## Sammanfattning

In this study, a coupled multi-species

transport and chemical equilibrium model has been

established. The model is capable of predicting time

dependent variation of pore solution and solid-phase

composition in concrete. Multi-species transport

approaches, based on the Poisson–Nernst–Planck

(PNP) theory alone, not involving chemical processes,

have no real practical interest since the chemical action

is very dominant for cement based materials. Coupled

mass transport and chemical equilibrium models can

be used to calculate the variation in pore solution and

solid-phase composition when using different types of

cements. For example, the physicochemical evaluation

of steel corrosion initiation can be studied by

calculating the molar ratio of chloride ion to hydroxide

ion in the pore solution. The model can, further, for

example, calculate changes of solid-phase composition

caused by the penetration of seawater into the

concrete cover. The mass transport part of the model is

solved using a non-linear finite element approach

adopting a modified Newton–Raphson technique for

minimizing the residual error at each time step of the

calculation. The chemical equilibrium part of the

problem is solved by using the PHREEQC program.

The coupling between the transport part and chemical

part of the problem is tackled by using a sequential

operator splitting technique and the calculation results

are verified by comparing the elemental spacial

distribution in concrete measured by the electron

probe microanalysis (EPMA).

transport and chemical equilibrium model has been

established. The model is capable of predicting time

dependent variation of pore solution and solid-phase

composition in concrete. Multi-species transport

approaches, based on the Poisson–Nernst–Planck

(PNP) theory alone, not involving chemical processes,

have no real practical interest since the chemical action

is very dominant for cement based materials. Coupled

mass transport and chemical equilibrium models can

be used to calculate the variation in pore solution and

solid-phase composition when using different types of

cements. For example, the physicochemical evaluation

of steel corrosion initiation can be studied by

calculating the molar ratio of chloride ion to hydroxide

ion in the pore solution. The model can, further, for

example, calculate changes of solid-phase composition

caused by the penetration of seawater into the

concrete cover. The mass transport part of the model is

solved using a non-linear finite element approach

adopting a modified Newton–Raphson technique for

minimizing the residual error at each time step of the

calculation. The chemical equilibrium part of the

problem is solved by using the PHREEQC program.

The coupling between the transport part and chemical

part of the problem is tackled by using a sequential

operator splitting technique and the calculation results

are verified by comparing the elemental spacial

distribution in concrete measured by the electron

probe microanalysis (EPMA).

Originalspråk | engelska |
---|---|

Sidor (från-till) | 1577-1592 |

Tidskrift | Materials and Structures |

Volym | 44 |

Utgåva | 9 |

DOI | |

Status | Published - 2011 |

## Ämnesklassifikation (UKÄ)

- Materialteknik