# Novel Application of Voltammetric Sensors to Characterize the Electrochemical Behavior of Porous Media

## TL;DR

This paper explores using voltammetric sensors to study electrochemical behavior in concrete, showing they can detect environmental changes nondestructively.

## Contribution

The study introduces embedded voltammetric sensors as a novel nondestructive method for electrochemical monitoring of porous materials like concrete.

## Key findings

- The redox process related to OH– adsorption/desorption remains consistent across environments.
- Concrete's electrochemical behavior shifts from quasi-reversible to diffusion-kinetic due to pore network properties.
- PCA confirms the sensor's ability to distinguish between different concrete states.

## Abstract

The objective of this study is to assess the feasibility
of using
embedded voltammetric sensors for the electrochemical characterization
of porous materials, specifically concrete, and to analyze how environmental
conditions influence their response. Cyclic voltammograms were recorded
in solutions simulating various pore-solution conditions of concrete
as well as in concrete specimens under different states (water-saturated,
carbonated, and chloride-contaminated), using a gold electrode as
the sensing element. The morphology of the voltammograms and characteristic
electrochemical parameters (peak current and potential, ΔE
p, i
B/i
b, αn, R
u) were examined to identify similarities and differences in the sensor’s
behavior across both environments. Subsequently, principal component
analysis (PCA) was applied to evaluate the reproducibility of the
response and the sensor’s discriminating capability in a porous
medium such as concrete. The results indicate that the identified
redox process, associated with OH– adsorption/desorption,
preserves its electrochemical nature in both environments; however,
in concrete, the control mechanism shifts from quasi-reversible to
diffusion-kinetic, governed by ionic resistance and the tortuosity
of the pore network. The PCA results demonstrate that the embedded
sensor effectively differentiates between reference, carbonated, and
chloride-contaminated concrete, confirming its potential as a nondestructive
diagnostic tool for in situ electrochemical monitoring of porous materials
containing interstitial moisture.