New use of an Ag electrode and a potentiodynamic method to control the presence of chlorides in porous media like concrete

Abstract

Chloride detection in porous materials is important for the soil characterisation and the durability control of reinforced concrete structures. Chloride content in soil can affect soil fertility, and the presence of chlorides in reinforced concrete structures can trigger the corrosion of reinforcement, which leads to structure failure.In both cases, the material in which chlorides are detected is a porous medium. Traditionally in this type of materials, chlorides have been controlled by means of tedious laboratory tests, in which specimens of the material are used, as are passive sensor systems like potentiometric sensors. In the former, tests are usually costly and do not allow effective control in real time. In the latter, as the sensor is not excited, overlapping reactions occur on its surface that can lead to errors when estimating chloride content.In aqueous media, chloride detection is efficiently carried out by electrochemical sensors using potentiodynamic techniques. However, they have hardly been employed in porous media, in which the porous network contains the so-called "pore solution". The present work aims to evaluate the feasibility of using an Ag electrode together with a triangular sweep potentiodynamic signal using concretes of different porosities as a porous medium. This opens up a new study field in electrochemical sensor technology.