CN110737967A - concrete structure durability prediction method, system and terminal - Google Patents
concrete structure durability prediction method, system and terminal Download PDFInfo
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- CN110737967A CN110737967A CN201910854373.8A CN201910854373A CN110737967A CN 110737967 A CN110737967 A CN 110737967A CN 201910854373 A CN201910854373 A CN 201910854373A CN 110737967 A CN110737967 A CN 110737967A
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Abstract
The invention provides a concrete structure durability prediction method which comprises the steps of S1, obtaining concrete structure parameters under the action of freeze-thaw cycle and chlorine salt corrosion, S2, constructing and optimizing a concrete structure durability prediction model under the combined action of the freeze-thaw cycle and the chlorine salt corrosion based on Fick' S law, S3, determining a chlorine ion diffusion coefficient of a concrete structure by adopting the concrete structure durability prediction model S2 according to the parameters of S1, and S4, realizing concrete structure durability prediction according to the chlorine ion diffusion coefficient.
Description
Technical Field
The invention relates to concrete structures, in particular to a method, a system and a terminal for predicting the durability of a concrete structure under the combined action of freeze-thaw cycles and chloride corrosion.
Background
Concrete structures are widely used in marine construction by because of their flexible form, low maintenance cost, long service life, and superior dynamic performance, compared to land-based structures, concrete structures in offshore environments have durability that faces more specific and severe challenges during service, manifested by erosion of marine media and coupling of multiple deterioration mechanisms due to harsh environmental conditions, such as reinforced concrete structures in cold environments and coastal areas, which are not only subject to chloride corrosion, resulting in the phenomena of steel bar corrosion and concrete protective layer cracking, and severely affecting the useful life of the structure.
The existing schemes in the field of concrete durability are basically divided into three types:
1) for example, the invention patent published by Zhongjian four-way engineering research institute limited, " methods and systems for lossless measurement and estimation of concrete durability" in application (patent) No. CN201410066949.1, which is based on reinforced concrete with certain raw materials and mix proportion, draws characteristic relationship curves of maturity-chloride ion diffusion coefficient, and based on the characteristic relationship curves of maturity-chloride ion diffusion coefficient, reversely deduces the chloride ion diffusion coefficient of concrete with different periods of field test, the concrete is complex materials including aggregate, mortar and aggregate-mortar interface transition zones, and the concrete structure durability is affected by component and environmental changes.
2) For example, the invention patent ' methods for determining marine concrete durability prediction model parameters based on grey correlation' published by southeast university, application (patent) No. CN201611204413.7, which takes the performance index of marine concrete as an objective function, screens out the influence factor parameters of the objective function from the existing document, calculates the correlation degree between the objective sequence and the factor sequence by using a grey correlation method, determines the influence factor weight influencing the objective function, multiplies each factor value by the grey correlation coefficient, and then brings the multiplied factor value into a neural network model for training and operation to realize the prediction of the index.
3) For example, the invention patent published by Jiangsu science and technology university, "method for evaluating concrete surface coating to prolong durability life of concrete structure", application (patent) No. CN201811518845.4, the invention puts the concrete sample into chloride environment for exposure, takes out the sample after different age, measures the chloride depth distribution in the protective layer, calculates the chloride diffusion coefficient according to the Fick second law, the patent needs to sample from the structure to predict the structure durability, which will cause damage to the concrete structure, secondly, the patent samples from the concrete structure, different parts have the same chloride diffusion depth not due to the difference of environment, which will bring prediction error.
Disclosure of Invention
In view of the defects in the prior art, the invention aims to provide concrete structure durability prediction methods, systems and terminals.
According to , there are provided methods for predicting durability of a concrete structure, comprising:
s1, obtaining concrete structure parameters under the actions of freeze-thaw cycle and chloride corrosion;
s2, constructing a concrete structure durability prediction model under the combined action of optimization freeze-thaw cycle and chlorine salt erosion based on Fick (Fick) law;
s3, determining the chloride ion diffusion coefficient of the concrete structure by adopting the concrete structure durability prediction model of S2 according to the parameters of S1;
and S4, realizing the durability prediction of the concrete structure according to the chloride ion diffusion coefficient.
Preferably, in S1, the concrete structure parameters include: W/C (water cement ratio), the number of freeze-thaw cycles, exposure time, aggregate volume fraction, Ditz/Dcp (the ratio of the diffusion coefficient of cement mortar to the diffusion coefficient of cement mortar in the transition zone of the cement mortar and the aggregate), and ambient temperature.
Preferably, in S2, the concrete structure durability prediction model specifically includes:
whereinThe initial porosity of the concrete, a is the hydration degree of the concrete, w/C is the water cement ratio, α is mu, k is the empirical coefficient, N is the number of freeze-thaw cycles, C is the concentration of chloride salt in the concrete, t is the exposure time, D0Is the ionic diffusion coefficient in water;
is the laplacian operator; t is0Is a standard room temperature; t is the ambient temperature, EaIs the activation energy and R is the Faraday constant.
Preferably, in S3, the determining the chloride ion diffusion coefficient of the concrete structure according to the concrete structure durability prediction model includes:
s301, obtaining a calculation formula of the chloride ion diffusion coefficient in the concrete structure according to the concrete structure durability prediction model;
and S302, calculating the chloride ion diffusion coefficient of the concrete structure according to the calculation formula and the influence factors.
More preferably, in S301, the calculation formula of the diffusion coefficient of chloride ions in the concrete structure is as follows:
h is the concrete height, l is the transmission depth of chloride ions in the concrete structure; c1Is the chloride concentration at the boundary of the concrete structure; deffNamely calculating the diffusion coefficient of the obtained chloride ions;
the partial differential equation is mainly used for solving the concentration of chloride ions in the concrete structure; t is0Is a standard room temperature; t is the ambient temperature, EaIs the activation energy and R is the Faraday constant.
Preferably, in S4, the predicting the durability of the concrete structure according to the chloride ion diffusion coefficient specifically includes:
determining the chloride ion diffusion coefficient of the intact concrete structure;
obtaining the ratio of the chloride ion diffusion coefficient obtained in the step S3 to the chloride ion diffusion coefficient of the intact concrete structure;
a threshold value is set and the ratio exceeding the threshold value is considered to have been damaged.
According to a second aspect of the present invention, there is provided concrete structure durability prediction systems, comprising:
a parameter acquisition module: the device is used for inputting or acquiring concrete structure parameters under the actions of freeze-thaw cycle and chloride corrosion;
a model construction module: constructing a concrete structure durability prediction model under the combined action of optimization freeze-thaw cycle and chloride corrosion based on Fick's law;
a calculation module: according to the parameters of the parameter acquisition module, determining the chloride ion diffusion coefficient of the concrete structure by adopting the concrete structure durability prediction model of the model construction module;
a prediction module: and forecasting the durability of the concrete structure according to the chloride ion diffusion coefficient obtained by the calculation module.
Preferably, the parameter acquiring module acquires the parameters including: W/C (water cement ratio), the number of freeze-thaw cycles, exposure time, aggregate volume fraction, Ditz/Dcp (the ratio of the diffusion coefficient of cement mortar to the diffusion coefficient of cement mortar in the transition zone of the cement mortar and the aggregate), and ambient temperature.
Preferably, the calculation module includes:
obtaining a calculation formula of the chloride ion diffusion coefficient in the concrete structure according to the concrete structure durability prediction model;
and calculating the chloride ion diffusion coefficient of the concrete structure according to the calculation formula and the concrete structure parameters under the actions of freeze-thaw cycle and chloride corrosion.
Preferably, the prediction module comprises:
the classification module is used for calculating the diffusion coefficient of chloride ions according to the concrete structure parameters under the actions of freeze-thaw cycles and chloride corrosion, performing classification treatment on the obtained diffusion coefficient of chloride ions, and calculating the ratio of the diffusion coefficient of chloride ions to the diffusion coefficient of chloride ions of the intact concrete structure, namely the diffusion coefficient ratio;
and the judging module is used for comparing the obtained diffusion coefficient ratio with a set threshold value and judging whether the concrete structure is seriously damaged or not.
According to a third aspect of the present invention, there are provided terminals comprising a memory, a processor and a computer program stored on the memory and executable on the processor, the processor when executing the program being operable to perform the concrete structure durability prediction method described above.
Compared with the prior art, the invention has at least beneficial effects as follows:
the concrete structure durability test system covers at least 6 most relevant influence factors (W/C, freezing and thawing cycle times, exposure time, aggregate volume fraction, Ditz/Dcp and temperature) of the durability of the concrete structure under the double actions of freezing and thawing cycle and chloride salt erosion, fully considers the coupling action among the factors, can reasonably predict the change of each index, and is compared with the test result, so that the coincidence degree is better.
The method further optimizes the concrete structure durability prediction model under the combined action of freeze-thaw cycle and chloride corrosion, establishes a quantitative calculation formula of chloride ion diffusion coefficient according to the optimized model, and has the advantages of high precision, simple form, easy expansion and the like.
According to the invention, the chloride ion diffusion coefficient in the concrete structure is calculated according to the numerical value of the concrete related index, and the chloride ion diffusion coefficient is classified into numerical values and compared with a preset value, so that the durability of the concrete structure under the double actions of freeze-thaw cycle and chloride salt erosion can be simply and reasonably predicted.
Drawings
Other features, objects and advantages of the invention will become more apparent upon reading of the detailed description of non-limiting embodiments with reference to the following drawings:
FIG. 1 is a flow chart illustrating a method for predicting the durability of a concrete structure in an embodiment of the present invention;
fig. 2 is a block diagram of a concrete structure durability prediction system in accordance with an embodiment of the present invention;
FIG. 3 is a graph illustrating the destruction of a concrete structure by chlorine attack in an embodiment of the present invention;
fig. 4 is a graph illustrating the destruction of a concrete structure subjected to freeze-thaw cycles in an embodiment of the present invention.
Detailed Description
The present invention is described in detail below with reference to specific examples, which will assist those skilled in the art to further the present invention but not to limit the invention in any way.
According to the method, parameters such as W/C, the number of freeze-thaw cycles, the exposure time, the volume fraction of the aggregate, the Ditz/Dcp (the diffusion coefficient of the cement mortar to the aggregate transition region and the diffusion coefficient of the cement mortar) and the temperature are used as influencing factors, the Fick second law is corrected, a concrete structure durability prediction model under the combined action of the freeze-thaw cycles and the erosion of chloride is optimized, and the chloride diffusion coefficient is obtained according to the optimized model, so that the concrete structure durability prediction is realized.
Specifically, referring to fig. 1, a flow chart of a method for predicting durability of a concrete structure in embodiment is shown, which includes:
s1, obtaining concrete structure parameters under the actions of freeze-thaw cycle and chloride corrosion;
the concrete structure parameters in the step comprise six parameters: W/C (water cement ratio), the number of freeze-thaw cycles, exposure time, aggregate volume fraction, Ditz/Dcp (the ratio of the diffusion coefficient of cement mortar to the diffusion coefficient of cement mortar in the transition zone of the cement mortar and the aggregate), and ambient temperature. Wherein: the W/C parameter can be used for researching the durability of concrete with different water-cement ratios; the freezing and thawing cycle number parameter is used for researching the durability of the concrete after suffering different freezing and thawing cycle numbers; the exposure time parameter is used for researching the durability of the concrete under different exposure times; the Ditz/Dcp (cement mortar and aggregate transition zone) parameters can be used for researching the durability of concrete under different Ditz/Dcp conditions; the environmental temperature parameters can be used for researching the durability of the concrete at different environmental temperatures; the aggregate volume fraction parameter can be used to study the durability of concrete with different aggregate volume fractions. The coupling effect among all factors can be fully considered through the 6 parameters, and the change of each index can be reasonably predicted. These structural parameters can be obtained according to actual engineering conditions or from design data.
S2, constructing a concrete structure durability prediction model under the combined action of optimization freeze-thaw cycle and chlorine salt erosion based on Fick (Fick) law;
in the step, the Fick law is corrected, and the concrete structure durability prediction model is constructed as follows:
wherein
a is the hydration degree of concrete, w/C is the water cement ratio, α, mu, k is an empirical coefficient which can be respectively 0.42, 0.0008, 0.3 and 0.2 in the embodiment, N is the number of freeze-thaw cycles, C is the concentration of chloride in the concrete, t is the exposure time, D0Is the ionic diffusion coefficient in water;
is the laplacian operator; t is0Is a standard room temperature and is set as 298K; t is the ambient temperature, EaIs the activation energy, the value is 27.0KJ/mol, and R is the Faraday constant.
The obtained model is based on the concrete structure durability prediction model under the combined action of freeze-thaw cycle and chloride salt erosion, can be more accurate, and is more suitable for the concrete structure durability prediction under the combined action of freeze-thaw cycle and chloride salt erosion. The evolution of the porosity in the concrete along with the number of freeze-thaw cycles and the combination effect of the chloride ions and the solid phase of the cement matrix in the transmission process can be considered, so that the calculation precision of the chloride ion transmission rate in the freeze-thaw environment is effectively enhanced.
S3, determining the chloride ion diffusion coefficient of the concrete structure by adopting an S2 concrete structure durability prediction model according to the parameters of S1; specifically, the method comprises the following steps:
s301, obtaining a calculation formula of the chloride ion diffusion coefficient in the concrete structure according to the concrete structure durability prediction model, wherein the concrete formula is as follows:
h is the height of the concrete, l is the transmission depth of chloride ions in the concrete; c1Is the chloride concentration at the boundary of the concrete structure; deffNamely calculating the diffusion coefficient of the obtained chloride ions;
the partial differential equation is mainly used for solving the concentration of chloride ions in the concrete structure; t is0Is a standard room temperature and is set as 298K; t is the ambient temperature, EaIs the activation energy, the value is 27.0KJ/mol, and R is the Faraday constant.
And S302, calculating the chloride ion diffusion coefficient of the concrete structure according to a calculation formula of the chloride ion diffusion coefficient in the concrete structure and the 6 influence factors (the concrete structure parameters under the action of freeze-thaw cycle and chloride corrosion).
And S4, realizing the durability prediction of the concrete structure according to the diffusion coefficient of the chloride ions.
Specifically, when the freeze-thaw cycle is performed to times, the concrete is severely damaged, the internal pore structure is degraded, and the surface of the concrete is peeled off, at this time, chloride ions can rapidly enter the concrete through the degraded pore structure and directly reach the steel bars, so that the diffusion coefficient of the chloride ions can be used for predicting the durability of the concrete-8cm2S, the chloride ion diffusion coefficient D of the concrete structure thus calculated with the above formulaeffAnd the ratio of the diffusion coefficient of the perfect concrete is used as a prediction condition, a set threshold value is used as a ratio judgment condition, and for example, when the ratio is greater than the threshold value 10, the concrete is considered to have suffered serious damage. Of course, the threshold may be set according to actual needs, and is not limited to 10, and in other embodiments, the threshold may be other values, where the larger the ratio, the larger the concrete is seriously damaged, and the smaller the ratio, the smaller the concrete is seriously damaged.
Referring to fig. 2, there is shown a block diagram of an embodiment of concrete structure durability prediction systems, which can be used to implement the prediction method described above.
A parameter acquisition module: the device is used for inputting or acquiring concrete structure parameters under the actions of freeze-thaw cycle and chloride corrosion; the parameter acquisition module acquires parameters including: W/C (water cement ratio), the number of freeze-thaw cycles, the exposure time, the volume fraction of the aggregate, the Ditz/Dcp (the ratio of the diffusion coefficient of the cement mortar to the diffusion coefficient of the aggregate in the transition zone) and the ambient temperature;
a model construction module: constructing a concrete structure durability prediction model under the combined action of optimization freeze-thaw cycle and chloride corrosion based on Fick's law;
a calculation module: according to the parameters of the parameter acquisition module, determining the chloride ion diffusion coefficient of the concrete structure by adopting the concrete structure durability prediction model of the model construction module;
a prediction module: and forecasting the durability of the concrete structure according to the chloride ion diffusion coefficient obtained by the calculation module.
In a preferred embodiment, the calculation module comprises: obtaining a calculation formula of the chloride ion diffusion coefficient in the concrete structure according to the concrete structure durability prediction model; and calculating the chloride ion diffusion coefficient of the concrete structure according to the calculation formula and the influence factors.
In a preferred embodiment, the prediction module comprises a classification module for calculating chloride ion diffusion coefficients according to concrete structure parameters under the actions of freeze-thaw cycles and chloride corrosion and performing classification treatment on the obtained chloride ion diffusion coefficients to obtain a final diffusion coefficient ratio, and a judgment module for comparing the diffusion coefficient ratio obtained by the classification module with a set threshold value to judge whether the concrete structure is seriously damaged.
In another embodiment of the present invention, there are also provided terminals, including a memory, a processor and a computer program stored in the memory and executable on the processor, wherein the processor when executing the program can be used to execute the method for predicting the durability of a concrete structure.
The steps in the method provided in the above-mentioned embodiment of the present invention may be implemented by using corresponding modules in the system, and those skilled in the art may refer to the technical solution of the system to implement the step flow of the method, that is, the embodiment in the system may be understood as a preferred example for implementing the method, and the implementation techniques adopted by each module in the system are the same as the corresponding steps in the method, and are not described herein again.
Specific application examples are described in conjunction with the concrete structure durability prediction method and system of the above embodiments to help further understanding of the technical solution of the present invention.
Example 1:
china has vast coastal and coastal areas, where large numbers of reinforced concrete structures are subjected to both chloride corrosion and freeze-thaw cycles, whereby the durability of the structure is rapidly lost, as shown in FIG. 3.
In the embodiment, a system internal language environment is established, and the main bodies of the system internal language environment are Matlab language and C + + language;
firstly, relevant parameters are obtained according to actual engineering data, and then concrete durability influence parameters which need to be analyzed actually are input through an input module. In the embodiment, specific parameters for the above case are as follows:
W/C is 0.4;
the Ditz/Dcp (cement mortar and aggregate transition zone) is 3;
the environmental temperature is-10 ℃ to 10 ℃;
the volume fraction A of the aggregate is 0.5;
the number of freeze-thaw cycles is 100;
the exposure time was taken to be 100 days.
Because the internal environment of the concrete is quite complex, the concrete is converted based on the current parameters through concrete test research work, so that properties and parameters of the concrete are obtained:
calculating the initial porosity of the concrete according to the water-cement ratio parameters,
for subsequent concrete jointsConstructing a durability prediction model; where a is 1-exp (-3.15 × w/c), a is calculated from the water-cement ratio.
And k is 0.6441 & A & Ditz/Dcp & exp ((4.7875 +169.54((0.44-w/c) ^3+0.0396(0.44-w/c)))), and an empirical coefficient k is calculated according to the water-cement ratio parameter and is used for a subsequent concrete structure durability prediction model, wherein the parameters Ditz/Dcp (cement mortar and aggregate transition zone) and the aggregate volume fraction A mainly serve for adjusting the empirical coefficient k.
And the model construction module corrects the Fick law according to the data obtained after conversion, so that a more accurate durability prediction model which is more suitable for the concrete structure under the combined action of freeze-thaw cycle and chloride corrosion is obtained.
In this example, the original Fick law is
After correction, the method comprises the following steps:
mu is the ratio of water content in concrete, is determined by experiment, 0.3 is obtained in this example, β is an empirical coefficient of a correction formula, 0.0008 is obtained in this example, the ratio is determined by the water cement ratio of concrete, etc., is determined by experiment.
A calculation module: obtaining a calculation formula of the chloride ion diffusion coefficient in the concrete structure according to the durability prediction model:
according to the calculation formula and the input parameter value, the chloride ion diffusion coefficient in the concrete structure is 1.42 x 10-8cm2/s。
The prediction module calculates the diffusion coefficient of the chloride ions and carries out the treatment of classification, and the diffusion coefficient of the intact concrete is 1 x 10-8cm2Calculating the ratio of the diffusion coefficient of the chloride ions to the diffusion coefficient of the chloride ions of the intact concrete structure, namely the diffusion coefficient ratio is 1.42; the threshold value is set to 10, and when the diffusion coefficient ratio is compared with the threshold value of 10, 1.42 does not exceed 10, and it is considered that the damage is not serious.
The change of the structural durability can be effectively predicted through the embodiment, the structural repair is carried out at a reasonable time point, and the structural durability is prolonged.
Example 2 of implementation:
in cold areas in the north, thousands of tons of salt are scattered to roads, bridges and the like every year, and although the phenomenon of road icing is relieved, the roads, bridges and the like in China are damaged by premature chlorine salt erosion. Meanwhile, the durability of the structure cannot be reasonably predicted, and reasonable repair cannot be timely carried out, so that serious irreversible damage is formed. As shown in fig. 4.
In this embodiment, the concrete structure durability prediction method is different from the method in embodiment 1 in that:
the specific parameters take the following values:
the value of W/C is 0.4;
the value of the Ditz/Dcp (cement mortar and aggregate transition zone) is 3;
the environmental temperature is-20 ℃ to 10 ℃;
the volume fraction A of the aggregate is 0.5;
the number of freeze-thaw cycles is 200;
the exposure time was taken to be 100.
Because the internal environment of the concrete is quite complex, the concrete is converted based on the current parameters through concrete test research work, so that properties and parameters of the concrete are obtained:
calculating the initial porosity of the concrete according to the water-cement ratio parameters,
a durability prediction model for the subsequent concrete structure; where a is 1-exp (-3.15 × w/c), a is calculated from the water-cement ratio.
And k is 0.6441. A. Ditz/Dcp. exp ((4.7875 +169.54((0.44-w/c) ^3+0.0396(0.44-w/c)))), and an empirical coefficient k is calculated according to the water-cement ratio parameter and is used for a subsequent concrete structure durability prediction model, wherein the parameters Ditz/Dcp (cement mortar and aggregate transition zone) and the aggregate volume fraction mainly have the function of adjusting the empirical coefficient k.
A model construction module: and correcting the Fick law according to the data obtained after conversion, thereby obtaining a more accurate durability prediction model which is more suitable for the concrete structure under the combined action of freeze-thaw cycle and chloride corrosion.
In this example, the original Fick law isAfter correction, the method comprises the following steps:
mu is the ratio of water content in concrete, is determined by experiment, 0.3 is taken in the example, β is the empirical coefficient of the correction formula, 0.0008 is taken in the example, which is determined by the water cement ratio of concrete, etc., is determined by experiment.
A calculation module: obtaining a calculation formula of the chloride ion diffusion coefficient in the concrete structure according to the durability prediction model:
according to the calculation formula and the input parameter values, the chloride ion diffusion coefficient of the concrete structure is 2.46 x 10-8cm2/s。
The prediction module calculates the diffusion coefficient of the chloride ions and carries out the treatment of grouping , and the diffusion coefficient of the intact concrete is 1 x 10-8cm2Calculating the ratio of the diffusion coefficient of the chloride ions to the diffusion coefficient of the chloride ions of the intact concrete structure, namely the diffusion coefficient ratio is 2.46; setting the threshold value to be 10, comparing the diffusion coefficient ratio with the threshold value of 10, and judging that the concrete is not seriously damaged if 2.46 does not exceed 10.
The embodiment can be applied to northern cold areas using deicing salts, and can reasonably repair roads, bridges and other structures when serious damage does not occur through reasonably predicting the durability of the roads, bridges and other concrete structures.
The method simply and reasonably predicts the durability of the concrete structure under the double actions of freeze-thaw cycle and chloride corrosion, fully considers the coupling action among all factors, can reasonably predict the change of all indexes, and has better coincidence degree compared with the test result.
The foregoing description of specific embodiments of the present invention has been presented. It is to be understood that the present invention is not limited to the specific embodiments described above, and that various changes and modifications may be made by one skilled in the art within the scope of the appended claims without departing from the spirit of the invention.
Claims (10)
1, A method for predicting durability of a concrete structure, comprising:
s1, obtaining concrete structure parameters under the actions of freeze-thaw cycle and chloride corrosion;
s2, constructing a concrete structure durability prediction model under the combined action of optimization freeze-thaw cycle and chlorine salt erosion based on Fick' S law;
s3, determining the chloride ion diffusion coefficient of the concrete structure by adopting the concrete structure durability prediction model of S2 according to the parameters of S1;
and S4, realizing the durability prediction of the concrete structure according to the chloride ion diffusion coefficient.
2. The method for predicting durability of a concrete structure according to claim 1, wherein the concrete structure parameters at S1 include:
the water-cement ratio W/C;
the number of freeze-thaw cycles;
(ii) exposure time;
aggregate volume fraction;
the diffusion coefficient of the cement mortar and the aggregate transition area and the ratio Ditz/Dcp of the diffusion coefficient of the cement mortar;
the ambient temperature.
3. The method for predicting the durability of a concrete structure according to claim 1, wherein in S2, the concrete structure durability prediction model is specifically:
wherein
a is the hydration degree of concrete, w/C is the water cement ratio, α, mu, k is the empirical coefficient, N is the number of freeze-thaw cycles, C is the chloride salt concentration in concrete, t is the exposure time, D0Is the diffusion coefficient of ions in water；
Is the laplacian operator; t is0Is a standard room temperature and is set as 298K; t is the ambient temperature, EaIs the activation energy, the value is 27.0KJ/mol, and R is the Faraday constant.
4. The method for predicting the durability of a concrete structure according to claim 1, wherein the step of determining the chloride ion diffusion coefficient of the concrete structure according to the model for predicting the durability of the concrete structure in S3 comprises:
s301, obtaining a calculation formula of the chloride ion diffusion coefficient in the concrete structure according to the concrete structure durability prediction model;
and S302, calculating the chloride ion diffusion coefficient of the concrete structure according to the calculation formula and the influence factors.
5. The method for predicting durability of a concrete structure according to claim 4, wherein in S301, the formula for calculating the diffusion coefficient of chloride ions in the concrete structure is as follows:
h is the height of the concrete, l is the transmission depth of chloride ions in the concrete; c1Is the chloride concentration at the boundary of the concrete structure; deffNamely calculating the diffusion coefficient of the obtained chloride ions;the partial differential equation is mainly used for solving the chloride ion concentration in the concrete structure; t is0Is a standard room temperature and is set as 298K; t is the ambient temperature, EaIs the activation energy, the value is 27.0KJ/mol, and R is the Faraday constant.
6. The method for predicting the durability of a concrete structure according to claim 1, wherein the step of predicting the durability of a concrete structure according to the diffusion coefficient of chloride ions in step S4 comprises:
determining the chloride ion diffusion coefficient of the intact concrete structure;
obtaining the ratio of the chloride ion diffusion coefficient obtained in the step S3 to the chloride ion diffusion coefficient of the intact concrete structure;
a threshold value is set and the ratio exceeding the threshold value is considered to have been damaged.
A system for predicting durability of a concrete structure of 7, kinds, comprising:
a parameter acquisition module: the device is used for inputting or acquiring concrete structure parameters under the actions of freeze-thaw cycle and chloride corrosion;
a model construction module: constructing a concrete structure durability prediction model under the combined action of optimization of freeze-thaw cycle and chlorine salt erosion based on Fick's law;
a calculation module: according to the parameters of the parameter acquisition module, determining the chloride ion diffusion coefficient of the concrete structure by adopting the concrete structure durability prediction model of the model construction module;
a prediction module: and forecasting the durability of the concrete structure according to the chloride ion diffusion coefficient obtained by the calculation module.
8. The concrete structure durability prediction method according to claim 7, wherein the calculation module comprises:
obtaining a calculation formula of the chloride ion diffusion coefficient in the concrete structure according to the concrete structure durability prediction model;
and calculating the chloride ion diffusion coefficient of the concrete structure according to the calculation formula and the concrete structure parameters under the actions of freeze-thaw cycle and chloride corrosion.
9. The concrete structure durability prediction method according to claim 7, wherein the prediction module comprises:
the classification module is used for calculating the diffusion coefficient of chloride ions according to the concrete structure parameters under the actions of freeze-thaw cycles and chloride corrosion, performing classification treatment on the obtained diffusion coefficient of chloride ions, and calculating the ratio of the diffusion coefficient of chloride ions to the diffusion coefficient of chloride ions of the intact concrete structure to obtain the final diffusion coefficient ratio;
and the judging module is used for comparing the obtained diffusion coefficient ratio with a set threshold value and judging whether the concrete structure is seriously damaged or not.
10, terminal comprising a memory, a processor and a computer program stored on the memory and executable on the processor, wherein the processor when executing the program is operable to perform the method of predicting the durability of a concrete structure as claimed in any of claims 1-6 to .
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| CN111754038A (en) * | 2020-06-22 | 2020-10-09 | 中交四航工程研究院有限公司 | Method for predicting concrete solid member transportation and installation time |
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| CN111310360B (en) * | 2020-03-26 | 2024-02-09 | 东南大学 | Concrete damage transmission assessment method under sulfate erosion in splash zone |
| CN111310360A (en) * | 2020-03-26 | 2020-06-19 | 东南大学 | Concrete damage transmission assessment method under sulfate erosion in splash zone |
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| CN114965967A (en) * | 2022-04-18 | 2022-08-30 | 太原理工大学 | Method for predicting service life of concrete after high temperature under multiple actions |
| CN114861496A (en) * | 2022-05-05 | 2022-08-05 | 哈尔滨工业大学 | Concrete mesoscopic structure chloride ion erosion model based on cold region natural environment effect |
| CN117471071A (en) * | 2023-10-30 | 2024-01-30 | 重庆交通大学 | Port infrastructure structure durability safety early warning system and port infrastructure structure durability safety early warning method |
| CN117471071B (en) * | 2023-10-30 | 2024-06-04 | 重庆交通大学 | Port infrastructure structure durability safety early warning system and port infrastructure structure durability safety early warning method |
| CN117740665A (en) * | 2024-02-21 | 2024-03-22 | 中冶建筑研究总院（深圳）有限公司 | Method, system and device for evaluating chloride corrosion durability of concrete structure |
| CN117740665B (en) * | 2024-02-21 | 2024-06-04 | 中冶建筑研究总院（深圳）有限公司 | Method, system and device for evaluating chloride corrosion durability of concrete structure |
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