Effect of the sample–electrode contact impedance on the appearance of dispersion in the AC impedance spectroscopy of cement-based materials

Abstract

In this study, two differential methods were used to investigate the effect of the electrode-sample contact impedance on the appearance of dispersion. The results indicated that a large contact impedance can significantly change the dispersion indexes of middle-frequency capacitive loop by changing the shape of the capacitive loop in this frequency range, and a small contact impedance does not lead to the appearance of dispersion in the ACIS of cement-based materials. Although the experimental results suggest that maintaining the surface humidity of the sample and filling conductive glue at the interface between the sample and electrodes are beneficial for reducing the contact impedance, the ideal contact method between the electrode and sample under certain curing conditions to obtain very small contact impedance should be further investigated. Therefore, the effect of contact impedance on the appearance of dispersion must be evaluated when discussing dispersion to determine the real cause of dispersion.

Keywords:

• sample–electrode contact impedance
• AC impedance spectroscopy
• appearance of dispersion
• cement-based materials

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This study was funded by the Science and Technology Hall of Fujian Province, 2015J06012 National Science Foundation of China, 51778551, 51502279 China Postdoctoral Science Foundation, 2017M612140.