Prediction of a Chloride Ion Penetration Profile for a Concrete

Prediction is based on a one-dimensional finite difference solution of Fick's second law of diffusion, with a variable external chloride concentration and a two-layer representation of the concrete.

Please supply the following parameters (defaults provided)

Environmental Parameters Guidance

Specify external chloride concentration as a cyclic step function: level1 for duration1 and level2 for duration2

External chloride concentration 1 moles/liter assumed constant for duration 1

Duration 1 days

External chloride concentration 2 moles/liter assumed constant for duration 2

Duration 2 days

Total duration of exposure days

Unexposed boundary condition is

Structural Design Parameters

Member thickness m

Depth of Reinforcement mm

Concrete Mixture Parameters

w/c ratio

Degree of hydration

Volume fraction of aggregate %

Air content %

Initial chloride concentration of concrete g chloride/g cement Guidance

Diffusion Coefficients (D)

Click here to view database of concrete diffusivities from literature.

Note that all diffusivities should be apparent diffusivities as we are modelling transport in the pore space of the concrete using Fick's second law.

D (bulk concrete) m*m/s

The surface layer of the concrete may have a different (lower or higher) D value than the bulk concrete due to carbonation or poor curing practices. Input the surface layer D value and the thickness of this layer. To bypass this feature, set the skin layer thickness to 0.0 or use D(surface concrete)= D(bulk concrete).

D (surface concrete) m*m/s

Thickness of surface layer mm

Chloride Binding Parameters Guidance

Based on a Langmuir isotherm of the form:
  C(bound)=(alpha*C(free))/(1.+beta*C(free))

where C(bound) is in (mole Cl-)/kg cement and
C(free) is in (mole Cl-)/L

Alpha

Beta

Rate constant for binding s-1

Chloride Reaction Parameters Guidance

Assuming the formation of Freidel's salt from all of the 
C3A and C4AF initially available in the cement powder.

C3A content of cement % on a mass basis

C4AF content of cement % on a mass basis

Rate constant for aluminate reactions with chloride s-1

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E-mail address

For more information, contact:

Mr. Dale Bentz