Title: Assessment of Diffusion Coefficient of Chloride Ions in Mortars Using Different Types of Binders
Author(s): N. Otsuki, M. Hisada, H. Minagawa, and S. Miyazato
Publication: Symposium Paper
Appears on pages(s): 107-122
Keywords: binders; fly ash; mortar; portland cement; silica fume; test
Electro-migration and diffusion of ions in electrolyte solution are theoretically described by the Nemst-Plank equation. Also, electro-migration and diffusion of ion can be related by using the Einstein’s equation in dilute solution. In concrete, however, the relationship between electro-migration and diffusion is still unclear, for the influence of the concentrations in pore solution is unknown. Previous work of the authors has shown that it is possible to assess the diffusion coefficients of chloride ion in an ordinary Portland cement mortar through conduction tests by following the Nemst-Plank equation, Debye-Huckel theory and electro-neutrality. This paper evaluates the adaptability of this method to mortars made of several binders, such as ordinaly Portland cement, high-early strength Portland cement, sulfate-resistant Portland cement, low-heat Portland cement, Portland blast-furnace slag cement, ordinary Portland cement with fly ash, ordinary Portland cement with silica fume. In these cases, the concentrations of calcium, sodium, potassium, chloride, and hydroxide ions are different from that of the ordinary Portland cement case. Thus, the adaptability of this method is confirmed in mortar made of a wide range of binders.