A method for predicting the temperature and humidity field of early-age concrete slabs

Abstract

This application discloses a method for predicting the temperature and humidity field of early-age concrete slabs, relating to the field of materials testing and preparation. The prediction method first establishes a two-way coupled finite element model of concrete based on cement hydration kinetics, heat conduction, and humidity diffusion theory. Second, it conducts indoor self-drying, indoor surface drying, and outdoor internal temperature and humidity tests on the concrete to obtain the evolution curves of internal temperature and humidity and the external environment. Subsequently, it identifies the early-age concrete's temperature and humidity parameters based on an adaptive differential evolution algorithm. Finally, it establishes a finite element model of the temperature and humidity field of early-age concrete slabs to obtain the temperature and humidity fields under different curing methods. This application considers the two-way coupling of temperature and humidity, meaning that internal humidity affects the hydration process, and humidity changes affect heat conduction. By obtaining concrete temperature and humidity parameters under different curing conditions, the accuracy of temperature and humidity field prediction is significantly improved, providing a scientific basis for the prevention of early cracking in concrete slabs and construction quality control.

Description

Technical Field

[0001] This application relates to the field of materials testing and preparation, and in particular to a method for inverting the damp heat parameters of early-age concrete slabs and predicting the temperature and humidity field. Background Technology

[0002] The early-age stage refers to the unstable phase evolution of concrete within 28 days after pouring, including the fluid stage, semi-solid stage, and early-age hardening stage. When a concrete slab is in the early-age hardening stage, it will develop a series of early-age properties under the combined effects of temperature and humidity fields, cement hydration, boundary conditions, and self-weight constraints, including initial curing warpage, early cracking, and residual stress. Therefore, conducting mechanical behavior analysis of concrete slabs in the early-age hardening stage can reveal the damage mechanism of concrete slabs and provide initial state parameters for the design of concrete slabs during service life. On the other hand, as one of the early-age mechanical behaviors, early cracking is closely related to construction methods and material proportions. Therefore, conducting mechanical analysis of concrete slabs in the early-age hardening stage can also help optimize the construction methods and material proportions of concrete slabs.

[0003] Early-age cracking of concrete is related to the combined effects of temperature and humidity fields and is influenced by the evolution of concrete physicochemical parameters. Due to the influence of temperature and humidity on the evolution of hydration degree, the influence of temperature change rate on humidity field, and the feedback effect of phase change heat on temperature field, early-age concrete slabs exhibit a two-way coupling effect of moisture and heat, and their cracking mechanism is very complex. Therefore, it is necessary to establish a temperature and humidity field prediction model for early-age concrete slabs that considers the two-way coupling effect of moisture and heat, and ensure the rationality of the model's physicochemical parameters and boundary conditions. This is the premise for revealing the cracking mechanism of concrete slabs in the early-age hardening stage, and is also the key to optimizing the construction method and material mix of concrete slabs.

[0004] In existing technologies, most concrete slab temperature and humidity field prediction models employ a sequential decoupling approach for mechanical analysis, neglecting the influence of the humidity field on the evolution of hydration and the temperature field. Furthermore, they struggle to guarantee the accuracy of the concrete slab's hydrothermal parameters (concrete physicochemical parameters and model boundary conditions), thus reducing analytical precision. Regarding the study of model physicochemical parameters, current research largely uses empirical formulas based on measured data to account for the influence of hydration on early-age concrete hydrothermal parameters, applicable only to concrete with specific mix proportions. As for the application of model boundary conditions, current boundary conditions are mostly determined based on empirical formulas applicable to single-field analysis, or through boundary parameter inversion based on a single temperature or humidity field model, neglecting the bidirectional coupling effect of humidity and the influence of cement hydration on heat and moisture transfer at the model boundary. Unlike single-field models, bidirectional coupling models of humidity and humidity are computationally complex with numerous parameters, and currently lack efficient parameter inversion methods. In terms of numerical model calculations, to improve computational efficiency, existing research employs a sequential decoupling approach, considering only the influence of the temperature field on the humidity field, neglecting the bidirectional coupling effect between the humidity and temperature fields, thereby reducing the computational precision of the temperature and humidity field model.

[0005] In summary, traditional research methods neglect the impact of bidirectional moisture coupling on heat and moisture transfer in concrete, and the moisture and humidity parameters used for concrete slabs are inaccurate. This leads to significant discrepancies between the predicted temperature and humidity fields and the actual engineering conditions, making them unsuitable for analyzing early-age cracking mechanisms, optimizing construction methods, and optimizing material mix proportions in concrete slabs. Therefore, a method for predicting the temperature and humidity fields of early-age concrete slabs is urgently needed to address these issues. Summary of the Invention

[0006] This application provides a method for predicting the temperature and humidity field of early-age concrete slabs, providing a scientific basis for the prevention and control of early-age cracking in concrete slabs and for construction quality control.

[0007] This application provides a method for predicting the temperature and humidity field of early-age concrete slabs, including: Step S100: Based on the theories of hydration kinetics, heat conduction, and humidity diffusion, establish a two-way coupled finite element model of concrete moisture and heat. Step S200: Obtain the internal temperature and humidity of indoor and outdoor concrete and external environmental parameters under different curing conditions; Step S300: Based on the adaptive differential evolution algorithm, combined with the concrete hygrothermal bidirectional coupling finite element model, the internal temperature and humidity of the concrete and external environmental parameters, the hygrothermal parameters of early-age concrete are identified. Step S400: Based on the identified damp heat parameters, establish a finite element model of the temperature and humidity field of early-age concrete slabs to obtain the temperature and humidity field under different curing methods.

[0008] Preferably, step S100 includes: Step S110: Establish a two-way coupled finite element model of concrete based on the energy conservation theory and the mass conservation theory; Step S120: Define model parameters; Step S130: Set the boundaries and initial conditions.

[0009] Preferably, step S100 includes: Step S111: Based on the energy conservation theory, establish the heat conduction equation for early-age cement concrete, as shown in formula (1): Formula (1); In equation (1), This represents the thermal conductivity coefficient of concrete; This indicates the specific heat capacity of concrete. Indicates the density of concrete; Indicates the temperature inside the concrete; This indicates the heat source generated during hydration; This represents the latent heat of vaporization of water; This indicates the latent heat of vaporization of water; This indicates the moisture content of the concrete. This represents the slope of the isothermal adsorption curve. Indicates the relative humidity inside the concrete; Indicates the temperature and humidity coefficient; Indicates humidity related to self-drying; Step S112: Based on the theory of mass conservation, establish the moisture diffusion equation for early-age cement concrete, as shown in formula (2): Formula (2); In equation (2), Indicates the moisture diffusion coefficient of concrete. Indicates the temperature and humidity coefficient; Step S120 includes hydration parameters and concrete temperature and humidity parameters: Hydration parameters include the heat release and heat release rate of cement concrete, as shown in formula (8): Formula (8); In equation (8), This indicates the amount of heat released per cubic meter of cement. Indicates the degree of hydration. This indicates the amount of cement used per unit cubic meter of cement concrete. This indicates the total heat release of cement. This indicates the rate of heat release during the hydration of cement concrete. Indicates the hydration time parameter. Indicates the equivalent age. Indicates the hydration shape parameter, Indicates the hydration humidity correction factor. Indicates the activation energy of the hydration reaction. Represents the ideal gas constant. Indicates reference temperature. Indicates the temperature inside the concrete; The temperature and humidity parameters of concrete include thermal conductivity, specific heat capacity, and humidity diffusivity. The thermal conductivity is shown in formula (10): Formula (10); In equation (10), This represents the thermal conductivity of cement concrete in a saturated state. This represents the thermal conductivity of concrete when the degree of hydration is 1. The variable specific heat capacity is shown in formula (11): Formula (11); In equation (11), This indicates the specific heat capacity of cement concrete. This indicates the mass fraction of coarse aggregate in concrete. This indicates the specific heat capacity of coarse aggregate. This indicates the mass fraction of fine aggregate in concrete. This indicates the specific heat capacity of the fine aggregate. This indicates the mass fraction of cement in concrete. This indicates the specific heat capacity of unhydrated cement. This represents the hypothetical specific heat capacity of cement during hydration. Indicates the mass fraction of water. This indicates the specific heat capacity of water. Indicates the temperature inside the concrete; The humidity diffusion coefficient is shown in formula (12): Formula (12); In equation (12), Indicates the moisture diffusion coefficient of concrete. This represents the maximum moisture diffusion coefficient of hardened concrete. This represents the ratio of the minimum to the maximum value of the humidity diffusion coefficient. Indicates the relative humidity inside the concrete; This represents the relative humidity when the humidity diffusion coefficient is half of its maximum value. Represents the empirical coefficient. Indicates the temperature inside the concrete. Indicates reference temperature. Indicates the activation energy of the hydration reaction. Represents the ideal gas constant. Indicates hydration degree as The capillary porosity of cement stone at that time Indicates hydration degree as The capillary porosity of cement stone at that time Indicates the degree of hydration. Indicates the final degree of hydration. Indicates the humidity diffusion porosity correction factor; Step S130: Boundary conditions include temperature field and humidity field. Temperature field includes solar radiation, effective radiation, and convective heat transfer. Humidity field includes humidity loss due to convection. Initial conditions include initial temperature and initial humidity.

[0010] Preferably, the equivalent age in formula (8) is as shown in formula (7): Formula (7); In equation (7), Indicates the actual age of the concrete. This represents the hydration humidity correction factor.

[0011] Preferably, the hydration time parameter and hydration shape parameter in formula (8) are as shown in formula (9): Formula (9); In equation (9), Indicates the hydration time parameter. Indicates the hydration shape parameter, This represents the correction factor for the hydration time parameter. This represents an empirical value for the hydration time parameter. This represents the correction factor for the hydration shape parameter. This represents the empirical value of the hydration shape parameter.

[0012] Preferably, the maximum humidity diffusivity of hardened concrete As shown in formula (13): Formula (13); In equation (13), This represents a correction factor for the maximum diffusion coefficient of hardened concrete. This represents the average cubic compressive strength of concrete. This represents the maximum value of the moisture diffusion coefficient of hardened concrete predicted by the empirical formula.

[0013] Preferably, in step S130: Solar radiation is as shown in formula (14): Formula (14); In equation (14), Indicates daily hourly solar radiation. c represents the solar radiation absorptivity, and c represents the effective sunshine duration. This indicates the total daily solar radiation. The effective radiation is shown in formula (15): Formula (15); In equation (15), Indicates effective radiation. This represents the effective radiation correction factor. Indicates surface emissivity, This represents the Stefan-Boltzmann constant. Indicates the road surface temperature. Indicates representative temperature. This represents the indoor correction factor for representative temperature. Indicates the sky emission rate. Indicates the dew point temperature; The heat flux density related to convective heat transfer is shown in formula (16): Formula (16); In equation (16), This represents the heat flux density related to convective heat transfer. This represents the convective heat transfer correction factor. Indicates the convective heat transfer coefficient. Indicates air temperature. Indicates near-surface wind speed; The humidity loss is shown in formula (20): Formula (20); In equation (20), Indicates the convective humidity coefficient. This represents the rate of change in humidity caused by convection. Indicates air humidity. This represents the empirical coefficient for convective humidity transfer. This indicates the near-surface wind speed. A coefficient representing the degree of hydration. Indicates the water-cement ratio; The initial temperature is shown in formula (19): Formula (19); Indicates the initial temperature. and All of these represent unit conversion factors. This represents the average specific heat of the aggregate and unhydrated cement. Indicates the temperature of the aggregate. This indicates the mass of dry aggregate in a unit cubic meter of concrete. Indicates the temperature of the cement. This indicates the mass of unhydrated cement per cubic meter of concrete. This indicates the mass of water absorbed by the aggregate in a unit cubic meter of concrete. Indicates the temperature of the water. This indicates the mass of water in one cubic meter of concrete. The initial relative humidity of the concrete is calculated from the time the concrete is poured, and its initial relative humidity is 1.

[0014] Preferably, step S200 includes: Step 210: Conduct an indoor self-drying test: Seal the concrete specimen, measure the changes in internal temperature and humidity, and obtain the first set of damp heat parameters; Step S220: Conduct an indoor surface drying test: expose the surface of the specimen, measure the temperature and humidity at different depths, and obtain the second set of damp heat parameters; Step S230: Conduct outdoor temperature and humidity monitoring: Test the concrete in a real environment, record meteorological data, and obtain environmental parameters.

[0015] Preferably, step S300 includes: Step S310: Construct the error function to transform the problem of identifying hygrothermal parameters into the problem of minimizing the prediction error of the hygrothermal bidirectional coupled finite element model, as shown in formula (23): Formula (23); In equation (23), , They represent the first spatial points Temperature model calculated values ​​and measured values ​​at each time point; , They represent the first The spatial point number Humidity calculated and measured values ​​at specific times; Step S320: Run the adaptive differential evolution algorithm. The adaptive mutation coefficient used in the adaptive differential evolution algorithm is shown in formula (24): Formula (24); In formula (24), F represents the coefficient of variation. G represents half of the initial coefficient of variation. These represent the current evolutionary step and the maximum number of generations, respectively. Represents an empirical coefficient related to the number of iterations; Step S330: Based on the experiment in step S200, the damp heat parameters are obtained by inversion.

[0016] Preferably, step S330 includes: Step S331: Based on the indoor self-drying test, the first set of hygrothermal parameters of the concrete hygrothermal bidirectional coupled finite element model under indoor sealed conditions are obtained by inversion. Step S332: Based on the indoor surface drying test, the second set of hygrothermal parameters of the concrete hygrothermal bidirectional coupled finite element model under indoor surface drying conditions are obtained by inversion. Step S333: Based on the parameters from outdoor temperature and humidity monitoring, the thermal parameters of the concrete wet-heat bidirectional coupled finite element model are obtained by inversion.

[0017] The prediction method of this application has at least the following beneficial effects: (1) The prediction method of this application firstly establishes a two-way coupled finite element model of concrete based on cement hydration kinetics, heat conduction and humidity diffusion theory; secondly, it conducts indoor self-drying, indoor surface drying and outdoor internal temperature and humidity tests of concrete to obtain the internal temperature and humidity and external environment evolution curves of concrete; then, based on the adaptive differential evolution algorithm, combined with the two-way coupled finite element model of concrete and concrete temperature and humidity parameters, it conducts early-age concrete temperature and humidity parameter identification; finally, it establishes a finite element model of early-age concrete slab temperature and humidity field to obtain the temperature and humidity field under different curing methods. This application considers the two-way coupling of moisture and heat, that is, the internal humidity will affect the hydration process and the humidity change will affect the heat conduction. By obtaining concrete temperature and humidity parameters under different curing conditions, the accuracy of early-age concrete slab temperature and humidity field prediction is significantly improved, providing a scientific basis for the prevention and control of early cracking of concrete slabs and construction quality control.

[0018] (2) The model of this application introduces a hydration degree humidity correction coefficient to consider the adverse effects of low humidity conditions on the hydration process, which can significantly improve the model prediction accuracy.

[0019] (3) The hydration time and shape parameters of the model calculated by traditional empirical formulas do not take into account the influence of cement particle size distribution on hydration. This application introduces correction coefficients for shape and time parameters. The corrected hydration time and shape parameters can comprehensively consider the influence of cement ratio and particle size distribution on cement hydration, thus greatly improving the accuracy of model calculation.

[0020] (4) Traditional concrete humidity diffusion coefficient does not take into account the influence of early-age concrete pore evolution on humidity diffusion. This application introduces a humidity diffusion pore correction coefficient to take into account the actual situation of the decrease in diffusion coefficient caused by the decrease in early-age concrete porosity. In addition, the maximum value of hardened concrete humidity diffusion coefficient predicted by empirical formula is based only on strength and does not take into account the influence of concrete mix proportion on diffusion coefficient. Therefore, the prediction accuracy is limited. This application considers the influence of concrete mix proportion on diffusion coefficient by introducing a diffusion coefficient correction coefficient and combining it with experimental calibration, which can effectively improve the model calculation accuracy.

[0021] (5) This application designed three different temperature and humidity tests inside concrete under different conditions, which can stepwise invert the parameters of the two-way coupling model of moisture and heat in early-age concrete, avoiding the identification of too many parameters in one test and ensuring the convergence of moisture and heat parameter inversion.

[0022] (6) This application uses an adaptive differential evolution algorithm to ensure the efficiency and accuracy of parameter inversion.

[0023] (7) Based on the identified early-age concrete humid heat parameters, this application established a finite element model of the temperature and humidity field of early-age concrete slabs, ensuring the accuracy of prediction. Attached Figure Description

[0024] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of this application. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings: Figure 1 This is a flowchart of the prediction method in this application; Figure 2 These are temperature time history curves of concrete in indoor self-drying tests, where (a) represents the temperature time history curve with a water-cement ratio of 0.4, and (b) represents the temperature time history curve with a water-cement ratio of 0.44. Figure 3 These are time-history curves of concrete humidity during indoor self-drying tests. (a) represents the time-history curve of humidity with a water-cement ratio of 0.4, and (b) represents the time-history curve of humidity with a water-cement ratio of 0.44. Figure 4 These are time-history curves of concrete temperature during indoor surface drying tests. (a) represents the time-history curve of water-cement ratio 0.4, and (b) represents the time-history curve of water-cement ratio 0.44. Figure 5 These are time-history curves of concrete humidity in an indoor surface drying test. (a) represents the time-history curve of humidity with a water-cement ratio of 0.4, and (b) represents the time-history curve of humidity with a water-cement ratio of 0.44. Figure 6 These are actual meteorological parameter measurement charts from outdoor experiments, where (a) represents the ambient temperature and humidity chart, and (b) represents the solar radiation and wind speed chart. Figure 7 These are time-history curves of concrete temperature and humidity under uncured conditions in outdoor tests. (a) represents the temperature time-history curve, and (b) represents the relative humidity time-history curve. Figure 8 These are time-history curves of concrete temperature and humidity under plastic film curing conditions in outdoor tests, where (a) represents the temperature time-history curve and (b) represents the relative humidity time-history curve. Figure 9 These are time history curves of concrete temperature and humidity under geotextile curing conditions in outdoor tests, where (a) represents the temperature time history curve and (b) represents the relative humidity time history curve. Figure 10 This is an air temperature and humidity map of a certain region in June, where (a) represents the temperature map and (b) represents the humidity map. Figure 11 These are temperature and humidity evolution curves of the board under different curing methods, where (a) represents the temperature evolution curve and (b) represents the humidity evolution curve. Figure 12 These are hydration degree evolution curves of the plate under different maintenance methods; Figure 13 These are temperature and humidity distribution diagrams of the board under different curing methods, where (a) represents the temperature distribution diagram and (b) represents the humidity distribution diagram; Figure 14 This is a distribution map of hydration degree under different maintenance methods. Detailed Implementation

[0025] The features and exemplary embodiments of various aspects of this application will be described in detail below. To make the objectives, technical solutions, and advantages of this application clearer, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only intended to explain this application and not to limit it. For those skilled in the art, this application can be implemented without some of these specific details. The following description of the embodiments is merely to provide a better understanding of this application by illustrating examples.

[0026] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising..." does not exclude the presence of additional identical elements in the process, method, article, or apparatus that includes the element.

[0027] This embodiment discloses a method for predicting the temperature and humidity field of early-age concrete slabs, such as... Figure 1 As shown, it includes: Step S100: Based on the theories of hydration kinetics, heat conduction, and humidity diffusion, establish a two-way coupled finite element model of concrete moisture and heat. Step S200: Obtain the internal temperature and humidity of indoor and outdoor concrete and external environmental parameters under different curing conditions; Step S300: Based on the adaptive differential evolution algorithm, combined with the concrete hygrothermal bidirectional coupling finite element model, the internal temperature and humidity of the concrete and external environmental parameters, the hygrothermal parameters of early-age concrete are identified. Step S400: Based on the identified damp heat parameters, establish a finite element model of the temperature and humidity field of early-age concrete slabs to obtain the temperature and humidity field under different curing methods.

[0028] Step S100 includes steps S110, S120 and S130.

[0029] Step S110 includes steps S111 and S112; Step S111: Based on the energy conservation theory, considering the heat of hydration and the influence of water phase change on the temperature field, the heat conduction equation of early-age cement concrete is obtained as shown in formula (1): Formula (1); In formula (1): This represents the thermal conductivity coefficient of concrete (W / ( )); This indicates the specific heat capacity of concrete (J / ( )); The density of concrete (kg / m³) 3 ); Indicates the temperature inside the concrete; This indicates the heat source generated during hydration, in W / m³. 3 ; The moisture content of concrete is expressed in kg / kg. This indicates the latent heat of vaporization of water (kJ / kg). ; The latent heat of vaporization of water is expressed as a value between 0 and 1, determined experimentally. This represents the slope of the isothermal adsorption curve. This represents the temperature and humidity coefficient (1 / ℃). ; Indicates humidity related to self-drying; Indicates the relative humidity inside the concrete; Step S112: Based on the theory of mass conservation, considering the water consumption caused by hydration reaction (self-drying) and the influence of humidity change caused by temperature change rate on the humidity field, the humidity diffusion equation of early-age cement concrete can be obtained as shown in equation (2): Formula (2); In formula (2): Indicates the relative humidity inside the concrete; The moisture diffusion coefficient of concrete is expressed in m. 2 / s; Indicates the temperature and humidity coefficient (1 / ℃). Indicates the temperature inside the concrete; In equations (1) and (2), the humidity related to self-drying is calculated according to equation (3): Formula (3); In formula (3): , These represent the degree of hydration and the final degree of hydration, respectively. This indicates the final relative humidity resulting from self-drying, calibrated through testing; This represents the empirical coefficient of self-drying evolution, with a value between 10 and 60, calibrated experimentally.

[0030] Step S120: Define model parameters I. Hydration Model Parameters An exponential model is used to describe the change in hydration degree over time, as shown in equation (4): Formula (4); In equation (4): , These represent the degree of hydration and the final degree of hydration, respectively. The hydration time parameter is expressed in hours (h). Indicates hydration shape parameters; Indicates the water-cement ratio; Indicates the equivalent age.

[0031] In equation (4), the equivalent age The calculation is performed according to the Arrhenius equation, as shown in equation (5): Formula (5); In equation (5): The activation energy of the hydration reaction is expressed in J / mol. This represents the ideal gas constant, 8.314 J / mol / K; This indicates the reference temperature, typically taken as 293.15K; T represents the temperature inside the concrete, which is used as the element node temperature in the finite element method. The activation energy of the hydration reaction is calculated according to equation (6): Formula (6); In formula (6): , These represent the mass fractions of tricalcium aluminate and tetracalcium aluminoferrite in cement, respectively. This represents the Blaine specific surface area of ​​cement.

[0032] It should be noted that when the relative humidity is below 80%, cement hydration tends to stop. If the influence of humidity on hydration is not considered, the degree of hydration of concrete under poor curing conditions will be overestimated, thereby significantly reducing the accuracy of model prediction. Therefore, this embodiment introduces the hydration degree humidity correction coefficient shown in Equation (7) to consider the adverse effects of low humidity on the hydration process. Equation (7) is a decreasing function of humidity. When the relative humidity is above 95%, the correction coefficient calculated by Equation (7) is greater than 0.98, indicating that the humidity has little influence on the degree of hydration within this humidity range. When the relative humidity is between 85% and 90%, the correction coefficient calculated by Equation (7) is 0.384 to 0.760, indicating that the humidity has a significant influence on hydration within this humidity range. When the relative humidity is below 80%, the correction coefficient calculated by Equation (7) is less than 0.165, indicating that hydration tends to stop within this humidity range.

[0033] Formula (7); In equation (7): Indicates the hydration humidity correction factor; This indicates the actual age of the concrete.

[0034] Based on equations (4) and (7), the heat release and heat release rate of cement concrete can be obtained as shown in equation (8): Formula (8); In equation (8): This represents the amount of heat released per cubic meter of cement, expressed in J / m³. 3 ; This indicates the amount of cement used per cubic meter of cement concrete, expressed in g / m³. 3 ; This represents the total heat release of cement, in J / g; This represents the hydration heat release rate of cement concrete, in W / m³. 3 .

[0035] It should be noted that the hydration time and shape parameters calculated by traditional empirical formulas do not consider the influence of cement particle size distribution on hydration, thus reducing the accuracy of model calculations. This embodiment uses isothermal calorimetry combined with formula (9) to calculate the hydration parameters (the correction coefficients for shape and time parameters are respectively...). and The corrected hydration time and shape parameters can comprehensively consider the influence of cement mix proportion and particle size distribution on cement hydration, thus significantly improving the accuracy of model calculations. The calibrated baseline cement hydration model parameters are shown in Table 1.

[0036] Formula (9); In equation (9): This represents an empirical value for the hydration time parameter, ranging from 10 to 100. This represents an empirical value for the hydration shape parameter, ranging from 0.1 to 1.

[0037] Table 1. Calibrated hydration model parameters

[0038] II. Concrete Temperature and Humidity Parameters Table 2 Cement Concrete Mix Proportions

[0039] For the concrete mix proportions shown in Table 2, the thermal conductivity of the concrete after 28 days of saturation was tested using a thermal conductivity meter, and the time-varying thermal conductivity was calculated according to formula (10): Formula (10); In formula (10): This represents the thermal conductivity of cement concrete in a saturated state, expressed in W / ( For C1 and C2 mix concrete, the values ​​are 2.249 W / ( ) and 2.183W / ( ); This represents the thermal conductivity of concrete when the degree of hydration is 1.

[0040] Using the mixing law, the time-varying specific heat capacity of cement concrete can be calculated according to formula (11): Formula (11); In equation (11): This indicates the specific heat capacity of cement concrete. Indicates the temperature inside the concrete; Indicates the degree of hydration; , , , These represent the mass fractions of coarse aggregate, fine aggregate, cement, and water in concrete, respectively. , , , , , These represent the specific heat capacities (J / m³) of cement concrete, coarse aggregate, fine aggregate, unhydrated cement, water, and hypothetical cement during hydration, respectively. ), of which granite aggregate limestone aggregate , , , .

[0041] It should be noted that as hydration progresses, the volume fraction of capillary pores within the concrete decreases significantly. Traditional concrete moisture diffusion coefficients do not consider the impact of early-age concrete pore evolution on moisture diffusion. This embodiment introduces a moisture diffusion porosity correction coefficient to account for the decrease in diffusion coefficient caused by the reduction in early-age concrete porosity. Furthermore, the maximum value of the hardened concrete moisture diffusion coefficient predicted using empirical formulas only considers strength and does not account for the influence of concrete mix proportions (such as admixtures, aggregate content, and cement content) on the diffusion coefficient, thus limiting prediction accuracy. This embodiment, by introducing a diffusion coefficient correction coefficient and combining it with experimental calibration, considers the influence of concrete mix proportions on the diffusion coefficient, effectively improving the accuracy of model calculations.

[0042] The humidity diffusion coefficient is calculated using equation (12): Formula (12); In equation (12): This represents the maximum moisture diffusion coefficient (m) of hardened concrete. 2 / s); This represents the ratio of the minimum to the maximum value of the humidity diffusion coefficient, preferably 0.05. Indicates the relative humidity inside the concrete; This represents an empirical coefficient, preferably 15; , Indicates the temperature inside the concrete; Indicates reference temperature, °C; , These represent the degree of hydration and the final degree of hydration, respectively. Indicates hydration degree as Capillary porosity of cement stone at that time; Indicates hydration degree as Capillary porosity of cement stone at that time; This represents the humidity diffusion porosity correction factor, calibrated experimentally. This represents the relative humidity corresponding to a diffusion coefficient that is half of its maximum value. Its value is between 0.75 and 0.8, with 0.8 being the preferred value.

[0043] The maximum value of the moisture diffusion coefficient of hardened concrete is predicted using the following formula (13): Formula (13); In equation (13): The correction factor representing the maximum diffusion coefficient of hardened concrete is determined through testing; This represents the maximum value of the moisture diffusion coefficient of hardened concrete predicted by the empirical formula. This represents the average cubic compressive strength of concrete, expressed in MPa.

[0044] Step S130, Model Boundary Conditions and Initial Conditions I. Temperature Field 1. Solar radiation is mainly shortwave radiation. If hourly measured data is unavailable, equation (14) can be used for approximate calculation: Formula (14); In equation (14): Represents daily hourly solar radiation, J / ( ); c represents the effective sunshine duration, which is the default. , h; Represents the total daily solar radiation, J / m 2 ; It represents the solar radiation absorptivity, which is related to maintenance conditions and ranges from 0 to 0.9. The specific value is determined through testing.

[0045] 2. Effective radiation includes road surface longwave radiation and atmospheric back radiation, calculated according to the following formula (15): Formula (15); In equation (15): Indicates effective radiation, W / m 2 ; This represents the Stefan-Boltzmann constant. W / (m -2 K -4 ); This represents the surface emissivity, which is between 0.8 and 0.9, preferably 0.85. This represents the effective radiation correction factor, which is preferably set to 1, but can also be calibrated experimentally. This represents the indoor correction factor for representative air temperature, calibrated through experiments. Indicates the sky emissivity; Dew point temperature, in °C; , These represent the road surface temperature and the representative air temperature, respectively, in °C.

[0046] 3. The heat flux density related to convective heat transfer is calculated using the following formula (16): Formula (16); In equation (16): This represents the heat flux density related to convective heat transfer, in W / m³. 2 ; This represents the convective heat transfer coefficient, W / ( ); This represents the convective heat transfer correction factor, which is calibrated experimentally. This indicates the wind speed near the ground surface (20cm above the ground), in m / s; , These represent the surface temperature of the road surface and the air temperature, respectively, in °C.

[0047] II. Initial Temperature For concrete specimens with bottom insulation, there is no heat flux density loss at the bottom of the model, as shown in formula (17): Formula (17); In equation (17): This indicates the distance from the bottom of the model to its surface. For the road surface structure, the temperature at the bottom of the model is equal to the ground temperature, as shown in formula (18): Formula (18); In formula (18): This indicates the distance from the bottom of the model to its surface. This represents the ground temperature of the isothermal layer (°C), which is approximately equal to the annual average air temperature plus 2°C. Considering the composition of concrete, its initial temperature is calculated according to equation (19). : Formula (19); In equation (19): , All represent unit conversion factors, preferred. , ; The mass of dry aggregate in a unit cubic meter of concrete is expressed in kg. The mass of unhydrated cement in a unit cubic meter of concrete is expressed in kg. The mass of water in a unit cubic meter of concrete is expressed in kg. The mass of water absorbed by aggregate in a unit cubic meter of concrete, expressed in kg; Indicates the temperature of the aggregate, in °C; The temperature of the cement is expressed in °C. The temperature of water is expressed in °C. This represents the average specific heat of aggregates and unhydrated cement (J / m³). The value can be calculated using the mixed law, or approximately taken as 920 J / kg℃.

[0048] The initial temperature of the underlying structural layer was estimated using the finite element method.

[0049] III. Humidity Field Considering the influence of the concrete water-cement ratio on convective moisture transfer, the traditional empirical formula for the surface moisture transfer coefficient was modified, and equation (20) was used to calculate the moisture loss due to convection: Formula (20); In equation (20): This represents the rate of change in humidity caused by convection, expressed in m / s. Indicates air humidity; The convective humidity coefficient is expressed in m / s and is determined experimentally. This represents the empirical coefficient of convective moisture transfer, calibrated through experiments; This represents near-surface wind speed, in m / s; Indicates water-cement ratio, % This represents a coefficient related to the degree of hydration.

[0050] The water holding capacity of early-age concrete is calculated using equation (21): Formula (21); In equation (21): Indicates the equivalent age (d) of concrete, when hour, ; This indicates the internal temperature of the concrete, expressed in Kelvin (K). Indicate the water-cement ratio, when hour, ,when hour, ; This represents the empirical coefficient for the water-cement ratio; Assuming the humidity gradient at the bottom of the model is equal to 0, as shown in formula (22): Formula (22); In equation (22): This indicates the distance from the bottom of the model to its surface. IV. Initial Humidity The initial relative humidity of the concrete is calculated from the time the concrete is poured, and its initial relative humidity is 1.

[0051] Step S200 includes steps S210, S220 and S230.

[0052] Step 210, Indoor self-drying test During the self-drying test, insulation cotton, foam adhesive, foam boxes, and foam boards were used to insulate the sides and bottom of the specimen. The time history curves of temperature and humidity of the cement concrete and the evolution curves of air temperature and humidity at a distance of 8 cm from the top of the specimen were measured. The sampling interval was 0.5 h, and the sampling period was 28 days. Since the concrete surface was not insulated, the specimen was affected by surface convection heat transfer, effective radiation, and temperature conduction. Therefore, the parameters to be inverted in the thermal boundary conditions of the hygrothermal two-way coupled model are: convective heat transfer correction coefficients. Effective radiation correction factor Representative indoor temperature correction factor The parameters to be inverted in the humidity diffusion equation include the final relative humidity caused by self-drying. and self-drying evolution empirical coefficient The hydrothermal parameters of the inverted hydrothermal two-way coupled model are shown in Table 3.

[0053] Table 3. Humidity and heat parameters retrieved from indoor self-drying tests

[0054] Step S220, Indoor Surface Drying Test During the surface drying test, an insulation layer was applied to the sides and bottom of the specimen, and the time history curves of temperature and humidity of the cement concrete and the evolution curves of air temperature and humidity were measured at distances of 2 cm, 4 cm, and 8 cm from the top of the specimen. The sampling interval was 0.5 h, and the sampling duration was 28 days. Since the concrete surface was not sealed or insulated, the specimen was affected by convective heat transfer, moisture transfer, effective radiation, temperature conduction, and humidity diffusion. Therefore, the parameters to be inverted in the thermal boundary conditions of the two-way coupled humid-thermal model include: the convective heat transfer correction coefficient. Effective radiation correction factor Representative indoor temperature correction factor The humidity boundary conditions include parameters to be inverted, which are empirical coefficients for convective moisture transfer. The parameters to be inverted, including the temperature and humidity parameters of concrete, include: the correction factor for the maximum diffusion coefficient of hardened concrete. Humidity diffusion porosity correction factor The parameter to be inverted in the heat conduction equation is the latent heat of vaporization of water. As shown in Table 4 below.

[0055] Table 4 Model parameters retrieved from indoor surface drying test

[0056] Step S230, Outdoor temperature and humidity monitoring During outdoor cement concrete temperature and humidity testing, insulation layers were applied to the sides and bottom of the specimen. The concrete surface was left untreated or covered with either plastic film or geotextile. Simultaneously, time-history curves of cement concrete temperature and humidity, wind speed evolution, air temperature and humidity evolution, and solar radiation evolution were measured at distances of 2cm, 4cm, and 8cm from the top of the specimen. The sampling interval was 0.5 hours, and the sampling duration was 3 days. During this time, the specimen was affected by solar radiation, effective radiation, convective heat transfer, moisture transfer, temperature conduction, and humidity diffusion. Therefore, the parameters to be inverted in the thermal boundary conditions of the two-way coupled humidity and heat model include: convective heat transfer correction coefficient. and solar radiation absorptivity As shown in Table 5 below.

[0057] Table 5. Thermal parameters retrieved from outdoor tests under different curing conditions

[0058] Step S300 includes steps S310, S320 and S330; Step S310, constructing the error function shown in equation (23), transforms the problem of identifying hygrothermal parameters into a problem of minimizing the prediction error of a two-way coupled hygrothermal finite element model, that is: Formula (23); In equation (23): , They represent the first The spatial point number Temperature model calculated values ​​and measured values ​​at each time point; , They represent the first The spatial point number Humidity calculated and measured values ​​at specific times; , These represent the number of spatial and temporal sampling points for temperature and humidity used during the inverse calculation, respectively. The sampling time interval is between 0.25h and 1h, and in this embodiment it is 0.5h.

[0059] Step S320: Traditional differential evolution algorithms use a fixed coefficient of variation, which can easily get stuck in local optima. This embodiment uses an adaptive coefficient of variation that is related to the number of iterations to improve the early global search capability of the differential evolution algorithm while ensuring fine local search in the later stage, thereby improving the overall optimization performance of the algorithm. The adaptive coefficient of variation used in this embodiment is shown in Equation (24). Other control parameters of the differential evolution algorithm, such as population size NP and crossover probability CR, can adopt the conventional settings of the differential evolution algorithm. For example, NP is 5-10 times the number of parameters to be optimized, and CR is 0.5-1.0.

[0060] Formula (24); In equation (24): Represents half of the initial coefficient of variation, preferably ; g、 These represent the current evolutionary step and the maximum number of generations, respectively.

[0061] F represents the coefficient of variation; This represents an empirical coefficient related to the number of iterations.

[0062] Step S330 includes steps S331, S332 and S333; Step S331: Obtain the hydrothermal parameters based on the self-drying test. For the concrete shown in Table 2, model parameter identification was carried out based on self-drying tests, and the temperature and humidity time history curves of the concrete under indoor sealed conditions obtained by inversion are as follows: Figure 2 and Figure 3 As shown, the hydrothermal parameters in the inverted hydrothermal bidirectional coupling model are shown in Table 6.

[0063] Table 6. Humidity and heat parameters identified from indoor self-drying tests.

[0064] Step S332: Model parameters obtained from surface drying test inversion The ambient temperature and humidity of each specimen in the indoor surface drying test and Figure 2 and Figure 3 Concrete with a water-cement ratio of 0.44 is exposed to the same ambient temperature and humidity. Based on this, the self-drying parameters (final relative humidity) in Table 6 are compared. Self-drying evolution empirical coefficient Substituting the parameters into the two-way coupled finite element model of humidity and heat, the humidity diffusion model parameter identification was carried out, and the inverted concrete temperature and humidity time history curve under indoor surface dry conditions was as follows: Figure 4 and Figure 5As shown, the hydrothermal parameters in the inverted hydrothermal two-way coupled model are shown in Table 7.

[0065] Table 7. Humidity and heat parameters identified by indoor surface drying test

[0066] Step S333: Model parameters obtained based on outdoor temperature and humidity monitoring. Cement concrete with a water-cement ratio of 0.4 was prepared around 6:00 pm. Continuous monitoring of outdoor meteorological parameters and concrete temperature and humidity was conducted, including air temperature and humidity and solar radiation. Figure 6 As shown, based on this, the equation parameters (final relative humidity) in Tables 6 and 7 are... Self-drying evolution empirical coefficient And the latent heat of vaporization of water ), concrete temperature and humidity parameters (correction factor for the maximum diffusion coefficient of hardened concrete) Humidity diffusion porosity correction factor Humidity boundary condition parameters (convectional humidity empirical coefficient) Substituting the data into a two-way coupled finite element model of humidity and heat, outdoor thermal parameters were identified, and the resulting time-history curves of concrete temperature and humidity under different outdoor curing conditions were obtained, as shown below. Figures 7-9 As shown, the thermal parameters in the inverted hydrothermal two-way coupled model are shown in Table 8.

[0067] Table 8 Thermal parameters identified from outdoor temperature and humidity monitoring experiments

[0068] Step S400: Establish a finite element model of the temperature and humidity field of early-age cement concrete pavement to obtain the temperature and humidity field under different curing methods. Based on the concrete damp-heat parameters obtained from step S300, and according to the typical pavement structure layer thickness and material parameters shown in Table 9, a finite element model of the early-age concrete temperature and humidity field is established. Meteorological parameters are determined based on measured values ​​from a meteorological station in a certain region over two consecutive years (e.g., 2022 to 2023). Detailed model parameters are shown in Tables 10 and 11. Figure 10 .

[0069] Table 9 Structural layer thickness and material parameters

[0070] Table 10 Variable values ​​used in the temperature and humidity field analysis of concrete slabs

[0071] Table 11 Meteorological parameters of a certain region in different seasons

[0072] This embodiment only provides the calculated results of temperature and humidity fields under different curing methods. The time history curves of temperature in the board and humidity at 2cm from the top of the board under different curing methods are shown below. Figure 11 As shown, the influence of curing methods on the evolution of hydration degree at different depths within the slab is as follows: Figure 12 As shown. Furthermore, this embodiment calculates the temperature and humidity distribution of the board under different curing methods, as follows. Figure 13 As shown. To quantify the impact of curing time on slab strength evolution, the degree of hydration at different depths of the slab was calculated 28 days after paving, as shown. Figure 14 As shown.

[0073] The above description is merely a specific implementation of this application. Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems, modules, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here. It should be understood that the protection scope of this application is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in this application, and these modifications or substitutions should all be covered within the protection scope of this application.

Claims

1. A method for predicting the temperature and humidity field of early-age concrete slabs, characterized in that, include: Step S100: Based on the theories of hydration kinetics, heat conduction, and humidity diffusion, establish a two-way coupled finite element model of concrete moisture and heat. Step S200: Obtain the internal temperature and humidity of indoor and outdoor concrete and external environmental parameters under different curing conditions; Step S300: Based on the adaptive differential evolution algorithm, combined with the concrete hygrothermal bidirectional coupling finite element model, the internal temperature and humidity of the concrete and external environmental parameters, the hygrothermal parameters of early-age concrete are identified. Step S400: Based on the identified damp heat parameters, establish a finite element model of the temperature and humidity field of early-age concrete slabs to obtain the temperature and humidity field under different curing methods.

2. The prediction method according to claim 1, characterized in that, Step S100 includes: Step S110: Establish a two-way coupled finite element model of concrete based on the energy conservation theory and the mass conservation theory; Step S120: Define model parameters; Step S130: Set the boundaries and initial conditions.

3. The prediction method according to claim 2, characterized in that, Step S100 includes: Step S111: Based on the energy conservation theory, establish the heat conduction equation for early-age cement concrete, as shown in formula (1): Official (1); In equation (1), This represents the thermal conductivity coefficient of concrete; This indicates the specific heat capacity of concrete; Indicates the density of concrete; Indicates the temperature inside the concrete; This indicates the heat source generated during hydration; This represents the latent heat of vaporization of water; This indicates the latent heat of vaporization of water; This indicates the moisture content of the concrete. This represents the slope of the isothermal adsorption curve. Indicates the relative humidity inside the concrete; Indicates the temperature and humidity coefficient; Indicates humidity related to self-drying; Step S112: Based on the theory of mass conservation, establish the moisture diffusion equation for early-age cement concrete, as shown in formula (2): Official (2); In equation (2), Indicates the moisture diffusion coefficient of concrete. Indicates the temperature and humidity coefficient; Step S120 includes hydration parameters and concrete temperature and humidity parameters: Hydration parameters include the heat release and heat release rate of cement concrete, as shown in formula (8): Official (8); In equation (8), This indicates the amount of heat released per cubic meter of cement. Indicates the degree of hydration. This indicates the amount of cement used per unit cubic meter of cement concrete. This indicates the total heat release of cement. This indicates the rate of heat release during the hydration of cement concrete. Indicates the hydration time parameter. Indicates the equivalent age. Indicates the hydration shape parameter, Indicates the hydration humidity correction factor. Indicates the activation energy of the hydration reaction. Represents the ideal gas constant. Indicates reference temperature. Indicates the temperature inside the concrete; The temperature and humidity parameters of concrete include thermal conductivity, specific heat capacity, and humidity diffusivity. The thermal conductivity is shown in formula (10): Official (10); In equation (10), This represents the thermal conductivity of cement concrete in a saturated state. This represents the thermal conductivity of concrete when the degree of hydration is 1. The variable specific heat capacity is shown in formula (11): Official (11); In equation (11), This indicates the specific heat capacity of cement concrete. This indicates the mass fraction of coarse aggregate in concrete. This indicates the specific heat capacity of coarse aggregate. This indicates the mass fraction of fine aggregate in concrete. This indicates the specific heat capacity of the fine aggregate. This indicates the mass fraction of cement in concrete. This indicates the specific heat capacity of unhydrated cement. This represents the hypothetical specific heat capacity of cement during hydration. Indicates the mass fraction of water. This indicates the specific heat capacity of water. Indicates the temperature inside the concrete; The humidity diffusion coefficient is shown in formula (12): Official (12); In equation (12), Indicates the moisture diffusion coefficient of concrete. This represents the maximum moisture diffusion coefficient of hardened concrete. This represents the ratio of the minimum to the maximum value of the humidity diffusion coefficient. Indicates the relative humidity inside the concrete; This represents the relative humidity when the humidity diffusion coefficient is half of its maximum value. Represents the empirical coefficient. Indicates the temperature inside the concrete. Indicates reference temperature. Indicates the activation energy of the hydration reaction. Represents the ideal gas constant. Indicates hydration degree as The capillary porosity of cement stone at that time Indicates hydration degree as The capillary porosity of cement stone at that time Indicates the degree of hydration. Indicates the final degree of hydration. Indicates the humidity diffusion porosity correction factor; Step S130: Boundary conditions include temperature field and humidity field. Temperature field includes solar radiation, effective radiation, and convective heat transfer. Humidity field includes humidity loss due to convection. Initial conditions include initial temperature and initial humidity.

4. The prediction method according to claim 3, characterized in that, The equivalent age in formula (8) is shown in formula (7): Official (7); In equation (7), Indicates the actual age of the concrete. This represents the hydration humidity correction factor.

5. The prediction method according to claim 3, characterized in that, The hydration time parameter and hydration shape parameter in formula (8) are shown in formula (9): Official (9); In equation (9), Indicates the hydration time parameter. Indicates the hydration shape parameter, This represents the correction factor for the hydration time parameter. This represents an empirical value for the hydration time parameter. This represents the correction factor for the hydration shape parameter. This represents the empirical value of the hydration shape parameter.

6. The prediction method according to any one of claims 3 to 5, characterized in that, Maximum humidity diffusivity of hardened concrete As shown in formula (13): Official (13); In equation (13), This represents a correction factor for the maximum diffusion coefficient of hardened concrete. This represents the average cubic compressive strength of concrete. This represents the maximum value of the moisture diffusion coefficient of hardened concrete predicted by the empirical formula.

7. The prediction method according to claim 3, characterized in that, In step S130: Solar radiation is as shown in formula (14): Official (14); In equation (14), Indicates daily hourly solar radiation. c represents the solar radiation absorptivity, and c represents the effective sunshine duration. This indicates the total daily solar radiation. The effective radiation is shown in formula (15): Official (15); In equation (15), Indicates effective radiation. This represents the effective radiation correction factor. Indicates surface emissivity, This represents the Stefan-Boltzmann constant. Indicates the road surface temperature. Indicates representative temperature. This represents the indoor correction factor for representative temperature. Indicates the sky emission rate. Indicates the dew point temperature; The heat flux density related to convective heat transfer is shown in formula (16): Official (16); In equation (16), This represents the heat flux density related to convective heat transfer. This represents the convective heat transfer correction factor. Indicates the convective heat transfer coefficient. Indicates air temperature. Indicates near-surface wind speed; The humidity loss is shown in formula (20): Official (20); In equation (20), Indicates the convective humidity coefficient. This represents the rate of change in humidity caused by convection. Indicates air humidity. This represents the empirical coefficient for convective moisture transfer. This indicates the near-surface wind speed. A coefficient representing the degree of hydration. Indicates the water-cement ratio; The initial temperature is shown in formula (19): Official (19); Indicates the initial temperature. and All of these represent unit conversion factors. This represents the average specific heat of the aggregate and unhydrated cement. Indicates the temperature of the aggregate. This indicates the mass of dry aggregate in a unit cubic meter of concrete. Indicates the temperature of the cement. This indicates the mass of unhydrated cement per cubic meter of concrete. This indicates the mass of water absorbed by the aggregate in a unit cubic meter of concrete. Indicates the temperature of the water. This indicates the mass of water in a unit cubic meter of concrete; The initial relative humidity of the concrete is calculated from the time the concrete is poured, and its initial relative humidity is 1.

8. The prediction method according to claim 1, characterized in that, Step S200 includes: Step 210: Conduct an indoor self-drying test: Seal the concrete specimen, measure the changes in internal temperature and humidity, and obtain the first set of damp heat parameters; Step S220: Conduct an indoor surface drying test: expose the surface of the specimen, measure the temperature and humidity at different depths, and obtain the second set of damp heat parameters; Step S230: Conduct outdoor temperature and humidity monitoring: Test the concrete in a real environment, record meteorological data, and obtain environmental parameters.

9. The prediction method according to claim 8, characterized in that, Step S300 includes: Step S310: Construct the error function to transform the problem of identifying hygrothermal parameters into the problem of minimizing the prediction error of the hygrothermal bidirectional coupled finite element model, as shown in formula (23): Official (23); In equation (23), , They represent the first spatial points Temperature model calculated values ​​and measured values ​​at each time point; , They represent the first The spatial point number Humidity calculated and measured values ​​at specific times; Step S320: Run the adaptive differential evolution algorithm. The adaptive mutation coefficient used in the adaptive differential evolution algorithm is shown in formula (24): Official (24); In formula (24), F represents the coefficient of variation. G represents half of the initial coefficient of variation. These represent the current evolutionary step and the maximum number of generations, respectively. Represents an empirical coefficient related to the number of iterations; Step S330: Based on the experiment in step S200, the damp heat parameters are obtained by inversion.

10. The prediction method according to claim 9, characterized in that, Step S330 includes: Step S331: Based on the indoor self-drying test, the first set of hygrothermal parameters of the concrete hygrothermal bidirectional coupled finite element model under indoor sealed conditions are obtained by inversion. Step S332: Based on the indoor surface drying test, the second set of hygrothermal parameters of the concrete hygrothermal bidirectional coupled finite element model under indoor surface drying conditions are obtained by inversion. Step S333: Based on the parameters from outdoor temperature and humidity monitoring, the thermal parameters of the concrete wet-heat bidirectional coupled finite element model are obtained by inversion.

Images