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Numerical model of multi-ion transport in concrete during electrochemical lithium migration

L.M.S. Souza1, 2, R.B. Polder1, 3, O. Çopuroğlu1

1 Faculty of Civil Engineering and Geosciences, Delft University of Technology, the Netherlands
2 Tecgraf Institute, Pontifical Catholic University of Rio de Janeiro, Brazil
3 RPCP, Gouda, the Netherlands

Electrochemical lithium migration has been investigated as a possible treatment for concrete structures affected by alkali-silica reaction (ASR) by several authors. However, there is still no consensus on its effectiveness. Understanding the mechanisms behind lithium migration and its numerical modelling are essential in order to explore feasibility of lithium treatment in ASR affected concrete.

In this paper, a mathematical model for multi-ion transport in concrete (or mortar) is presented. A multi-ion model was considered as the presence of other ions in the pore solution may influence lithium transport. The model was numerically implemented for two-chamber migration experiments with mortar specimens. The experiments were conducted during a week under 40 V and LiOH solutions were used as anolyte. The model predicted well the final lithium content in the specimens. It also indicated that the removal of all sodium and potassium ions was necessary before lithium reached the catholyte chamber.

Key words: Alkali–silica reaction, migration, lithium-based treatment, numerical modelling