Evaluation of Additional Protection Methods to Control Reinforcement Corrosion

2016 ◽  
Vol 711 ◽  
pp. 37-44 ◽  
Author(s):  
Fabio Bolzoni ◽  
Silvia Beretta ◽  
Andrea Brenna ◽  
Maria Vittoria Diamanti ◽  
Luciano Lazzari ◽  
...  
Keyword(s):  
Service Life ◽  
Limit State ◽  
Chloride Concentration ◽  
Concrete Cover ◽  
Reinforcement Corrosion ◽  
Simplified Approach ◽  
Model Code ◽  
Open Questions ◽  
Additional Protection ◽  
Prevention Methods

The prevention of reinforcement corrosion is primarily achieved by using high quality concrete, adequate concrete cover and suitable casting and curing. Additional prevention methods are adopted when severe environmental conditions occur on structures requiring very long service life. While existing standards, EN 206 or Eurocode 2, adopt prescriptive approach, performance based methods can improve the evaluation of the service life and enable the comparison of available design options. The reliability of the prediction is very important and even widely used models (e.g. fib Model Code) still have open questions. In this paper different additional protection are evaluated: corrosion inhibitors, stainless steel rebars, concrete coatings. A simplified approach is used, considering that the serviceability limit state, i.e. initiation of corrosion in chloride containing environments, can be modeled through the analytical solution of the 2nd Fick’s law of diffusion. The main factors influencing corrosion initiation (critical chlorides concentration, chlorides diffusion coefficient, surface chloride concentration, concrete cover) are represented by distribution of values and the probability distribution of service life is evaluated by Monte Carlo simulation.

scholarly journals Probabilistic chloride diffusion modelling in cracked concrete structures by transient BEM formulation

2022 ◽  
Vol 15 (4) ◽  
Author(s):  
Vinícius de Barros Souza ◽  
Edson Denner Leonel
Keyword(s):  
Service Life ◽  
Structural Engineering ◽  
Chloride Concentration ◽  
Concrete Cover ◽  
Chloride Diffusion ◽  
Reinforcement Corrosion ◽  
Cracked Concrete ◽  
Cover Thickness ◽  
Probabilistic Context ◽  
Reinforced Concrete Corrosion

Abstract Reinforcement corrosion is a concern in the structural engineering domain, since it triggers several pathological manifestations, reducing the structural service life. Chloride diffusion has been considered one of main causes of reinforcements' corrosion in reinforced concrete. Corrosion starts when the chloride concentration at the reinforcements interface reaches the threshold content, leading to depassivation, whose assessment of its time of starts is a major challenge. This study applied the transient Boundary Element Method (BEM) approach for modelling chloride diffusion in concrete pores. The subregion BEM technique effectively represented the cracks inherent to the material domain, and environmental effects were also considered. Because of the inherent randomness of the problem, the service life was evaluated within the probabilistic context; therefore, Monte Carlo Simulation (MCS) assessed the probabilistic corrosion time initiation. Three applications demonstrated the accuracy and robustness of the model, in which the numerical results achieved by BEM were compared against numerical, analytical, and experimental responses from the literature. The probabilistic modelling substantially reduced the structural service life when the cracks length was longer than half of concrete cover thickness in highly aggressive environments.

Research on Life Prediction for One Gravity Piered Wharf Based on the Regulated Reliability Index

2012 ◽  
Vol 256-259 ◽  
pp. 1101-1111
Author(s):  
Wei Hua Li ◽  
Xiang Zhuang Gao ◽  
Cong Tao Sun ◽  
Hai Bing Zheng
Keyword(s):  
Service Life ◽  
Concrete Structure ◽  
Chloride Concentration ◽  
Concrete Cover ◽  
Chloride Diffusion ◽  
Reinforcement Corrosion ◽  
Sea Sand ◽  
Long Term Behavior ◽  
Very High

The long-term behavior of concrete structure shows that the main cause of deterioration is reinforcement corrosion. One of the most aggressive exposure conditions for concrete is marine environment. What is worse, the structure mixed with sea sand. Under these conditions, chloride-induced reinforcement corrosion rate could be very high, often leading to reduction of the service life. This paper investigates long-term corrosive beams in the above-mentioned cases. Chloride distribution is analyzed. From Fick’s second law, the parameters for chloride diffusion can be obtained. Then, the service life of the concrete structure is predicted via empolying probability analysis. The characteristics of randomness (concrete cover, diffusion coefficient, surface chloride concentration and so on) have been taken into consideration.

Physical and Chemical Deterioration of Reinforced Concrete Reefs in Tongyeong Reefs Coastal Waters, Korea

2008 ◽  
Vol 42 (3) ◽  
pp. 110-118 ◽  
Author(s):  
H. S. Kim ◽  
C. G. Kim ◽  
W. B. Na ◽  
J. Woo ◽  
J. K. Kim
Keyword(s):  
Reinforced Concrete ◽  
Service Life ◽  
Dissolved Oxygen ◽  
Extreme Event ◽  
Chemical Properties ◽  
Chloride Concentration ◽  
Concrete Cover ◽  
Marine Habitat ◽  
Seawater Salinity ◽  
Physical And Chemical

As part of a marine habitat enhancement project, the physical and chemical deterioration of reinforced concrete reefs that were fully immersed in Tongyeong waters of Korea was investigated. For the investigation, marine environmental factors such as seawater, salinity, pH, dissolved oxygen, sea-bottom materials, and water depth of the targeted sites were surveyed from 1997 to 2001. Then, four reinforced concrete reefs from four different sites were recovered and tested by using various destructive and nondestructive methods. Based on the observations and test results, it was seen that the reinforced concrete reefs have sound physical and chemical properties, except for chloride concentration and its associated factors. However, because of the lack of dissolved oxygen in the targeted seawaters and its continuous supply, it is concluded that the originally designed service life will be achieved, and in fact the concrete reefs will have an even longer service life than expected. By considering an extreme event such as impact loading under installation and construction, a new minimum concrete cover depth of 40 mm is introduced into practice.

Analysis on Concrete Neutralization and Life Evaluation of Reinforced Concrete Chimney

2013 ◽  
Vol 671-674 ◽  
pp. 1672-1675
Author(s):  
Yan Hui Li ◽  
Yang Yang Zhang ◽  
Jing Cun Wei ◽  
Yun Feng Wu
Keyword(s):  
Reinforced Concrete ◽  
Service Life ◽  
Concrete Structure ◽  
Concrete Cover ◽  
Initiation Time ◽  
Reinforcement Corrosion ◽  
Single Factor ◽  
Routine Examination ◽  
Life Evaluation ◽  
Reinforced Concrete Chimney

Through calculation and analysis on routine examination and neutralization of reinforced concrete chimney, the service life of concrete structure was evaluated only considering neutralization of concrete single factor. The results show that the neutralization of the reinforced concrete chimney was serious than that of other similar projects. The initiation time of reinforcement corrosion were 19.3a, cracking time of concrete cover were 27.35a.

scholarly journals Reinforced Concrete under the Action of Carbonization and Chloride Aggression: a Probabilistic Model for Service Life Prediction

2019 ◽  
Vol 18 (4) ◽  
pp. 284-291 ◽  
Author(s):  
S. N. Leonovich ◽  
E. E. Shalyi ◽  
L. V. Kim
Keyword(s):  
Reinforced Concrete ◽  
Service Life ◽  
Life Prediction ◽  
Ph Value ◽  
Chloride Concentration ◽  
Protective Layer ◽  
Service Life Prediction ◽  
Simultaneous Action ◽  
Shelf Zone ◽  
Reinforcement Corrosion

Reinforcement corrosion of marine and coastal hydraulic structures due to chloride aggression and concrete carbonization leads to a sharp decrease in structure safety. The reinforcement is subjected to a depassivation process as soon as a chloride concentration on its surface exceeds a certain threshold concentration, or the pH value in a concrete protective layer is decreased to a threshold value due to carbonation. Electrochemical reactions are realized with formation of corrosion products due to penetration of oxygen up to reinforcement surface. This leads to cracking of the concrete protective layer and decrease in reinforcement cross-section. The paper proposes a method for predicting a complex degradation of reinforced concrete structures with due account of various mechanisms of corrosion wear that allows to develop efficient methods for improvement of structure durability and maintainability which are operated in the marine environment. A methodology for forecasting of reinforced concrete service life prediction has been developed under a combined effect of carbonization and chloride aggression while using finite-difference and probability models. The paper takes into account initiation periods of reinforcement corrosion and propagation periods for conditions of Sakhalin shelf zone. Field surveys of Kholmsk and Korsakov port facilities are presented in the paper. Carbonization front and chloride content have been estimated according to depth of the concrete protective layer. The paper proposes a model that allows to determine an average period prior to repair while taking into account rate of concrete protective layer degradation caused by simultaneous action of two corrosion processes: carbonization and chloride aggression.

scholarly journals How Reliable is the Durability of RC Structures?

10.14311/634 ◽  
2004 ◽  
Vol 44 (5-6) ◽  
Author(s):  
B. Teplý ◽  
P. Rovnaník ◽  
Z. Keršner ◽  
P. Rovnaníková
Keyword(s):  
Service Life ◽  
Reliability Index ◽  
Statistical Evaluation ◽  
Limit State ◽  
Latin Hypercube Sampling ◽  
Simulation Method ◽  
Concrete Cover ◽  
Life Assessment ◽  
Rc Structures ◽  
Limiting Condition

The goal of this paper is to show some trends and time profiles of the reliability index relevant to the Serviceability Limit State considering the design service life of RC structures. The interactive web page “RC_LifeTime” – originated by the authors – is used (see http://www.stm.fce.vutbr.cz/). The depassivation of reinforcing steel due to carbonation is considered conservatively as a limiting condition. It is based on model concrete carbonation with 12 random input variables; the Latin Hypercube Sampling simulation method is used. RC_LifeTime offers the following options: Service Life Assessment – a statistical evaluation of service life, where optionally the target value of reliability index ß may be an additional input value and then the corresponding service life is the output value; Concrete Cover Assessment – a statistical evaluation of concrete cover value for the target service life, where optionally the required concrete cover value may be input in this case and the relevant reliability index ß describes the reliability of reinforcement depassivation. 

scholarly journals Durability design of concrete structures, Part 1: Analysis fundamentals

2009 ◽  
Vol 7 (1) ◽  
pp. 1-18 ◽  
Author(s):  
Radomir Folic
Keyword(s):  
Service Life ◽  
Limit State ◽  
Natural Extension ◽  
Concrete Structures ◽  
International Committee ◽  
Chloride Ingress ◽  
Freezing And Thawing ◽  
Model Code ◽  
Design Service Life ◽  
Present Design

Concrete structures (CS) are designed so that they can satisfy requirements regarding safety, serviceability, durability and aesthetics throughout their design service life. Present design procedures regarding CS required by national or international codes and standards such as Model Code Euro International Committee of Concrete (1993) now Federation Internationale du Beton (FIB), Eurocodes, ACI, RILEM, etc. are predominantly based on strength principles and limit state formulation. The durability aspect is a natural extension of the classical resistance verification where deterioration effects are normally neglected. The reliability is assessed through the given performance that must be delivered within the design service life, the so-called performance-based design. This approach can be adopted for a performance based on service life design. In the recent years design is related to durability through the analysis of carbonation, resistance to chloride ingress, improved freezing and thawing resistance, etc. The review of literature and some recommendations are presented referring to the design of structures aiming to attain greater durability of CS. The accent is put on the theory of reliability, failure probability and service life probability. The basics of this analysis are given through the principles of performances and service life, and deterministic and scholastic methods using the lifetime safety factor.

scholarly journals DAMAGE TO CONCRETE BRIDGES DUE TO REINFORCEMENT CORROSION

Transport ◽  
2002 ◽  
Vol 17 (5) ◽  
pp. 163-170 ◽  
Author(s):  
Zenonas Kamaitis
Keyword(s):  
Service Life ◽  
Concrete Structures ◽  
Steel Corrosion ◽  
Concrete Cover ◽  
Concrete Bridges ◽  
National Standards ◽  
Chloride Diffusion ◽  
Reinforcement Corrosion ◽  
Concrete Carbonation ◽  
Cover Cracking

The mechanisms of reinforcement corrosion in concrete are the subject of extensive research. Although reliable methods for predicting the corrosive deterioration of concrete structures do not yet exist. This paper describes the durability problem of reinforced concrete bridges based on the mechanisms of carbonation depth or chloride profile. The deterioration model considering concrete carbonation, chloride penetration and concrete cover cracking is adopted to describe the service life of concrete structures. The corrosion models include environmental conditions, concrete carbonation or chloride diffusion rates, quality of concrete cover, steel corrosion rates and many other factors that make the predicting of service life of structures extremely difficult. Finally, the author gives the details of the methods of durabilio/ verification and the proposals for its including in the national standards and practical guides.

scholarly journals Modelling of Corrosion-Induced Concrete Cover Cracking Due to Chloride Attacking

Materials ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1440
Author(s):  
Pei-Yuan Lun ◽  
Xiao-Gang Zhang ◽  
Ce Jiang ◽  
Yi-Fei Ma ◽  
Lei Fu
Keyword(s):  
Service Life ◽  
Corrosion Current ◽  
Practical Experience ◽  
Concrete Cover ◽  
Premature Failure ◽  
Rc Structures ◽  
Structural Capacity ◽  
Cover Cracking ◽  
Deterioration Process ◽  
Cracking Process

The premature failure of reinforced concrete (RC) structures is significantly affected by chloride-induced corrosion of reinforcing steel. Although researchers have achieved many outstanding results in the structural capacity of RC structures in the past few decades, the topic of service life has gradually attracted researchers’ attention. In this work, based on the stress intensity, two models are developed to predict the threshold expansive pressure, corrosion rate and cover cracking time of the corrosion-induced cracking process for RC structures. Specifically, in the proposed models, both the influence of initial defects and modified corrosion current density are taken into account. The results given by these models are in a good agreement with practical experience and laboratory studies, and the influence of each parameter on cover cracking is analyzed. In addition, considering the uncertainty existing in the deterioration process of RC structures, a methodology based on the third-moment method in regard to the stochastic process is proposed, which is able to evaluate the cracking risk of RC structures quantitatively and predict their service life. This method provides a good means to solve relevant problems and can prolong the service life of concrete infrastructures subjected to corrosion by applying timely inspection and repairs.

Production of High-Performance Composite Concrete Segment and Experimental Investigation of Materials

2010 ◽  
Vol 168-170 ◽  
pp. 1042-1045
Author(s):  
Ying Li Gao ◽  
Bao Guo Ma
Keyword(s):  
Service Life ◽  
Concrete Structure ◽  
High Performance ◽  
Concrete Cover ◽  
Chloride Diffusion ◽  
Chloride Diffusion Coefficient ◽  
Volume Deformation ◽  
Volume Stability ◽  
High Performance Composite ◽  
Structure Layer

Tunnel lining concrete segment is the most critical and important structural member of shield tunneling. This investigation designed and produced high-performance composite concrete segment (HCCS). Some key indexes that affect the properties of segment were tested, such as impermeability, volume stability, mechanical property, etc. The results indicated that the impermeability of HCCS concrete cover was excellent and the chloride diffusion coefficient decreased one order of magnitude compared to that of the ordinary segment concrete cover, while the service-life of HCCS increased more than ten-fold. The volume stability of HCCS concrete cover and concrete structure layer were good and the better compatibility in the volume deformation of the whole structure was shown. Furthermore, the mechanical properties of concrete cover and concrete structure layer met the project requirement perfectly, ensuring the higher durability and longer service-life of HCCS effectively.

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