Electrochemical protection against corrosion for steel bars in reinforced concrete structures exposed to seawater

2019 ◽  
pp. 185-190
Author(s):  
Yu. L. Kuzmin ◽  
O. A. Stavitsky

The paper analyzes ways to ensure long service life (up to 50 years) of reinforced concrete marine structures. It has been established that durability and maintenance-free operation of floating and coastal offshore structures for 50 and more years depend on corrosion of steel reinforcement which could be avoided by applying electrochemical protection. The parameters of electrochemical protection against corrosion of steel fittings are given.

2021 ◽  
Author(s):  
Sergey Leonovich ◽  
Evgeniy Shalyy ◽  
Elena Polonina ◽  
Elena Sadovskaya ◽  
Lev Kim ◽  
...  

Section I of the monograph is devoted to an urgent problem - forecasting the durability of port reinforced concrete structures, the destruction of which is associated with corrosion of steel reinforcement caused by chloride aggression and carbonation of concrete. The analysis of models for calculating the service life of structures and experimental data is carried out, the life cycles for the main degradation processes in concrete and reinforcement, the periods of initiation and propagation of corrosion are considered, the influence of environmental factors (temperature, humidity) and the quality of concrete (In/C, cement consumption, diffusion coefficient) on the kinetics of chloride penetration and the movement of the carbonation front is taken into account. Probabilistic models of basic variables are considered, the limiting states of port reinforced concrete structures for the durability of reinforced concrete structures based on the reliability coefficient for service life are formulated. Sections II and III describe modern methods of restoration and restoration of reinforced concrete port structures subjected to corrosion destruction using nanofibrobeton. The concept of multilevel reinforcement has been implemented. Methods of experimental fracture mechanics were used to evaluate the joint work of exploited concrete and reinforcement nanofibre concrete. It is intended for scientific and engineering staff of universities, research and design organizations.


Author(s):  
Mohamed A. Ismail ◽  
Han-Seung Lee ◽  
Mohd Warid Hussin

Corrosion of steel reinforcement embedded in concrete is one of the main causes of degradation of reinforced concrete structures. Degradation occurs in reinforced concrete structures from corrosion caused by the Chloride ingress into concrete. That degradation has a severe impact on the structure in terms of maintenance and rehabilitation costs. Therefore, early detection of reinforcement corrosion is important for efficient maintenance, repair and planning. Meanwhile, the evaluation of the corrosion of reinforcement by non-destructive measurements have been used a lot. In particular CM-II (corrosion meter) is used to measure the polarization resistance, but has some disadvantages. Embedded mini-sensor has been developed in order to overcome these disadvantages. In this study, measurement of corrosion by using the mini-sensor is compared with the measured results by CM-II to verify the validity of the newly developed mini senor. Results show that there are agreement in trends of the parameters measured and as such the developed mini sensor has a promising start to be used.


Author(s):  
Сергей Леонович ◽  
Sergey Leonovich ◽  
Валентин Доркин ◽  
Valentin Dorkin ◽  
Оксана Чернякевич ◽  
...  

The monograph is devoted to the prediction of the longevity of reinforced concrete structures, the destruction of which is associated with corrosion of steel reinforcement caused by chloride aggression or concrete carbonation. On the basis of a comprehensive analysis of models for calculating the service life of structures and experimental data, preference is given to the mathematical model Dura Crete. Life cycles for the main degradation processes in concrete and reinforcement, periods of initiation and propagation of corrosion are considered. Particular attention is paid to the influence of environmental factors and the quality of concrete on the kinetics of chloride penetration and movement of the carbonization front. Formulated limit state design reinforced concrete durability in chloride attacks and carbonation. The basic provisions of the method of calculating the durability of reinforced concrete structures, based on the use of the reliability coefficient for the service life. The practical assessment of service life of reinforced concrete elements taking into account stochastic processes in concrete and reinforcement is made. Verification of the model reliability is performed. For all those interested in the issues of building materials and processes occurring in them.


Author(s):  
Дронов ◽  
Andrey Dronov

Two types of steel reinforcement depassivation process: carbonation of concrete and chloride penetration are considered in the article. The comparison between the corrosion due to carbonation of concrete and the chloride-induced corrosion was carried out. It was found out, that chlorides induced corrosion is potentially more dangerous than that resulting from carbonation. Method of durable tests of reinforced concrete structures under the action of the gravitational load and the corrosive chloride environment is described in the article. The results of experimental research on reinforced concrete structures with corrosive damages to steel reinforcement are given in the article. The properties of corrosion cracking in the case of the pitting corrosion were determined. The character of corrosive damage distribution along the reinforcement bars and its effect on the strength of reinforced concrete beams were determined.


Materials ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 979 ◽  
Author(s):  
Margherita Pauletta ◽  
Nicola Rovere ◽  
Norbert Randl ◽  
Gaetano Russo

Maintenance of reinforced concrete structures is a prevailing topic, especially with regard to lifeline structures and bridges, many of which are now designed with a service life beyond 100 years. Reinforcement made of ordinary (carbon) steel may corrode in aggressive environments. Stainless steel, being much more resistant to corrosion, is a valid solution to facilitate the protection of the works, increasing the service life and reducing the need for repair and maintenance. Despite the potential for stainless steel to reduce maintenance costs, studies investigating the influence of stainless steel on the behavior of reinforced concrete structures are limited. This study investigated the bond behavior of stainless steel rebars by means of experimental tests on reinforced concrete specimens with different concrete cover thicknesses, concrete strengths, and bar diameters. In each case, identical specimens with carbon steel reinforcement were tested for comparison. The failure modes of the specimens were examined, and a bond stress–slip relationship for stainless steel bars was established. This research shows that the bond behavior of stainless steel rebars is comparable to that of carbon steel bars.


2015 ◽  
Vol 1 (2) ◽  
pp. 42
Author(s):  
E. Moreno ◽  
M. I. Prieto ◽  
M. N. González ◽  
N. Llauradó

ResumenLa carbonatación del hormigón o la intrusión de cloruros en suficiente cantidad para alcanzar el nivel de las barras, es desencadenante de la corrosión de la armadura. Uno de los efectos más significativos de la corrosión del acero de refuerzo en estructuras de hormigón armado es la disminución de las propiedades relacionadas con la ductilidad del acero. El reforzamiento tiene un efecto decisivo en la ductilidad global de las estructuras de hormigón armado. Se utilizan diferentes códigos para clasificar el tipo de acero en función de su ductilidad usando los valores mínimos de varios parámetros. El uso de indicadores de ductilidad asociados a diferentes propiedades puede ser ventajoso en muchas ocasiones. Se considera necesario para definir la ductilidad por medio de un solo parámetro que tiene en cuenta los valores de resistencia y deformación simultáneamente. Hay una serie de criterios para definir la ductilidad del acero mediante un único parámetro. El presente estudio experimental se ocupa de la variación en la ductilidad de las barras de acero embebido en hormigón cuando se expone a la corrosión acelerada. Este trabajo analiza la idoneidad de un nuevo indicador de la ductilidad utilizado en barras corroídas. AbstractThe carbonation of concrete or the chlorides ingress in such quantity to reach the level of bars is triggers of reinforcement corrosion. One of the most significant effects of reinforcing steel corrosion on reinforced concrete structures is the decline in the ductility-related properties of the steel. Reinforcement ductility has a decisive effect on the overall ductility of reinforced concrete structures. Different Codes classify the type of steel depending on their ductility defined by the minimum values of several parameters. Using indicators of ductility associating different properties can be advantageous on many occasions. It is considered necessary to define the ductility by means of a single parameter that considers strength values and deformation simultaneously. There are a number of criteria for defining steel ductility by a single parameter. The present experimental study addresses the variation in the ductility of concrete-embedded steel bars when exposed to accelerated corrosion. This paper analyzes the suitability of a new indicator of ductility used in corroded bars.


2013 ◽  
Vol 438-439 ◽  
pp. 784-788
Author(s):  
Jin Wu

Corrosion of steel bars has a serious influence on durability and safety of reinforced concrete structures, which should be effectively monitored for the maintenance of reinforced concrete structures. This paper reviews several main techniques firstly, and presents the ongoing work at Nanjing University of Aeronautics and Astronautics to develop sensors to monitor the corrosion of reinforcement in concrete. It is hoped that the paper will be helpful to the field engineers and laboratory researchers who are monitoring and studying the corrosion of reinforcement in concrete structures.


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