CN109243544A - Concrete inner transmission matter calculation method under environment and material physical chemistry essential - Google Patents
Concrete inner transmission matter calculation method under environment and material physical chemistry essential Download PDFInfo
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Abstract
This invention describes concrete inner transmission matter calculation methods under a kind of environment and material physical chemistry essential, specifically includes the following steps: step 1: the physics chemical action essence of lower cement-based material transmission process is acted on based on erosion environment, by the thermodynamical model of physics chemical action is coupled into the Nernst-Planck equation for considering moisture convection action between hole solution and hydrated product in cement-based material；Step 2: operator splitting algorithm is used, PHREEQC is successively transferred by MATLAB language and carries out the calculating of the calculating of thermodynamical model and COMSOL progress Nernst-Planck equation and moisture convection action between hole solution and hydrated product, and realizes reciprocation between the two；Step 3: calculated result shows the spatial and temporal distributions of moisture in cement-based material, ion concentration in pore solution and hydrated product content；The invention belongs to civil engineering materials field, numerical model established by the present invention can provide most intuitive theoretical foundation for the durability Design of cement-based material and the prediction of reinforced concrete structure service life.
Description
Technical field
The invention belongs to civil engineering materials fields, make in particular to a kind of environment and material physical chemistry essence
With lower concrete inner transmission matter calculation method.
Background technique
Now and in the long duration from now on, reinforced concrete structure is as structure shape main in field of civil engineering
Formula plays extremely important effect.In recent years, with the fast development of China's economic society, China already and will locate for a long time
In the construction of large-scale infrastructure, the concrete works of great amount of investment over ten billion have just built up or have built or just in wine
It makes among design.For example, the Construction of Hangzhou Bay Cross-sea Bridge for the overall length 36km being open to the traffic for 2008；It is open to the traffic within 2011 complete
The Jiaozhou Bay of Qingdao bridge spanning the sea of long 34.48km；It will be open to traffic at present, invest the pearl Hongkong and Macro bridge for surpassing hundred billion yuan.However,
Under the conditions of these locating severe Service Environments and expend ten hundreds of national economy infrastructure concrete works it is durable
Property issue concerns the development of national economy and the life security of the people.
The reinforced concrete structure in coastal environments, corrosion caused by the invasion of chloride ion are that its durability reduces most
Main cause.Under the action of the factors such as diffusion, convection current, electromigration, capillary attraction, chloride ion is invaded in concrete, is reached
Rebar surface.When rebar surface amount of chloride ions is accumulated to a certain amount of, it will cause rebar surface Damage of Passive Film, in oxygen
In the presence of moisture, reinforcing bar corrodes.So erosion environment acts on the mass transfer of lower cement-based material always
It is the hot spot studied both at home and abroad.But previous research work is often gathered in superorganic mode, not from transmission process
The essence of generation establishes corresponding theoretical model.For this purpose, the invention proposes a kind of environment and material physical chemistry essential
Lower concrete inner transmission matter calculation method.
Summary of the invention
The purpose of the present invention is to solve problems of the prior art, the present invention provides a kind of environment and material object
Concrete inner transmission matter calculation method under Physicochemical essential.
To achieve the above object, the technical solution adopted by the present invention is as follows:
Concrete inner transmission matter calculation method under environment and material physical chemistry essential, specifically includes the following steps:
Step 1: the physics chemical action essence of lower cement-based material transmission process is acted on based on erosion environment, by cement
The thermodynamical model of physics chemical action is coupled into consideration moisture convection action between hole solution and hydrated product in sill
In Nernst-Planck equation；
Step 2: using operator splitting algorithm, successively transfers PHREEQC by MATLAB language and carries out hole solution and water
The calculating of thermodynamical model and COMSOL carry out the calculating of Nernst-Planck equation and moisture convection action between change product,
And realize reciprocation between the two；
Step 3: calculated result shows moisture in cement-based material, ion concentration in pore solution and hydrated product content
Spatial and temporal distributions.
Further, in step 1, the physics chemical action between the hole solution and hydrated product includes C-S-H gel
Adsorption effect hole solution and hydrated product between dissolve deposition.
Further, in step 1, the thermodynamical model is the electric double layer by C-S-H gel surface complex reaction
What model and the phase equilibrium model of hole solution and hydrated product dissolution deposition reaction were established.
Further, in step 2, the interactive implementation method is that PHREEQC is calculated ion concentration
It is assigned as the initial value under each time step onto each finite elements unit grid node, is carried out by interpolating function
Then Nernst-Planck equation is acquired each finite elements unit grid node again by the solution of Nernst-Planck equation
Upper ion concentration carries out the PHREEQC to interact between hole solution and hydrated product as the input parameter of thermodynamical model and counts
It calculates.
Further, in step 1, the physics chemical action of the cement-based material transmission process is in the nature that concentration difference expands
Physical chemistry between the effect of dissipating, the convection action of Water Transport, interionic couple action and hole solution and hydrated product
Effect.
Further, in step 1, the erosion environment is villaumite environment.
Further, the villaumite environment is the etching medium of chloride ion-containing.
Further, the calculation method may be implemented erosion environment and act on mass transfer in lower cement-base composite material
Three-dimensional computations.
The beneficial effect of the present invention compared with the existing technology is: numerical model established by the present invention can be cement-based material
Durability Design and the prediction of reinforced concrete structure service life most intuitive theoretical foundation is provided.It is currently used in cement
The calculation method of mass transfer in sill is all based on greatly Fick law and develops, and theoretical model exists uncertain.
Chloride ion invades in concrete in environment, carries out mass transfer, in addition to being spread, convection current, the effect of the factors such as electromigration
Outside, also by hydrolysis product of cement to its physical and chemical adsorption function influence.In current domestic and international mathematical calculation model used
In, empirical model is generallyd use to consider the physical and chemical adsorption effect of hydrated product, mainly includes that linear isothermal adsorbs mould
Type, Langmuir isotherm adsorption model, Freundlich isotherm adsorption model and BET isotherm adsorption model, and these models are all
For empirical model, the essence adsorbed in concrete chloride ion transmission process all cannot accurately be described.So in current number
In value calculating method, different operating conditions generally requires to use different experience Adsorption Models to ensure the accurate of numerical result
Property, so that the numerical computation method of mass transfer in current cement-based material be caused to there is very big uncertainty.Therefore, this hair
It is bright based on erosion environment and storeroom physical chemistry essential, using physics chemical action between hole solution and hydrated product come
Consider suction-operated of the hydrated product to chloride ion, to obtain corresponding numerical computation method, solves previous numerical value and calculate
Uncertainty in the presence of method.In addition, the present invention use operator splitting algorithm, respectively in COMSOL and PHREEQC into
The calculating of row Nernst-Planck equation and thermodynamical model also realizes that erosion environment acts on substance in lower cement-based material and passes
The numerical value of defeated three-dimensional calculates.
Detailed description of the invention
Fig. 1 is the schematic diagram of the numerical model solver of mass transfer in cement-based material；
The full water degree of concrete when Fig. 2 is 10 days；
Cl in hole solution when Fig. 3 is 10 days-Concentration (mM) distribution map；
The pH figure of hole solution when Fig. 4 is 10 days；
The Na of hole solution when Fig. 5 is 10 days+Concentration (mM) distribution map；
The K of hole solution when Fig. 6 is 10 days+Concentration (mM) distribution map；
The Ca of hole solution when Fig. 7 is 10 days2+Concentration (mM) distribution map；
The SO of hole solution when Fig. 8 is 10 days4 2-Concentration (mM) distribution map；
His figure of the distribution of cement Friedel ' s salt (Fs) content, every liter of concrete of mol in concrete when Fig. 9 is 10 days；
Figure 10 be 10 days when concrete in cement AFm content distribution map, every liter of concrete of mol；
Figure 11 be 10 days when concrete in cement AFt content distribution map, every liter of concrete of mol；
Figure 12 be 10 days when concrete in cement CH content distribution map, every liter of concrete of mol；
Figure 13 be 10 days when concrete in cement C-S-H content distribution map, every liter of concrete of mol；
The full water degree of concrete when Figure 14 is 180 days；
Cl in hole solution when Figure 15 is 180 days-Concentration (mM) distribution map；
The pH figure of hole solution when Figure 16 is 180 days；
The Na of hole solution when Figure 17 is 180 days+Concentration (mM) distribution map；
The K of hole solution when Figure 18 is 180 days+Concentration (mM) distribution map；
The Ca of hole solution when Figure 19 is 180 days2+Concentration (mM) distribution map；
The SO of hole solution when Figure 20 is 180 days4 2-Concentration (mM) distribution map；
Figure 21 be 180 days when concrete in cement Friedel ' s salt (Fs) content distribution map, every liter of concrete of mol；
Figure 22 be 180 days when concrete in cement AFm content distribution map, every liter of concrete of mol；
Figure 23 be 180 days when concrete in cement AFt content distribution map, every liter of concrete of mol；
Figure 24 be 180 days when concrete in cement CH content distribution map, every liter of concrete of mol；
Figure 25 be 180 days when concrete in cement C-S-H content distribution map, every liter of concrete of mol.
Specific embodiment
The present invention will be described in detail with reference to the accompanying drawing.
It is passed in concrete under environment and material physical chemistry essential specific embodiment 1: present embodiment discloses
Matter calculation method, specifically includes the following steps:
Step 1: the physics chemical action essence of lower cement-based material transmission process is acted on based on erosion environment, by cement
The thermodynamical model of physics chemical action is coupled into consideration moisture convection action between hole solution and hydrated product in sill
In Nernst-Planck equation, while the effect for considering Water Transport and porosity change are to cement-based material transmission performance
It influences；Wherein, the effect of Water Transport is embodied in two aspects: first is that the transmission of moisture drives the migration of ion；Second is that moisture
Transmit the influence to ion diffusion coefficient in cement-based material Pore Solution；The porosity change transmits cement-based material
The influence of performance is presented as influence of the porosity change to ion diffusion coefficient in cement-based material Pore Solution.
Step 2: using operator splitting algorithm, successively transfers PHREEQC by MATLAB language and carries out hole solution and water
The calculating of thermodynamical model and COMSOL carry out the calculating of Nernst-Planck equation and moisture convection action between change product,
And realize reciprocation between the two；
Step 3: calculated result shows moisture in cement-based material, ion concentration in pore solution and hydrated product content
Spatial and temporal distributions.
Specific embodiment 2: present embodiment is the further explanation made to specific embodiment one, this embodiment party
Formula discloses concrete inner transmission matter calculation method under environment and material physical chemistry essential, specifically includes the following steps:
Step 1: the physics chemical action essence of lower cement-based material transmission process is acted on based on erosion environment, by cement
The thermodynamical model of physics chemical action is coupled into consideration moisture convection action between hole solution and hydrated product in sill
In Nernst-Planck equation, while the effect for considering Water Transport and porosity change are to cement-based material transmission performance
It influences；Wherein, the effect of Water Transport is embodied in two aspects: first is that the transmission of moisture drives the migration of ion；Second is that moisture
Transmit the influence to ion diffusion coefficient in cement-based material Pore Solution；The porosity change transmits cement-based material
The influence of performance is presented as influence of the porosity change to ion diffusion coefficient in cement-based material Pore Solution.
Step 2: using operator splitting algorithm, successively transfers PHREEQC by MATLAB language and carries out hole solution and water
The calculating of thermodynamical model and COMSOL carry out the calculating of Nernst-Planck equation and moisture convection action between change product,
And realize reciprocation between the two；
Step 3: calculated result shows moisture in cement-based material, ion concentration in pore solution and hydrated product content
Spatial and temporal distributions.
Further, in step 1, the physics chemical action between the hole solution and hydrated product includes C-S-H gel
Adsorption effect hole solution and hydrated product between dissolve deposition.
Specific embodiment 3: present embodiment is the further explanation made to specific embodiment one, this embodiment party
Formula discloses concrete inner transmission matter calculation method under environment and material physical chemistry essential, specifically includes the following steps:
Step 1: the physics chemical action essence of lower cement-based material transmission process is acted on based on erosion environment, by cement
The thermodynamical model of physics chemical action is coupled into consideration moisture convection action between hole solution and hydrated product in sill
In Nernst-Planck equation, while the effect for considering Water Transport and porosity change are to cement-based material transmission performance
It influences；Wherein, the effect of Water Transport is embodied in two aspects: first is that the transmission of moisture drives the migration of ion；Second is that moisture
Transmit the influence to ion diffusion coefficient in cement-based material Pore Solution；The porosity change transmits cement-based material
The influence of performance is presented as influence of the porosity change to ion diffusion coefficient in cement-based material Pore Solution.
Step 2: using operator splitting algorithm, successively transfers PHREEQC by MATLAB language and carries out hole solution and water
The calculating of thermodynamical model and COMSOL carry out the calculating of Nernst-Planck equation and moisture convection action between change product,
And realize reciprocation between the two；
Step 3: calculated result shows moisture in cement-based material, ion concentration in pore solution and hydrated product content
Spatial and temporal distributions.
Further, in step 1, the physics chemical action between the hole solution and hydrated product includes C-S-H gel
Adsorption effect hole solution and hydrated product between dissolve deposition.
Further, in step 1, the thermodynamical model is the electric double layer by C-S-H gel surface complex reaction
What model and the phase equilibrium model of hole solution and hydrated product dissolution deposition reaction were established.
Specific embodiment 4: present embodiment is the further explanation made to specific embodiment one, this embodiment party
Formula discloses concrete inner transmission matter calculation method under environment and material physical chemistry essential, specifically includes the following steps:
Step 1: the physics chemical action essence of lower cement-based material transmission process is acted on based on erosion environment, by cement
The thermodynamical model of physics chemical action is coupled into consideration moisture convection action between hole solution and hydrated product in sill
In Nernst-Planck equation, while the effect for considering Water Transport and porosity change are to cement-based material transmission performance
It influences；Wherein, the effect of Water Transport is embodied in two aspects: first is that the transmission of moisture drives the migration of ion；Second is that moisture
Transmit the influence to ion diffusion coefficient in cement-based material Pore Solution；The porosity change transmits cement-based material
The influence of performance is presented as influence of the porosity change to ion diffusion coefficient in cement-based material Pore Solution.
Step 2: using operator splitting algorithm, successively transfers PHREEQC by MATLAB language and carries out hole solution and water
The calculating of thermodynamical model and COMSOL carry out the calculating of Nernst-Planck equation and moisture convection action between change product,
And realize reciprocation between the two；
Step 3: calculated result shows moisture in cement-based material, ion concentration in pore solution and hydrated product content
Spatial and temporal distributions.
Further, in step 2, the interactive implementation method is that PHREEQC is calculated ion concentration
It is assigned as the initial value under each time step onto each finite elements unit grid node, is carried out by interpolating function
Then Nernst-Planck equation is acquired each finite elements unit grid node again by the solution of Nernst-Planck equation
Upper ion concentration carries out the PHREEQC to interact between hole solution and hydrated product as the input parameter of thermodynamical model and counts
It calculates.
Specific embodiment 5: present embodiment is the further explanation made to specific embodiment one, this embodiment party
Formula discloses concrete inner transmission matter calculation method under environment and material physical chemistry essential, specifically includes the following steps:
Step 1: the physics chemical action essence of lower cement-based material transmission process is acted on based on erosion environment, by cement
The thermodynamical model of physics chemical action is coupled into consideration moisture convection action between hole solution and hydrated product in sill
In Nernst-Planck equation, while the effect for considering Water Transport and porosity change are to cement-based material transmission performance
It influences；Wherein, the effect of Water Transport is embodied in two aspects: first is that the transmission of moisture drives the migration of ion；Second is that moisture
Transmit the influence to ion diffusion coefficient in cement-based material Pore Solution；The porosity change transmits cement-based material
The influence of performance is presented as influence of the porosity change to ion diffusion coefficient in cement-based material Pore Solution.
Step 2: using operator splitting algorithm, successively transfers PHREEQC by MATLAB language and carries out hole solution and water
The calculating of thermodynamical model and COMSOL carry out the calculating of Nernst-Planck equation and moisture convection action between change product,
And realize reciprocation between the two；
Step 3: calculated result shows moisture in cement-based material, ion concentration in pore solution and hydrated product content
Spatial and temporal distributions.
Further, the physics chemical action of cement-based material transmission process described in step 1 is in the nature concentration difference diffusion
Physical chemistry between effect, the convection action of Water Transport, interionic couple action and hole solution and hydrated product is made
With.
Specific embodiment 6: present embodiment is the further explanation made to specific embodiment one, this embodiment party
Formula discloses concrete inner transmission matter calculation method under environment and material physical chemistry essential, specifically includes the following steps:
Step 1: the physics chemical action essence of lower cement-based material transmission process is acted on based on erosion environment, by cement
The thermodynamical model of physics chemical action is coupled into consideration moisture convection action between hole solution and hydrated product in sill
In Nernst-Planck equation, while the effect for considering Water Transport and porosity change are to cement-based material transmission performance
It influences；Wherein, the effect of Water Transport is embodied in two aspects: first is that the transmission of moisture drives the migration of ion；Second is that moisture
Transmit the influence to ion diffusion coefficient in cement-based material Pore Solution；The porosity change transmits cement-based material
The influence of performance is presented as influence of the porosity change to ion diffusion coefficient in cement-based material Pore Solution.
Step 2: using operator splitting algorithm, successively transfers PHREEQC by MATLAB language and carries out hole solution and water
The calculating of thermodynamical model and COMSOL carry out the calculating of Nernst-Planck equation and moisture convection action between change product,
And realize reciprocation between the two；
Step 3: calculated result shows moisture in cement-based material, ion concentration in pore solution and hydrated product content
Spatial and temporal distributions.
Further, in step 1, the erosion environment is villaumite environment.
Specific embodiment 7: present embodiment is the further explanation made to specific embodiment one, this embodiment party
Formula discloses concrete inner transmission matter calculation method under environment and material physical chemistry essential, specifically includes the following steps:
Step 1: the physics chemical action essence of lower cement-based material transmission process is acted on based on erosion environment, by cement
The thermodynamical model of physics chemical action is coupled into consideration moisture convection action between hole solution and hydrated product in sill
In Nernst-Planck equation, while the effect for considering Water Transport and porosity change are to cement-based material transmission performance
It influences；Wherein, the effect of Water Transport is embodied in two aspects: first is that the transmission of moisture drives the migration of ion；Second is that moisture
Transmit the influence to ion diffusion coefficient in cement-based material Pore Solution；The porosity change transmits cement-based material
The influence of performance is presented as influence of the porosity change to ion diffusion coefficient in cement-based material Pore Solution.
Step 2: using operator splitting algorithm, successively transfers PHREEQC by MATLAB language and carries out hole solution and water
The calculating of thermodynamical model and COMSOL carry out the calculating of Nernst-Planck equation and moisture convection action between change product,
And realize reciprocation between the two；
Step 3: calculated result shows moisture in cement-based material, ion concentration in pore solution and hydrated product content
Spatial and temporal distributions.
Further, in step 1, the erosion environment is villaumite environment.
Further, the villaumite environment is the etching medium of chloride ion-containing.
It is passed in concrete under environment and material physical chemistry essential specific embodiment 8: present embodiment discloses
Matter calculation method, specifically includes the following steps:
Step 1: the physics chemical action essence of lower cement-based material transmission process is acted on based on erosion environment, by cement
The thermodynamical model of physics chemical action is coupled into consideration moisture convection action between hole solution and hydrated product in sill
In Nernst-Planck equation, while the effect for considering Water Transport and porosity change are to cement-based material transmission performance
It influences；Wherein, the effect of Water Transport is embodied in two aspects: first is that the transmission of moisture drives the migration of ion；Second is that moisture
Transmit the influence to ion diffusion coefficient in cement-based material Pore Solution；The porosity change transmits cement-based material
The influence of performance is presented as influence of the porosity change to ion diffusion coefficient in cement-based material Pore Solution.
Step 2: using operator splitting algorithm, successively transfers PHREEQC by MATLAB language and carries out hole solution and water
The calculating of thermodynamical model and COMSOL carry out the calculating of Nernst-Planck equation and moisture convection action between change product,
And realize reciprocation between the two；
Step 3: calculated result shows moisture in cement-based material, ion concentration in pore solution and hydrated product content
Spatial and temporal distributions.
The calculation method realizes the three-dimensional computations that erosion environment acts on mass transfer in lower cement-base composite material.
Embodiment 1
Under environment that the present invention records and material physical chemistry essential concrete inner transmission matter calculation method be by with
What lower principle was realized:
Erosion environment acts in lower cement-based material and determines that the physics chemical action of mass transfer has: concentration difference diffusion,
Interaction between the convection action of Water Transport, interionic couple action and hole solution and hydrated product.
Wherein, the interaction between hole solution and hydrated product includes the surface complex reaction and Kong Rong of C-S-H gel
Dissolution deposition reaction between liquid and aquation.The thermodynamical model to balance each other can indicate the molten of hydrated product in ion transmission process
Solution/deposition reaction indicates corresponding balanced reaction by the law of mass action:
Wherein, KpIndicate the thermodynamic equilibrium constant of phase p in hydrated product；ni,pIndicate the chemistry of dissolution reaction intermediate ion i
Stoichiometric coefficient；ciAnd γiIndicate the concentration and vivacity of hole solution intermediate ion i.The vivacity of hole solution intermediate ion i and hole
Relationship can be indicated by Davies equation between effects of ion intensity:
Or WATEQ Deby-Huckel equation indicates:
Wherein, ziIndicate the charge number of ion i institute band；aiAnd biIt indicates and ion relevant parameter (depending on ionic radius)；
A and B is parameter related with temperature.And μ indicates hole solution ionic strength:
Wherein, N indicates the species number of effects of ion.
In addition, Gouy-Chapman electric double layer Surface Complexation Model considers hydrated product physisorption.Aquation produces
In object, CSH gel surface has suction-operated, it is believed that the site that CSH can react only has silicone hydroxyl, equally passes through equation
(1) law of mass action and element conservation can calculate corresponding reacting dose, and the charge that can further obtain CSH gel surface is close
Spend σ (C/m2):
Wherein, F indicates Faraday constant (96485C/mol), and A indicates the specific surface area (m of CSH2/ g), S indicates gel
The concentration (g/l) of phase, zcAnd zARespectively indicate the chemical valence of adsorbed zwitterion, ГHAnd ГOHIndicate adsorbed proton and hydrogen
The density of oxygen radical ion, ГCAnd ГARespectively indicate the density of adsorbed zwitterion.
Relationship according to Gouy-Chapman theory, between surface charge density and surface potential are as follows:
Wherein, ψ0Indicate C-S-H surface potential；C is the molar concentration of electrolyte；Z is the price of symmetrical electrolyte solution
Sinh () indicates hyperbolic sine function.
Further, the ion concentration distribution of diffusion layer can pass through the approximate Boltzmanns equation solution of Donnan:
Wherein, cDDL,iIndicate the concentration of electric double layer intermediate ion；
Consider that the electroneutral of electric double layer, electric double layer intermediate ion concentration need to meet following equations simultaneously:
σ+σd=0 (9)
The thickness t of diffusion layer in electric double layerd:
td=χ κ-1(χ is proportionality constant 1.55) (10)
Wherein, κ-1Indicate Debye length；εrIndicate the relative dielectric constant of water；T indicates temperature.
The effects of in cement-based material transmission course of material by concentration difference diffusion, the convection current of Water Transport and interionic galvanic couple,
It is realized by Nernst-Planck equation:
Wherein, t is the time of erosion environment effect；R is ideal gas constant (8.314J K-1mol-1)；T is thermodynamics
Temperature (K)；ciRespectively concentration (the mol/m of ion i3)；F is Faraday constant (96485J/V/eq)；ziFor ion institute band
Charge number (dimensionless)；DiFor diffusion coefficient of the transmission ion in cement-based material Pore Solution；RiFor hole solution intermediate ion i's
Source item can be acquired according to thermodynamical model above-mentioned.ν (m/s) indicates the flow velocity of moisture, can be acquired by Richards equation:
Here, g is acceleration of gravity (9.8m/s2)；P is capillary pore pressure (Pa)；ρ is the density (1000kg/m of water3)； η
For the coefficient of kinetic viscosity (Pas) (related with temperature, to be 0.001ps at 20 DEG C) of moisture；κsSatisfy water for cement-based material
Infiltration coefficient (m under state2)；κrFull water degree for relative coefficient of permeability, cement-based material is related；C (θ) is capillary capacity letter
Number, is defined as:
Wherein, Hp(θ)=p (θ)/ρ g is indicated pore pressure head (m).C (θ) be when solving Richards equation
Critically important relational expression indicates that concrete satisfies water degree with the changing rule of pore pressure size, as the backwater model of porous material
(Water Retention Curve,WRC).Zhou model is used in the present invention:
C (θ)=β [θ+(α -1) θ2] (16)
Wherein, α and β is fitting parameter, and l is empirical parameter, about 6 or so.Cement base is carried out using Zhou model herein
The numerical value of material Water Transport calculates.
Diffusion coefficient D of formula (12) intermediate ion in cement-based material Pore Solutioni, by effective tortuosity of pore structure and company
The influence of logical degree and porosity change:
Wherein, DCl_RCM(ρ=ρ0, θ=1) quick chloride ion measured by chloride ion transport ratio test method (RCM) expansion
Dissipate coefficient；ρ and ρ0Respectively indicate the porosity and initial porosity of cement-based material；DCl_freeIt is ion i in Free water
Diffusion coefficient；f1(ρ) indicates that the variation of porosity to the influence function of diffusion coefficient, can be obtained by following formula:
f1(θ) indicates influence function of the variation to diffusion coefficient of full water degree:
f2(θ)=θ7/3 (20)
Wherein, θ indicates the full water degree of cement-based material:
W and wsMoisture content respectively under the moisture content of cement-based material and complete water-saturated state.
Above-mentioned equation joint constitutes the value theory model that Particle Field develops in cement-based material under non-water-saturated state.The mould
The basic variable that type solves is concentration, the amount and water of each solid matter of hydrated product of each ion in cement-based material hole solution
The saturation degree of cement-based material.
The present invention uses operator splitting algorithm, MATLAB language is based on, by hole solution and water in the above value theory equation
Change Thermodynamic effect between product and Nernst-Planck equation and Richard ' s equation respectively in PHREEQC solver and
COMSOL is solved, and realizes the interaction between the two by MATLAB language.Its program is realized as shown in Fig. 1, specific to walk
It is rapid as follows:
1) calculating of model initial value.Pass through test or the theoretical amount and coagulation for extrapolating hydrolysis product of cement first
The concentration of each ion in native hole solution, however since both presence of error are not at complete thermodynamic equilibrium state, institute
With further the amount of hydrated product and the concentration of each ion of hole solution under initial equilibrium conditions must be calculated by PHRERQC.
2) Nernst-Planck transmission equation finite element model is defined.The geometrical model of FEM calculation is established, definition passes
The parameter and boundary condition of defeated model, and by each ion concentration of initial hole solution obtained in previous step and concrete
Porosity assign into finite element mode, divide the unit grid of finite element.
3) time step of Nernst-Planck transmission equation is determined.Some experimental studies show chlorine in concrete
The absorption of ion reaches balance ten days or so, so being calculated accordingly using 10 time steps.
4) Nernst-Planck transmission equation transmits hydrated product initial obtained by result and step 1) in 10 days and carries out
Calculation of thermodynamic equilibrium saves calculated result.Then again by the hole of thermodynamical reaction resulting ion concentration and concrete
Rate is assigned as initial value into Nernst-Planck transmission finite element model.
5) such as step 2) is repeated to 4), until reaching the timing node to be calculated, is then post-processed.
Solve the following parameter of numerical model palpus: (1) content of each phase constituent of hydrated product only accounts for CH, C-S- herein
H, AFt and AFm, which can be tested by quantitative XRD and be obtained, or the theoretical calculation based on element conservation obtains； (2)
The concentration of free ion, i.e. K in hole solution+、Na+、Ca2+、SO4 2-、Cl-And OH-, can be by extracting concrete hole solution test
Its ion concentration is surveyed, or is obtained by theoretical calculation；(3) capillary porosity rate, can be by carrying out 50 DEG C of constant temperature to full water test specimen
Drying is obtained to constant weight；(4) chlorine can be surveyed from electromigration coefficient by the chloride ion migration tests method of quick unstable state
It tries and obtains；(5) initial capillary moisture content in concrete；(6) water characteristic curve of concrete material.
Illustrate the application of numerical model established by the present invention and calculation method below with reference to concrete case, case is villaumite
Under environment in non-full water cement sill Particle Field evolution the numerical example model: take 100 × 100 × 400mm3Cube
Test specimen, by 100 × 100mm2Face is exposed in 5.0%NaCl solution, 100 × 100mm2Face and 100 × 400mm2Bottom surface exposure
In 33% relative humidity conditions, excess-three face is sealed using epoxy resin.It is relatively wet to be exposed to 33% for test specimen at that time
It spends in environment, reciprocation will occur with external environment in boundary, and meet Newman (Neumann) boundary condition, i.e. boundary
Place's flow is proportional to differential water pressures in environment and concrete pore, and model uses 2 × 10-8kg·m-2·s-1·Pa-1Ratio it is normal
Number.Initial capillary porosity rate is 0.271；Chloride ion electromigration coefficient 9.2 × 10-12m2/s；The Intrinsic Permeation coefficient of moisture
2.333×10-20m2, backwater model parameter α and β are respectively 4.29915 and 0.0345km-1.Net is carried out using free tetrahedron
Lattice subdivision is encrypted grid on boundary.Total 7657 domain unit grids, minimum cell size 0.08mm.
Initial ion concentration is shown in Table 1 in hole solution；According to element conservation, hydrated product content can be by the chemical constituent of cement
The match ratio (table 3) of (table 2) and concrete material obtains.
1 model of table uses the concentration of each ion of hole solution
2 chemistry of cement component (%) of table
Match ratio (the kg/m of 3 mortar of table3)
Free ion concentration in hole solution can be obtained under any time according to the model and calculation method established above
The situation of full water degree in distribution, the distribution of hydrated product content and cement-based material.It saves space, only provides 10 days and 180
It calculated result, full water degree, the Cl of concrete when attached drawing 2- attached drawing 8 is respectively 10 days-Concentration (mM), pH, Na+'s
Concentration (mM), K+Concentration (mM), Ca2+Concentration (mM), SO4 2-Concentration (mM) distribution map；Fig. 9-Figure 13 is respectively 10
It when concrete in Friedel ' s salt (Fs), AFm, AFt, CH, C-S-H content distribution (every liter of concrete of mol)；Attached drawing
Full water degree, the Cl of concrete when 14- attached drawing 20 is respectively 180 days-Concentration (mM), pH, Na+Concentration (mM), K+It is dense
Spend (mM), Ca2+Concentration (mM), SO4 2-Concentration (mM) distribution map；When Figure 21-Figure 25 is respectively 180 days in concrete
The distribution (every liter of concrete of mol) of Friedel ' s salt (Fs), AFm, AFt, CH, C-S-H content.
The foregoing is only a preferred embodiment of the present invention, is not intended to restrict the invention, for the skill of this field
For art personnel, the invention may be variously modified and varied.All within the spirits and principles of the present invention, made any
Modification, equivalent replacement, improvement etc., should all be included in the protection scope of the present invention.
Claims (8)
1. concrete inner transmission matter calculation method under environment and material physical chemistry essential, which is characterized in that specifically include with
Lower step:
Step 1: the physics chemical action essence of lower cement-based material transmission process is acted on based on erosion environment, by cement matrix
The thermodynamical model of physics chemical action is coupled into the Nernst- for considering moisture convection action between hole solution and hydrated product in material
In Planck equation；
Step 2: using operator splitting algorithm, successively transfers PHREEQC by MATLAB language and carries out hole solution and hydrated product
Between thermodynamical model calculating and COMSOL carry out the calculating of Nernst-Planck equation and moisture convection action, and realize
Reciprocation between the two；
Step 3: calculated result show moisture in cement-based material, ion concentration in pore solution and hydrated product content when
Space division cloth.
2. concrete inner transmission matter calculation method under environment according to claim 1 and material physical chemistry essential: its
Be characterized in that: in step 1, the physics chemical action between the hole solution and hydrated product includes that the surface of C-S-H gel is inhaled
Deposition is dissolved between attached effect and hole solution and hydrated product.
3. concrete inner transmission matter calculation method under environment according to claim 2 and material physical chemistry essential: its
Be characterized in that: in step 1, the thermodynamical model is the double ionic-layer theory and hole by C-S-H gel surface complex reaction
What solution and the phase equilibrium model of hydrated product dissolution deposition reaction were established.
4. concrete inner transmission matter calculation method under environment according to claim 1 and material physical chemistry essential: its
It is characterized in that: in step 2, the interactive implementation method are as follows: PHREEQC is calculated into ion concentration and passes through interpolation
Function is assigned as the initial value under each time step onto each finite elements unit grid node, and Nernst-Planck is carried out
Then Nernst-Planck equation is acquired ion concentration on each finite elements unit grid node again and made by the solution of equation
The PHREEQC to interact between hole solution and hydrated product calculating is carried out for the input parameter of thermodynamical model.
5. concrete inner transmission matter calculation method under environment according to claim 1 and material physical chemistry essential: its
Be characterized in that: in step 1, the physics chemical action of the cement-based material transmission process is in the nature concentration difference diffusion, water
Divide the physics chemical action between convection action, interionic couple action and hole solution and the hydrated product of transmission.
6. concrete inner transmission matter calculation method under environment according to claim 1 and material physical chemistry essential: its
Be characterized in that: in step 1, the erosion environment is villaumite environment.
7. concrete inner transmission matter calculation method under environment according to claim 6 and material physical chemistry essential: its
Be characterized in that: the villaumite environment is the etching medium of chloride ion-containing.
8. concrete inner transmission matter calculation method under environment according to claim 1 and material physical chemistry essential: its
Be characterized in that: the calculation method can be realized the three-dimensional meter that erosion environment acts on mass transfer in lower cement-base composite material
It calculates.
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