Method for assessing the protective effect of a coating on a marine concrete structure

Abstract

The application discloses a method for evaluating the protection effect of a coating on a marine concrete structure, and the method comprises the following steps: testing the chloride ion content in the target surface coating concrete; establishing the relationship between the coating chloride ion diffusion coefficient ratio and the natural aging time under the environment of the engineering concrete based on the chloride ion content, the ultraviolet cumulative radiation of the environment where the engineering concrete is located, and the ultraviolet cumulative radiation accepted by the target surface coating concrete during the aging process; obtaining the time when the chloride ion in the engineering concrete diffuses to the surface of the concrete under the environment of the engineering concrete according to the initial coating chloride ion diffusion coefficient, the coating thickness and the fitting constant; and determining the protection effect of the coating on the engineering concrete according to the time when the chloride ion in the engineering concrete diffuses to the surface of the concrete. Therefore, the protection effect of the coating on the concrete structure can be more accurately judged, and the method can be widely applied to the field of evaluating the protection effect of the coating on the concrete structure.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of evaluating the protective effect of a coating on a marine concrete structure, and in particular to a method for evaluating the protective effect of a coating on a marine concrete structure. BACKGROUND

[0002] Chloride ion erosion induced steel bar corrosion is the main cause of durability degradation of marine reinforced concrete structures. For marine structures in harsh marine environments, spraying corrosion-resistant materials on the surface of the structure can effectively reduce the erosion of chloride ions and prolong the service life of the structure. Currently, surface coating protection is often used to improve the durability of concrete structures in harsh marine environments. Currently, there are many surface coating systems suitable for marine environments. Different types of surface coating systems are greatly affected by different marine environments and coating material characteristics. How to evaluate the applicability and long-term protective effect of surface coatings in different marine environments is currently the main technical problem. The resistance of surface coatings to chloride ion penetration is an important indicator of coating performance. The Water Transport Engineering Structure Durability Design Standard (JTS153) provides an index and test method for the resistance of coatings to chloride ion penetration. This method uses an indoor diffusion test, which is simple and fast, but does not take into account the continuous aging of coatings in actual service environments and the continuous reduction of the resistance of coatings to chloride ion penetration, resulting in a large difference between the results and the actual environmental coating long-term protective effect. Therefore, it is crucial to accurately determine the protective effect of the coating on the concrete structure. SUMMARY

[0003] Therefore, the embodiments of the present application provide a method for evaluating the protective effect of a coating on a marine concrete structure to more accurately determine the protective effect of the coating on the concrete structure.

[0004] One aspect of the present application provides a method for evaluating the protective effect of a coating on a marine concrete structure, comprising: testing the chloride ion content in target surface-coated concrete, wherein the target surface-coated concrete is a test sample obtained after coating, aging and corrosion of the test concrete made of the same material and with the same mixing ratio as the engineering concrete; based on the chloride ion content, the cumulative ultraviolet radiation of the environment where the engineering concrete is located, and the cumulative ultraviolet radiation received by the target surface-coated concrete during the aging process, establishing the relationship between the coating chloride ion diffusion coefficient ratio and the natural aging time in the environment where the engineering concrete is located, wherein the coating chloride ion diffusion coefficient ratio is the ratio of the chloride ion diffusion coefficient after aging for a period of time to the initial coating chloride ion diffusion coefficient; according to the initial coating chloride ion diffusion coefficient, the coating thickness and the fitting constant, obtaining the time for the chloride ion in the engineering concrete to diffuse to the surface of the concrete in the environment where the engineering concrete is located; and determining the protective effect of the coating on the engineering concrete according to the time for the chloride ion in the engineering concrete to diffuse to the surface of the concrete.

[0005] According to some embodiments of the present application, the step of obtaining the target surface-coated concrete comprises: obtaining a concrete test piece according to the raw materials and mixing ratio of the engineering concrete; coating the concrete test piece with a coating to obtain first surface-coated concrete; and placing the first surface-coated concrete in an aging test box for aging at different ages to obtain second surface-coated concrete, wherein the aging comprises ultraviolet radiation on the first surface-coated concrete; and placing the second surface-coated concrete in different corrosion zones of a seawater simulation test box for corrosion to obtain the target surface-coated concrete.

[0006] According to some embodiments of the present application, the step of obtaining the target surface-coated concrete further comprises: coating the concrete test piece with a coating after curing to obtain first surface-coated concrete; and placing the first surface-coated concrete in an aging test box after curing.

[0007] According to some embodiments of the present application, the step of testing the chloride ion content in the target surface-coated concrete comprises: removing the coating on the target surface-coated concrete and layering and grinding to obtain a powder sample; and sampling the powder sample according to the powder sampling diameter and the powder sampling depth to obtain a concrete sample, wherein the powder sampling depth is equal to or greater than the deepest chloride ion penetration depth, and the powder sampling diameter is equal to or greater than the maximum aggregate particle size.

[0008] According to some embodiments of the present application, the step of testing the chloride ion content in the target surface-coated concrete further comprises: sieving and drying the concrete sample; mixing the concrete sample with a nitric acid solution; and testing the chloride ion content in the concrete sample by an automatic potentiometric titrator.

[0009] According to some embodiments of the present application, the relationship between the coated chloride ion diffusion coefficient ratio and the natural aging time in the environment where the engineering concrete is located is established based on the chloride ion content, the cumulative ultraviolet radiation of the environment where the engineering concrete is located, and the cumulative ultraviolet radiation received by the target surface coated concrete during the aging process, and includes: obtaining the natural cumulative ultraviolet radiation of the environment where the engineering concrete is located; obtaining the test cumulative ultraviolet radiation received by the target surface coated concrete during the aging process; and obtaining the relationship between the time of the target surface coated concrete during the aging process and the natural aging time of the engineering concrete based on the same ultraviolet radiation causing the same amount of coating damage according to the natural cumulative ultraviolet radiation and the test cumulative ultraviolet radiation.

[0010] According to some embodiments of the present application, the relationship between the coated chloride ion diffusion coefficient ratio and the natural aging time in the environment where the engineering concrete is located is established based on the chloride ion content, the cumulative ultraviolet radiation of the environment where the engineering concrete is located, and the cumulative ultraviolet radiation received by the target surface coated concrete during the aging process, and further includes: obtaining the chloride ion content corresponding to different aging ages of the target surface coated concrete; and obtaining the relationship between the coated chloride ion diffusion coefficient ratio and the natural aging time in the environment where the engineering concrete is located according to the relationship between the chloride ion content, the time of the target surface coated concrete during the aging process, and the natural aging time of the engineering concrete.

[0011] According to some embodiments of the present application, the relationship between the coated chloride ion diffusion coefficient ratio and the natural aging time in the environment where the engineering concrete is located is obtained according to the relationship between the chloride ion content and the time of the target surface coated concrete during the aging process and the natural aging time of the environment where the engineering concrete is located, and in this step, the calculation formula of the relationship between the coated chloride ion diffusion coefficient ratio and the natural aging time is: D t / D0=ae bt wherein a and b are fitting constants, t is the natural aging time, D t is the chloride ion diffusion coefficient after aging t time, and D0 is the initial coated chloride ion diffusion coefficient.

[0012] According to some embodiments of the present application, the time of the chloride ion in the engineering concrete diffusing to the surface of the concrete in the environment where the engineering concrete is located is obtained according to the initial coated chloride ion diffusion coefficient, the coating thickness, and the fitting constants, and in this step, the calculation formula of the time of the chloride ion in the engineering concrete diffusing to the surface of the concrete is: Wherein, t1 is the time of chloride ion diffusion to the surface of the concrete in the engineering concrete, D0 is the initial coating chloride ion diffusion coefficient, L is the coating thickness, a and b are fitting constants.

[0013] According to some embodiments of the present application, the determination of the protection effect of the coating on the engineering concrete according to the time of chloride ion diffusion to the surface of the concrete in the engineering concrete comprises: the longer the time of chloride ion diffusion to the surface of the concrete in the engineering concrete, the better the protection effect of the coating on the engineering concrete.

[0014] The embodiment of the present application also discloses a computer program product or a computer program, which comprises computer instructions stored in a computer readable storage medium. The processor of the computer device can read the computer instructions from the computer readable storage medium, and the processor executes the computer instructions to make the computer device execute the foregoing method.

[0015] The embodiment of the present application tests the chloride ion content in the target surface coating concrete by manufacturing the target surface coating concrete of the same material and the same mixing ratio as the engineering concrete, brushing the coating, aging and corroding the target surface coating concrete, and establishing the relationship between the coating chloride ion diffusion coefficient ratio and the natural aging time based on the chloride ion content, the cumulative ultraviolet radiation of the environment where the engineering concrete is located, and the cumulative ultraviolet radiation received by the target surface coating concrete in the aging process. The relationship between the target surface coating concrete cultured in the laboratory and the engineering concrete in the actual scene is constructed, so that the evaluation of the protection effect is more in line with the actual scene and more accurate. According to the initial coating chloride ion diffusion coefficient, the coating thickness and the fitting constant, the time of chloride ion diffusion to the surface of the concrete in the engineering concrete under the environment is obtained, and the protection effect of the coating on the engineering concrete is determined according to the time of chloride ion diffusion to the surface of the concrete in the engineering concrete, wherein the fitting constant is affected by the environment. The diffusion model of the coating chloride ion diffusion coefficient, the coating thickness, the environment and the time of chloride ion diffusion to the surface of the concrete is established, the relationship between the coating chloride ion diffusion coefficient ratio and the natural aging time is combined, so as to accurately and long-term evaluate the long-term protection effect of the coating on the concrete structure. BRIEF DESCRIPTION OF DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0017] Figure 1A step flow chart of the method for evaluating the protection effect of the coating on the marine concrete structure provided by the embodiment of the present application is provided.

[0018] Figure 2 Another step flow chart of the method for evaluating the protection effect of the coating on the marine concrete structure provided by the embodiment of the present application is provided.

[0019] Figure 3 The relationship between the ratio of the chloride ion diffusion coefficient of the coating with different aging times and the natural aging time;

[0020] Figure 4 The influence of the coating thickness on the time of chloride ion diffusion to the surface of the concrete;

[0021] Figure 5 The influence of the chloride ion diffusion coefficient of the coating on the time of chloride ion diffusion to the surface of the concrete;

[0022] Figure 6 A schematic block diagram of the device for evaluating the protection effect of the coating on the marine concrete structure provided by the embodiment of the present application is provided. DETAILED DESCRIPTION

[0023] In order to make the purposes, technical solutions and advantages of the present application clearer, the present application is further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and do not limit the present application.

[0024] Chloride ion erosion induced steel corrosion is the main reason for the durability degradation of marine reinforced concrete structures. At present, a coating is usually brushed on the surface of the concrete structure to protect the engineering concrete and improve the service life of the concrete. However, due to the influence of the environment of the engineering concrete, the characteristics of the coating material and the like, the protection effect of the coating on the engineering concrete is not the same, what kind of coating is suitable for what kind of environment, and how long the coating will be damaged, which are all contents to be considered. Therefore, it is necessary to evaluate the protection effect of the coating on the engineering concrete. At present, the commonly used method is still the indoor diffusion test, which is simple and fast, but does not consider that the coating is continuously aged with the environment and climate, and the chloride ion penetration resistance of the coating is continuously reduced, which causes a large difference between the results and the long-term protection effect of the coating in the actual environment. In addition, it is crucial to understand the time of chloride ion diffusion to the surface coating for the quantitative evaluation of the service life of the surface coating concrete structure, because the high-performance concrete usually adopts fly ash and ground slag powder, and its early hydration is slow, but with the extension of the concrete age, its hydration continues, the internal density improves, and the chloride ion penetration resistance increases. At present, the research data is lacking, and it is difficult to effectively support the quantitative design of the durability of the surface coating concrete structure. Therefore, the present application provides a more accurate method for evaluating the protection effect of the coating on the marine concrete structure.

[0025] ReferenceFigure 1 , Figure 1 The step flow chart of the method for evaluating the protection effect of the coating on the marine concrete structure provided by the embodiment of the present application comprises steps S100-S400:

[0026] Step S100, test the chloride ion content in the target surface coating concrete, wherein the target surface coating concrete is a test sample obtained after brushing the coating, aging and corrosion on the engineering concrete made of the same material and the same mixing ratio.

[0027] Specifically, an indoor engineering concrete corresponding sample, i.e., the target surface coating concrete, is configured. The material of the target surface coating concrete is the same as that of the engineering concrete, and the mixing ratio of the material is the same, and is also brushed with the coating, and is artificially aged and corroded. The target surface coating concrete is configured to more conveniently detect the invasion rule of chloride ions through the indoor sample, and to accurately calculate the chloride ion diffusion of the engineering concrete by establishing the relationship between the indoor sample and the engineering concrete in the actual scene, so as to obtain the protection effect of the coating.

[0028] The specific steps of configuring the target surface coating concrete comprise steps S110-S140.

[0029] Step S110, according to the raw materials and mixing ratio of the engineering concrete, a concrete test piece is prepared.

[0030] Specifically, the raw materials of the engineering concrete and the mixing ratio are obtained to prepare the concrete test piece. It should be noted that the concrete test piece is usually a cube, and according to prior knowledge, the size of the prepared concrete test piece is convenient for the experiment to occur, and an example can be a cube of 10cmx10cmx10cm. Then the concrete test piece is subjected to standard curing, wherein the standard curing refers to curing the test block in an environment with a temperature of 20±3℃ and a relative humidity of more than 90%. When there is no standard curing room, the concrete test piece can be cured in water with a temperature of 20±3℃. The PH value of the water should not be less than 7. The strength after curing for 28 days under standard conditions is used as the basis for acceptance evaluation of the concrete strength.

[0031] Step S120, brush the coating on the concrete test piece to obtain the first surface coating concrete.

[0032] Specifically, the first surface-coated concrete is obtained by brushing the surface of the concrete test piece with the coating system used in the project and the construction method, and is used for testing after 7 days of on-site maintenance under the same conditions, in order to maintain the same conditions as the project concrete and ensure the accuracy of the subsequent construction of the target surface-coated concrete and the relationship with the project concrete. It is understood that the same condition maintenance refers to the maintenance of the test block and the component in the same temperature and humidity environment, which serves as the basis for the component's form removal, pool removal, factory delivery, hoisting, tensioning, tension release, temporary load, and continuous construction and structure acceptance. The strength test of the same condition maintenance test piece should be carried out when the equivalent curing age is reached. The equivalent curing age can be taken as the age corresponding to the daily average temperature accumulated to 600℃.d, and the temperature below 0℃ is not counted. The equivalent curing age should not be less than 14 days, and should not be more than 60 days.

[0033] Step S130, placing the first surface-coated concrete into an aging test box to perform aging of different ages to obtain second surface-coated concrete, wherein the aging includes ultraviolet radiation on the first surface-coated concrete.

[0034] Specifically, the first surface-coated concrete is placed into the aging test box to perform aging of different ages to obtain second surface-coated concrete after the end of the maintenance. Exemplarily, the aging test can be 0h, 500h, 1000h, 2000h aging test. It should be noted that the aging includes ultraviolet radiation on the first surface-coated concrete.

[0035] Step S140, placing the second surface-coated concrete into different corrosion zones of a seawater simulation test box to perform corrosion to obtain target surface-coated concrete.

[0036] Specifically, after the aging test is completed, the second surface-coated concrete of different aging ages is placed into different corrosion zones of a seawater simulation test box to perform seawater corrosion test for a period of time. The seawater simulation test box can simulate typical corrosion environments such as atmospheric zone, water level fluctuation zone, splash zone, and underwater zone. The content of the corrosion medium in the simulation solution in the test box is determined according to the seawater concentration of the project location. The environmental temperature is determined according to the average environmental temperature of the project location.

[0037] The test of the chloride ion content in the target surface-coated concrete includes the following steps:

[0038] The coating on the target surface-coated concrete is removed and layered to obtain a powder sample concrete.

[0039] The powder sample concrete is sampled according to the powder sampling diameter and the powder sampling depth, wherein the powder sampling depth is equal to or greater than the deepest chloride ion penetration depth, and the powder sampling diameter is equal to or greater than the maximum aggregate size.

[0040] The concrete sample is sieved and dried.

[0041] Mixing the concrete sample with nitric acid solution;

[0042] Test the chloride ion content in the powder sample by automatic potentiometric titrator.

[0043] Specifically, after removing the coating covering the surface of the concrete, the concrete powder sample is ground layer by layer by using a numerical control machine, the powder diameter is not less than 60 mm and not less than 3 times the maximum particle size of the aggregate, the powder depth is set according to the test time, but the powder depth should reach the deepest chloride ion penetration depth, that is, the concentration of the concrete powder sample is close to the initial chloride ion concentration of the concrete; the ground concrete powder sample is sieved, for example, sieved by a 0.16 mm nominal diameter sieve, and the mass of the powder sample passing through the 0.16 mm sieve is not less than 15 g; the concrete sample is dried, for example, the concrete sample is dried in a 105℃ drying oven. Mix the concrete sample with nitric acid solution, for example, place the concrete sample in a 200ml conical flask, add 100ml of 15% nitric acid solution, tightly plug the conical flask, and place the conical flask on a shaker for 24h; test the chloride ion content in the sample by automatic potentiometric titrator.

[0044] Step S200, based on the chloride ion content, the cumulative ultraviolet radiation of the environment where the engineering concrete is located, and the cumulative ultraviolet radiation received by the target surface coated concrete during the aging process, a relationship between the coating chloride ion diffusion coefficient ratio and the natural aging time in the environment where the engineering concrete is located is established, wherein the coating chloride ion diffusion coefficient ratio is the ratio of the chloride ion diffusion coefficient after aging for a period of time to the initial coating chloride ion diffusion coefficient.

[0045] wherein the reference Figure 2 , Figure 2 Another step flow chart of the method for evaluating the protective effect of the coating on the marine concrete structure provided by the embodiment of the present application, step S200 includes the following steps:

[0046] Step S210, obtaining the natural ultraviolet cumulative radiation of the environment where the engineering concrete is located;

[0047] Step S220, obtaining the test ultraviolet cumulative radiation received by the target surface coated concrete during the aging process;

[0048] Step S230, based on the natural ultraviolet cumulative radiation and the test ultraviolet cumulative radiation, obtaining the relationship between the time of aging of the target surface coated concrete and the natural aging time of the engineering concrete according to the relationship that the same ultraviolet radiation can cause the same aging damage to the coating.

[0049] Specifically, in order to construct the accurate relationship between the target surface coated concrete and the actual engineering concrete, the cumulative radiation of natural ultraviolet rays in the environment where the engineering concrete is located and the cumulative radiation of test ultraviolet rays received by the target surface coated concrete during the aging process are obtained respectively. Based on the relationship that the same ultraviolet radiation can cause the same aging damage to the coating, combined with the obtained cumulative radiation of natural ultraviolet rays and the cumulative radiation of test ultraviolet rays, the relationship between the aging time of the target coated concrete and the natural aging time of the engineering concrete is obtained. Exemplarily: according to the data research, the total annual cumulative radiation in Qingdao area is about 80.21 MJ / m 2 , and the radiation intensity is larger from June to September. According to GB / T 1865-2009, the total radiation corresponding to the aging of 500h, 1000h and 2000h is 108 MJ / m 2 , 216 MJ / m 2 , 432 MJ / m 2 , according to the relationship that the same ultraviolet radiation can cause the same aging damage to the coating, the relationship between the aging time of the target coated concrete and the natural aging time of the engineering concrete can be obtained, that is, in Qingdao area, to achieve the same aging degree as the aging of 500h, 1000h and 2000h in the aging test, the corresponding natural aging time in Qingdao area is 1.35 years, 2.70 years and 5.40 years respectively.

[0050] The step S200 further comprises the following steps:

[0051] Step S240, obtaining the chloride ion content corresponding to different aging ages of the target surface coated concrete.

[0052] Step S250, obtaining the relationship between the coating chloride ion diffusion coefficient ratio and the natural aging time in the environment where the engineering concrete is located according to the relationship between the chloride ion content, the aging time of the target surface coated concrete and the natural aging time of the engineering concrete.

[0053] Specifically, the chloride ion content corresponding to different aging ages of the target surface coated concrete is obtained through measurement, and according to the chloride ion content, the relationship between the time of aging of the target surface coated concrete and the natural aging time of the engineering concrete is combined to obtain the relationship between the coating chloride ion diffusion coefficient ratio and the natural aging time under the actual environment. It should be noted that according to the chloride ion content of the target surface coated concrete in the aging age, the relationship between the chloride ion content and the natural aging time of the engineering concrete is obtained by combining the time of aging of the target surface coated concrete and the natural aging time of the engineering concrete. According to the chloride ion content, the aging age and the volume of the target surface coated concrete, the chloride ion diffusion flux can be calculated, and according to the first Fick diffusion law, the chloride ion diffusion flux of the coating is proportional to the coating chloride ion diffusion coefficient, so the relationship between the coating chloride ion diffusion coefficient ratio and the natural aging time is constructed. The calculation formula of the relationship between the coating chloride ion diffusion coefficient ratio and the natural aging time is: D t / D0=ae bt Wherein, a and b are fitting constants, t is the natural aging time, D t is the chloride ion diffusion coefficient after aging t time, D0 is the initial coating chloride ion diffusion coefficient, and the initial coating chloride ion diffusion coefficient is the coating chloride ion diffusion coefficient before aging. The fitting constant is generated according to the influence of the environment.

[0054] Step S300, according to the initial coating chloride ion diffusion coefficient, the coating thickness, the fitting constant, the time of the chloride ion in the engineering concrete diffusing to the surface of the concrete in the environment where the engineering concrete is located is obtained.

[0055] Specifically, the coating chloride ion diffusion coefficient ratio is the ratio of the chloride ion diffusion coefficient after aging for a period of time to the initial coating chloride ion diffusion coefficient, and according to the initial coating chloride ion diffusion coefficient, the coating thickness and the fitting constant, the time of the chloride ion in the engineering concrete diffusing to the surface of the concrete in the environment where the engineering concrete is located is obtained. The calculation formula of the time of the chloride ion in the engineering concrete diffusing to the surface of the concrete is:

[0056] Wherein, t1 is the time of the chloride ion in the engineering concrete diffusing to the surface of the concrete, D0 is the initial coating chloride ion diffusion coefficient, L is the coating thickness, and a and b are fitting constants. It can be understood that according to the calculation formula of the time of the chloride ion in the engineering concrete diffusing to the surface of the concrete, the relationship between the coating chloride ion diffusion coefficient ratio and the natural aging time is combined: D t / D0=ae bt The time of the chloride ion in the engineering concrete diffusing to the surface of the concrete after aging for a period of time can be inferred. Therefore, the method for evaluating the long-term protection effect of the marine environment surface coating on the concrete structure is constructed.

[0057] Step S400, according to the time of chloride ion diffusion in the engineering concrete to the concrete surface to determine the protective effect of the coating on the engineering concrete.

[0058] Specifically, the longer the time of chloride ion diffusion in the engineering concrete to the concrete surface, the better the protective effect of the coating on the engineering concrete. Further, the relationship between the coating diffusion coefficient ratio of different aging times and the natural aging time can be constructed, and the relationship between the coating thickness and the time of chloride ion diffusion in the engineering concrete to the concrete surface is constructed, so as to evaluate the influence of the coating thickness on the time of chloride ion diffusion to the concrete surface; and the relationship between the coating diffusion coefficient and the time of chloride ion diffusion to the concrete surface can be constructed, so as to evaluate the influence of the coating diffusion coefficient on the time of chloride ion diffusion to the concrete surface.

[0059] The following provides specific examples:

[0060] A pier column of a certain cross-sea bridge in Qingdao using a surface coating is taken as an example for further description.

[0061] The concrete cubic specimens of 10cm×10cm×10cm are made by using the raw materials and mix proportion of the engineering concrete of a certain cross-sea bridge in Qingdao (see Table 1), and after standard curing for 28d, the concrete surface is brushed with the coating according to the coating matching system (see Table 2) and construction method used in the engineering, and after on-site curing for 7d under the same conditions, it is used for test.

[0062] The concrete mix proportion of the pier column of the cross-sea bridge is shown in Table 1:

[0063] Table 1

[0064]

[0065] The coating matching performance is shown in Table 2:

[0066] Table 2

[0067]

[0068]

[0069] The surface-coated concrete after curing is put into a xenon lamp aging test box to carry out aging test at 0h, 500h, 1000h and 2000h of age; the test parameters of the aging test box are as follows: aging box irradiance (300nm-400nm): 60W / m 2 ; relative humidity: (40-60)%; black label temperature: (65±2)℃; rainfall cycle: 18min / 102min (water spraying time / non-water spraying time); box temperature: 38±3℃.

[0070] After the aging test, because the pier column structure is in the splash zone of the marine environment, the surface coating concrete of different aging ages is placed in the splash zone of the seawater simulation test box to carry out a 90-day seawater corrosion test. The splash zone is set to spray 3 times a day, and each spraying time is set to 15 minutes to simulate the effect of the splash zone. According to the sampling and testing analysis of seawater in Qingdao, the Cl - and SO4 2- contents in seawater are 17568 mg / L and 2690 mg / L respectively, and the pH value is 7.4. The above medium is used to prepare a simulated seawater solution; the average environmental temperature in Qingdao is 12.3℃, and the temperature of the seawater simulation test box is set to 12.3℃.

[0071] After the seawater corrosion test of the coated concrete is completed, the coating covering the surface of the concrete is removed, and the concrete powder sample is ground layer by layer using a numerical control machine. The powder diameter is 80 mm and greater than 3 times the maximum particle size of the aggregate, and the maximum depth of the powder is 12 mm. The ground concrete powder sample is sieved through a 0.16 mm sieve, and the mass of the powder sample passing through the 0.16 mm sieve is not less than 15 g. After the concrete powder sample is dried in a 105℃ drying oven, it is placed in a 200 ml conical flask, 100 ml of 15% nitric acid solution is added, the conical flask is tightly sealed with a stopper, and the conical flask is placed on a shaker for 24 hours. The automatic potentiometric titrator is used to test the chloride ion content in the powder sample, and then the chloride ion content in the concrete after different aging times and corrosion tests is obtained, i.e. the chloride ion contents in the concrete with aging times of 0h, 500h, 1000h and 2000h are 0.0147%, 0.0371, 0.1118% and 0.1834% respectively.

[0072] For fluorocarbon resin, polyurethane and other high molecular organic coatings, the ultraviolet rays in sunlight are the main factor promoting the breakage of polymer molecular chains in the polymer. Fluorocarbon resin, polyurethane and other coatings exposed to the atmosphere for a long time can accelerate aging failure due to the influence of solar radiation. According to the data research, the total annual cumulative radiation in Qingdao is about 80.21 MJ / m 2 , and the radiation intensity is larger from June to September. According to GB / T1865-2009, the total radiation amounts corresponding to aging times of 500h, 1000h and 2000h are 108 MJ / m 2 , 216 MJ / m 2 and 432 MJ / m 2 , respectively. According to the relationship that the same ultraviolet radiation amount can cause the same aging damage to the coating, the corresponding natural aging times in Qingdao are 1.35 years, 2.70 years and 5.40 years, respectively.

[0073] According to Fick's first diffusion quantification, the chloride ion diffusion flux J of the coating is directly proportional to the chloride ion diffusion coefficient D of the coating. Therefore, the relationship between the coating diffusion coefficient ratio and the natural aging time under actual conditions is established, as shown in formula (1):

[0074] D t / D0=1.30e 0.46t (1)

[0075] Where a and b are fitting constants, in formula (1), a = 1.30, b = 0.46, t is the natural aging time, and D t R is the chloride ion diffusion coefficient after aging time t, and D0 is the chloride ion diffusion coefficient of the initial coating. R is obtained from experiments. 2 =0.868, R 2 To determine the degree of agreement between the experimental data and the fitted function, when R... 2 The closer R is to 1, the higher the degree of fit. 2 =0.8681, it's easy to see the high degree of agreement. (Construction as follows) Figure 3 Further analysis of the relationship between the diffusion coefficient ratio of coatings with different aging times and the natural aging time reveals that the longer the natural aging time, the higher the reduction factor of the diffusion coefficient of coatings with different aging times.

[0076] The time t1 for chloride ions to diffuse to the concrete surface in marine environment surface-coated concrete is calculated according to the following formula (2), where D0 is the chloride ion diffusion coefficient of the initial coating, taken as 1.0 × 10⁻⁶. -16 m 2 / s; L is the coating thickness, which is 400μm for the concrete coating system used in the engineering piers; a and b are fitting constants, which can be taken as 1.30 and 0.46 respectively for the coating system used in this project.

[0077]

[0078] When the thickness of the coating system used in a certain project in Qingdao is 400μm, the time for chloride ions to penetrate the coating to the concrete surface is 2.12 years. According to the coating concrete exposure test, no chloride ions penetrated into the surface concrete at the 1-year exposure age, but at the 3-year exposure age, there was a small amount of chloride ion content in the surface concrete, which was composed of the initial chloride ion concentration of the concrete and a small amount of chloride ions diffused to the concrete surface from the external chloride ions. Therefore, it can be judged that the time for chloride ions to diffuse into the concrete is about 2 years, indicating that the surface coating chloride ion diffusion model established in this patent is reasonable and reliable.

[0079] In addition, combined Figure 4The time required for chloride ions to diffuse to the interface between the coating and the concrete was analyzed. The coating thickness has a great influence on the time for chloride ions to penetrate the coating to the surface of the concrete. When the coating thickness is 50 μm, the time is 0.056 years, and when the coating thickness increases to 500 μm, the time is 2.78 years. In combination with Figure 5 The influence of the coating diffusion coefficient on the time required for chloride ions to diffuse to the interface between the coating and the concrete was analyzed. The coating diffusion coefficient also has a great influence on the time for chloride ions to penetrate the coating to the surface of the concrete. When the coating diffusion coefficient decreases from 5.0 x 10 -16 m 2 / s to 0.5 x 10 -16 m 2 / s, the time for chloride ions to penetrate the coating to the surface of the concrete increases from 0.62 years to 3.18 years. In addition to the coating system and the performance of the coating, the coating construction quality also has a great influence on the performance of the coating.

[0080] Through indoor simulation tests and further construction of a model relating the indoor sample to the actual engineering concrete, the chloride ion penetration of marine concrete structures in marine environments can be more accurately and conveniently measured, and the protective effect of the coating on the marine concrete structure can be evaluated. The method is simple, and the evaluation model is theoretically scientific. According to the environmental characteristics of the project and taking into account the coating materials and the supporting system used in the project, a more accurate method for evaluating the long-term protective effect of marine environment surface coatings on concrete structures is proposed. The method can be used for the selection of coating protection materials and supporting systems for concrete structures in different marine environments, and can provide an important technical reference for evaluating the influence of different types of surface coatings on the durability of concrete structures.

[0081] In one aspect, referring to Figure 6 The present embodiment also provides a device for evaluating the protective effect of a coating on a marine concrete structure, comprising at least: a first module 610, a second module 620, a third module 630, and a fourth module 640.

[0082] Specifically, the first module 610 tests the chloride ion content in the target surface-coated concrete, the second module 620 is connected with the first module 610, obtains the chloride ion content, and establishes the relationship between the coating chloride ion diffusion coefficient ratio and the natural aging time in the actual engineering environment based on the cumulative ultraviolet radiation of the engineering concrete in the environment and the cumulative ultraviolet radiation received by the target surface-coated concrete in the aging process, the third module 630 is connected with the second module 620, and the time for the chloride ion in the engineering concrete to diffuse to the surface of the concrete in the actual engineering environment is obtained according to the initial coating chloride ion diffusion coefficient, the coating thickness and the fitting constant, and the fourth module 640 is connected with the third module 630, and the protection effect of the coating on the engineering concrete is determined according to the time for the chloride ion in the engineering concrete to diffuse to the surface of the concrete.

[0083] In some alternative embodiments, the functions / operations mentioned in the block diagrams can not occur in the order mentioned in the operation diagrams. For example, depending on the functions / operations involved, two blocks shown in succession can actually be executed substantially concurrently or the blocks can sometimes be executed in reverse order. Furthermore, the embodiments presented and described in the flow diagrams of the application are only examples. The intent is to provide a thorough understanding of the technology. The disclosed methods are not limited to the operations and logical flows presented in this document. Alternative embodiments are contemplated, in which the order of various operations is changed and in which sub-operations described as part of a larger operation are executed independently.

[0084] Furthermore, although the present application is described in the context of functional modules, it is to be understood that one or more of the functions and / or features described can be integrated in a single physical device and / or software module, or one or more functions and / or features can be implemented in separate physical devices or software modules. It is also to be understood that detailed discussion of the actual implementation of each module is unnecessary to an understanding of the present application. Rather, the actual implementation is within the routine skill of engineers familiar with the properties, functions and internal relationships of the various functional modules in the devices disclosed herein. Accordingly, the present application is not limited to purely hardware implementations, but also encompasses software implementations, including virtual machines and virtual components. Therefore, the present application is not limited to purely hardware implementations, but also encompasses software implementations, including virtual machines and virtual components. Accordingly, the present application is not limited to purely hardware implementations, but also encompasses software implementations, including virtual machines and virtual components. It is also to be understood that the specific concepts disclosed are merely illustrative and are not intended to limit the scope of the present application, which is defined by the full scope of the appended claims and equivalents thereof.

[0085] If the functions are implemented in the form of software function units and sold or used as independent products, they can be stored in a computer readable storage medium. Based on this understanding, the technical solutions of the present application or the parts of the technical solutions that essentially contribute to the prior art or the parts of the technical solutions can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes a plurality of instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present application. The aforementioned storage medium includes: a U disk, a mobile hard disk, a read-only memory (ROM, Read-Only Memory), a random access memory (RAM, Random Access Memory), a magnetic disk or an optical disk, and various media that can store program codes.

[0086] The logic and / or steps represented in the flowcharts or otherwise described herein, for example, can be considered as a list of executable instructions for implementing logic functions, which can be embodied in any computer-readable medium for use by or in connection with an instruction execution system, apparatus or device, such as a computer-based system, a system including a processor or other system that can fetch the instructions from the instruction execution system, apparatus or device and execute the instructions, or in conjunction with these instructions execution systems, apparatus or devices. For the purpose of this specification, the "computer-readable medium" can be any device that can contain, store, communicate, propagate or transport programs for use by or in connection with an instruction execution system, apparatus or device, or in conjunction with these instruction execution systems, apparatus or devices.

[0087] More specific examples (a non-exhaustive list) of the computer-readable medium include the following: an electrical connection having one or more wires (electrical devices), a portable computer diskette (magnetic devices), a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber device, and a portable compact disc read-only memory (CDROM). In addition, the computer-readable medium can even be paper or other suitable medium on which the program can be printed, because the program can be electronically obtained, for example, by optical scanning of the paper or other medium, followed by editing, interpreting or otherwise processing, if necessary, in other suitable ways, to be electronically obtained and then stored in the computer memory.

[0088] It should be understood that aspects of the application can be implemented in hardware, software, firmware or a combination thereof. In the above embodiments, various steps or methods can be implemented in software or firmware which is stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware, and in another embodiment, any of the following technologies, known in the art, can be used: a combination of discrete logic circuits having logic gates for implementing logic functions upon an application of data signals, application specific integrated circuits having logic gates, field programmable gate arrays (FPGA), or other components, in combination or as the case can be.

[0089] In the description of the specification, the description of the terms "one embodiment", "some embodiments", "an example", "a specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the application. In the specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any appropriate manner in one or more embodiments or examples.

[0090] Although the embodiments of the present application have been shown and described, it would be appreciated by those skilled in the art that changes, modifications, alternatives and variations can be made to the embodiments without departing from the principles and spirit of the application, and the scope of the present application is defined by the claims and their equivalents.

[0091] The above is a specific description of the preferred embodiments of the present application, but the present application is not limited to the described embodiments, and those skilled in the art can make various equivalent modifications or replacements without departing from the spirit of the present application, and these equivalent modifications or replacements are all included in the scope defined by the claims of the present application.

Claims

1. A method of assessing the protective effect of a coating on a marine concrete structure, characterised in that, The method comprises the following steps: testing the chloride ion content in target surface-coated concrete, wherein the target surface-coated concrete is a test sample obtained by brushing a coating, aging and corrosion after being made of the same material and the same mixing proportion as engineering concrete; based on the chloride ion content, the cumulative ultraviolet radiation of the environment where the engineering concrete is located, and the cumulative ultraviolet radiation received by the target surface-coated concrete during the aging process, a relationship between the coating chloride ion diffusion coefficient ratio and the natural aging time in the environment where the engineering concrete is located is established, wherein the coating chloride ion diffusion coefficient ratio is the ratio of the chloride ion diffusion coefficient after aging for a period of time to the initial coating chloride ion diffusion coefficient; obtaining the time when the chloride ion in the engineering concrete diffuses to the surface of the concrete in the environment where the engineering concrete is located according to the initial coating chloride ion diffusion coefficient, the coating thickness and the fitting constant; determining the protection effect of the coating on the engineering concrete according to the time when the chloride ion in the engineering concrete diffuses to the surface of the concrete; the calculation formula of the relationship between the coating chloride ion diffusion coefficient ratio and the natural aging time is: ， wherein, and b is a fitting constant, t is the natural aging time, D t D0 is the initial coating chloride diffusion coefficient. D 0 is the initial coating chloride diffusion coefficient.

2. A method of assessing the protective effect of a coating on a marine concrete structure according to claim 1, characterised in that, the step of obtaining the target surface-coated concrete comprises: obtaining a concrete test piece according to the raw materials and mixing proportion of the engineering concrete; brushing a coating on the concrete test piece to obtain first surface-coated concrete; placing the first surface-coated concrete in an aging test box for aging treatment at different ages to obtain second surface-coated concrete, wherein the aging treatment comprises ultraviolet radiation on the first surface-coated concrete; placing the second surface-coated concrete in different corrosion partitions of a seawater simulation test box for corrosion treatment to obtain target surface-coated concrete.

3. A method of assessing the effectiveness of a coating for the protection of a marine concrete structure according to claim 2, characterised in that, The step of obtaining the target surface-coated concrete further comprises: brushing a coating on the concrete test piece after curing to obtain first surface-coated concrete; placing the first surface-coated concrete in an aging test box after curing treatment.

4. The method of assessing the protective effect of a coating on a marine concrete structure according to claim 1, wherein The step of testing the chloride ion content in the target surface-coated concrete comprises: removing the coating on the target surface-coated concrete and grinding layer by layer to obtain a powder sample concrete; sampling the powder sample concrete according to the powder sampling diameter and the powder sampling depth, wherein the powder sampling depth is equal to or greater than the deepest chloride ion penetration depth, and the powder sampling diameter is equal to or greater than the maximum aggregate particle size.

5. A method of assessing the effectiveness of a coating for the protection of a marine concrete structure according to claim 4, characterised in that, The step of testing the chloride ion content in the target surface-coated concrete further comprises: sieving and drying the concrete sample; mixing the concrete sample with nitric acid solution; testing the chloride ion content in the concrete sample by an automatic potentiometric titrator.

6. The method of assessing the protective effect of a coating on a marine concrete structure according to claim 1, wherein The step of establishing the relationship between the coating chloride ion diffusion coefficient ratio and the natural aging time in the environment where the engineering concrete is located based on the chloride ion content, the cumulative ultraviolet radiation of the environment where the engineering concrete is located, and the cumulative ultraviolet radiation received by the target surface-coated concrete during the aging process comprises: obtaining the natural ultraviolet cumulative radiation of the environment where the engineering concrete is located; Obtaining the test ultraviolet radiation cumulative radiation received by the target surface coated concrete during the aging process; Based on the relationship that the same ultraviolet radiation can cause the same amount of coating damage, according to the natural ultraviolet radiation cumulative radiation and the test ultraviolet radiation cumulative radiation, the relationship between the time of the target surface coated concrete aging and the natural aging time of the engineering concrete is obtained.

7. A method of assessing the protective effect of a coating on a marine concrete structure according to claim 6, characterised in that, The relationship between the coating chloride diffusion coefficient ratio and the natural aging time in the environment of the engineering concrete is established based on the chloride ion content, the ultraviolet radiation cumulative radiation of the environment where the engineering concrete is located, and the ultraviolet radiation cumulative radiation received by the target surface coated concrete during the aging process, and further includes: Obtaining the chloride ion content corresponding to different aging ages of the target surface coated concrete; According to the relationship between the chloride ion content, the time of the target surface coated concrete aging and the natural aging time of the engineering concrete, the relationship between the coating chloride diffusion coefficient ratio and the natural aging time in the environment of the engineering concrete is obtained.

8. The method of assessing the protective effect of a coating on a marine concrete structure according to claim 1, wherein According to the initial coating chloride diffusion coefficient, the coating thickness, and the fitting constant, the time of the chloride ion in the engineering concrete diffusing to the surface of the concrete in the environment is obtained, and in this step, The calculation formula of the time of the chloride ion in the engineering concrete diffusing to the surface of the concrete is: , wherein t is the time for chloride diffusion to the surface of the concrete, D 0 is the initial coating chloride diffusion coefficient, L is the coating thickness, b is a fitting constant.

9. The method of assessing the protective effect of a coating on a marine concrete structure according to claim 1, wherein According to the time of the chloride ion in the engineering concrete diffusing to the surface of the concrete, the protection effect of the coating on the engineering concrete is determined, which includes: The longer the time of the chloride ion in the engineering concrete diffusing to the surface of the concrete, the better the protection effect of the coating on the engineering concrete.

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