scholarly journals ENSAIOS NÃO DESTRUTIVOS PARA AVALIAÇÃO DA RIGIDEZ EM ELEMENTOS DE CONCRETO ARMADO / NON-DESTRUCTIVE TESTS FOR ASSESSING STIFFNESS IN REINFORCED CONCRETE ELEMENTS

2021 ◽  
Vol 7 (2) ◽  
pp. 20009-20018
Author(s):  
Felipe Borges Fonseca ◽  
Horácio Ferreira Dias Gonçalves ◽  
Claudete Oliveira Kenvyn ◽  
Cristian Cley Paterniani Rita ◽  
Wendell de Queiróz Lamas ◽  
...  
Keyword(s):  
Reinforced Concrete ◽  
Concrete Elements ◽  
Non Destructive

scholarly journals Analyzing of Coatings on Steel - Reinforced Concrete Elements by Mobile NMR

2016 ◽  
Vol 62 (1) ◽  
pp. 65-82 ◽  
Author(s):  
J. Orlowsky
Keyword(s):  
Reinforced Concrete ◽  
Potential Effect ◽  
Building Site ◽  
Steel Reinforced Concrete ◽  
Mobile Nmr ◽  
The Individual ◽  
First Time ◽  
Concrete Elements ◽  
Non Destructive

Abstract A large number of infrastructural concrete buildings are protected against aggressive environments by coating systems. The functionality of these coating systems is mainly affected by the composition and thickness of the individual polymeric layers. For the first time ever, a mobile nuclear magnetic resonance (NMR) sensor allows a non-destructive determination of these important parameters on the building site. However, before this technique can be used on steel-reinforced concrete elements, the potential effect of the reinforcement on the measurement, i.e. the NMR signal, needs to be studied. The results show a shift of the NMR profile as well as an increase of the signals amplitude in the case of the reinforced samples, while calculating the thickness of concrete coating leading to identical results.

scholarly journals Electrochemical Diagnostics of Sprayed Fiber-Reinforced Concrete Corrosion

2019 ◽  
Vol 9 (18) ◽  
pp. 3763 ◽  
Author(s):  
Wioletta Raczkiewicz ◽  
Paweł Grzegorz Kossakowski
Keyword(s):  
Reinforced Concrete ◽  
Pulse Method ◽  
Fiber Reinforced Concrete ◽  
Steel Fibers ◽  
Reinforcement Corrosion ◽  
Fiber Reinforced ◽  
Steel Fiber Reinforced Concrete ◽  
Differences Of Opinion ◽  
Concrete Elements ◽  
Non Destructive

Sprayed fiber-reinforced concrete is used in construction for the execution and repair of reinforced concrete elements. It is believed that the addition of steel fibers is most effective, due to their parameters and low costs. Some researchers, however, suggest that the addition of steel fibers can contribute to the initiation of corrosion of the main reinforcement. In consideration of the differences of opinion on the corrosion resistance of sprayed fiber-reinforced concrete, it has become necessary to analyze this issue. The article presents comparative studies of corrosion assessments of the main reinforcement in specimens made of ordinary concrete and concrete with steel fibers. The tests were performed using a semi non-destructive galvanostatic pulse method, which allows location of the areas of corrosion and estimation of the reinforcement corrosion activity. In order to initiate the corrosion processes the specimens were subjected to freezing cycles in NaCl solution. In addition, the shrinkage and compressive strength of specimens were measured, and the observation of specimen structure under a scanning microscope was performed. It was found that galvanostatic pulse method allowed estimation of the reinforcement corrosion progress. The corrosion of the main reinforcement in steel fiber reinforced concrete specimens was less advanced than in the specimens without fibers.

scholarly journals COMPARISON OF CONCRETE COMPRESSIVE STRENGTH VALUES OBTAINED USING REBOUND HAMMER AND DRILLED CORE SPECIMENS

2015 ◽  
Author(s):  
Raimondas SADZEVICIUS ◽  
Tatjana SANKAUSKIENE ◽  
Petras MILIUS
Keyword(s):  
Reinforced Concrete ◽  
Concrete Strength ◽  
Hydraulic Structures ◽  
Test Results ◽  
Concrete Compressive Strength ◽  
Main Attention ◽  
Concrete Core ◽  
Rebound Hammer ◽  
Concrete Elements ◽  
Non Destructive

Durability of reinforced concrete structures depends on the maintenance conditions, surveillance, and well-timed repair of structures or reconstructions. Usually, the main attention falls on the durability determination based on the evaluation of change of main physical –mechanical properties, especially, on the compression strength of concrete. In this study, tests with the rebound hammer and concrete cores extracted from the existing reinforced concrete elements in hydraulic structures are presented. The comparison of strength values obtained with the rebound hammer and the concrete core specimens of reinforced concrete in hydraulic structures is carried out. The research was performed during the scientific expedition in the period of 2010–2014. The investigated objects are allocated in hydroschemes of Druskininkai, Marijampolė, Klaipėda districts. It was established that the results obtained using the non-destructive method were by 17 % higher than the ones obtained by performing the destructive test. However, it can be said that despite this fact, the non-destructive method offers simplicity and rapidity in use: test results are readily available on site and there is a possibility to test concrete strength of those structures where cores cannot be drilled due to thin-walled or densely reinforced structures.

scholarly journals Effect of Concrete Addition of Selected Micro-fibers on the Reinforcing Bars Corrosion in the Reinforced Concrete Specimens

2016 ◽  
Vol 16 (3) ◽  
pp. 38-46 ◽  
Author(s):  
W. Raczkiewicz
Keyword(s):  
Reinforced Concrete ◽  
Electrochemical Corrosion ◽  
Pulse Method ◽  
Concrete Cover ◽  
Reinforcement Corrosion ◽  
Reinforcing Bars ◽  
Freezing And Thawing ◽  
Protective Properties ◽  
Concrete Elements ◽  
Non Destructive

Abstract The micro-fibers increase the consistency and uniformity of concrete, which can improve the protective properties of concrete cover and thus should reduce the corrosion of the reinforcement bars in the reinforced concrete elements. The article presents a study which main objective was to specify the effect on concrete mix the addition of steel or polypropylene micro-reinforcement fibers on the reinforcing bars corrosion process. The research included measuring the reinforcement corrosion progress caused by the chloride impact as well as cyclical freezing and thawing specimens test. To measure the electrochemical corrosion progress the non-destructive i.e. galvanostatic pulse method was used. The results were used to conduct a comparative analysis.

Using Non-Destructive Methods for the Characterization of Concrete in Aggressive Environments

2015 ◽  
Vol 15 ◽  
pp. 62-70
Author(s):  
Khial Nassima ◽  
Rachid Mehaddene
Keyword(s):  
Reinforced Concrete ◽  
Financial Impact ◽  
Cement Matrix ◽  
Ion Concentrations ◽  
Time Required ◽  
Concrete Elements ◽  
Non Destructive ◽  
Destructive Methods

The durability of reinforced concrete structures is reduced by the chloride penetration and susceptibility of the reinforcement to chloride induced corrosion which is considered a critical physic-chemical case. As the financial impact of the phenomena is very important, it seems essential to determine it influence on strength of reinforced concrete elements subjected to aggressive environnement such us the presence of chlorides when exposed to marine environnement. As such, the determination of the ion concentrations of chlorides profile within the cement matrix is of major importance, it tool to estimate the time required by the chlorides to reach the reinforcements in sufficient quantity to depassivate the steel.

scholarly journals ASSESSMENT OF THE CURRENT STATE OF THE CONCRETE STRUCTURE OF THE TRIBUNE

2020 ◽  
Vol 12 (2) ◽  
pp. 72-76
Author(s):  
MIROSLAV BRODŇAN ◽  
PETER KOTEŠ
Keyword(s):  
Reinforced Concrete ◽  
Concrete Structure ◽  
Reinforced Concrete Structure ◽  
Complex State ◽  
Load Bearing ◽  
Current State ◽  
Concrete Elements ◽  
Non Destructive ◽  
Destructive Methods

The paper is focused on diagnostics of reinforced concrete structure of the tribune of Závodisko Bratislava. The structure was realized by a combination of monolithic and prefabricated concrete elements as well as steel load-bearing elements. The complex state of the rough construction was evaluated, including the verification survey of the foundation of the construction. Non-destructive and destructive methods were used. Based on the results of the diagnostics and recalculation, it was decided to further progress the finish of the tribune.

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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