scholarly journals Diagnostics of Concrete and Steel in Elements of an Historic Reinforced Concrete Structure

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 306
Author(s):  
Paweł Tworzewski ◽  
Wioletta Raczkiewicz ◽  
Przemysław Czapik ◽  
Justyna Tworzewska
Keyword(s):  
Reinforced Concrete ◽  
Detection System ◽  
Thickness Distribution ◽  
Pulse Method ◽  
Test Methods ◽  
Concrete Cover ◽  
Reinforced Concrete Structure ◽  
Corrosion Risk ◽  
Cover Thickness ◽  
Non Destructive

Existing buildings, especially historical buildings, require periodic or situational diagnostic tests. If a building is in use, advanced non-destructive or semi-destructive methods should be used. In the diagnosis of reinforced concrete structures, tests allowing to assess the condition of the reinforcement and concrete cover are particularly important. The article presents non-destructive and semi-destructive research methods that are used for such tests, as well as the results of tests performed for selected elements of a historic water tower structure. The assessment of the corrosion risk of the reinforcement was carried out with the use of a semi-destructive galvanostatic pulse method. The protective properties of the concrete cover were checked by the carbonation test and the phase analysis of the concrete. X-ray diffractometry and thermal analysis methods were used for this. In order to determine the position of the reinforcement and to estimate the concrete cover thickness distribution, a ferromagnetic detection system was used. The comprehensive application of several test methods allowed mutual verification of the results and the drawing of reliable conclusions. The results indicated a very poor state of the reinforcement, loss in the depth of cover and sulphate corrosion.

scholarly journals Condition assessment of selected reinforced concrete structural elements of the bus station in Kielce

2019 ◽  
Vol 284 ◽  
pp. 06007
Author(s):  
Paweł Tworzewski ◽  
Wioletta Raczkiewicz ◽  
Wioletta Grzmil ◽  
Przemysław Czapik
Keyword(s):  
Detection System ◽  
Thickness Distribution ◽  
Concrete Cover ◽  
Composition Analysis ◽  
Reinforcing Bars ◽  
X Ray Diffraction ◽  
Phenolphthalein Solution ◽  
Corrosion Risk ◽  
Cover Thickness ◽  
Non Destructive

The paper presents the results of the research aimed at assessing the condition of reinforcement and concrete cover in selected elements of the structure of the most recognizable structure in Kielce, i.e. PKS station, located at Czarnowska Street. Currently, demolition works are underway resulting from the planned modernization. The assessment of the corrosion risk of the reinforcement in the construction elements was carried out with the use of a semi-non-destructive electrochemical method. The use of this method made it possible to determine the probability of reinforcement corrosion in the selected areas and to estimate its rate. The protective properties of concrete cover were checked by the carbonation test (test using a 1% phenolphthalein solution) and phase composition analysis (X-ray diffraction analysis). In order to determine the position of the reinforcing bars and to estimate the concrete cover thickness distribution in the areas corresponding to the aforementioned measurements, ferromagnetic detection system was used.

MODELING THE PROCESS OF INSPECTION OF REINFORCED CONCRETE SUPPORTS OF TECHNOLOGICAL OVERPASSES

2021 ◽  
Vol 14 (1) ◽  
pp. 68-73
Author(s):  
N Rogov ◽  
S. Nikolenko ◽  
Svetlana Sazonova
Keyword(s):  
Reinforced Concrete ◽  
Concrete Strength ◽  
Technical Condition ◽  
Concrete Cover ◽  
Magnetic Method ◽  
Strength Of Materials ◽  
Elastic Rebound ◽  
Cover Thickness ◽  
Non Destructive

The paper presents the process of assessing the technical condition of reinforced concrete supports of existing technological overpasses. The characteristics of overpasses are given. Defects identified in the process of assessing the technical condition are shown. The paper describes the control of concrete strength by the non-destructive method of elastic rebound using the Digi Shmidt 2000 device and the determination of the concrete cover thickness and the location of reinforcement by the magnetic method using the Profometer-5S device. The layout of the working reinforcement in the reinforced concrete supports of the overpass section has been determined. The results of verification calculations of the structures of technological ramps are given, taking into account the revealed defects and damages, the strength of materials and the specified actual loads. Proposals are given for improving the performance of concrete of reinforced concrete supports of overpasses.

scholarly journals Manufacturing Errors of Concrete Cover as a Reason of Reinforcement Corrosion in a Precast Element—Case Study

Coatings ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 702 ◽  
Author(s):  
Kamil Bacharz ◽  
Wioletta Raczkiewicz ◽  
Magdalena Bacharz ◽  
Wioletta Grzmil
Keyword(s):  
Protective Coatings ◽  
Pulse Method ◽  
Technical Condition ◽  
Concrete Cover ◽  
Reinforcement Corrosion ◽  
Manufacturing Errors ◽  
Precast Elements ◽  
Cover Thickness ◽  
Reinforcement Distribution ◽  
Non Destructive

The article concerns the assessment of technical condition of the precast loggia wall in a large panel building after 25 years of use as well as the cause of its damage. As a result of the study, cracks and losses of the concrete cover were found. Corrosion products were visible on exposed reinforcing rods. The reinforcement distribution and concrete cover thickness in loggia wall were estimated using a rebar detector. The corrosion assessment of reinforcement was performed using a semi non-destructive galvanostatic pulse method that allows the location of areas of corrosion and estimate the reinforcement corrosion activity. The phase composition of the concrete cover was analyzed. The test results showed an insufficient thickness of the concrete cover as the main cause of loggia wall damage. The research indicated that manufacturing errors made in the prefabrication plants affect the technical condition of precast elements and may lead to the damage of the structure well before the expected of its service life. In the case of manufacturing errors causing the implementation of an element with a concrete cover that does not meet the standard requirements for thickness and tightness, it is recommended to use protective coatings to increase the element’s durability to the designed level.

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.

scholarly journals Using the galvanostatic pulse method to estimate the corrosion of reinforcement in structural elements

2021 ◽  
Vol 2 (3) ◽  
pp. 4865-4876
Author(s):  
Wioletta Raczkiewicz ◽  
Artur Wójcicki ◽  
Adam Wójcicki
Keyword(s):  
Reinforced Concrete ◽  
Complex Analysis ◽  
Pulse Method ◽  
Diagnostic Methods ◽  
Risk Level ◽  
Reinforcement Corrosion ◽  
Stationary Potential ◽  
Steel Bars ◽  
Corrosion Risk ◽  
Non Destructive

ABSTRACT Early steel bars corrosion in reinforced concrete elements is difficult to detect because of the lack of visible changes on the concrete surface. To assess reinforcement corrosion risk level without structure damage some non-destructive diagnostic methods are applied. One of them is the galvanostatic pulse method. This semi-non-destructive electrochemical method allows to determine the corrosion areas and estimate the steel bars corrosion activity. Using this method it is possible to measure some electrical parameters (corrosion current density, stationary potential and reinforcement concrete cover resistivity) that allow to indirectly estimate the reinforcement corrosion progress in concrete. So far this method has been generally applied to bridges. The article presents results of studies in which the galvanostatic pulse method was used to determine reinforcement corrosion risk in structures elements different than bridges. Two types of reinforced concrete columns were tested under different environment conditions and two groups of laboratory specimens which were subjected to freezing and thawing cycles in NaCl solution or stayed in natural air–dry conditions. The apparatus GP-5000 GalvaPulseTM was used. Based on the obtained results the conclusions were drawn. The galvanostatic pulse method allows to assess the progress of the reinforcement corrosion process in tested elements. However, it is necessary to measure simultaneously all parameters and make their complex analysis.   RESUMEN La corrosión temprana de las barras de acero en elementos de hormigón armado es difícil de detectar debido a la falta de cambios visibles en la superficie del hormigón. Para evaluar el nivel de riesgo de corrosión de la armadura sin dañar la estructura se aplican algunos métodos de diagnóstico no destructivos. Uno de ellos es el método del pulso galvanostático. Este método electroquímico semi no destructivo permite determinar las áreas de corrosión y estimar la actividad de corrosión de las barras de acero. Utilizando este método es posible medir algunos parámetros eléctricos (densidad de corriente de corrosión, potencial estacionario y resistividad de la cubierta del hormigón de la armadura) que permiten estimar indirectamente el progreso de la corrosión de la armadura en el hormigón. Hasta ahora este método se ha aplicado generalmente a los puentes. El artículo presenta los resultados de estudios en los que se utilizó el método de impulsos galvanostáticos para determinar el riesgo de corrosión de las armaduras en elementos de estructuras diferentes a los puentes. Se ensayaron dos tipos de columnas de hormigón armado en diferentes condiciones ambientales y dos grupos de probetas de laboratorio que se sometieron a ciclos de congelación y descongelación en solución de NaCl o permanecieron en condiciones naturales de secado al aire. Se utilizó el aparato GP-5000 GalvaPulseTM. A partir de los resultados obtenidos se extrajeron las siguientes conclusiones El método de impulsos galvanostáticos permite evaluar el progreso del proceso de corrosión de la armadura en los elementos ensayados. Sin embargo, es necesario medir simultáneamente todos los parámetros y realizar su complejo análisis.

Assessment of the aftertreatment quality of concrete

2021 ◽  
Author(s):  
Lisa Ptacek ◽  
Alfred Strauss ◽  
Clémence Bos ◽  
Martin Peyerl
Keyword(s):  
Reinforced Concrete ◽  
Concrete Structure ◽  
Test Methods ◽  
Reinforced Concrete Structure ◽  
Process Step ◽  
Simple Tool ◽  
Lack Of Control ◽  
Complex Construction

<p>The curing of concrete is extremely important for the durability of a reinforced concrete structure. In practice, due to the complex construction processes, the very limited phases and the lack of control, aftertreatment is often neglected by executing companies. Hence infrastructure operators are therefore very interested in having a robust, simple tool that enables aftertreatment to be easily checked and, as a result, to convey the importance of this process step to the client. In the project presented here, classic and novel test methods are presented and discussed, as well as their suitability for the detection of the aftertreatment quality on laboratory samples and subsequently on some real structures.</p>

scholarly journals Experimental Study on Bond Performance and Damage Detection of Corroded Reinforced Concrete Specimens

2020 ◽  
Vol 2020 ◽  
pp. 1-15
Author(s):  
Yubin Tian ◽  
Junran Liu ◽  
Hengheng Xiao ◽  
Yi Zhang ◽  
Qingcheng Mo ◽  
...  
Keyword(s):  
Reinforced Concrete ◽  
Nonlinear Coefficient ◽  
Concrete Cover ◽  
Empirical Formulas ◽  
Accelerated Corrosion ◽  
Bond Slip ◽  
Passivation Film ◽  
Bond Performance ◽  
Damage Degree ◽  
Cover Thickness

This paper presents the results of an experimental research designed to investigate the combined effects of corrosion rate, concrete cover thickness, and stirrup spacing on the bond performance between reinforcement and concrete of reinforced concrete (RC) specimens. The RC specimens were immersed into sodium chloride solution to eliminate the passivation film on reinforcement. Then, an accelerated corrosion method was applied to corrode reinforcement embedded in concrete specimens. Pullout test was carried out to establish empirical formulas for ultimate slip and ultimate bond strength of RC specimens with three different corrosion rates, different concrete cover thicknesses, and different stirrup spacings. In addition, the bond-slip relation model was developed to predict and evaluate the bond performance of RC specimens. Finally, the ultrasonic technology was used to detect the damage of RC specimens, and the corresponding nonlinear coefficient β was proposed to characterize the damage degree of RC specimens. The susceptibility of β on the damage of specimens was compared with that of ultrasonic velocity, indicating β was more appropriate to evaluate the damage of RC specimens.

Analysis on Fire Resistance of Reinforced Concrete Beams Base on the Failure Probability

2010 ◽  
Vol 452-453 ◽  
pp. 197-200 ◽  
Author(s):  
Zhen Qing Wang ◽  
Zhi Cheng Xue ◽  
Mu Qiao
Keyword(s):  
Reinforced Concrete ◽  
High Temperature ◽  
Fire Resistance ◽  
Failure Probability ◽  
Reliability Index ◽  
Concrete Beams ◽  
Reinforced Concrete Beam ◽  
Concrete Cover ◽  
Reinforced Concrete Beams ◽  
Cover Thickness

For the mechanical properties of reinforced concrete under high temperature with large deterioration, the reliability of reinforced concrete beams have been largely discounted. A calculation of fire resistance based on failure probability is given by this paper. Reinforced concrete beam is usually working with cracks. Since each section with cracks has possibility of destruction, the reliability of the beam is calculated by the minimum value of n crack-sections’ resistance. The plastic zone resistance of concrete under high temperature is considered in this paper. A simple and feasible time-variant model of the resistance of reinforced concrete beams under fire and a reliability index analysis method of reinforced concrete beams under fire has been given. The action of ISO834 temperature rising curve on the reliability index of different specifications of concrete beams at different time is analyzed. The action of main parameters on the reliability index changes with time is shown. The fire resistance considers the failure probability is given. The results show that increase the reinforcement ratio and concrete cover thickness appropriately are effective measures to improve the fire resistance limit of reinforced concrete beams.

scholarly journals The Investigation of The Different Types of the Ground Rebar Spacers with Proposing New Design Rebar Space Mixed of Concrete Palstic

2020 ◽  
Vol 1 (1) ◽  
pp. 01-06
Author(s):  
Sevar Neamat ◽  
Mahmood Shamsborhan
Keyword(s):  
Reinforced Concrete ◽  
Concrete Structure ◽  
Plastic Material ◽  
Vital Role ◽  
Concrete Cover ◽  
Cementitious Material ◽  
Advantages And Disadvantages ◽  
Different Types ◽  
Review Study ◽  
Cover Thickness

The reinforcing spacers are commonly prepared from cementitious material, plastic or metals. These spacers are prepared to provide the reinforcing steel with ensuring that the requested concrete cover thickness is attained to guard surrounded steel from corrosion. Also, they pretend a vital role in the concrete structure performance. The toughness of reinforced concrete buildings remains extremely reliant on the features of the protection of concrete to be strong with thickness. A disappointment in finding cover thickness is considered the main impact on early deterioration within the steel, whichever in chance is a chief weaken method in reinforced concrete constructions. The specified study offerings a review study on the investigation of the advantages and disadvantages of six factors in various types concerning the ground rebar spacers studies. As a result, different types of ground rebar spacers have been compared and the new rebar spacer has been designed mixed of concrete_ plastic material

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