Modelling of the processes during steady-state migration tests: Quantification of transference numbers

Due to the increasing application of electrical fields to concrete, not only as a material characterisation method, but also as repair method, a great interest in the study of the processes associated with the application of these techniques has awaked. However, in spite of the fact that transference numbers are fundamental parameters in the description of migration processes, no references to a systematic study of these parameters during a migration experiment have been found in the literature. In the present paper, a series of steady state migration tests with different chloride concentrations have been performed. The experimental results have been used to validate a behaviour model based on transference numbers which is also developed in the paper. This behaviour model allows the pursuit of transference numbers of every species involved during the test, which gives a complete picture of the behaviour of the system during the migration experiment. A nomenclature of transference numbers is proposed as well.