scholarly journals Non-uniform corrosion of steel rebar and its influence on reinforced concrete elements` reliability

2020 ◽  
Vol 26 (2) ◽  
pp. 67-72 ◽  
Author(s):  
Yaroslav Blikharskyy ◽  
Nadiia Kopiika ◽  
Jacek Selejdak
Keyword(s):  
Reinforced Concrete ◽  
Analytical Modelling ◽  
Uniform Corrosion ◽  
Material Anisotropy ◽  
Topical Problem ◽  
Structural Element ◽  
Reliable Technique ◽  
Steel Rebar ◽  
Corrosion Of Steel ◽  
Concrete Elements

AbstractRemarkable place of reinforced concrete structures in construction field has been noted in wide number of recent researches. Subsequently, their degradation due to aggressive environment has become the topical problem nowadays. Therefore, the formulation of reliable technique for corroded element strength decrement is of great importance, and could be achieved only with the use of complex experimental and theoretical analysis. In this article an attempt is made to propose the mathematical approach to corrosive process modelling, taking into consideration the specifics of its development. According to thorough literature review on existing studies, main specifics of the process were indicated for further suppositions and assumptions formulation. Accordingly, the complex theoretical investigation with corresponding mathematical computations was conducted and results of analytical modelling were discussed. As the initial data for analytical modelling results of previously conducted experiments were used. Analysis of the obtained results shows rather high correspondence with the real conditions of structural element exploitation, taking into consideration material anisotropy and complexity of the corroded zone spread along the rebar cross-section. Proposed methodology for limit force decrease evaluation in general demonstrates reliable results and could be used for further evaluation of corrosion impacts on reinforced concrete elements bearing capacity.

scholarly journals Historical reinforced concrete structures – used materials and calculating algorithms

2015 ◽  
Vol 14 (2) ◽  
pp. 105-112 ◽  
Author(s):  
Bartosz Szostak ◽  
Maciej Trochonowicz
Keyword(s):  
Mechanical Properties ◽  
Reinforced Concrete ◽  
Concrete Structures ◽  
Reinforced Concrete Structures ◽  
Structural Element ◽  
Historical Building ◽  
Historical Material ◽  
Low Strength ◽  
Concrete Elements

During designing in historical object we can have a problem with historical reinforced concrete elements. Many designers, classifies this elements as low strength. They are convicted that this type of elements in historical building can be only a monument and cannot be used in this construction as an structural element. It is very important in this type of buildings to keep as many historical material as it is possible. Authors researched the literature which has been a guide in the design and execution of these elements. By comprising used algorithms and physico-mechanical properties of old materials with algorithms and materials, which are using today, we are able to estimate the strength of such elements.

AR-glass/carbon-based textile-reinforced concrete elements for detecting water infiltration within cracked zones

2018 ◽  
Vol 18 (5-6) ◽  
pp. 1383-1400 ◽  
Author(s):  
Yiska Goldfeld ◽  
Gali Perry
Keyword(s):  
Reinforced Concrete ◽  
Short Circuit ◽  
Reinforced Concrete Beam ◽  
Water Infiltration ◽  
Test Results ◽  
Textile Reinforced Concrete ◽  
Structural Element ◽  
Glass Carbon ◽  
Concrete Elements ◽  
Carbon Based

The study examines the use of hybrid carbon-based textile-reinforced concrete elements with self-sensing capabilities to quantitatively detect wetting events within cracked zones. The self-sensory structural element combines the advantages of AR-glass and carbon-based textile-reinforced concrete for thin-walled structural elements with those stemming from the electrical properties of reinforced carbon rovings. The article investigates the sensitivity of sensory carbon rovings to distinguish between the magnitudes of various wetting events, which is associated with the severity of the cracking, according to two electrical setups (DC and AC circuits). The sensing concept takes advantage of the continuous configuration of the carbon rovings, which enables direct connection of the roving ends to the data acquisition system, and of the manufacturing process that two carbon rovings are placed adjacent to one another. Therefore, it is assumed that wetting events electrically short-circuit the two adjacent rovings. The sensitivity of the two electrical setups is experimentally investigated and performed on a couple of bared carbon rovings and on a cracked textile-reinforced concrete beam. Test results demonstrate the sensitivity of the sensing capabilities of the carbon rovings to detect and distinguish between the magnitudes of the wetting events and consequently the severity of the cracking.

scholarly journals Effect of Cathodic Protection on Reinforced Concrete with Fly Ash Using Electrochemical Noise

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2438
Author(s):  
Jorge García-Contreras ◽  
Citlalli Gaona-Tiburcio ◽  
Irene López-Cazares ◽  
Guillermo Sanchéz-Díaz ◽  
Juan Carlos Ibarra Castillo ◽  
...  
Keyword(s):  
Reinforced Concrete ◽  
Fly Ash ◽  
Cathodic Protection ◽  
Electrochemical Noise ◽  
Uniform Corrosion ◽  
Concrete Mixtures ◽  
Impressed Current ◽  
The Difference ◽  
Passive Current ◽  
Corrosion Of Steel

Corrosion of steel reinforcement is the major factor that limits the durability and serviceability performance of reinforced concrete structures. Impressed current cathodic protection (ICCP) is a widely used method to protect steel reinforcements against corrosion. This research aimed to study the effect of cathodic protection on reinforced concrete with fly ash using electrochemical noise (EN). Two types of reinforced concrete mixtures were manufactured; 100% Ordinary Portland Cement (OCP) and replacing 15% of cement using fly ash (OCPFA). The specimens were under-designed protected conditions (−1000 ≤ E ≤ −850 mV vs. Ag/AgCl) and cathodic overprotection (E < −1000 mV vs. Ag/AgCl) by impressed current, and specimens concrete were immersed in a 3.5 wt.% sodium chloride (NaCl) Solution. The analysis of electrochemical noise-time series showed that the mixtures microstructure influenced the corrosion process. Transients of uniform corrosion were observed in the specimens elaborated with (OPC), unlike those elaborated with (OPCFA). This phenomenon marked the difference in the concrete matrix’s hydration products, preventing Cl− ions flow and showing passive current and potential transients in most specimens.

SETTING A DIAGRAM APPROACH TO CALCULATING VIBRATED, CENTRIFUGED AND VIBROCENTRIFUGED REINFORCED CONCRETE COLUMNS WITH A VARIATROPIC STRUCTURE

2020 ◽  
pp. 22-34
Author(s):  
Л. Р. Маилян ◽  
С. А. Стельмах ◽  
Е. М. Щербань ◽  
М. П. Нажуев
Keyword(s):  
Experimental Data ◽  
Reinforced Concrete ◽  
Bearing Capacity ◽  
Cross Section ◽  
Concrete Columns ◽  
Reinforced Concrete Columns ◽  
The Cross ◽  
Concrete Elements ◽  
Diagram Approach

Состояние проблемы. Железобетонные элементы изготавливаются, как правило, по трем основным технологиям - вибрированием, центрифугированием и виброцентрифугированием. Однако все основные расчетные зависимости для определения их несущей способности выведены, исходя из основного постулата - постоянства и равенства характеристик бетона по сечению, что реализуется лишь в вибрированных колоннах. Результаты. В рамках диаграммного подхода предложены итерационный, приближенный и упрощенный способы расчета несущей способности железобетонных вибрированных, центрифугированных и виброцентрифугированных колонн. Выводы. Расчет по диаграммному подходу показал существенно более подходящую сходимость с опытными данными, чем расчет по методике норм, а также дал лучшие результаты при использовании дифференциальных характеристик бетона, чем при использовании интегральных и, тем более, нормативных характеристик бетона. Statement of the problem. Reinforced concrete elements are typically manufactured according to three basic technologies - vibration, centrifugation and vibrocentrifugation. However, all the basic calculated dependencies for determining their bearing capacity were derived using the main postulate, i.e., the constancy and equality of the characteristics of concrete over the cross section, which is implemented only in vibrated columns. Results. Within the framework of the diagrammatic approach, iterative, approximate and simplified methods of calculating the bearing capacity of reinforced concrete vibrated, centrifuged and vibrocentrifuged columns are proposed. Conclusions. The calculation according to the diagrammatic approach showed a significantly better convergence with the experimental data than that using the method of norms, and also performs better when using differential characteristics of concrete than when employing integral and particularly standard characteristics of concrete.

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