Crack depth determination at large concrete structures using scanning impact-echo-techniques

2015 ◽  
pp. 977-980 ◽  
Keyword(s):  
Crack Depth ◽  
Concrete Structures ◽  
Impact Echo ◽  
Depth Determination

Crack-Depth Determination by a Neural Network with a Synthetic Training Data Set

1993 ◽  
pp. 803-810 ◽  
Author(s):  
M. Takadoya ◽  
M. Notake ◽  
M. Kitahara ◽  
J. D. Achenbach ◽  
Q. C. Guo ◽  
...  
Keyword(s):  
Neural Network ◽  
Crack Depth ◽  
Training Data ◽  
Data Set ◽  
Depth Determination ◽  
Synthetic Training Data

Development of Imaging Technique for Evaluating the RC Plate Containing Epoxy-Repaired Delamination

2006 ◽  
Vol 321-323 ◽  
pp. 348-351 ◽  
Author(s):  
Chia Chi Cheng ◽  
Kuang Chih Pei ◽  
Jiunn Hong Wu
Keyword(s):  
Transfer Functions ◽  
Imaging Technique ◽  
Crack Depth ◽  
Spectral Image ◽  
Impact Echo ◽  
Amplitude Spectra ◽  
Before And After ◽  
Force Time ◽  
The Impact ◽  
Crack Widths

The paper introduces a newly developed imaging technique for evaluating the integrity of concrete structures. The image of normalized amplitude spectra is obtained from B-scan of impact-echo tests. The normalizing process was carried out by obtaining the simulated transfer functions, in which the displacement of R-wave waveform of the impact-echo response multiplying a correcting factor is used as the simulated force-time function. Two specimens, one reinforced and the other unreinforced concrete plates, containing naturally delaminated cracks with crack widths 1 mm, 3 mm and 5 mm were constructed and repaired by injected epoxy into the delaminated cracks. The NDT method was performed on the specimens before and after the repairing work for comparison. The spectral image shows consistent high intensity at the crack-depth-frequency for specimens at crack stages and less in intensity for the ones at repaired stage.

scholarly journals FLEXURAL REINFORCED CONCRETE ELEMENTS NORMAL SECTION BEARING CAPACITY EVALUATION IN FRACTURE STAGE

2017 ◽  
Vol 9 (2) ◽  
pp. 70-78 ◽  
Author(s):  
Justas SLAITAS ◽  
Zbynek HLAVAC ◽  
Arnoldas ŠNEIDERIS
Keyword(s):  
Tensile Strength ◽  
Reinforced Concrete ◽  
Bearing Capacity ◽  
Crack Depth ◽  
Experimental Studies ◽  
Concrete Structures ◽  
Assessment Process ◽  
Reinforced Concrete Structures ◽  
Compression Zone ◽  
Normal Section

This article examines flexural reinforced concrete structures condition assessment process in existing buildings on the stage where the reinforcement stress is between the yield and the tensile strength. The research is made on V. Jokūbaitis proposed methodology directly measuring the compression zone height, allowing us to evaluate the behavior of reinforced concrete beam fracture sufficiently precisely. This paper confirms the hypothesis that, when reinforcement reaches yielding stress, elastic strain dominates in concrete‘s compression zone and it is reasonable to use triangular concrete compression zone diagram, without tensile concrete above crack evaluation. The methodology of reinforced concrete structures bearing capacity assessment according to limit normal section crack depth is proposed. There is established connection between bending moments, when reinforcement achieve yielding stress and tensile strength, which allows us to decide about structures bearing capacity reserve. The results are confirmed with experimental studies and calculated values obtained by methodologies based on different reduced stress diagrams of concrete‘s compressive zone.

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.

Determination of the Influence of Carbonation of Concrete and Corrosion of Steel on Reinforced Concrete Condition

2015 ◽  
Vol 1124 ◽  
pp. 225-230 ◽  
Author(s):  
Kristýna Timcakova ◽  
Daniela Štefková ◽  
Zdeněk Chobola
Keyword(s):  
Reinforced Concrete ◽  
Concrete Structures ◽  
Poor Quality ◽  
Protective Properties ◽  
Impact Echo ◽  
Concrete Condition ◽  
Almost All ◽  
Corrosion Of Steel ◽  
Impact Echo Method

Almost all reinforced concrete structures which are exposed to weather effects are threatened by corrosion. The corrosion of steel elements in structures has an influence on lifetime these constructions and adversely affects their properties. However, the steel in concrete structures is protected against corrosion due to the properties of concrete such as high pH or impermeability, but if the concrete is of poor quality and his protective properties are insufficient the corrosion can occur. A problem causes the action of carbon dioxide which has the effect of lowering the pH below the critical value and thereby accelerating the corrosion.Non-destructive methods such as Impact-echo method offer the possibility of easy and quickly detection of initial damage of structure and thus can prevent the occurrence of permanent damage to the whole construction.This article describes the development of corrosion which is caused by carbonation of the concrete and supported by action of chlorides by using Impact-echo method. The paper presents results obtained on the reinforced concrete samples with one steel rod passing through the center. After carbonation concrete the samples were exposed accelerated controlled degradation in aqueous NaCl solution for 4 months.

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