US20030040892A1
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Method for modeling the transport of ions in hydrated cement systems
Assignee: Université Laval
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Filing: 2001-05-24
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Granted: —
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Expires: 2021-05-24
Abstract
Abstract The present invention relates to a computational tool that allows to evaluate the degradation of cement-based materials under various types of chemical attacks such as sulfates, chlorides, and plain water. It is based on the physical principles of ionic mass conservation and chemical equilibrium between a solution and different solid phases. The effect of the dissolution or the precipitation of solid phases on the transport coefficients is considered. A method for determining an ion concentration in solution of at least two ions capable of undergoing transport in a cement-based material under a chemical attack and a solid phase profile for at least one component of said cement-based material is provided. A method for determining a diffusion coefficient for each of at least two ions capable of undergoing transport in a cement-based material is also provided.
Inventors
- 👤 Jacques Marchand
- 👤 Eric Samson
- 👤 Yannick Maltais
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 05:15
CPC Classifications
G; G01; G01N; G01N33/00; G01N33/38; G01N33/383
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
349 words
1 . A method for determining an ion concentration in solution of each of at least two ions capable of undergoing transport in a cement-based material under a chemical attack and a solid phase profile for at least one component of said cement-based material, said cement-based material having a solid skeleton and pores, said pores being at least one of liquid-filled and vapor-filled, a porosity of said cement-based material being provided, the method comprising the steps of: determining a first concentration for each said at least two ions and an electrical potential profile using a transport algorithm, wherein the transport algorithm is a function of a diffusion of said at least two ions, of an adsorption of said at least two ions, of an electrical coupling between said at least two ions and a chemical activity of said at least two ions and wherein an ionic solution of said material is not in equilibrium with various solid phases of an hydrated paste of said cement-based material; calculating a corrected concentration for each of said at least two ions and a first solid phase profile for each said at least one component using a chemical reactions algorithm, wherein at least one of a dissolution and a precipitation reactions is accounted for in order to maintain an equilibrium between said ionic solution and said various solid phases of said hydrated paste; calculating a changed transport properties profile to take into account an effect of said chemical reactions on said porosity of said material; and determining an ion concentration for each of said at least two ions and a solid phase profile for each of said at least one component using said changed transport properties profile, said corrected concentration and said first solid phase profile, wherein effects of said chemical reactions on an ionic transport are taken into account by correcting material transport properties whereby said ion concentration for each said at least two ions and said solid phase profile for each said at least one component in said cement-based material can be used to evaluate a degradation of said cement-based material.
Claim 2
Dependent Claim
349 words
1 . A method for determining an ion concentration in solution of each of at least two ions capable of undergoing transport in a cement-based material under a chemical attack and a solid phase profile for at least one component of said cement-based material, said cement-based material having a solid skeleton and pores, said pores being at least one of liquid-filled and vapor-filled, a porosity of said cement-based material being provided, the method comprising the steps of: determining a first concentration for each said at least two ions and an electrical potential profile using a transport algorithm, wherein the transport algorithm is a function of a diffusion of said at least two ions, of an adsorption of said at least two ions, of an electrical coupling between said at least two ions and a chemical activity of said at least two ions and wherein an ionic solution of said material is not in equilibrium with various solid phases of an hydrated paste of said cement-based material; calculating a corrected concentration for each of said at least two ions and a first solid phase profile for each said at least one component using a chemical reactions algorithm, wherein at least one of a dissolution and a precipitation reactions is accounted for in order to maintain an equilibrium between said ionic solution and said various solid phases of said hydrated paste; calculating a changed transport properties profile to take into account an effect of said chemical reactions on said porosity of said material; and determining an ion concentration for each of said at least two ions and a solid phase profile for each of said at least one component using said changed transport properties profile, said corrected concentration and said first solid phase profile, wherein effects of said chemical reactions on an ionic transport are taken into account by correcting material transport properties whereby said ion concentration for each said at least two ions and said solid phase profile for each said at least one component in said cement-based material can be used to evaluate a degradation of said cement-based material.
Claim 3
Dependent Claim
24 words
2 . A method as claimed in claim 1 , wherein said step of calculating a first concentration comprises solving a set of equations.
Claim 4
Dependent Claim
22 words
3 . A method as claimed in claim 2 , wherein said set of equations is solved using a finite elements method.
Claim 5
Dependent Claim
51 words
4 . A method as claimed in claim 1 , further comprising a step of providing input data, said input data comprising a porosity, a temperature, ionic pore solution concentrations, an amount of each solid phase, a diffusion coefficient for each ionic species, a water diffusivity and an initial water content.
Claim 6
Dependent Claim
23 words
5 . A method as claimed in claim 4 , wherein said input data further comprises a finite element mesh and boundary conditions.
Claim 7
Dependent Claim
25 words
6 . A method as claimed in claim 5 , wherein said chemical reactions algorithm is performed on each node of said finite element mesh.
Claim 8
Dependent Claim
28 words
7 . A method as claimed in claim 4 , wherein said input data further comprises a number of time steps and a length of said time steps.
Claim 9
Dependent Claim
56 words
8 . A method as claimed in claim 7 , further comprising a step of determining a profile of said ion concentration by repeating said steps of determining a first concentration, calculating a corrected concentration, calculating a changed transport properties profile and determining an ion concentration and solid phase profile for each of said time steps.
Claim 10
Dependent Claim
30 words
9 . A method as claimed in claim 1 , further comprising a step of generating an indication of said ion concentration and an indication of said solid phase profile.
Claim 11
Dependent Claim
33 words
10 . A method as claimed in claim 1 , further comprising a step of determining a porosity profile using said solid phase profile, said ion concentration profiles and said electrical potential profile.
Claim 12
Dependent Claim
22 words
11 . A method as claimed in claim 10 , further comprising a step of generating an indication of said porosity profile.
Claim 13
Dependent Claim
25 words
12 . A method as claimed in claim 1 , wherein said components are at least one of C—S—H, Gypsum, Portlandite, Mirabilite, Ettringite and Hydrogarnet.
Claim 14
Dependent Claim
38 words
13 . A method as claimed in claim 1 , wherein said ions are at least one of OH − , Na + , K + , SO 4 2− , Ca 2+ and Al(OH) 4 − .
Claim 15
Dependent Claim
29 words
14 . A method as claimed in claim 1 , wherein said step of determining a first concentration is carried out before said step of calculating a corrected concentration.
Claim 16
Dependent Claim
46 words
15 . A method as claimed in claim 1 , wherein said transport algorithm is further a function of a capillary suction, said capillary suction arising when said material is exposed to a gradient of relative humidity, said transport algorithm thereby determining a water content profile.
Claim 17
Dependent Claim
51 words
16 . A method as claimed in claim 15 , further comprising a step of providing input data, said input data comprising a porosity, a temperature, ionic pore solution concentrations, an amount of each solid phase, a diffusion coefficient for each ionic species, a water diffusivity and an initial water content.
Claim 18
Dependent Claim
28 words
17 . A method as claimed in claim 16 , wherein said input data further comprises a number of time steps and a length of said time steps.
Claim 19
Dependent Claim
56 words
18 . A method as claimed in claim 17 , further comprising a step of determining a profile of said ion concentration by repeating said steps of determining a first concentration, calculating a corrected concentration, calculating a changed transport properties profile and determining an ion concentration and solid phase profile for each of said time steps.
Claim 20
Dependent Claim
133 words
19 . A method for determining a diffusion coefficient for each of at least two ions capable of undergoing transport in a cement-based material, said cement-based material having a solid skeleton and pores, said pores being at least one of liquid-filled and vapor-filled, a porosity of said cement-based material being provided, the method comprising the steps of: determining a concentration for each said at least two ions and an electrical potential profile using a transport algorithm, wherein the transport algorithm is a function of a diffusion of said at least two ions, of an electrical coupling between said at least two ions and a chemical activity of each said at least two ions; and determining a diffusion coefficient for each of at least two ions using said concentration and said electrical potential profile.
Claim 21
Dependent Claim
133 words
19 . A method for determining a diffusion coefficient for each of at least two ions capable of undergoing transport in a cement-based material, said cement-based material having a solid skeleton and pores, said pores being at least one of liquid-filled and vapor-filled, a porosity of said cement-based material being provided, the method comprising the steps of: determining a concentration for each said at least two ions and an electrical potential profile using a transport algorithm, wherein the transport algorithm is a function of a diffusion of said at least two ions, of an electrical coupling between said at least two ions and a chemical activity of each said at least two ions; and determining a diffusion coefficient for each of at least two ions using said concentration and said electrical potential profile.
Claim 22
Dependent Claim
125 words
20 . A method as claimed in claim 19 , further comprising: providing input data, said input data comprising a set of tortuosity parameters and a measured electrical current for said material, and determining a diffusion coefficient for each of said ions by calculating a set of electrical currents each electrical current corresponding to one of said tortuosity parameter in said set of tortuosity parameters using said concentration, said electrical potential and each one of said tortuosity parameter in said set of tortuosity parameters; choosing an electrical current from said set with a value closest to said measured electrical current; determining a matching tortuosity parameter corresponding to said chosen electrical current; and determining said diffusion coefficient for each of said ions using said matching tortuosity.
References Cited (Backward Citations)
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Cited
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