Multiprobe chloride sensor for in situ monitoring of reinforced concrete structures

Montemor, M.F.; Alves, Joana; Simões, A.M.; Fernandes, João; Lourenço, Zita; Costa, A.; Appleton, Júlio; Ferreira, M.G.S.

doi:10.1016/j.cemconcomp.2006.01.005

Cited by 94 publications

(71 citation statements)

References 4 publications

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“…These two parallel sensors showed almost the same values, with a maximum difference of 1.6 mV. For both 0.1 M and 1.0 M chloride concentrations, the relationship between potential output of the sensor and the solution temperature can be expressed by a good linear equation as shown in Figure 4 Montemor [17] found similar influences of temperature on potential values of the Ag/AgCl electrode vs. calomel reference electrode. However, the slopes of the regressed lines in this study are very different from the theoretical slopes, this being partially attributed to the influence of temperature on the MnO 2 electrode.…”

Section: Influences Of Other Ions On Potentiometric Responsesupporting

confidence: 48%

“…Their equilibrium potential value depends on the chloride ion activity (concentration) of the surrounding solution according to Nernst's Law. The use of Ag/AgCl electrodes to determine chloride activity in simulated cement pore solution, in pressure-extracted cement pore water and even in mortar and concrete samples has been described in the literature [15][16][17]. The Ag/AgCl wire has even been used as a sensor for determination of water soluble chloride in admixtures and aggregates for cement [18].…”

Section: Introductionmentioning

confidence: 99%

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Fabrication and Performance of All-Solid-State Chloride Sensors in Synthetic Concrete Pore Solutions

Gao

Zhang

Yang

et al. 2010

Sensors

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Abstract:One type of all-solid-state chloride sensor was fabricated using a MnO 2 electrode and a Ag/AgCl electrode. The potentiometric response of the sensor to chloride in synthetic concrete pore solutions was systematically studied, and the polarization performance was also evaluated. The results show a good linear relationship between the potential reading of the sensor and the logarithm of chloride activity (concentration ranges from 0.05 to 5.0 M), and the potential value remains stable with increasing immersion time. ions have little influence on the potentiometric response of the sensor to chloride, but the pH has a significant influence on the potential value of the sensor at low chloride concentration. The potential reading of the sensor increases linearly with the solution temperature over the range from 5 to 45 C. Meanwhile, an excellent polarization behavior is proven by galvanostatic and potentiodynamic tests. All of the results reveal that the developed sensor has a great potential for monitoring chloride ions in concrete environments.

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Section: Influences Of Other Ions On Potentiometric Responsesupporting

confidence: 48%

Section: Introductionmentioning

confidence: 99%

Fabrication and Performance of All-Solid-State Chloride Sensors in Synthetic Concrete Pore Solutions

Gao

Zhang

Yang

et al. 2010

Sensors

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“…With anodization, the rate of AgCl formation depends on the applied current density and the time of the anodization [22]. Different current density and anodizing time have been reported for the preparation of sensors, e.g., 0.4 mA/cm 2 for 30 min [16,19], 2 mA/cm 2 for 30 min [17], 0.2 mA/cm 2 for 1 h [18], 0.4 mA/cm 2 for 2 h [3]. Logically, as with each electrochemical process of this kind, the anodization regime will affect the produced layer thickness, surface morphology and ionic/electron conductivity, respectively [5,10].…”

Section: Introductionmentioning

confidence: 99%

“…One of the most frequently used methods for Ag/ AgCl sensor preparation is anodization of Ag in a HCl solution [16][17][18][19]. The low pH of a HCl solution would limit the possible Ag 2 O formation [20,21] and would result in AgCl formation on the Ag substrate.…”

Section: Introductionmentioning

confidence: 99%

Microstructure, surface chemistry and electrochemical response of Ag|AgCl sensors in alkaline media

et al. 2018

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Characterization of the Ag/AgCl electrode is a necessary step toward its application as a chloride sensor in a highly alkaline medium, such as concrete. The nucleation and growth of AgCl on Ag in 0.1 M HCl was verified through cyclic voltammetry. Ag anodization was performed at current densities, determined by potentiodynamic polarization in the same (0.1 M HCl) medium. The morphology and microstructure of the AgCl layers were evaluated via electron microscopy, while surface chemistry was studied through energy-dispersive spectroscopy and X-ray photoelectron spectroscopy. At current density above 2 mA/cm 2 , the thickness and heterogeneity of the AgCl layer increased. In this condition, small AgCl particles formed in the immediate vicinity of the Ag substrate, subsequently weakening the bond strength of the Ag/AgCl interface. Silver oxide-based or carbon-based impurities were present on the surface of the sensor in amounts proportional to the thickness and heterogeneity of the AgCl layer. It is concluded that a well-defined link exists between the properties of the AgCl layer, the applied current density and the recorded overpotential during Ag anodization. The results can be used as a recommendation for preparation of chloride sensors with stable performance in cementitious materials.

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“…Recently, there have been attempts to measure the concentration of chloride ions using various types of sensors, and the penetration behavior of chloride ions in mortar has also been studied. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] On the other hand, electrochemical techniques are used in analysis of corrosion of reinforcing steel in mortar. Electrochemical Impedance Spectroscopy (EIS) has attracted attention in this connection in recent years.…”

Section: Introductionmentioning

confidence: 99%

Monitoring of Environmental Factors and Corrosion Analysis of Reinforcing Steel in Mortar

Vedarajan

Nishimura

2009

Mater. Trans.

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To understand environmental factors in mortar, the Cl ion concentration and pH were monitored by inserting microelectrodes into artificial pores in the mortar. At the same time, the corrosion behavior of the reinforcing steel was investigated by EIS. In the EIS measurements of the reinforcing steel, Warburg impedance by diffusion was confirmed in the initial period, but it could no longer be observed after 35 days. In comparison with a 10 mm cover thickness, a 20 mm cover thickness showed a higher impedance behavior. The Cl ion concentration in the mortar was obtained using Ag/AgCl microelectrodes, showing that this behavior is generally controlled by diffusion. When the diffusion equation was used in this work, the diffusion coefficient (D c ) showed a high value of D c ¼ 2 Â 10 À4 mm 2 /s. Similarly, the pH in the mortar was obtained using W/WO x microelectrodes. With a 20 mm cover thickness, pH was limited to approximately pH 11, but with a 10 mm cover thickness, pH continued to decrease to around pH 9.5. The latter phenomenon was considered to be the result of neutralization by penetration of the immersion solution from the surface. Based on the results of monitoring with the microelectrodes, solutions simulating those in the pores in mortar were prepared and used in EIS measurements. The charge transfer resistance R ct in the simulated solutions showed good correspondence with the impedance (Z 2mHz ) in the low frequency region (2 mHz) in the actual mortar. This is attributed to the fact that the corrosion of reinforcing steel was controlled by the solution conditions (mainly Cl concentration and pH) in the pores in mortar. If these solution conditions (Cl concentration, pH) exceed threshold values, it was found that the passivation film is destroyed, resulting in high corrosion.

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Multiprobe chloride sensor for in situ monitoring of reinforced concrete structures

Cited by 94 publications

References 4 publications

Fabrication and Performance of All-Solid-State Chloride Sensors in Synthetic Concrete Pore Solutions

Fabrication and Performance of All-Solid-State Chloride Sensors in Synthetic Concrete Pore Solutions

Microstructure, surface chemistry and electrochemical response of Ag|AgCl sensors in alkaline media

Monitoring of Environmental Factors and Corrosion Analysis of Reinforcing Steel in Mortar

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