scholarly journals Portable Measurement Systems Based on Microcontrollers to Test Durability of Structures: Mini-Review

2020 ◽  
Vol 6 ◽  
Author(s):  
Crhistian C. Segura ◽  
Johann F. Osma
Keyword(s):  
Reinforced Concrete ◽  
Visual Inspection ◽  
Low Cost ◽  
Electrochemical Techniques ◽  
Embedded Sensors ◽  
Reinforced Concrete Structures ◽  
Future Trends ◽  
Measurement Systems ◽  
Steel Bars ◽  
Electrochemical Devices

Corrosion presence is a recurrent concern in buildings and structures that use steel as their core or as reinforcement, due to the change of steel's properties caused by this phenomena. Therefore, methods to detect and quantify corrosion had been developed; some are based on electrical and electrochemical measurements. On reinforced concrete structures, sometimes there are exposed steel bars which are visible, but on those, a visual inspection could determine corrosion presence. There exist different options to measure the steel bars' corrosion and its level. The more straight forward consists of cutting through the concrete until the bar is exposed and connecting a measurement device there. A disadvantage of this technique is that steel has to be exposed to the environment during the measurement; as an alternative, novel contact-less electrochemical techniques are getting more popular. Recent advances in low-cost and portable electrochemical devices and embedded sensors can change how the structures are tested. Moreover, there is a discussion about how those devices, if developed for other fields as biosensors, can assist in other areas. This mini-review also gives some hints of what the future trends could be due to the combination of those areas.

scholarly journals Lumped damage mechanics as a diagnosis tool of reinforced concrete structures in service: case studies of a former bridge arch and a balcony slab

2021 ◽  
Vol 15 (58) ◽  
pp. 21-32
Author(s):  
Rafael Cunha ◽  
Camila Vieira ◽  
David Amorim
Keyword(s):  
Reinforced Concrete ◽  
Case Studies ◽  
Damage Mechanics ◽  
Low Cost ◽  
Concrete Structures ◽  
Structural Condition ◽  
Numerical Analyses ◽  
Engineering Practice ◽  
Reinforced Concrete Structures ◽  
Diagnosis Tool

Reinforced concrete structures may need repair in order to ensure the designed durability. Such necessity vary in cause and effect, but the structural diagnosis serves as the basis for adopting intervention measures. The assessment of the structural condition usually is made in loco, but sometimes numerical analyses are required as a low cost and effective preliminary diagnosis. In general, numerical analyses use hundreds or thousands of finite elements and nonlinear theories that are not often used in engineering practice. As an alternative, lumped damage mechanics (LDM) uses key concepts of classic fracture and damage mechanics in plastic hinges throughout well-known quantities such as ultimate moment and cracking moment. Such theory describes the concrete cracking by a damage variable, which can be used as a diagnosis criterion. Therefore, this paper presents LDM as a diagnosis tool to analyse actual structures. The case studies presented in this paper are a former bridge arch tested in China and a balcony that collapsed in Brazil. The results show that LDM numerical response of those structures are quite close to laboratory observations (former bridge arch) and in loco measurements (balcony).

Nonlinear Analysis of Bearing Capacity of Reinforced Concrete Structures Using Strip Method

2013 ◽  
Vol 470 ◽  
pp. 921-924
Author(s):  
Hai Chao Tan
Keyword(s):  
Reinforced Concrete ◽  
Bearing Capacity ◽  
Nonlinear Analysis ◽  
Rectangular Cross Section ◽  
Concrete Structures ◽  
Reinforced Concrete Structures ◽  
Strip Method ◽  
Basic Assumptions ◽  
Steel Bars ◽  
Fortran Language

As the progress of theory and computer technology, nonlinear analysis is widely applied in civil engineering. Strip method, as one of the numerical methods, is used widely especially in the analysis of beams, columns and shell structures. The first half of this paper introduces the theoretical model and the basic assumptions of the strip method; the latter half of this paper compiles the strip method into computer program using FORTRAN language. At last, using beams with rectangular cross-section of reinforced concrete structures as an example, the paper analyze the factors, such as the strength of the steel bars, which have an impact on the bearing capacity of reinforced concrete structures.

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.

scholarly journals Non-Invasive Electrochemical Biosensors Operating in Human Physiological Fluids

Sensors ◽  
2020 ◽  
Vol 20 (21) ◽  
pp. 6352 ◽  
Author(s):  
Magnus Falk ◽  
Carolin Psotta ◽  
Stefan Cirovic ◽  
Sergey Shleev
Keyword(s):  
Cyclic Voltammetry ◽  
Impedance Spectroscopy ◽  
Low Cost ◽  
Electrochemical Techniques ◽  
Electrochemical Biosensors ◽  
Self Monitoring ◽  
Non Invasive ◽  
Electrochemical Devices ◽  
Healthcare Technologies ◽  
Exciting Area

Non-invasive healthcare technologies are an important part of research and development nowadays due to the low cost and convenience offered to both healthcare receivers and providers. This work overviews the recent advances in the field of non-invasive electrochemical biosensors operating in secreted human physiological fluids, viz. tears, sweat, saliva, and urine. Described electrochemical devices are based on different electrochemical techniques, viz. amperometry, coulometry, cyclic voltammetry, and impedance spectroscopy. Challenges that confront researchers in this exciting area and key requirements for biodevices are discussed. It is concluded that the field of non-invasive sensing of biomarkers in bodily fluid is highly convoluted. Nonetheless, if the drawbacks are appropriately addressed, and the pitfalls are adroitly circumvented, the approach will most certainly disrupt current clinical and self-monitoring practices.

Corrosion Assessment and Control Techniques for Reinforced Concrete Structures

2020 ◽  
pp. 226-259
Author(s):  
Md Daniyal ◽  
Sabih Akhtar
Keyword(s):  
Reinforced Concrete ◽  
Electrochemical Techniques ◽  
Substantial Reduction ◽  
Concrete Structures ◽  
Steel Corrosion ◽  
Reinforced Concrete Structures ◽  
Steel Reinforced Concrete ◽  
Inspection Systems ◽  
Critical Requirement ◽  
Corrosion Of Steel

The steel reinforced concrete structures perform well in various environmental conditions, but structures may undergo premature damage in aggressive environments such as marine or acidic, primarily due to steel corrosion, and substantial reduction in service life occurs. This also causes huge economical loss and create safety and environmental problems. The repair and maintenance of steel reinforced concrete structures for their safety needs effective monitoring and inspection systems for evaluating the corrosion condition of steel. Since the corrosion of steel reinforcement occurs through electrochemical reactions, electrochemical methods are suitable to study the corrosion processes. In this chapter, some commonly used electrochemical techniques have been comprehensively explained. In addition, there is a critical requirement to develop effective and long-lasting techniques to control the corrosion of steel. Hence, some of the commonly used corrosion control methods have been comprehensively described in this chapter.

Magnetic variation in construction steels under tensile stress. Empirical research with Helmholtz coils

2021 ◽  
Vol 71 (341) ◽  
pp. e243
Author(s):  
D. Ferrández ◽  
C. Morón ◽  
P. Saiz ◽  
A. Morón
Keyword(s):  
Reinforced Concrete ◽  
Electromotive Force ◽  
Concrete Structures ◽  
Tensile Tests ◽  
Reinforced Concrete Structures ◽  
Secondary Circuit ◽  
Helmholtz Coils ◽  
Steel Bars ◽  
Magnetic Variation ◽  
The Magnetic Field

Steel is responsible for providing resistance to flexotraction to reinforced concrete structures. Steel is responsible for providing reinforced concrete structures with a flexural strength. For this reason, it is important to study its behaviour under different tensile states. This study used measuring equipment that was able to determine variations in magnetic properties of B500-SD steel bars during standard tensile tests. The magnetic field generated by a Helmholtz coil was collected through a secondary circuit. This enables the induced electromotive force to relate with the steel deflection stages when subjected to the tests. Moreover, it was possible to determine the variation of magnetic permeability when submitting 12mm and 16mm diameter bars to different tensile states. This method could prove extremely useful in determining the tensile state of ribbed steel bars that are embedded into the concrete structure.

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