Mess- und Auswertungstechnik zur Riss- und Faserdetektion bei Betonbauteilen

Measurement methods for steel and textile reinforced concrete elements have to provide precise values (in the scale of microns) in a "rough" and strongly dispersive environment. Contactless, non-destructive (NDT), optical measurement methods allow the monitoring of test data and enable the interpretation of the complex composition and the structural behaviour. In the First part of the present thesis load induced deformations and cracks are first analysed and detected, then illustrated and interpreted using photogrammetry and methods of image processing. Photogrammetric images consist of a target grid on the surface of a structural element. The evaluation leads to the three-dimensional movement of the target. Then, the deformations are investigated and cracks as well as the crack openings are extracted by analysing discrete steps. This way, the threedimensional shrinking and deformations, the course of cracks and the crack openings due to tension or shear in tests, real structural elements and junctions are calculated. The main focus of this thesis is a complete analysis of series of tension tests on textile-reinforced elements including the inspection of the position of the rovings. Using image processing, cracks are detected by means of the line detection methods with mathematical morphology. Displacements on a concrete surface are correlatively investigated with a random speckle signal. Due to the line detection method, crack positions can be determined with pixel-size accuracy, which are then used for the correlative displacement detection on both crack sides for the sub-pixel-size accurate crack opening calculation. Deformations and cracks are investigated in tests by interpreting surface images of construction elements. The measurement technique can be extended using similar methods for the investigation of reinforcement in cross sections. The aim is to correlate the position of the reinforcement and the deformation and crack images. In the second part of this thesis different cross sections of structural elements are investigated to analyse incorporated the fibres and their properties. Glass fibres (filaments) are used as textile reinforcement and visualized in bond with the concrete matrix. Using image processing methods, the number, position and size of the filaments and the bond area to the surrounding concrete or pores are identified. For successive sections a three-dimensional illustration and analysis is feasible. At last the image processing methods are extended to the investigation of non-directional steel fibres in concrete to determine their numbers, positions and orientations for the analysis of construction elements. Furthermore, image processing methods are used to identify the position of the rovings in textile reinforced concrete elements. Measurements of an intended detection of the reinforcement in construction elements show the considerable influence on the cracks and deformations in a loading test.

Grantor dc:publisher

Publikationsserver der RWTH Aachen University

Year dc:date

2010

Author dc:creator

• Lange, Johannes

Contributors dc:contributor

• Benning, Wilhelm

• info:eu-repo/classification/ddc/620
• Photogrammetrie
• Stahlfaser
• Glasfaser
• Textilbeton
• Messtechnik
• Beton
• Bauwesen
• Bildverarbeitung
• Bildkorrelation
• Deformationsmessung
• Ingenieurwissenschaften
• Betonriss
• Rissdetektion
• crack detection

Statement dc:rights

• info:eu-repo/semantics/openAccess

Language dc:language

ger

Identifier

https://publications.rwth-aachen.de/search?p=id:%22RWTH-CONV-113284%22

OAI record oai:identifier

https://publications.rwth-aachen.de/oai2d?verb=GetRecord&metadataPrefix=oai_dc&identifier=oai%3Apublications.rwth-aachen.de%3A50751