index is The weight of the chloride salt corrosion index is The weight of the carbonization erosion index is Establish a comprehensive corrosion assessment index formula: In the formula, It is represented as a comprehensive corrosion assessment index.

7. The method for assessing the corrosivity of reinforced concrete in power transmission and transformation projects according to claim 1, characterized in that: In step 5, the method for determining the degree of erosion based on the results is as follows: Preset erosion threshold as ,and ,when At that time, it was determined to be a minor degree of erosion. At that time, it was determined to be of a moderate degree of erosion. At that time, it was judged to be a severe degree of erosion. At that time, it was determined to be an extremely severe degree of erosion.

8. A system for assessing the corrosivity of reinforced concrete in power transmission and transformation projects, characterized in that: The system is used to perform the corrosion assessment method for reinforced concrete in power transmission and transformation projects as described in any one of claims 1-7: The freeze-thaw damage index construction module is used to collect temperature data of the location of the power transmission and transformation project, as well as the self-characteristic data of the reinforced concrete to be evaluated. Based on the collected temperature data and self-characteristic data, the freeze-thaw damage index formula is constructed. The temperature data covers temperature cycle, variation range and temperature change time. The self-characteristic data includes the total volume, water content and pore volume of the reinforced concrete. The sulfate erosion index construction module is used to determine the type of erosion products generated based on the sulfate concentration data of groundwater at the location of the power transmission and transformation project. Based on the type of erosion products, the module constructs the corresponding sulfate erosion index formula using groundwater pH value, erosion time, aluminum ion concentration, and calcium ion concentration data. When the project is in a marine environment, the module incorporates magnesium ion concentration data from the ocean into the analysis system to construct a new sulfate erosion index formula. The chloride erosion index construction module is used to pre-set the chloride ion content threshold and construct the chloride erosion index formula based on the groundwater chloride ion concentration, chloride ion content threshold, and reinforced concrete porosity data at the location of the power transmission and transformation project. The carbonation erosion index construction module is used to extract relative humidity data of the air at the site of the power transmission and transformation project, construct a humidity influence function, and construct a carbonation erosion index formula based on the humidity influence function, the total volume of reinforced concrete, the total pore volume of reinforced concrete, the carbon dioxide concentration in the environment at the site of the power transmission and transformation project, and the water-cement ratio of reinforced concrete. The comprehensive corrosion assessment index construction module is used to assign corresponding weights to the overall corrosion based on the importance of the corrosion type represented by each formula to the overall corrosion, establish a comprehensive corrosion assessment index formula that can comprehensively assess corrosion, and determine the degree of corrosion based on the results.

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