A method for assessing the life extension of marine concrete structures based on coatings.

Abstract

This invention proposes a method for assessing the lifespan extension of marine concrete structures based on coatings. The method includes: obtaining the coating failure time of the coated concrete; obtaining a first chloride ion concentration in the coated concrete during the coating failure time; determining a first chloride ion flux in the coated concrete based on the first chloride ion concentration and the depth of the coated concrete; obtaining the diffusion time of a second chloride ion flux in blank concrete, which is defined as the equivalent time, where the blank concrete is concrete placed in the same environment as the coated concrete, and the second chloride ion flux is equal to the first chloride ion flux; and determining the difference between the coating failure time and the equivalent time as the lifespan extension time of the concrete structure due to the coating. This method enables accurate assessment of the lifespan extension of the concrete structure due to the coating.

Description

Technical Field

[0001] This invention relates to the field of coating-based assessment of the life extension of marine concrete structures, and particularly to a coating-based method for assessing the life extension of marine concrete structures. Background Technology

[0002] In seawater or coastal environments, to reduce the impact of chloride ions in seawater on the concrete structures of coastal infrastructure, coatings are typically applied to protect the surface of these concrete structures, thereby extending their service life. Currently, most models calculating the lifespan extension of coatings on concrete structures neglect the time-varying characteristics of chloride ion concentration on the coated concrete surface. They often use the time required for the chloride ion concentration on the surface of the reinforcing steel in the coated concrete to reach the chloride ion concentration in uncoated concrete after coating failure as the lifespan extension period. However, this ignores the fact that when the chloride ion concentration on the surface of the reinforcing steel exceeds the critical chloride ion concentration, it falls within the rust expansion and cracking stage of reinforced concrete, making it unsuitable for lifespan prediction models of concrete structures in the corrosion development stage. This leads to inaccurate assessments of the coating's lifespan extension on concrete structures. Summary of the Invention

[0003] This invention aims to at least solve one of the technical problems existing in the prior art. To this end, this invention proposes a coating-based method for assessing the service life extension of marine concrete structures, which can accurately assess the effect of coatings on the service life extension of concrete structures.

[0004] In a first aspect, embodiments of the present invention provide a method for assessing the life extension time of marine concrete structures based on coatings, including:

[0005] Obtain the coating failure time of the coated concrete;

[0006] Obtain the first chloride ion concentration in the coated concrete within the coating failure time;

[0007] The first chloride ion flux in the coated concrete is determined based on the first chloride ion concentration in the concrete and the depth of the coated concrete.

[0008] The diffusion time of the second chloride ion flux in blank concrete is obtained and determined as the equivalent time. The blank concrete is concrete placed in the same environment as the coated concrete. The second chloride ion flux is equal to the first chloride ion flux.

[0009] The difference between the coating failure time and the equivalent time is determined as the extension of the coating's lifespan for the concrete structure.

[0010] In some embodiments of the present invention, obtaining the coating failure time of the coated concrete includes:

[0011] The first surface chloride ion concentration of the coated concrete is obtained, where the first surface chloride ion concentration is the chloride ion concentration on the surface of the coated concrete.

[0012] Based on a preset linear relationship between the first surface chloride ion concentration and the exposure time, the exposure time corresponding to the highest value of the first surface chloride ion concentration is obtained and determined as the coating failure time of the coated concrete. The exposure time is the time when the coated concrete is placed in a preset environment.

[0013] In some embodiments of the present invention, determining the first chloride ion flux in the coated concrete based on the first chloride ion concentration in the concrete and the depth of the coated concrete includes:

[0014] Obtain the depth positions of multiple preset first depth points in the coated concrete;

[0015] The chloride ion concentration of the first concrete corresponding to the first depth point is determined as the chloride ion concentration at the first depth point.

[0016] The first chloride ion flux of the coated concrete is obtained by calculating the depth value of each first depth point and the corresponding chloride ion concentration at the first depth point.

[0017] In some embodiments of the present invention, determining the first chloride ion flux in the coated concrete based on the first chloride ion concentration in the concrete and the depth of the coated concrete includes:

[0018] Based on the preset formula for calculating the chloride ion concentration at the first depth point, the chloride ion concentration at each first depth point is calculated by taking the depth value of the first depth point, the preset first effective chloride ion diffusion coefficient, and the coating failure time.

[0019] The first chloride ion flux of the coated concrete is calculated based on the chloride ion concentration at each first depth point and the thickness between any two first depth points.

[0020] The formula for the chloride ion concentration at the first depth point is:

[0021]

[0022] C x C represents the chloride ion concentration at the first depth point when the first depth point is at depth x. 0x Let t be the initial chloride ion concentration in the coated concrete, k be the comprehensive environmental material influence coefficient, and t be the initial chloride ion concentration in the coated concrete. maxD is the coating failure time. t-C is the first effective chloride ion diffusion coefficient, and x is the first depth value corresponding to the first depth point;

[0023] The formula for calculating the first chloride ion flux is:

[0024] Q c =C x1 ×Δx1+C x2 ×Δx² + ....... + C xn ×Δx n

[0025] Q c For the first chloride ion flux, C x1 C x2 , ...C xn Let Δx1, Δx2, ..., Δx be the chloride ion concentration at the first depth point when the depth value x takes the values ​​1, 2, ..., n. n The thickness is the distance between any two of the first depth points.

[0026] In some embodiments of the present invention, the method for selecting the first depth point is as follows:

[0027] Where the depth within the coated concrete is less than a preset depth threshold, a first depth point is determined every 1 mm.

[0028] Where the depth within the coated concrete is greater than the depth threshold, a first depth value is determined every 2 mm.

[0029] In some embodiments of the present invention, the method for obtaining the first effective chloride ion diffusion coefficient is as follows:

[0030] Obtain the experimental chloride ion diffusion coefficient of the coated concrete within the experimental time.

[0031] The first effective chloride ion diffusion coefficient is calculated based on the experimental time, the experimental chloride ion diffusion coefficient, and the coating failure time.

[0032] The formula for calculating the first effective chloride ion diffusion coefficient is as follows:

[0033] D t-C Let be the first effective chloride ion diffusion coefficient, and let be the first effective chloride ion diffusion coefficient at time t. max The chloride ion diffusion coefficient in the coated concrete at time t0 is the experimental time, and D0 is the experimental chloride ion diffusion coefficient. maxLet t be the coating failure time. max When the age is greater than the preset age, t max The value is the preset age; m is the age factor of the concrete diffusion coefficient.

[0034] In some embodiments of the present invention, t is obtained in the formula for calculating the first effective chloride ion diffusion coefficient. max The methods for obtaining values ​​include:

[0035] Compare the coating failure time with the preset maximum age;

[0036] When the coating failure time is greater than the maximum age, the t in the formula for calculating the first effective chloride ion diffusion coefficient... max The value is taken as the maximum age.

[0037] In some embodiments of the present invention, the time for obtaining the diffusion of the second chloride ion flux in blank concrete is determined as an equivalent time, including:

[0038] The second chloride ion flux in the blank concrete is determined based on the second chloride ion concentration in the blank concrete and the depth of the blank concrete.

[0039] By comparing the second chloride ion flux with the first chloride ion flux, when the second chloride ion flux is equal to the first chloride ion flux, the placement time of the blank concrete is determined as the equivalent time, where the placement time is the time the blank concrete is placed in the same environment as the coated concrete.

[0040] In some embodiments of the present invention, determining the second chloride ion flux in the blank concrete based on the second chloride ion concentration of the blank concrete includes:

[0041] Obtain the preset second depth point in the blank concrete;

[0042] Based on the preset formula for calculating the chloride ion concentration at the second depth point, the chloride ion concentration at each second depth point is calculated by considering the location of the second depth point, the preset second effective chloride ion diffusion coefficient, and the placement time.

[0043] The second chloride ion flux of the blank concrete is calculated based on the chloride ion concentration at each second depth point and the thickness between any two second depth points.

[0044] The formula for calculating the chloride ion concentration at the second depth point is as follows:

[0045]

[0046] C y C represents the chloride ion concentration at the second depth point when the second depth point is at depth y. 0y C represents the initial chloride ion concentration of the blank concrete. s The maximum chloride ion concentration on the second surface of the blank concrete is y, where y is the second depth value corresponding to the second depth point, and D is the chloride ion concentration on the surface of the blank concrete. t t is the second effective chloride ion diffusion coefficient, and t is the placement time.

[0047] In some embodiments of the present invention, the step of calculating the chloride ion concentration at each second depth point based on a preset second depth point chloride ion concentration calculation formula, taking into account the location of the second depth point, a preset second effective chloride ion diffusion coefficient, and the placement time, includes:

[0048] The concentration curve at the second depth point is obtained based on the relationship between the chloride ion concentration at the second depth point and the second depth value.

[0049] The concentration curves of the second depth point corresponding to different placement times are compared, and the comparison results are visualized.

[0050] In a second aspect, embodiments of the present invention provide a coating-based concrete structure life extension assessment device, including at least one control processor and a memory for communicatively connecting to the at least one control processor; the memory stores instructions executable by the at least one control processor, which, when executed by the at least one control processor, enables the at least one control processor to perform the coating-based marine concrete structure life extension assessment method as described in the first aspect above.

[0051] Thirdly, embodiments of the present invention provide an electronic device including a coating-based marine concrete structure life extension assessment device as described in the second aspect above.

[0052] Fourthly, embodiments of the present invention provide a computer-readable storage medium storing computer-executable instructions for performing the coating-based marine concrete structure life extension assessment method as described in the first aspect above.

[0053] The coating-based method for assessing the lifespan extension of marine concrete structures according to embodiments of the present invention has at least the following beneficial effects: obtaining the coating failure time of the coated concrete; obtaining the first chloride ion concentration in the coated concrete during the coating failure time; determining the first chloride ion flux in the coated concrete based on the first chloride ion concentration and the depth of the coated concrete; obtaining the diffusion time of the second chloride ion flux in blank concrete, which is determined as the equivalent time, wherein the blank concrete is concrete placed in the same environment as the coated concrete, and the second chloride ion flux is equal to the first chloride ion flux; and determining the difference between the coating failure time and the equivalent time as the extension time of the coating for the lifespan of the concrete structure. In practical applications, when the coating covering the surface of the coated concrete completely fails, the chloride ion concentration on the surface of the coated concrete has exceeded the critical chloride ion concentration, and has penetrated into the interior of the coated concrete. Therefore, by calculating the first chloride ion flux in the coated concrete at the coating failure time, the equivalent time required for the second chloride ion flux, which is equal to the first chloride ion flux, in blank concrete is obtained, thus obtaining the time required for chloride ions to enter the concrete. Then, by using the difference between the coating failure time and the equivalent time, i.e., subtracting the time that chloride ions have already entered the concrete during the coating failure process, the life extension time of the coated concrete by the coating can be accurately obtained. Attached Figure Description

[0054] Figure 1 This is a flowchart of a coating-based method for assessing the life extension of marine concrete structures, provided in an embodiment of the present invention.

[0055] Figure 2 This is a flowchart for obtaining the coating failure time provided in another embodiment of the present invention;

[0056] Figure 3 This is a flowchart of the first chloride ion flux in coated concrete provided in another embodiment of the present invention;

[0057] Figure 4 This is a flowchart for obtaining the equivalent time provided in another embodiment of the present invention;

[0058] Figure 5 This is a flowchart of obtaining the second chloride ion flux provided in another embodiment of the present invention;

[0059] Figure 6 This is a schematic diagram illustrating the relationship between chloride ion concentration on the first surface of coated concrete and exposure time, provided in another embodiment of the present invention.

[0060] Figure 7 This is a schematic diagram showing the distribution of chloride ion concentration in blank concrete under different placement times, provided by another embodiment of the present invention.

[0061] Figure 8 This is a schematic diagram of the relationship between chloride ion permeation flux and placement time in blank concrete provided by another embodiment of the present invention. Detailed Implementation

[0062] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0063] In the description of this invention, it should be understood that the orientation descriptions, such as up, down, front, back, left, right, etc., are based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0064] In the description of this invention, "several" means one or more, "more than" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. The use of "first" and "second" in the description is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0065] In the description of this invention, unless otherwise explicitly defined, terms such as "set up," "install," and "connect" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this invention in conjunction with the specific content of the technical solution.

[0066] This invention provides a method for assessing the lifespan extension of marine concrete structures based on coatings, which has at least the following beneficial effects: obtaining the coating failure time of the coated concrete; obtaining the first chloride ion concentration in the coated concrete within the coating failure time; determining the first chloride ion flux in the coated concrete based on the first chloride ion concentration and the depth of the coated concrete; obtaining the diffusion time of the second chloride ion flux in blank concrete, which is determined as the equivalent time, wherein the blank concrete is concrete placed in the same environment as the coated concrete, and the second chloride ion flux is equal to the first chloride ion flux; and determining the difference between the coating failure time and the equivalent time as the extension time of the concrete structure lifespan due to the coating. In practical applications, when the coating covering the surface of the coated concrete completely fails, the chloride ion concentration on the surface of the coated concrete has exceeded the critical chloride ion concentration, and has penetrated into the interior of the coated concrete. Therefore, by calculating the first chloride ion flux in the coated concrete at the coating failure time, the equivalent time required for the second chloride ion flux, which is equal to the first chloride ion flux, in blank concrete is obtained, thus obtaining the time required for chloride ions to enter the concrete. Then, by using the difference between the coating failure time and the equivalent time, i.e., subtracting the time that chloride ions have already entered the concrete during the coating failure process, the life extension time of the coated concrete by the coating can be accurately obtained.

[0067] The control method of the present invention will be further described below with reference to the accompanying drawings.

[0068] Reference Figure 1 , Figure 1 The flowchart illustrates a coating-based method for assessing the lifespan extension of marine concrete structures, which includes, but is not limited to, the following steps:

[0069] Step S110: Obtain the coating failure time of the coated concrete;

[0070] Step S120: Obtain the first chloride ion concentration in the coated concrete within the coating failure time;

[0071] Step S130: Determine the first chloride ion flux in the coated concrete based on the first chloride ion concentration in the first concrete and the depth of the coated concrete.

[0072] Step S140: Obtain the diffusion time of the second chloride ion flux in the blank concrete and determine it as the equivalent time. The blank concrete is the concrete placed in the same environment as the coated concrete. The second chloride ion flux is equal to the first chloride ion flux.

[0073] Step S150: The difference between the coating failure time and the equivalent time is determined as the extension of the coating's lifespan for the concrete structure.

[0074] It should be noted that the aging and failure time of the coating on the coated concrete is the coating failure time.

[0075] It should be noted that after the coating fails, the chloride ion concentration on the surface of the coated concrete may have exceeded the critical chloride ion concentration, causing the coated concrete to expand and crack. Therefore, it is important to obtain the chloride ion concentration in the coated concrete at the moment of coating failure.

[0076] It should be noted that the first chloride ion flux in the coated concrete is obtained by measuring the chloride ion concentration in the first concrete and the depth of the coated concrete. Based on the principle of equal chloride ion penetration, the time required for a second chloride ion flux equal to the first chloride ion flux to diffuse in the blank concrete is calculated and used as the equivalent time required for the first chloride ion flux to diffuse in the coated concrete. It is important to note that the cultivation environment of the blank concrete must be the same as that of the coated concrete, as the chloride ion concentration and diffusion rate differ under different environments.

[0077] It should be noted that the diffusion time of the second chloride ion flux in the blank concrete is determined as the equivalent time. This is because when the coating reaches its failure time, chloride ions have already penetrated into the interior of the coated concrete and caused damage. Therefore, when it is necessary to calculate the extended lifespan of the coated concrete under the protection of the coating, the failure time should be subtracted from the time it takes for chloride ions to enter the interior of the coated concrete, i.e., the equivalent time, to finally obtain the extended lifespan of the coated concrete.

[0078] In another embodiment, reference Figure 2 , Figure 2 This is a flowchart of obtaining the coating failure time provided in another embodiment of the present invention. Step S110 includes:

[0079] Step S111: Obtain the chloride ion concentration on the first surface of the coated concrete. The chloride ion concentration on the first surface is the chloride ion concentration on the surface of the coated concrete.

[0080] Step S112: Based on the preset linear relationship between the first surface chloride ion concentration and the exposure time, obtain the exposure time corresponding to the highest value of the first surface chloride ion concentration, and determine it as the coating failure time of the coated concrete. The exposure time is the time when the coated concrete is placed in the preset environment.

[0081] It should be noted that, based on exposure test or engineering survey data, a linear relationship between the chloride ion concentration on the first surface of the coated concrete and the exposure time is established under a preset environment: C s =kt, where C sLet be the chloride ion concentration on the first surface, k be the comprehensive influence coefficient of the environmental materials, and t be the exposure time. The maximum chloride ion concentration on the second surface of the uncoated blank concrete is obtained and used as the maximum chloride ion concentration on the first surface. The chloride ion concentration on the blank surface of the blank concrete is closely related to factors such as the type of concrete cementitious material, exposure age, and service environment. The chloride ion concentration on the second surface of the blank concrete is obtained based on exposure tests under a preset environment. It is understood that the preset environment refers to marine environments under different scenarios. After using the maximum chloride ion concentration on the second surface as the maximum chloride ion concentration on the coating surface, according to C... s =kt is the time when the chloride ion concentration on the surface of the coated concrete reaches its maximum value, which is taken as the coating failure time. Because after the chloride ion concentration on the first surface of the coated concrete reaches its maximum value, excess chloride ions that subsequently penetrate into the coated concrete from the outside will accumulate at the interface between the coating and the concrete, which can easily cause the coating to bulge and break down. Therefore, for a conservative period, this time is taken as the coating failure time.

[0082] In another embodiment, reference Figure 3 , Figure 3 This is a flowchart of the first chloride ion flux in coated concrete provided by another embodiment of the present invention, step S130, including:

[0083] Step S131: Obtain the depth positions of multiple preset first depth points in the coated concrete;

[0084] Step S132: Determine the chloride ion concentration of the first concrete corresponding to the first depth point as the chloride ion concentration of the first depth point;

[0085] Step S133: Calculate the first chloride ion flux of the coated concrete based on the depth value of each first depth point and the corresponding chloride ion concentration at the first depth point.

[0086] It should be noted that because the chloride ion concentration is different at different depths in the coated concrete, multiple first depth points need to be preset in the coated concrete. The depth positions of each first depth point can be the same or different. The chloride ion flux corresponding to each first depth point is calculated by calculating the chloride ion concentration at each first depth point, and then the first chloride ion flux in the entire coated concrete is obtained.

[0087] In another embodiment, step S130 further includes:

[0088] Based on the preset formula for calculating the chloride ion concentration at the first depth point, the chloride ion concentration at each first depth point is calculated by considering the depth value of the first depth point, the preset first effective chloride ion diffusion coefficient, and the coating failure time.

[0089] The first chloride ion flux of the coated concrete is calculated based on the chloride ion concentration at each first depth point and the thickness between any two first depth points.

[0090] The formula for the chloride ion concentration at the first depth point is:

[0091]

[0092] C x C represents the chloride ion concentration at the first depth point when the first depth point is at depth x. 0x Let t be the initial chloride ion concentration in the coated concrete, k be the comprehensive environmental material influence coefficient, and t be the initial chloride ion concentration in the coated concrete. max D represents the coating failure time. t-C is the first effective chloride ion diffusion coefficient, and x is the first depth value corresponding to the first depth point;

[0093] The formula for calculating the first chloride ion flux is:

[0094] Q c =C x1 ×Δx1+C x2 ×Δx² + ....... + C xn ×Δx n

[0095] Q c For the first chloride ion flux, C x1 C x2 , ...C xn Let Δx1, Δx2, ..., Δx be the chloride ion concentration at the first depth point when the depth value x takes the values ​​1, 2, ..., n. n The thickness is the distance between any two first depth points.

[0096] It should be noted that, through

[0097] The spatiotemporal distribution curve of chloride ion concentration in the coated concrete was obtained, where x is the depth from the surface of the coated concrete in mm, and C 0x D represents the initial chloride ion concentration (%) of the coated concrete. t-C Exposure time is t max The first effective chloride ion diffusion coefficient of the coated concrete at that time is expressed in units of 10. -12 m 2 / s. Then via Q c =C x1 ×Δx1+C x2 ×Δx² + ....... + C xn ×Δx n The chloride ion flux in the entire coated concrete, Δx1, Δx2, ..., Δx, is obtained. nThe thickness between any two first depth points is Δx1, which is the thickness between the first depth point and the surface of the coated concrete, while the others are the thickness between any two first depth points.

[0098] In another embodiment, the method for selecting the first depth point includes:

[0099] In the coated concrete, where the depth is less than the preset depth threshold, a first depth point is determined every 1 mm.

[0100] In the coated concrete, where the depth exceeds the depth threshold, a first depth value is determined every 2 mm.

[0101] It should be noted that the chloride ion concentration varies more significantly near the surface of the coated concrete, therefore the first depth point is selected more frequently and densely. Conversely, the chloride ion concentration varies less further away from the surface, so the frequency of selecting the first depth point can be reduced to decrease subsequent calculations. The depth threshold is an empirical value.

[0102] In another embodiment, the method for obtaining the first effective chloride ion diffusion coefficient is as follows:

[0103] Obtain the experimental chloride ion diffusion coefficient of the coated concrete within the experimental time.

[0104] The first effective chloride ion diffusion coefficient was calculated based on the experimental time, the experimental chloride ion diffusion coefficient, and the coating failure time.

[0105] The formula for calculating the first effective chloride ion diffusion coefficient is as follows:

[0106] D t-C The first effective chloride ion diffusion coefficient is given by the value of the first effective chloride ion diffusion coefficient at time t. max The chloride ion diffusion coefficient in the coated concrete at time t0, where t0 is the experimental time and D0 is the experimental chloride ion diffusion coefficient. max Let t be the coating failure time. max When the age is greater than the preset age, t max The value is the preset age; m is the age factor of the concrete diffusion coefficient.

[0107] It should be noted that the formula for calculating the first effective chloride ion diffusion coefficient is: D0 is the effective chloride ion diffusion coefficient of the coated concrete substrate at exposure time t0 (10). -12 m 2 / s). In the formula for calculating the first effective chloride ion diffusion coefficient, t is obtained. maxThe method for determining the value includes: comparing the coating failure time with the preset maximum age; when the coating failure time is greater than the maximum age, the t value in the formula for calculating the first effective chloride ion diffusion coefficient is... max The value is taken as the maximum age. This is because it is generally believed that the maximum decay age of the chloride ion diffusion coefficient in concrete is 20 years, and 20 years is used when calculating the first effective chloride ion diffusion coefficient.

[0108] In another embodiment, reference Figure 4 , Figure 4 This is a flowchart of obtaining equivalent time provided in another embodiment of the present invention; step S140 includes:

[0109] Step S141: Determine the second chloride ion flux in the blank concrete based on the second chloride ion concentration and the depth of the blank concrete.

[0110] Step S142: Compare the second chloride ion flux with the first chloride ion flux. When the second chloride ion flux is equal to the first chloride ion flux, the placement time of the blank concrete is determined as the equivalent time. The placement time is the time that the blank concrete is placed in the same environment as the coated concrete.

[0111] It should be noted that the time it takes for the chloride ion permeation flux in the blank concrete to equal the chloride ion permeation flux in the coated concrete when the coating fails is taken as the equivalent time for the diffusion process of the coated concrete. That is, the second chloride ion flux, which is equal to the first chloride ion flux, is obtained, and the time required for the blank concrete to reach the second chloride ion flux is determined. This is the time required for chloride ions to permeate into the coated concrete when the coating fails.

[0112] In another embodiment, reference Figure 5 , Figure 5 This is a flowchart of obtaining the second chloride ion flux provided in another embodiment of the present invention. The second chloride ion flux in the blank concrete is determined based on the second chloride ion concentration in the blank concrete, including:

[0113] Step S1411: Obtain the preset second depth point in the blank concrete;

[0114] Step S1412: Based on the preset formula for calculating the chloride ion concentration at the second depth point, calculate the chloride ion concentration at each second depth point by considering the location of the second depth point, the preset second effective chloride ion diffusion coefficient, and the placement time.

[0115] Step S1413: Calculate the second chloride ion flux of the blank concrete based on the chloride ion concentration at each second depth point and the thickness between any two second depth points.

[0116] The formula for calculating the chloride ion concentration at the second depth point is as follows:

[0117]

[0118] C y C represents the chloride ion concentration at the second depth point when the second depth point is at depth y. 0y C represents the initial chloride ion concentration in the blank concrete. s Let be the maximum chloride ion concentration on the second surface of the blank concrete, y be the second depth value corresponding to the second depth point, and D be the maximum chloride ion concentration on the second surface of the blank concrete. t t represents the second effective chloride ion diffusion coefficient, and t represents the storage time.

[0119] It should be noted that a second depth point is also preset in the blank concrete. This is because the chloride ion concentration is higher closer to the concrete surface and lower farther away. Considering both accuracy and simplicity of calculation, the second depth points are set more densely in areas where the depth is less than the depth threshold, and less frequently in areas where the depth is greater than the depth threshold. Furthermore, the second effective chloride ion diffusion coefficient is: Where D t D0 is the second effective chloride ion diffusion coefficient, where D0 is the second effective chloride ion diffusion coefficient of the blank concrete at a placement time of t0 (10 -12 m 2 / s), m is the diffusion coefficient of the concrete matrix and its age factor, and t is the placement time. The placement time obtained when the first chloride ion flux and the second chloride ion flux are equal is taken as the equivalent time t. E-age The difference between the failure time and the equivalent time is obtained. Δt = t max -t E-age As a coating, it extends the time of coating on the concrete.

[0120] In another embodiment, after step S1412, the method further includes:

[0121] The concentration curve at the second depth point is obtained based on the relationship between the chloride ion concentration at the second depth point and the second depth value.

[0122] The concentration curves at the second depth point corresponding to different placement times were compared, and the comparison results were visualized.

[0123] It should be noted that, in order to more intuitively represent the chloride ion concentration at different placement depths, a curve showing the relationship between the chloride ion concentration at the second depth point and the value at the second depth can be plotted. The concentration curves at the second depth point corresponding to different placement times can be visualized in the same coordinate system, resulting in a spatiotemporal relationship diagram of chloride ion concentration in blank concrete.

[0124] The following are specific application scenarios:

[0125] Data from exposure experiments and engineering surveys conducted in northern marine environments with a duration of up to 12 years were referenced. Figure 6 , Figure 6 This is a schematic diagram illustrating the relationship between the surface chloride ion concentration and exposure time of coated concrete according to another embodiment of the present invention. The study found that in actual seawater environments, the surface chloride ion concentration of coated concrete continuously increases with the extension of exposure time, and the first surface chloride ion concentration shows a linear relationship with exposure time: C s =kt, and the linear correlation coefficient R² is relatively high, where C s denoted as chloride ion concentration on the coated concrete surface; k is the comprehensive environmental material influence coefficient, taken as 0.035.

[0126] Numerous studies have shown that the chloride ion concentration on the surface of uncoated concrete is closely related to factors such as the type of concrete cementitious material, exposure age, and service environment. In particular, the chloride ion concentration on the concrete surface increases rapidly within 1 to 3 years. Based on exposure tests in the splash zone under northern marine environments, the maximum chloride ion concentration on the surface of high-performance concrete is approximately 1.00%. Therefore, the maximum chloride ion concentration on the surface of uncoated concrete is taken as the maximum chloride ion concentration on the surface of coated concrete, and is set to 1.00%.

[0127] Based on the relationship between chloride ion concentration on the surface of coated concrete and exposure time, it can be seen that the chloride ion concentration on the surface of coated concrete reaches its maximum value of 1.00% after an exposure time of 28.57 years, i.e., t max 28.57 years was used. The time when the chloride ion concentration on the surface of the coated concrete reaches its maximum value was taken as the coating failure time. This is because after the chloride ion concentration on the surface of the coated concrete reaches its maximum value, excess chloride ions that subsequently penetrate into the coated concrete from the outside will accumulate at the interface between the coating and the concrete, which can easily cause the coating to bulge and break down. Therefore, this time was taken as the coating failure time as a conservative estimate.

[0128] use Calculate the spatiotemporal distribution curve of chloride ion concentration in coated concrete when the surface coating fails. The initial chloride ion concentration C0 of the coated concrete is taken as 0.012%. The age factor m of the concrete diffusion coefficient is taken as 0.48. t-C For an exposure time of t max The effective chloride ion diffusion coefficient of the coated concrete substrate at 28.57 years (10) -12 m 2 The chloride ion diffusion coefficient of concrete is generally considered to have a maximum decay age of 20 years. Therefore, 20 years is used when calculating the effective diffusion coefficient of the coated concrete substrate. According to exposure tests, the chloride ion diffusion coefficient D0 of concrete at age 1 is 0.80 × 10⁻⁶. -12 m 2 / s, according to The calculated first effective chloride ion diffusion coefficient is 0.19 × 10⁻⁶. -12 m 2 / s.

[0129] Based on the chloride ion concentration distribution in coated concrete at different depths, using Q c =C x1 ×Δx1+C x2 ×Δx² + ....... + C xn ×Δx n Calculate the first chloride ion flux in coated concrete The depth ranges from 0 to 4 mm, with each layer being 1 mm thick. Layers beyond 4 mm are 2 mm thick. When calculating the first chloride ion flux, the initial chloride ion concentration in the concrete is deducted. The chloride ion concentration at different depths in the coated concrete when the coating fails is shown in Table 1.

[0130] use Calculate the chloride ion concentration distribution curves in blank concrete at different ages (1 year, 2 years, 3 years, 5 years, 7 years, 10 years, etc.), and refer to... Figure 7 The values, from top to bottom, represent 10 years, 7 years, 5 years, 3 years, 2 years, and 1 year. It can be seen that the longer the blank concrete has been left, the higher the chloride ion concentration at the same depth. (See also...) Figure 8 According to Q c =C y1 ×Δy1+C y2 ×Δy² + ....... + C yn ×Δy n The second chloride ion flux in blank concrete at different ages (1 year, 2 years, 3 years, 5 years, 7 years, 10 years, etc.) was calculated, and a mathematical formula was established for the second chloride ion flux in blank concrete in relation to the placement time: Q = 1.974ln(t) + 5.413. The time when the chloride ion flux in blank concrete equals the chloride ion flux in coated concrete at coating failure was taken as the equivalent time t for the diffusion process of coated concrete. E-age That is, based on the mathematical formula for the second chloride ion flux in blank concrete and the placement time, the equivalent time t of the diffusion process in the coated concrete is calculated. E-age The equivalent time is 7.05 years. Table 1 shows the chloride ion concentration at different depths in blank concrete within the equivalent time. The left side shows the data for coated concrete, and the right side shows the data for blank concrete.

[0131] Table 1

[0132]

[0133] According to Δt=t max -t E-ageIt can quantitatively assess the improvement in service life of concrete structures by the surface coating in the splash zone under seawater conditions in northern my country, which is 21.52 years.

[0134] Compared with the prior art, this application has the following advantages:

[0135] (1) Considering the influence of the time-varying characteristics of surface chloride ion concentration in coated concrete on chloride ion transport in the structure, the theoretical basis is more sufficient, the results are more consistent with the actual chloride ion transport process in coated concrete under actual conditions, and the prediction results are more accurate. This application, based on long-term exposure tests and engineering surveys in actual environments, has determined a linear model between the surface chloride ion concentration and exposure age of coated concrete, and further established a spatiotemporal distribution model of chloride ions in coated concrete considering the time-varying effect of surface chloride ion concentration based on the time-varying model of surface chloride ion concentration. The traditional concrete structure life calculation model is... t is the lifespan of the concrete structure, x is the thickness of the concrete cover, and D is the thickness of the concrete cover. t C is the diffusion coefficient in concrete, C0 is the chloride ion concentration on the surface of the coated concrete when the coating fails, and C x C represents the chloride ion concentration on the surface of the blank concrete. s The chloride ion concentration on the surface of the coated concrete is used. This model is primarily based on the fact that the chloride ion concentration on the concrete surface increases rapidly in the early stages. In engineering design and evaluation, based on conservative considerations for predicted lifespan, the time-varying effect of surface chloride ion concentration is generally not considered. Therefore, this model is suitable for predicting the durability lifespan of blank concrete structures without surface coating. However, for coated concrete structures, the increase in surface chloride ion concentration is much lower than that of uncoated concrete. Therefore, this application considers the time-varying effect of surface chloride ion concentration, and the established lifespan prediction model for coated concrete structures is more scientific and reliable.

[0136] (2) A quantitative calculation method for surface coating failure time is proposed. Currently, there are no clear research conclusions regarding coating failure time. Generally, the lifespan of the coating itself is assumed, without considering the impact of the actual environment on the coating's self-damage. Therefore, the basis for assuming the coating's lifespan is insufficient. This application proposes using the time when the chloride ion concentration on the coated concrete surface reaches its maximum value as the coating failure time. This is mainly because after the chloride ion concentration on the coated concrete surface reaches its maximum value, excess chloride ions that subsequently penetrate from the outside will accumulate at the coating-concrete interface, easily causing coating bulging and damage. As a conservative estimate, using this time as the coating failure time has a more sufficient theoretical basis.

[0137] (3) Chloride ion penetration resistance is an important indicator for evaluating the protective performance of coatings. The "Durability Design Standard for Waterway Engineering Structures" (JTS153) provides an evaluation method based on rapid indoor tests, with chloride ion penetration as the main indicator. This application proposes the principle of equal chloride ion penetration, using the time when the chloride ion penetration in blank concrete is equal to that in coated concrete as the equivalent time t for the diffusion process of coated concrete. E-age A mathematical formula was established to correlate the total chloride ion permeation flux with the exposure time in blank concrete. The equivalent time t for the failure of the surface-coated concrete was determined using a mathematical model. E-age Using the difference between the coating failure time and the equivalent time as a quantitative measure of the service life extension of the surface coating on concrete structures is theoretically sound and methodologically reliable.

[0138] It will be understood by those skilled in the art that all or some of the steps and systems in the methods disclosed above can be implemented as software, firmware, hardware, and suitable combinations thereof. Some or all of the physical components can be implemented as software executed by a processor, such as a central processing unit, digital signal processor, or microprocessor, or as hardware, or as an integrated circuit, such as an application-specific integrated circuit. Such software can be distributed on a computer-readable medium, which can include computer storage media (or non-transitory media) and communication media (or transient media). As is known to those skilled in the art, the term computer storage media includes volatile and non-volatile, removable and non-removable media implemented in any method or technology for storing information (such as computer-readable instructions, data structures, program modules, or other data). Computer storage media includes, but is not limited to, RAM, ROM, EEPROM, flash memory or other memory technologies, CD-ROM, digital versatile disc (DVD) or other optical disc storage, magnetic cartridges, magnetic tape, disk storage or other magnetic storage devices, or any other medium that can be used to store desired information and is accessible to a computer. Furthermore, as is known to those skilled in the art, communication media typically include computer-readable instructions, data structures, program modules, or other data in modulated data signals such as carrier waves or other transmission mechanisms, and may include any information delivery medium.

[0139] The above provides a detailed description of the preferred embodiments of the present invention. However, the present invention is not limited to the above embodiments. Those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of the present invention. All such equivalent modifications or substitutions are included within the scope defined by the claims of the present invention.

Claims

1. A method for evaluating the time to life extension of a marine concrete structure based on coating, characterized by, include: Obtain the coating failure time of the coated concrete; Obtain the first chloride ion concentration in the coated concrete within the coating failure time; The first chloride ion flux in the coated concrete is determined based on the first chloride ion concentration in the concrete and the depth of the coated concrete. The diffusion time of the second chloride ion flux in blank concrete is obtained and determined as the equivalent time. The blank concrete is concrete placed in the same environment as the coated concrete. The second chloride ion flux is equal to the first chloride ion flux. The second chloride ion flux is determined based on the second concrete chloride ion concentration of the blank concrete and the depth of the blank concrete. The difference between the coating failure time and the equivalent time is determined as the extension of the coating's lifespan for the concrete structure. The method of obtaining the coating failure time of the coated concrete includes: The first surface chloride ion concentration of the coated concrete is obtained, where the first surface chloride ion concentration is the chloride ion concentration on the surface of the coated concrete; based on a preset linear relationship between the first surface chloride ion concentration and exposure time, the exposure time corresponding to the highest value of the first surface chloride ion concentration is obtained and determined as the coating failure time of the coated concrete, where the exposure time is the time when the coated concrete is placed in a preset environment; The step of determining the first chloride ion flux in the coated concrete based on the first chloride ion concentration in the concrete and the depth of the coated concrete includes: The depth positions of multiple preset first depth points in the coated concrete are obtained; based on the preset first depth point chloride ion concentration calculation formula, the first depth point chloride ion concentration corresponding to each first depth point is calculated by the depth value of the first depth point, the preset first effective chloride ion diffusion coefficient and the coating failure time; the first chloride ion flux of the coated concrete is calculated according to the chloride ion concentration of each first depth point and the thickness between any two first depth points. The formula for the chloride ion concentration at the first depth point is: C1(x) is the first depth point chloride concentration when the first depth point is x depth, C0 is the initial chloride concentration in the coated concrete, k is the environmental material comprehensive influence coefficient, t is the coating failure time, D1 is the first effective chloride diffusion coefficient, x1 is the first depth value corresponding to the first depth point; The formula for calculating the first chloride ion flux is: for the first chloride ion flux, , ,… the first depth point chloride ion concentration for the depth value x of the first depth point taking values 1, 2, … n, , ,… is the thickness between any two of the first depth points.

2. The coating-based time-to-life extension assessment method for marine concrete structures according to claim 1, characterized in that, The method for selecting the first depth point is as follows: Where the depth within the coated concrete is less than a preset depth threshold, a first depth point is determined every 1 mm. Where the depth within the coated concrete is greater than the depth threshold, a first depth value is determined every 2 mm.

3. The coating-based time-to-life extension assessment method for marine concrete structures according to claim 1, characterized in that, The method for obtaining the first effective chloride ion diffusion coefficient is as follows: Obtain the experimental chloride ion diffusion coefficient of the coated concrete within the experimental time. The first effective chloride ion diffusion coefficient is calculated based on the experimental time, the experimental chloride ion diffusion coefficient, and the coating failure time. The calculation formula of the first effective chlorine ion diffusion coefficient is: ; Dc(t0) is the first effective chloride ion diffusion coefficient, which is the chloride ion diffusion coefficient in the coated concrete at time t0, t max to is the experimental time, Dc(t0) is the experimental chloride ion diffusion coefficient, which is the chloride ion diffusion coefficient in the coated concrete at time t0, t max tcoated is the coated failure time, when t max tcoated is greater than the preset age, t max tcoated is equal to the preset age; m is the age factor of the concrete diffusion coefficient.

4. The method for assessing the service life extension of marine concrete structures based on coatings according to claim 3, characterized in that, In the formula for calculating the first effective chloride ion diffusion coefficient, the following is obtained: t max The methods for obtaining values ​​include: Compare the coating failure time with the preset maximum age; When the coating failure time is greater than the maximum age, the formula for calculating the first effective chloride ion diffusion coefficient is as follows: t max The value is taken as the maximum age.

5. The method for assessing the service life extension of marine concrete structures based on coatings according to claim 1, characterized in that, The time for obtaining the diffusion of the second chloride ion flux in blank concrete is determined as the equivalent time, including: The second chloride ion flux in the blank concrete is determined based on the second chloride ion concentration in the blank concrete and the depth of the blank concrete. By comparing the second chloride ion flux with the first chloride ion flux, when the second chloride ion flux is equal to the first chloride ion flux, the placement time of the blank concrete is determined as the equivalent time, where the placement time is the time the blank concrete is placed in the same environment as the coated concrete.

6. The method for assessing the service life extension of marine concrete structures based on coatings according to claim 5, characterized in that, The step of determining the second chloride ion flux in the blank concrete based on the second chloride ion concentration of the blank concrete includes: Obtain the preset second depth point in the blank concrete; Based on the preset formula for calculating the chloride ion concentration at the second depth point, the chloride ion concentration at each second depth point is calculated by considering the location of the second depth point, the preset second effective chloride ion diffusion coefficient, and the placement time. The second chloride ion flux of the blank concrete is calculated based on the chloride ion concentration at each second depth point and the thickness between any two second depth points. The formula for calculating the chloride ion concentration at the second depth point is as follows: The chloride ion concentration at the second depth point is at depth y. The initial chloride ion concentration of the blank concrete. y represents the maximum chloride ion concentration on the second surface of the blank concrete, where y is the chloride ion concentration on the surface of the blank concrete, and y is the second depth value corresponding to the second depth point. t is the second effective chloride ion diffusion coefficient, and t is the placement time.

7. The method for assessing the service life extension of marine concrete structures based on coatings according to claim 6, characterized in that, The method, based on a preset formula for calculating chloride ion concentration at a second depth point, calculates the chloride ion concentration at each second depth point by taking into account the location of the second depth point, a preset second effective chloride ion diffusion coefficient, and the placement time. This includes: The concentration curve at the second depth point is obtained based on the relationship between the chloride ion concentration at the second depth point and the second depth value. The concentration curves of the second depth point corresponding to different placement times are compared, and the comparison results are visualized.

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