Determining chloride content profiles in concrete using an electrical resistivity tomography device

Abstract

Chloride penetration in concrete can lead to steel corrosion which is one of the major pathologies affecting reinforced concrete's durability. The development of methods to investigate chloride penetration is essential to predict and update the service life of the structure. A non-destructive (ND) DC-electrical technique is used in this study: this Electrical Resistivity Tomography (ERT) device is arranged in a Wenner configuration and measures apparent resistivities. Apparent resistivities are then inverted in order to obtain a resistivity profile versus depth. In parallel, a calibration method relating the resistivity to the chloride content for each type of concrete is used to obtain the chloride profile versus depth. This methodology was applied to a chloride diffusion experimental program on two concrete formulations and one mortar. The profiles evaluated by NDT are then compared to those obtained by a destructive method (potentiometric titration). Both types of profile fit relatively well, thus, the presented methodology is validated for determining chloride content profiles by means of a non-destructive ERT device. The evaluation of the uncertainty range of successive processes (measurement, inversion and calibration) underlines the importance on including the uncertainties in the interpretation of the ND profiles in future research.

A Joint Inversion Approach of Capacitive and Resistive Measurements for the Estimation of Water Saturation Profiles in Concrete Structures

“…(3) is consistent with Archie's empirical law (1942) proposed by geologists in the oil prospecting field for non-clayey rocks, and then for porous materials such as concrete (Fares, 2018). The calibration of the dielectric permittivity results is performed under the model (Fares, 2018):…”

“…This study focuses on estimating the concrete saturation degree and handles two kinds of measurements: the DCelectrical resistivity and the dielectric permittivity. Both quantities are sensitive to the water content in concrete, and in a complementary way (Fares, 2018), and can, therefore, be used to evaluate the durability of concrete towards water ingress (Balayssac, 2017). The method consists of performing resistivity and permittivity measurements at the surface of the structure; then, an inversion procedure is required to retrieve the electromagnetic depth profiles.…”

Tomography of reinforced concrete

“…Research chloride entrance is basic to foresee and refresh the administration life of the structure. A nondamaging (ND) DC‐electrical method is utilized in this examination: This electrical resistivity tomography (ERT) gadget is arranged in a Wenner design and measures clear resistivities . Albert Einstein once said “look profound into nature, and afterward you will comprehend everything better.” Looking profound into nature has over the most recent couple of years become considerably more feasible using high‐goals X‐rays small scale figured tomography (microCT).…”

Towards the Determination of Chloride Profiles by means of Resistivity Measurements in Reinforced Concrete

“…Finally, electrical resistivity tomography methods also have the great advantage of investigating the concrete from the surface to the core in a non-destructive manner and of drawing as information the apparent resistivity. However, such data need to be inverted to obtain a resistivity profile with depth (Loke et al 1996, Chouteau et al 2002, Fares et al 2018. The calibration determines the conversion function to obtain the desired indicator: either the water content or the chloride content (Villain et al, Fares et al 2018).…”

“…However, such data need to be inverted to obtain a resistivity profile with depth (Loke et al 1996, Chouteau et al 2002, Fares et al 2018. The calibration determines the conversion function to obtain the desired indicator: either the water content or the chloride content (Villain et al, Fares et al 2018). But the presence of metal reinforcements disturbs the electric field and the measurement of apparent resistivities (Sengul et al 2009, Presuel-Moreno et al 2013, Garzon et al 2014 and can prevent the inversion process, which is why the RILEM recommends to place itself at a distance from the reinforcements (Polder, 2001).…”