Reliability and long-term evaluation of GO-MnO2 nano material as a newer corrosion monitoring sensor for reinforced concrete structures

2019 ◽  
Vol 100 ◽  
pp. 74-84 ◽  
Author(s):  
Subbiah Karthick ◽  
Srinivasan Muralidharan ◽  
Han-Seung Lee ◽  
Seung-Jun Kwon ◽  
Velu Saraswathy
Keyword(s):  
Reinforced Concrete ◽  
Concrete Structures ◽  
Corrosion Monitoring ◽  
Reinforced Concrete Structures ◽  
Nano Material ◽  
Term Evaluation

Improvement Of Curvilinear Diagrams Of Concrete Deformation

2019 ◽  
pp. 99-104
Keyword(s):  
Reinforced Concrete ◽  
Peak Load ◽  
Experimental Studies ◽  
Concrete Structures ◽  
Deformation Model ◽  
Reinforced Concrete Structures ◽  
Significant Difference ◽  
Deformation Diagrams

Problems when calculating reinforced concrete structures based on the concrete deformation under compression diagram, which is presented both in Russian and foreign regulatory documents on the design of concrete and reinforced concrete structures are considered. The correctness of their compliance for all classes of concrete remains very approximate, especially a significant difference occurs when using Euronorm due to the different shape and sizes of the samples. At present, there are no methodical recommendations for determining the ultimate relative deformations of concrete under axial compression and the construction of curvilinear deformation diagrams, which leads to limited experimental data and, as a result, does not make it possible to enter more detailed ultimate strain values into domestic standards. The results of experimental studies to determine the ultimate relative deformations of concrete under compression for different classes of concrete, which allowed to make analytical dependences for the evaluation of the ultimate relative deformations and description of curvilinear deformation diagrams, are presented. The article discusses various options for using the deformation model to assess the stress-strain state of the structure, it is concluded that it is necessary to use not only the finite values of the ultimate deformations, but also their intermediate values. This requires reliable diagrams "s–e” for all classes of concrete. The difficulties of measuring deformations in concrete subjected to peak load, corresponding to the prismatic strength, as well as main cracks that appeared under conditions of long-term step loading are highlighted. Variants of more accurate measurements are proposed. Development and implementation of the new standard GOST "Concretes. Methods for determination of complete diagrams" on the basis of the developed method for obtaining complete diagrams of concrete deformation under compression for the evaluation of ultimate deformability of concrete under compression are necessary.

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.

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