LONG-TERM CORROSION BEHAVIOR OF CONCRETE STRUCTURES IN CHLORIDE-BASED INDUSTRIAL ENVIRONMENTS: CASE STUDIES

2015 ◽  
Vol 2 (1) ◽  
Author(s):  
Ioan Pepenar
Keyword(s):  
Corrosion Protection ◽  
Prestressed Concrete ◽  
Concrete Structures ◽  
Corrosion Damage ◽  
Structural Elements ◽  
Damage State ◽  
Intervention Measures ◽  
Industrial Environments ◽  
Resistance Stability

The paper presents two cases of reinforced and prestressed concrete structures damaged by corrosion in chloride-based industrial environments having as main aggressive agents: chlorine, hydrochloric acid and chlorides. To evaluate the corrosion damage of the concrete structures, in-situ and laboratory tests using specific investigation techniques were performed. Investigation of the damage state of structures revealed that many of the examined structural elements showed severe damage due to corrosion. This damage was in various stages of development and had a different influence on the resistance, stability and durability of structures. The corrosion-damage of the structural elements was favoured and accentuated by the absence of efficient intervention measures (repair, corrosion protection) for these elements. In order to ensure normal service conditions of the reinforced and prestressed concrete structures there were proposed intervention measures to remedy existing damages, regarding repair, strengthening, replacing, and corrosion protection of the damaged elements.

A discussion on the origin and treatment of noise in industrial environments - Sandwich damping treatment applied to concrete structures

1968 ◽  
Vol 263 (1142) ◽  
pp. 455-459 ◽  
Keyword(s):  
Prestressed Concrete ◽  
Civil Engineering ◽  
Concrete Structures ◽  
Vibration Damping ◽  
Internal Damping ◽  
Concrete Construction ◽  
Noise And Vibration ◽  
Exciting Forces ◽  
Industrial Environments

Concentration of sources of noise and vibration into densely populated regions and into buildings of slender construction according to modern practice has shown the need for the introduction into civil engineering of definite methods of vibration damping. This is necessary in particular with prestressed concrete construction in which there is normally hardly any internal damping and the stronger the concrete the less the damping will be. The slender forms of construction and greater speed ranges of many machines leads to more chances of striking a condition of resonance in a vibrating structure, wherein the exciting forces will be opposed only by the damping forces. Too little damping will mean large amplitudes and much noise.

scholarly journals MEASUREMENT OF DEFLECTION LINE ON BRIDGES

2013 ◽  
Vol 95 (1) ◽  
pp. 64-75
Author(s):  
Rudolf Urban ◽  
Martin Štroner
Keyword(s):  
Prestressed Concrete ◽  
Concrete Structures ◽  
Measurement Procedure ◽  
Concrete Bridges ◽  
Prediction Methods ◽  
Prestressed Concrete Bridges ◽  
Long Span ◽  
Bridge Structures

Abstract Prestressed concrete bridges are very sensitive to the increase in long-term deflections. Reliable forecasts of deflections of bridge structures during construction and durability are crucial for achieving good durability. The main results of measurements are the changes of the deflection line of the bridge structures, which places special demands on the measurement procedure. Results from measurements are very useful for the improvement of mathematical prediction methods of behaviour of long span prestressed concrete structures.

scholarly journals A practical creep model for concrete elements under eccentric compression

2019 ◽  
Vol 52 (6) ◽  
Author(s):  
Haidong Huang ◽  
Reyes Garcia ◽  
Shan-Shan Huang ◽  
Maurizio Guadagnini ◽  
Kypros Pilakoutas
Keyword(s):  
Prestressed Concrete ◽  
Creep Behaviour ◽  
Concrete Structures ◽  
Creep Model ◽  
Small Scale ◽  
Compressive Creep ◽  
Eccentric Compression ◽  
Shrinkage And Creep ◽  
Concrete Elements

AbstractMany prestressed concrete bridges are reported to suffer from excessive vertical deflections and cracking during their service life. Creep softens the structure significantly, and therefore an accurate prediction of creep is necessary to determine long-term deflections in elements under eccentric axial compression such as prestressed concrete girders. This study proposes a modification to the creep damage model of Model Code 2010 to account for the effect of load eccentricity. The modified creep model considers damage due to differential drying shrinkage. Initially, the creep behaviour of small scale concrete specimens under eccentric compression load is investigated experimentally. Twelve small-scale concrete prisms were subjected to eccentric axial loading to assess their shrinkage and creep behaviour. The main parameters investigated include the load eccentricity and exposure conditions. Based on the experimental results, an inverse analysis is conducted to determine the main parameters of the modified creep model. Subsequently, a numerical hygro-mechanical simulation is carried out to examine the effect of load eccentricity on the development of shrinkage and creep, and on the interaction between drying, damage and creep. The results indicate that eccentric loading leads to different tensile and compressive creep through the cross section, which contradicts the current design approach that assumes that tensile and compressive creep are identical. The proposed model also predicts accurately the long-term behaviour of tests on reinforced concrete elements available in the literature. This study contributes towards further understanding of the long-term behaviour of concrete structures, and towards the development of advanced creep models for the design/assessment of concrete structures.

scholarly journals Modification, Degradation and Evaluation of a Few Organic Coatings for Some Marine Applications

2020 ◽  
Vol 1 (3) ◽  
pp. 408-442
Author(s):  
Guang-Ling Song ◽  
Zhenliang Feng
Keyword(s):  
Corrosion Protection ◽  
Environmental Influence ◽  
Corrosion Damage ◽  
Cost Effective ◽  
Evaluation Methods ◽  
Organic Coating ◽  
Organic Coatings ◽  
Coating System ◽  
Marine Applications

Organic coatings for marine applications must have great corrosion protection and antifouling performance. This review presents an overview of recent investigations into coating microstructure, corrosion protection performance, antifouling behavior, and evaluation methods, particularly the substrate effect and environmental influence on coating protectiveness, aiming to improve operational practice in the coating industry. The review indicates that the presence of defects in an organic coating is the root cause of the corrosion damage of the coating. The protection performance of a coating system can be enhanced by proper treatment of the substrate and physical modification of the coating. Environmental factors may synergistically accelerate the coating degradation. The long-term protection performance of a coating system is extremely difficult to predict without coating defect information. Non-fouling coating and self-repairing coatings may be promising antifouling approaches. Based on the review, some important research topics are suggested, such as the exploration of rapid evaluation methods, the development of long-term cost-effective antifouling coatings in real marine environments.

scholarly journals New developments for corrosion protection of concrete structures in Australia

2019 ◽  
Vol 289 ◽  
pp. 03003
Author(s):  
Atef Cheaitani ◽  
Samir Cheytani
Keyword(s):  
Corrosion Protection ◽  
Cathodic Protection ◽  
Research Work ◽  
Concrete Structures ◽  
Repair Work ◽  
New Developments ◽  
Work Related ◽  
Frequent Failure ◽  
Maintenance Requirements

The corrosion protection, repair and maintenance of reinforced concrete structures located along the coast of Australia has been a challenging task for engineers and asset owners over the past thirty years. Most of these structures are bridges and wharves which are situated in marine environments and are subject to tidal exposure. These environmental conditions create challenges in planning repair work, especially if electrochemical systems such as cathodic protection are installed for corrosion protection of these assets. While impressed current cathodic protection (ICCP) is a proven technology which can provide long-term corrosion prevention solutions for marine structures, this technology has been viewed by many asset owners as overly complex and expensive. There is the perception that ICCP systems require costly permanent monitoring programs and have high maintenance costs. These perceptions have been supported by the frequent failure of power supply units, and in some cases, widespread defects associated with ICCP systems such as grout acidification in concrete elements situated in tidal zones. The perception about the complexity of ICCP technology has led to the selection of less effective galvanic-based systems for the protection of assets, and systems which require no monitoring and have low maintenance requirements. This paper will present information on the new developments which have emerged from long-term experience and research work related to the simplification in the design, installation and improved monitoring of ICCP systems.

scholarly journals CARBONIZATION OF CONCRETE AND CORROSION OF REINFORCEMENT OF REINFORCED CONCRETE STRUCTURES OF UNDERGROUND SEWERAGE SYSTEMS

2021 ◽  
pp. 47-56
Author(s):  
Valeriy Makarenko ◽  
Volodymyr Gots ◽  
Tetiana Khomutetska ◽  
Yulia Makarenko ◽  
Tetiana Arhatenko ◽  
...  
Keyword(s):  
Reinforced Concrete ◽  
Diffusion Processes ◽  
Concrete Structures ◽  
Corrosion Damage ◽  
Exposure Period ◽  
Chloride Ions ◽  
Reinforced Concrete Structures ◽  
Term Operation ◽  
Nace Solution

The process of carbonization of concrete with different ratio of water to cement (W/C) was studied, and the influence of the environment on corrosion damage of reinforced concrete reinforcement was studied. The results of the study of carbonization of concrete on specially prepared model samples of concrete with a size of 250x250x250 mm with an exposure period in NACE solution for 500 days without external load are presented. Measurements of corrosion damage of reinforcing rods, which were placed inside concrete cubes, were performed. The method of estimating the amount of carbonization of concrete and corrosion of reinforcement is described in detail in known scientific papers. The obtained data testify to the active carbonization of concrete during the whole exposure period of the samples in NACE solution, however, concrete prepared at the ratio W/C = 0.5 and 0.6 is particularly significant in terms of carbonization intensity. Concrete with a ratio of W/C = 0.7 is less susceptible to damage. Moreover, a similar trend is observed for corrosion of fittings. This is due to the fact that the increase of the aqueous medium in the concrete mass facilitates diffusion processes of delivery to the reactive zone of chemically aggressive ingredients such as carbon dioxide, chloride ions, hydrogen, sulfur, sulfate ions, various types of bacteria and the like. The kinetics of concrete carbonization and corrosion of reinforcing bars in chemically aggressive NACE medium depending on the exposure period of the samples in the model solution was experimentally studied. It is established that with the increase of the water-cement ratio W/C from 0.5 to 0.7, the depth of carbonization and the layer thickness of corrosion products increase sharply. The flooding of the surface layers of the reinforcement and their strong embrittlement in the process of long-term operation of the reinforcement in the structure of reinforced concrete, which causes a decrease in crack resistance in general of reinforced concrete structures. The degradation of reinforcing steel during long-term operation in aggressive environments, which leads to premature corrosion damage to the reinforcement with subsequent destruction of the structure, was investigated experimentally with the involvement of high-precision metallographic equipment.

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