Integrated system for corrosion monitoring of reinforced concrete structures * *The manuscript of this chapter was submitted originally for the EUROCORR 2001 andrepresents the state of knowledge and development in early 2001. Scientific and technologicalprogress since then has led to improved solutions

2007 ◽  
pp. 146-158
Author(s):  
U. Schneck ◽  
T. Winkler ◽  
S. Mucke
Keyword(s):  
Reinforced Concrete ◽  
Concrete Structures ◽  
The State ◽  
Integrated System ◽  
Corrosion Monitoring ◽  
Reinforced Concrete Structures

Advanced Active Prestressed CFRP in RCC Structures

2015 ◽  
Vol 1129 ◽  
pp. 290-297
Author(s):  
Gopal L. Rai
Keyword(s):  
Reinforced Concrete ◽  
High Efficiency ◽  
Concrete Structures ◽  
Load Condition ◽  
Integrated System ◽  
Fatigue Properties ◽  
Reinforced Concrete Structures ◽  
Practical Applications ◽  
Cfrp Laminates ◽  
Reinforced Polymer

. The need for rehabilitation of reinforced concrete structures is rapidly increasing. Fibre reinforced polymer (FRP) composite materials for concrete structures have high strength-to-weight ratios that can provide high prestressing forces while adding minimal additional weight to a structure. They also have good fatigue properties and exhibit low relaxation losses, both of which can increase the service lives and the load carrying capacities of reinforced concrete structures. Carbon fiber reinforced polymer (CFRP) composite system is integrated system based on carbon fibres and epoxy resins. By prestressing the CFRP laminates, the material is used more efficiently as a part of its tensile capacity is utilised and it contributes to the load bearing capacity under both service and ultimate load condition. This is an ideal technique as it combines the advantage of using noncorrosive and lightweight advanced composite material in the form of FRP laminates with high efficiency offered by external prestressing. An innovative mechanical anchorage system was developed to prestress the FRP laminates directly by jacking and reacting against the RCC structure.This paper describes the use of Prestressed CFRP laminates for strengthening of RCC structures including practical applications on slabs and bridges. Also it elucidates the post strengthening testing carried out for the validation of this technique.

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.

INFLUENCE OF CONCRETE COMPOSITION ON THE CORROSIVE STATE OF THE STEEL ARMATURES AND DURABILITY OF REINFORCED CONCRETE STRUCTURES

2019 ◽  
pp. 33-39
Author(s):  
Petro Koval ◽  
Vladimir Zelenovskiy
Keyword(s):  
Reinforced Concrete ◽  
Concrete Structures ◽  
The State ◽  
Test Method ◽  
Design Stage ◽  
Reinforced Concrete Structures ◽  
Building Structures ◽  
Reinforcing Steel ◽  
Concrete Composition ◽  
Corrosion State

The influence of the composition of the concrete mixture on the state of reinforcing steel as the main problem of corrosion of reinforced concrete structures is considered. The main attention is paid to the need for individual and mandatory consideration of the influence of the properties of additives to concrete on the passivation of reinforcing steel. The purpose of conducting studies to determine the effect of concrete composition on the state of reinforcing steel is to analyze the causes of corrosion of reinforcement, determine the influence of the environment, apply appropriate prevention of this phenomenon and use methods to determine the corrosion state at the design stage of building structures for which reinforced concrete is used. The composition of concrete, in addition to the standard set in various quantitative combinations (cement, gravel, sand, water) today it is advisable to use special additives. Due to their correct and proportional application, you can create a mixture with significantly improved characteristics: with increased frost resistance, strength, durability, with accelerated or delayed setting of the mixture, etc. Nevertheless, you should not forget that the individuality of the composition of additives could affect the ability of concrete to passivate reinforcing steel. It is possible to eliminate the possibility of reducing the passivation of concrete by testing reinforced concrete samples for its protective properties in relation to the reinforcement. The test method is based on the passivation of reinforcing steel in an alkaline environment and consists in evaluating the protective effect of a sample of concrete in relation to a sample of steel reinforcement by comparing data obtained with a change in potential depending on changes in the density of electric current passing through the sample. The issue of quality and durability of reinforced concrete structures, both technically and economically, is attracting increasing attention of builders. It is obvious that in most cases an increase in the initial cost of manufacturing the structure and its reliable protection is economically justified, if this allows reducing the number and cost of repairs during operation. Keywords: reinforcement, corrosion, concrete, reinforced concrete, concrete additive, concrete composition, corrosion state of reinforcement, durability of reinforced concrete structures.

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