Chloride transport through cementitious membranes using pulsed current

Abstract

Microstructural changes and chloride transport in cement pastes are studied under DC current and pulsed electric fields. Impedance Spectroscopy and Ultrasonic Pulse Velocity measurements have been employed for quasi-real time monitoring of changes in the cement paste microstructure. The results show that the electric resistivity and ultrasound velocity (measured at 500 kHz) are modified during the migration experiments. At the end of test, Mercury Intrusion Porosimetry reveals an important increase in the fraction of gel pores. The experimental results show conduction enhanced through gel pores. The use of pulsed current is presented as an alternative method to minimize the negative effects produced by DC current.

Macro and micro aspects of the transport of chlorides in cementitious membranes

“…As each phenomenon occurs at a specific frequency, it is possible to tune the frequency of the electrical signal to act on the conduction paths, thus increasing the current efficiency on the ionic transport and diminishing the structural damage [10]. The use of pulsed current has been reported to be beneficial for preserving the integrity of the concrete microstructure [11].…”