Corrosion Sensor for Monitoring the Service Condition of Chloride-Contaminated Cement Mortar

Abstract

A corrosion sensor for monitoring the corrosion state of cover mortar was developed. The sensor was tested in cement mortar, with and without the addition of chloride to simulate the adverse effects of chloride-contaminated environmental conditions on concrete structures. In brief, a linear polarization resistance method combined with an embeddable reference electrode was utilized to measure the polarization resistance (Rp) using built-in sensor electrodes. Subsequently, electrochemical impedance spectroscopy in the frequency range of 1 kHz to 50 kHz was used to obtain the cement mortar resistance (Rs). The results show that the polarization resistance is related to the chloride content and Rs; ln (Rp) is linearly related to the Rs values in mortar without added chloride. The relationships observed between the Rp of the steel anodes and the resistance of the surrounding cement mortar measured by the corrosion sensor confirms that Rs can indicate the corrosion state of concrete structures.

Corrosion Monitoring of Reinforced Steel Embedded in Cement Mortar under Wet-And-Dry Cycles by Electrochemical Impedance Spectroscopy

“…The good fit of Nyquist plots at 26th cycle implies that Equations (5) and (6) can adequately represent the results due to the presence of thinner electrolyte layer [13]. In the dry state, high R p −1 values and high R s values would yield lower polarization resistance and accelerated mass transport rate of dissolved oxygen at the rebar-mortar interface, which would result in higher corrosion rates [10,14,16,17,26].…”

“…The occurrence of corrosion in reinforced structures is extremely high in the marine atmospheric environment. Several factors including high-temperature, relatively high humidity and high NaCl concentration contribute to the corrosion of reinforced structures in the marine environment [3][4][5]. The tide ebbing and flooding expose the reinforced structure via soaking in seawater, seawater film covering the structure during wet state and dry state.…”

Frontiers and Challenges in Electrochemical Corrosion Monitoring; Surface and Downhole Applications

“…A corrosion sensor was fabricated for monitoring the state of corrosion in a cover mortar [ 98 ]. The sensor was analyzed in cement mortar, with and without adding chloride to check the undesirable effects of chloride contaminated conditions on corrosion of concrete structures.…”

Anticorrosion Behaviour ofRhizophora mangleL. Bark-Extract on Concrete Steel-Rebar in Saline/Marine Simulating-Environment

“…These studies lend supports to the knowledge that the environments for steel-reinforced concrete attacks constitute the acidic [9, 12, 16, 30], alkaline [11, 15, 17, 23] and neutral [14, 18, 29] media, wherein environmental agents such as carbonation [20, 25, 28], chloride ions [10, 19, 21, 24], and sulphate ions [9, 13, 17] effects are indicated for the corrosion degradation mechanisms against steel-in-concrete. These have engendered monitoring techniques [26, 27] and solution approaches [20, 22, 29], over the years, for assessing and/or addressing different modes of reinforcing-steel corrosion in concrete. Some of the proffered solutions include the use of fibre reinforced polymer, stainless steel, protective coating, concrete pore sealers, and corrosion inhibitor as admixture in concrete [14, 26, 31–39].…”