Determination of chloride content in cement-based materials;
Comparison of results derived by conventional methods and chloride sensor readings

F. Pargar, D.A. Koleva, K. van Breugel

Section of Materials and Environment, Faculty of Civil Engineering and Geosciences, Delft University of Technology, the Netherlands

In this paper the potentiometric response of a Ag/AgCl electrode as a chloride sensor in cementitious materials of different mix design was studied. The chloride sensor’s response was discussed with respect to the presence of hydration products around the sensor. The free chloride content inferred from the sensor’s response was compared to the one obtained from destructive water and acid soluble chlorides. The measured free chloride content, obtained via sensor’s reading, was lower than the obtained water and acid soluble chlorides. The results indicated the influence of the cementitious mix design on the correlation between the free chloride content obtained via sensor’s reading, water and acid soluble chlorides.

Key words: Ag/AgCl sensor, free chloride, cement, chloride binding, water soluble chloride, acid soluble chloride