scholarly journals Chloride Levels That Initiated Corrosion of Duplex Stainless Steel Embedded in Mortar

2019 ◽  
Vol 2019 ◽  
pp. 1-6 ◽  
Author(s):  
Yu-You Wu ◽  
Francisco Presuel-Moreno
Keyword(s):  
Stainless Steel ◽  
Reinforced Concrete ◽  
Electrochemical Impedance ◽  
Concrete Structures ◽  
Chloride Concentration ◽  
Threshold Value ◽  
Open Circuit ◽  
Reinforced Concrete Structures ◽  
Premature Failure ◽  
Chloride Threshold

Chloride-induced corrosion of carbon steel has been widely recognized as one of the main causes of premature failure on the reinforced concrete structures. Various strategies and measures such as employing stainless steel reinforcements have been developed to address this problem. Past studies have been concerned with the identification and characterization of chloride threshold since corrosion would not initiate as long as the chloride concentration values at the reinforcing stainless steel depth remains below this threshold value. It is therefore a critical parameter for the design of new stainless steel reinforced concrete structures and the assessment of existing concrete structures. This study presents the finding on the chloride threshold of stainless steel UNS32304 embedded in mortar with two different mixes. Reinforced mortar specimens were subjected to ponding exposure and wet/dry cycle exposure with a sodium chloride solution. The specimens were monitored by using the measurements of the open circuit potential, electrochemical impedance spectroscopy, and linear polarization resistance. The paper also discusses the chloride threshold values of such stainless steel embedded in mortar and concrete with other mixes reported by other researchers and the factors that may affect these values.

Study on Corrosion Resistance of 2205 Stainless Steel Reinforcement in Simulated Concrete Pore Solution

2013 ◽  
Vol 838-841 ◽  
pp. 119-122
Author(s):  
Long Chen ◽  
Yu Qu ◽  
Yan Bing Tang ◽  
Xiang Fang
Keyword(s):  
Stainless Steel ◽  
Reinforced Concrete ◽  
Passive Film ◽  
Pore Solution ◽  
Concrete Structures ◽  
Chloride Concentration ◽  
Chloride Content ◽  
Steel Reinforcement ◽  
Reinforced Concrete Structures ◽  
Current Time

The steel rebar inside reinforced concrete structures is susceptible to corrosion when the chloride content at the surface of the steel exceeding the critical chloride concentration. Stainless steel reinforcements have proved to be the most reliable methods to assure the durability of reinforced concrete structures in marine environment for the compact passive films forming on its surfaces and higher critical chloride concentration. In the present work, the compactness of passive film on 2205 stainless steel in simulated concrete pore solution (SPS) is compared with carbon steel (Q235). the critical chloride concentration of Q235 and 2205 stainless steel reinforcement are discussed. Results indicate the slope(k) of double-log plot of current time for 2205 stainless steel is higher than Q235 , thekvalue is related with the compactness of passive film, the critical chloride concentration of 2205 stainless steel is much higher than Q235 steel in SPS.

scholarly journals COMBINED EFFECT OF CARBONATION AND CHLORIDE AGGRESSION: DEG-RADATION OF REINFORCED CONCRETE STRUCTURES

2018 ◽  
Author(s):  
L.V. KIM ◽  
E.E. SHALYI ◽  
S.N. LEONOVICH ◽  
N.A. BUDREVICH
Keyword(s):  
Reinforced Concrete ◽  
Ph Value ◽  
Concrete Structures ◽  
Chloride Concentration ◽  
Protective Layer ◽  
Sharp Decrease ◽  
Threshold Concentration ◽  
Steel Reinforcement ◽  
Reinforced Concrete Structures ◽  
Cross Sectional

Corrosion reinforcement marine hydraulic structures due to chloride aggression and carbonization of concrete leads to a sharp decrease in the safety of the structure. The steel reinforcement will be subjected to a so-called depassivation process, once the chloride concentration on surface exceeds a certain threshold concentration, or the pH value in the protective layer of concrete decreases to a threshold value due to carbonation. Electrochemical reactions begin to occur with the formation of corrosion products with the penetration of oxygen on the steel reinforcement surface. This leads to cracking of the protective layer of concrete. It should also be taken into account that, due to corrosion mechanisms, the cross-sectional area of the reinforcement also decreases. The article suggests a method for predicting the complex degradation of reinforced concrete structures, taking into account various mechanisms of corrosion wear, which will allow developing effective ways to improve the durability and maintainability of structures operated in the marine environment.

scholarly journals Probabilistic corrosion time initiation modelling in reinforced concrete structures using the BEM

2020 ◽  
Vol 13 (4) ◽  
Author(s):  
Giovanni Pais Pellizzer ◽  
Edson Denner Leonel
Keyword(s):  
Reinforced Concrete ◽  
Concrete Structures ◽  
Chloride Concentration ◽  
Analytical Models ◽  
Mechanical Degradation ◽  
Reinforced Concrete Structures ◽  
Structural Durability ◽  
Probabilistic Values ◽  
Propagation Period ◽  
Corrosion Time

Abstract The reinforcement’s depassivation in reinforced concrete structures occurs when the chloride concentration at the reinforcement’s interface reaches the threshold content. The depassivation phenomenon starts the propagation period, in which huge mechanical degradation processes are triggered. Moreover, it is well established that the propagation period is considerably shorter than the initiation period. Therefore, the accurate prediction of the corrosion time initiation is a major issue in structural durability domain. This study presents a transient formulation based on the Boundary Element Method (BEM) for the corrosion time initiation assessment. The diffusion fields evaluated by the BEM are utilized into a probabilistic framework, which enables the assessment of probabilistic values for corrosion time initiation. Therefore, the formulation handles properly the uncertainties in this problem, which is largely subjected to randomness. Three applications are presented. The robustness and accuracy of the proposed approach over classical analytical models are highlighted.

Electrochemical Impedance Spectroscopy as a Practical Tool for Monitoring the Carbonation Process on Reinforced Concrete Structures

2019 ◽  
Vol 44 (12) ◽  
pp. 10087-10103 ◽  
Author(s):  
Héctor Herrera Hernández ◽  
Francisco González Díaz ◽  
Gerardo Del Jesús Fajardo San Miguel ◽  
Julio César Velázquez Altamirano ◽  
Carlos Omar González Morán ◽  
...  
Keyword(s):  
Reinforced Concrete ◽  
Electrochemical Impedance Spectroscopy ◽  
Impedance Spectroscopy ◽  
Electrochemical Impedance ◽  
Concrete Structures ◽  
Reinforced Concrete Structures ◽  
Carbonation Process ◽  
Practical Tool

Effect of Cathodic Protection Systems with Zn-Mesh Sacrificial Anodes on Reinforced Concrete Structures in an Accelerated Marine Environment

2013 ◽  
Vol 800 ◽  
pp. 365-374 ◽  
Author(s):  
Jin A Jeong ◽  
Chung Kuk Jin
Keyword(s):  
Reinforced Concrete ◽  
Current Density ◽  
Cathodic Protection ◽  
Concrete Structures ◽  
Chloride Concentration ◽  
Reinforced Concrete Structures ◽  
Marine Environments ◽  
Concrete Piles ◽  
Sacrificial Anodes ◽  
Protection Potential

In the present study, corrosion and cathodic protection (CP) characteristics of concrete piles exposed to marine environments such as marine bridge columns or pier structures were evaluated under simulated conditions. The accelerated environmental tests were carried out at an elevated temperature (40°C) and a high chloride concentration (15%). The protection potential of CP systems with Zn-mesh sacrificial anodes applied to piles was inversely proportional to the water content in the concrete. When the CP system was applied after corrosion initiation and propagation (CProt), the protection current density was higher than when the CP system was applied at the beginning of structural construction (CPrev). However, the four-hour depolarization potential was higher in the latter case than in the former. In addition, it was found that even though the current density of the CPrev system was relatively lower than that of the CProt system, the CPrev system was also able to prevent corrosion. Consequently, both CProt and CPrev systems are very effective at preserving reinforced concrete structures, especially in marine environments.

Sign in / Sign up

Export Citation Format

Share Document