scholarly journals Foreign and domestic expertise in strengthening concrete structures with carbon fiber

2020 ◽  
Vol 164 ◽  
pp. 14014
Author(s):  
Dmitriy Topchiy ◽  
Egor Safenkov
Keyword(s):  
Reinforced Concrete ◽  
Concrete Structures ◽  
Protective Layer ◽  
Reinforced Concrete Structures ◽  
Building Structures ◽  
Technical Literature ◽  
Protective Properties ◽  
Manufacturing Defects ◽  
Accelerated Degradation ◽  
Number Of Publications

Over the last 10-15 years, Russia has faced a significant increase in the scope of reconstruction work (including restoration and overhaul) for buildings of various purposes aiming to extend the life cycle of existing facilities and to bring buildings in line with requirements of modern regulatory documents in terms of strength and increase in their energy efficiency. Strengthening the building structures with composite materials is by far the most ‘gentle’ method of restoring building structures and improving their operational performance. At the same time, there is only a small number of publications generalizing this type of strenghtening in the domestic scientific and technical literature. During the operation of buildings and structures (especially industrial ones) numerous factors cause accelerated degradation in building structures. This phenomenon is particulary strong in reinforced concrete structures due to their composite base. Practice shows that corrosive damage is one of the main factors of intensive constuction degradation of reinforced concrete structures. Therefore, these damages are caused by manufacturing defects (reduction of concrete protective layer), loss of concrete-against-reinforcement protective properties due to carbonization or damage. Corrosive damage greatly reduces the life capability and durability of reinforced concrete structures, which in turn leads to a decrease in the safety of construction site operations.

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 Directions of Convergence of the Requirements of the Main Domestic Standard for the Design of Concrete and Reinforced Concrete Structures SP 63.13330.2012 with the Requirements of the International Standard ISO 19338

2019 ◽  
pp. 93-98
Author(s):  
Sergey B. Krylov ◽  
Ravil S. Sharipov ◽  
Sergey A. Zenin ◽  
Yury S. Volkov
Keyword(s):  
Reinforced Concrete ◽  
Prestressed Concrete ◽  
Concrete Structures ◽  
National Standards ◽  
Reinforced Concrete Structures ◽  
Building Structures ◽  
Design Standards ◽  
Structural Concrete ◽  
International Standard ◽  
Assessment Requirements

Design standards on building structures should contain, first of all, the performance and assessment requirements of structures. At the same time, design standards should provide the possibility for design and construction of concrete and reinforced concrete parts of buildings and structures that meet the requirements of the Technical regulations "On the safety of buildings and structures". Taking into account the importance of ensuring the reliability and safety of buildings and structures erected with the use of structural concrete, the technical Committee of the international organization for standardization ISO TC 71 "Concrete, reinforced concrete and prestressed concrete", certifies national standards for compliance with the requirements of the international standard ISO 19338 "Performance and Assessment Requirements for Design Standards on Structural Concrete", developed by the same Committee. The standard describes the issues that should be included in the standards for the design of concrete and reinforced concrete structures (terms and definitions, basic requirements, performance requirements,loads and impacts, design estimates, requirements for manufacturing and construction, as well as quality control). These requirements are common to all standards in the design of concrete and reinforced concrete structures. In this regard, it is relevant and important to establish the possibility of presenting the National Code of rules SP 63.13330.2012 "SNiP 52.01-2003 Plain and Reinforced Concrete Structures. General Provisions" for certification for compliance with the requirements of ISO 19338. To achieve this goal, the relevant work has been done, based on the results of which were made the proposals for the submission of SP 63.13330.2012 for certification for compliance with ISO 19338:2014. These proposals are set out in the text of the article.

How does concrete strength affect the fire resistance?

2020 ◽  
Vol 11 (3) ◽  
pp. 311-324
Author(s):  
Eva Lubloy
Keyword(s):  
Reinforced Concrete ◽  
Fire Resistance ◽  
Fire Safety ◽  
Strength Class ◽  
Concrete Strength ◽  
Concrete Structures ◽  
Reinforced Concrete Structures ◽  
Building Structures ◽  
Content Type ◽  
Upper Limit

Purpose The aim of the research was to investigate the effect of concrete strength on the fire resistance of structures. At first, it may seem contradictory that higher concrete strengths can decrease the fire resistance of building structures. However, if the strength of the concrete exceeds a maximum value, the risk of spalling (the detachment of the concrete surface) significantly. Design/methodology/approach Prefabricated structural elements are often produced with higher strength. The higher concrete strengths generally do not cause a reduction in the load bearing capacity, but it can have serious consequences in case of structural fire design. Results of two prefabricated elements, namely, one slab (TT shaped panel) and one single layer wall panel, were examined. Results of the specimen with the originally designed composition and a specimen with modified concrete composition were examined, were polymer fibres were added to prevent spalling. Findings As a result of the experiments, more strict regulations in the standards the author is suggested including more strict regulations in the standards. It has been proved that to ensure the fire safety of the reinforced concrete structures, it is required after polymer fibres even in lower concrete strength class than prescribed by the standard. In addition, during the classification and evaluation of structures, it is advisable to introduce an upper limit of allowed concrete strength for fire safety reasons. Originality/value As a result of the experiments, the author suggests including more strict regulations in the standards. It has been proved that to ensure the fire safety of the reinforced concrete structures, it is necessary to require the addition of polymer fibres even in lower concrete strength class than prescribed by the standard. In addition, during the classification and evaluation of structures, it is advisable to introduce an upper limit of allowed concrete strength for fire safety reasons.

INFLUENCE OF CONCRETE COMPOSITION ON THE CORROSIVE STATE OF THE STEEL ARMATURES AND DURABILITY OF REINFORCED CONCRETE STRUCTURES

2019 ◽  
pp. 33-39
Author(s):  
Petro Koval ◽  
Vladimir Zelenovskiy
Keyword(s):  
Reinforced Concrete ◽  
Concrete Structures ◽  
The State ◽  
Test Method ◽  
Design Stage ◽  
Reinforced Concrete Structures ◽  
Building Structures ◽  
Reinforcing Steel ◽  
Concrete Composition ◽  
Corrosion State

The influence of the composition of the concrete mixture on the state of reinforcing steel as the main problem of corrosion of reinforced concrete structures is considered. The main attention is paid to the need for individual and mandatory consideration of the influence of the properties of additives to concrete on the passivation of reinforcing steel. The purpose of conducting studies to determine the effect of concrete composition on the state of reinforcing steel is to analyze the causes of corrosion of reinforcement, determine the influence of the environment, apply appropriate prevention of this phenomenon and use methods to determine the corrosion state at the design stage of building structures for which reinforced concrete is used. The composition of concrete, in addition to the standard set in various quantitative combinations (cement, gravel, sand, water) today it is advisable to use special additives. Due to their correct and proportional application, you can create a mixture with significantly improved characteristics: with increased frost resistance, strength, durability, with accelerated or delayed setting of the mixture, etc. Nevertheless, you should not forget that the individuality of the composition of additives could affect the ability of concrete to passivate reinforcing steel. It is possible to eliminate the possibility of reducing the passivation of concrete by testing reinforced concrete samples for its protective properties in relation to the reinforcement. The test method is based on the passivation of reinforcing steel in an alkaline environment and consists in evaluating the protective effect of a sample of concrete in relation to a sample of steel reinforcement by comparing data obtained with a change in potential depending on changes in the density of electric current passing through the sample. The issue of quality and durability of reinforced concrete structures, both technically and economically, is attracting increasing attention of builders. It is obvious that in most cases an increase in the initial cost of manufacturing the structure and its reliable protection is economically justified, if this allows reducing the number and cost of repairs during operation. Keywords: reinforcement, corrosion, concrete, reinforced concrete, concrete additive, concrete composition, corrosion state of reinforcement, durability of reinforced concrete structures.

Increase of Temperature and Fire Resistance for Reinforced-Concrete Structures by Surface Treatment with Protective Coating

2018 ◽  
Vol 788 ◽  
pp. 36-44
Author(s):  
Liudmyla Demydchuk ◽  
Dmytro Sapozhnyk
Keyword(s):  
Reinforced Concrete ◽  
Fire Resistance ◽  
Protective Coating ◽  
Concrete Structures ◽  
Fire Retardant ◽  
Reinforced Concrete Structures ◽  
Building Structures ◽  
Fire Tests ◽  
Normative Documents ◽  
Concrete Building

The normative documents of Ukraine (DBN V.1.1.7 ̶ 2016) [1] establish that the limit of fire resistance of reinforced-concrete building structures is determined by the calculation method or by fire tests, and shall be at least 45 minutes. Taking into account the modern construction technologies, namely, the reduction of the section of the main building reinforced-concrete structures, it is expedient to use fire-retardant coatings to provide the necessary fire resistance limit.

scholarly journals Response Modification Factors for Reinforced Concrete Structures Equipped with Viscous Damper Devices

2017 ◽  
Author(s):  
Heshmatollah Abdi ◽  
Farzad Hejazi ◽  
Mohd Saleh Jaafar ◽  
Izian Binti Abd Karim
Keyword(s):  
Reinforced Concrete ◽  
Seismic Design ◽  
Concrete Structures ◽  
Design Parameters ◽  
Reinforced Concrete Structures ◽  
Building Structures ◽  
Viscous Damper ◽  
Response Modification Factor ◽  
Finite Element Software ◽  
Modification Factor

The response modification factor is one of the seismic design parameters that determine the nonlinear performance of building structures during strong earthquakes. Most seismic design codes lead to reduced loads. Nevertheless, an extensive review of related literature indicates that the effect of viscous dampers on the response modification factor is no longer considered. In this study, the effect of implementing viscous damper devices in reinforced concrete structures on the response modification factor was investigated. Reinforced concrete structures with different stories were considered to evaluate the values of the response modification factors. A nonlinear statistic analysis was performed with finite element software. The values of the response modification factors were evaluated and formulated on the basis of three factors: strength, ductility, and redundancy. Results revealed that the response modification factors for reinforced concrete structures equipped with viscous damper devices are higher than those for structures without viscous damper devices. The number of damper devices and the height of buildings have significant effects on response modification factors. In view of the analytical results across different cases, we proposed an equation according to the values of damping coefficients to determine the response modification factors for reinforced concrete structures furnished with viscous damper devices.

scholarly journals A variety of designs construction and mounting

2019 ◽  
Vol 135 ◽  
pp. 02022
Author(s):  
Tamara Danchenko ◽  
Anatoly Lastovka ◽  
Sergey Amelchugov ◽  
Nadezhda Klinduh ◽  
Maria Berseneva
Keyword(s):  
Reinforced Concrete ◽  
Concrete Structures ◽  
High Strength ◽  
Climatic Conditions ◽  
Reinforced Concrete Structures ◽  
Building Structures ◽  
Metal Structures ◽  
Advantages And Disadvantages ◽  
Building Designs ◽  
Wooden Structures

Abstract in the article the main types of building structures are considered, which are distinguished by the type of material. For the purpose of studying, each type has brief information including its advantages and disadvantages in comparison with others. In the section reinforced concrete structures, the authors characterize this material from three sides - this is the method of manufacture, the type of concrete and its stressed state. As a result, it was found that when choosing a foundation, special attention is paid to: bearing capacity, type of building being built, soil characteristics. In addition to the above, it can be added that weight reduction, cost reduction and material consumption in reinforced concrete structures are possible through the use of high-strength concrete and reinforcement. Metal structures are the most popular building material. The possibilities of this material are very diverse: building designs, designs specifically for certain seismic and climatic conditions, and high decorative properties. Due to its strength and rigidity, buildings can withstand hurricane gusts of wind and earthquakes. In the manufacture of structures in the factory and during installation, steel is subjected to various technological operations: welding, cutting, machining. It was found that in this case the steel does not collapse, it retains the microstructure and mechanical properties. Finally, steel should not have a significant cost of manufacturing structures from it. Turning to the section of wooden structures, the authors list the main advantages - it is comfortable and environmentally friendly and material.

The Construction Quality Control Measures of Reinforced Concrete Cover Research

2014 ◽  
Vol 599-601 ◽  
pp. 1094-1097
Author(s):  
Shao Jun Zhang
Keyword(s):  
Reinforced Concrete ◽  
Concrete Structures ◽  
Protective Layer ◽  
Concrete Cover ◽  
Control Measures ◽  
Reinforced Concrete Structures ◽  
Molding Process ◽  
Steel Bar ◽  
Reinforced Concrete Member ◽  
Design Production

reinforced concrete structures reinforced protective layer deviation will directly affect the mechanical properties and durability of the reinforced concrete member, in relation to the structure of the use of safety and service life. The control to the protective layer of reinforced concrete structures include the following aspects: to do a good job of double sample, reinforced the blue prints.the design, production and installation of template engineering, reinforcing steel bar colligation molding process, placed, binding of fixed steel protective layer block and the requirements on the installation of the steel skeleton.

Quality Inspection of Reinforced Concrete Structures and Reinforcement

2012 ◽  
Vol 479-481 ◽  
pp. 1036-1040
Author(s):  
Na Rui Bu ◽  
Huan Qing Cai ◽  
Run Shan Bai ◽  
Zhi Qiang Li
Keyword(s):  
Reinforced Concrete ◽  
Concrete Structures ◽  
Structural Safety ◽  
Reinforced Concrete Structures ◽  
Quality Inspection ◽  
Building Structures ◽  
Building Structure ◽  
Construction Work ◽  
Modern Design ◽  
Practical Engineering

In the modern design and construction of building structures, building structural safety, reliability is a top priority for construction work. In combination with practical engineering quality inspection and reinforcement methods the building structure are analyzed and presented.

Talking about the Importance of the Construction of the Reinforced Protective Layer Control

2012 ◽  
Vol 256-259 ◽  
pp. 859-862
Author(s):  
Xin Ning Hou ◽  
Yong Sheng Zhang
Keyword(s):  
Reinforced Concrete ◽  
Concrete Structures ◽  
Protective Layer ◽  
Vital Role ◽  
Reinforced Concrete Structures ◽  
Tectonic Structures ◽  
Acceptable Quality ◽  
Force Mechanism ◽  
Layer Control ◽  
Construction Practice

Reinforced protective layer to ensure the durability of reinforced concrete structures important tectonic structures plays a vital role. Reinforced concrete reinforced the lack of a protective layer will affect the durability of the components, in serious cases, the member failure early. Meticulous construction, requires not only the structure of acceptable quality, also require durability is better. This paper tries to force mechanism of reinforced concrete together, combined with years of construction practice, to talk about the importance of control in the construction of reinforced protective layer.

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