Diffusion of a mixture of cations and anions dissolved in water

Research output: Contribution to journalArticle

Abstract

In service life modeling of concrete, the ion transport in the pore solution is crucial. The main deterioration phenomena associated
with ions in the pore solution are (1) corrosion due to external chloride ions reaching the embedded reinforcement bars; (2) carbonation
due to presence of dissolved carbon dioxide (which will form carbonic acid with water) supplied from the surrounding air; and (3) leaching
of hydroxide ions from the pore solution to the surrounding environment. Models dealing with diffusion of ions are usually based on
the mass balance equations for the individual diffusing ions together with constitutive relations for the mass density flows and for the mass
exchange among the constituents. The important consequences of electroneutrality among the diffusing ions, however, is often omitted in
models dealing with diffusion of ions in the pore solution of concrete. Here a method will be examined that allows diffusion of different
ions in water, which satisfies both the electroneutrality requirement and the mass balance laws. For simplicity the effect of built-up electric
double layers on the charged pore walls will not be treated.

Details

Authors
  • Björn Johannesson
Organisations
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Materials Engineering

Keywords

  • Diffusion, Carbonation, Leaching, Pore solution, Surface layer
Original languageEnglish
Pages (from-to)1261-1270
JournalCement and Concrete Research
Volume29
Issue number8
Publication statusPublished - 1999
Publication categoryResearch
Peer-reviewedYes

Related research output

Björn Johannesson, 2000, Division of Building Materials, LTH, Lund University. 502 p.

Research output: ThesisDoctoral Thesis (compilation)

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