scholarly journals Methodology for Assessing the Probability of Corrosion in Concrete Structures on the Basis of Half-Cell Potential and Concrete Resistivity Measurements

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Lukasz Sadowski
Keyword(s):  
Reinforced Concrete ◽  
Concrete Slab ◽  
Electrochemical Techniques ◽  
Concrete Structures ◽  
Reinforced Concrete Structures ◽  
Half Cell ◽  
Reinforced Concrete Slab ◽  
Cell Potential ◽  
Potential Measurement ◽  
Concrete Resistivity

In recent years, the corrosion of steel reinforcement has become a major problem in the construction industry. Therefore, much attention has been given to developing methods of predicting the service life of reinforced concrete structures. The progress of corrosion cannot be visually assessed until a crack or a delamination appears. The corrosion process can be tracked using several electrochemical techniques. Most commonly the half-cell potential measurement technique is used for this purpose. However, it is generally accepted that it should be supplemented with other techniques. Hence, a methodology for assessing the probability of corrosion in concrete slabs by means of a combination of two methods, that is, the half-cell potential method and the concrete resistivity method, is proposed. An assessment of the probability of corrosion in reinforced concrete structures carried out using the proposed methodology is presented. 200 mm thick 750 mm  ×  750 mm reinforced concrete slab specimens were investigated. PotentialEcorrand concrete resistivityρin each point of the applied grid were measured. The experimental results indicate that the proposed methodology can be successfully used to assess the probability of corrosion in concrete structures.

Half-cell potential measurements—Potential mapping on reinforced concrete structures

2003 ◽  
Vol 36 (7) ◽  
pp. 461-471 ◽  
Author(s):  
B. Elsener ◽  
C. Andrade ◽  
J. Gulikers ◽  
R. Polder ◽  
M. Raupach
Keyword(s):  
Reinforced Concrete ◽  
Concrete Structures ◽  
Reinforced Concrete Structures ◽  
Half Cell ◽  
Cell Potential ◽  
Potential Mapping

scholarly journals APPLICATION OF ARTIFICIAL NEURAL NETWORKS FOR ASSESSING THE REINFORCEMENT OF REINFORCED-CONCRETE FLOOR SLABS

2019 ◽  
Author(s):  
A. Liashkevich
Keyword(s):  
Neural Networks ◽  
Artificial Neural Networks ◽  
Reinforced Concrete ◽  
Concrete Slab ◽  
Concrete Structures ◽  
Building Design ◽  
Reinforced Concrete Structures ◽  
Reinforced Concrete Slab ◽  
Artificial Neural

In this article the problem of assessment of working documentation quality in terms of trustworthiness of the calculation of area of main reinforcement of reinforced-concrete structures is reviewed. In spite of development of automated designing systems, no application solutions for fully automated check of quality of working documentation for reinforced-concrete structures as regards sufficiency and necessity of reinforcement of them have been proposed until now. Moreover, this rather routine procedure can be fully automated to exclude the subjective nature of its results. Artificial neural networks (ANN) constitute the most promising mathematical model for this purpose. There are known examples demonstrating the possibility of applying the ANN for various types of calculations and analysis of experimental data for reinforced-concrete structures. In particular, the ANN allows predicting the actual deformation parameters of reinforced-concrete structures with significantly greater accuracy than any of the current national design standards. The article presents the results of calculations of reinforcement and sag for various input parameters using the example of reinforced-concrete slab structure. Using the simplest ANN with one hidden layer over the entire training sample, the predicted values with sufficient accuracy for practical use were obtained. It has been established that ANN makes it possible to predict effectively not only values of the required reinforcement for slab structures, but also their deformation. Within the framework of BIM-technologies used currently in building design, the use of ANN to assess the quality of ready-made design documentation in terms of reinforcement will reduce considerably the cost and time of relevant examinations with significantly higher trustworthiness of their results.В статье рассмотрена задача оценки качества рабочей документации в части достоверности расчета площади рабочей арматуры железобетонных конструкций. Несмотря на развитие систем автоматизированного проектирования, до настоящего времени не предложено прикладных решений для полностью автоматизированной проверки качества рабочей документации железобетонных конструкций на предмет достаточности и необходимости их армирования. При этом эта весьма относительно рутинная процедура может быть полностью автоматизирована для исключения субъективного характера ее результатов. Наиболее перспективной математической моделью для этой цели являются искусственные нейронные сети (ИНС). Известны примеры, демонстрирующие возможность прикладного применения ИНС для различного рода расчетов и анализа экспериментальных данных для железобетонных конструкций. В частности, ИНС позволяет с существенно большей точностью прогнозировать фактические параметры деформирования железобетонных конструкций, чем любые из действующих национальных норм проектирования. В статье на примере железобетонной плитной конструкции приведены результаты расчетов армирования и прогиба при различных значениях входных параметров. С помощью простейшей ИНС с одним скрытым слоем по всей обучающей выборке получены прогнозные значения с достаточной для практического их использования точностью. Установлено, что ИНС позволяет достаточно эффективно прогнозировать не только значения требуемого армирования для плитных конструкций, но и их деформации. В рамках используемых в настоящее время в строительном проектировании BIM-технологий применение ИНС для оценки качества готовой проектной документации в части армирования позволит значительно сократить стоимость и сроки соответствующих экспертиз при существенно более высокой достоверности их результатов.

scholarly journals MODERN STEEL-CONCRETE SPAN STRUCTURES OF SMALL AND MEDIUM-SPAN BRIDGES

2021 ◽  
pp. 25-34
Author(s):  
Roman Kaplin
Keyword(s):  
Reinforced Concrete ◽  
Concrete Slab ◽  
Concrete Structures ◽  
Reinforced Concrete Structures ◽  
Automatic Welding ◽  
Reinforced Concrete Slab ◽  
Load Bearing ◽  
Metal Elements ◽  
Advantages And Disadvantages ◽  
Concrete Girder

The paper reviews the most common reinforced concrete girder structures of modern bridges used in Ukraine and other countries. The scope, advantages and disadvantages of reinforced concrete structures are considered. The peculiarities of the use of reinforced concrete structures in European countries are reviewed. The most common typical structural solutions of reinforced concrete girder structures used worldwide are given. Options for facilitation of reinforced concrete structures without significant loss of load-bearing capacity are also highlighted. Options for facilitation of structures are presented in the article by lightening the metal load-bearing elements and reducing the weight of the reinforced concrete slab of the carriageway. Reducing the weight of metal elements can be obtained through the use of perforated elements, which can be performed by waste-free technology. To reduce the cost of materials and reduce the weight of the reinforced concrete slab, it is designed lightweight – hollow or ribbed. When removing concrete from the stretched zone, only the ribs of the width required to accommodate the welded frames and ensure the strength of the panels on an inclined cross section are retained. In this case, the plate in the span between the ribs work on the bend as beams of T-section. The top shelf of the plate also works on the local bend between the ribs. During the inspection, the article presents a new design of reinforced concrete girder structure, using perforated box metal elements, made by waste-free technology, and lightweight reinforced concrete slab of the carriageway with hollow formers. Metal blocks are connected to each other by bolts. Metal blocks are made of perforated sheet elements made of waste-free technology. Each block consists of two main beams, transverse diaphragms and a lower plate. The upper belt of the main beams is implemented with the device of horizontal shelves along the entire length of the beams, performing the function of a supporting element for the reinforced concrete slab. Combining all structural elements into a single finished unit is carried out in the factory by automatic welding, which, in turn, allows us to achieve the high factory readiness. The diaphragms of the block are made with a comb along the upper border, on which a profiled steel sheet is placed, which is a fixed formwork for a reinforced concrete slab. The plate is made of non-removable formwork. To ensure the joint operation of the metal part and the reinforced concrete slab, a system of discrete-continuous connections in the form of rigid stops connected in the longitudinal and transverse directions by reinforcing rods is proposed.

Passive corrosion control and active corrosion prevention of the reinforced concrete structures by electrochemical chloride removal and inhibitors

2013 ◽  
Vol 61 (1) ◽  
pp. 32-37 ◽  
Author(s):  
Guofu Qiao ◽  
Yi Hong ◽  
Tiejun Liu ◽  
Jinping Ou
Keyword(s):  
Reinforced Concrete ◽  
Concrete Structures ◽  
Concrete Cover ◽  
Reinforced Concrete Structures ◽  
Reinforcing Steel ◽  
Corrosion Control ◽  
Cell Potential ◽  
Content Type ◽  
Chloride Removal ◽  
Active Corrosion

Purpose – The aim of this paper was to investigate the passive corrosion control and active corrosion protective effect of the reinforced concrete structures by electrochemical chloride removal (ECR) method and inhibitors approach, respectively. Design/methodology/approach – The concentration of aggressive chloride ion distributed from the reinforcing steel to the surface of the concrete cover was analyzed during the ECR processes. Besides, the half-cell potential, the concrete resistance R c , the polarization resistance R p and the capacitance of double layer C dl of the steel/concrete system were used to characterize the electrochemical performance of the concrete prisms. Findings – The effectiveness of ECR could be enhanced by increasing the amplitude of potential or prolonging the time. Inhibitor SBT-ZX(I) could successfully prevent the corrosion development of the reinforcing steel in concrete. Originality/value – The research provides the scientific basis for the practical application of ECR and inhibitors in the field.

scholarly journals Experimental and Empirical Time to Corrosion of Reinforced Concrete Structures under Different Curing Conditions

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Ahmed A. Abouhussien ◽  
Assem A. A. Hassan
Keyword(s):  
Reinforced Concrete ◽  
Corrosion Test ◽  
Concrete Structures ◽  
Reinforced Concrete Structures ◽  
Cell Potential ◽  
Accelerated Corrosion ◽  
Curing Conditions ◽  
Expected Time ◽  
Corrosion Initiation ◽  
Accelerated Corrosion Test

Reinforced concrete structures, especially those in marine environments, are commonly subjected to high concentrations of chlorides, which eventually leads to corrosion of the embedded reinforcing steel. The total time to corrosion of such structures may be divided into three stages: corrosion initiation, cracking, and damage periods. This paper evaluates, both empirically and experimentally, the expected time to corrosion of reinforced concrete structures. The tested reinforced concrete samples were subjected to ten alternative curing techniques, including hot, cold, and normal temperatures, prior to testing. The corrosion initiation, cracking, and damage periods in this investigation were experimentally monitored by an accelerated corrosion test performed on reinforced concrete samples. Alternatively, the corrosion initiation time for counterpart samples was empirically predicted using Fick’s second law of diffusion for comparison. The results showed that the corrosion initiation periods obtained experimentally were comparable to those obtained empirically. The corrosion initiation was found to occur at the first jump of the current measurement in the accelerated corrosion test which matched the half-cell potential reading of around −350 mV.

scholarly journals Long-Term Efficiency of Two Organic Corrosion Inhibitors for Reinforced Concrete

2010 ◽  
Vol 636-637 ◽  
pp. 1059-1064 ◽  
Author(s):  
E.V. Pereira ◽  
R.B. Figueira ◽  
Manuela M. Salta ◽  
I.T.E. Fonseca
Keyword(s):  
Reinforced Concrete ◽  
Environmental Conditions ◽  
Corrosion Inhibitors ◽  
Electrochemical Techniques ◽  
Concrete Structures ◽  
Concrete Slabs ◽  
Reinforced Concrete Structures ◽  
Reinforcement Corrosion ◽  
Organic Corrosion Inhibitors

In this paper the efficiency of two organic corrosion inhibitors, a migratory and an admixture inhibitor, was evaluated by electrochemical techniques in solutions simulating the interstitial electrolyte of concrete and on concrete slabs exposed to natural environmental conditions over a five-year period. From obtained results, the usefulness of the two products is discussed aiming its application in new structures to prevent chlorides induced corrosion and as a curative method for repairing reinforced concrete structures contaminated with chlorides and affected by reinforcement corrosion.

Ultrasonic C-Scan Imaging: Preliminary Evaluation for Corrosion and Void Detection in Posttensioned Tendons

2003 ◽  
Vol 1827 (1) ◽  
pp. 44-52 ◽  
Author(s):  
Shivprakash Iyer ◽  
Andrea J. Schokker ◽  
Sunil K. Sinha
Keyword(s):  
Reinforced Concrete ◽  
Concrete Structures ◽  
Corrosion Monitoring ◽  
Reinforced Concrete Structures ◽  
Preliminary Evaluation ◽  
Cell Potential ◽  
Impact Echo ◽  
Bridge Structures ◽  
Processing Techniques ◽  
User Friendly

Corrosion of the nation’s transportation infrastructure is a widespread and costly problem. The most prevalent durability issue in reinforced concrete structures is chloride-induced corrosion of the reinforcing steel. A reliable method of determining grout voids and corrosion levels in posttensioned bridge structures is needed. Traditional techniques of corrosion monitoring (e.g., half-cell potential and corrosion rate measurement) are problematic when used in this type of structure, as are standard nondestructive evaluation (NDE) methods, such as impact echo. C-scan imaging, an ultrasonic technique used primarily in the composites industry for detecting delamination, is examined as a method of evaluating grouted posttensioned tendons. This method exhibits many promising qualities: it can be used for internal or external tendons and on metal or plastic ducts; access to only one side of a specimen is required; strong imaging allows easy interpretation of results; the technique poses no risk to users or the environment; and the method has strong potential for development as a handheld field tool. The C-scan technique may be valuable for the investigation of not only posttensioning applications but other types of reinforced concrete structures as well. Results of preliminary investigations on lab specimens indicate that the C-scan technique holds promise. The ultimate goal of the research is to provide a user-friendly, robust system for the NDE of posttensioned tendons for voids, corrosion, and wire breaks. Recommendations for optimal acquisition and processing techniques as well as for the future development of the equipment as a field tool are proposed.

Analysis of half-cell potential measurement for corrosion of reinforced concrete

2004 ◽  
Vol 18 (3) ◽  
pp. 155-162 ◽  
Author(s):  
Veerachai Leelalerkiet ◽  
Je-Woon Kyung ◽  
Masayasu Ohtsu ◽  
Masaru Yokota
Keyword(s):  
Reinforced Concrete ◽  
Half Cell ◽  
Cell Potential ◽  
Potential Measurement
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