TY - GEN A1 - Helmerich, Rosemarie A1 - Röllig, Mathias A1 - Maierhofer, Christiane A1 - Schultz, A. ED - Vincentsen, L. T1 - Bond Control in CFRP-strengthened RC-structures using Active Thermography T2 - Conference on Operation, Maintenance and Rehabilitation of Large Infrastructure Projects, Bridges and Tunnels CY - Copenhagen, Denmark DA - 2006-05-15 KW - Quality control KW - Impulse-Thermography (IR) KW - Debonding KW - Supervision of CFRP-Strengthening KW - Laboratory Testing PY - 2006 SN - 87-91044-03-0 SP - 1(?) EP - 8(?) PB - IABSE CY - Zürich AN - OPUS4-12407 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Arndt, Ralf A1 - Helmerich, Rosemarie A1 - Maierhofer, Christiane A1 - Röllig, Mathias ED - Forde, M. T1 - Quantitative Pulse-Phase-Thermography for Composites and Concrete Structures N2 - The active approach for non-destructive-testing in Civil Engineering (NDT-CE) with infraredthermography (IR), developed at the Federal Institute for Materials Research and Testing (BAM), is described in part one of this contribution. The active IR-approach is based on the principles of impulse- (IT) and pulse-phase-thermography (PPT). The concept is a direct result of a research project at the BAM in cooperation with the Technical University of Berlin (TUB) and was funded by the Deutsche Forschungsgemeinschaft (DFG). In the second part results of the new thermography-scanning system (thermo-scanner) of BAM on debonding of multi-layered structures, especially carbon fibre reinforced plates (CFRP) on concrete are presented. Both, the thermo-scanner developed at BAM, and the investigations carried out, are part of the EU-Project Sustainable Bridges. In the third part of the paper the characteristic frequency of the optimum phase-contrast as a means for the characterization of defects’ depth in CE by means of PPT is introduced. A new quantitative approach is tested and discussed on concrete structures with defects of polystyrene and gas concrete. T2 - 11th International Conference and Exhibiton "Structural Faults and Repair - 2006" CY - Edinburgh, Scotland, UK DA - 2006-06-13 KW - Quantitative NDT KW - Impulse-thermography KW - Pulse-phase-thermography KW - Blind / characteristic frequency KW - Concrete KW - Thermo-scanner KW - CFRP-laminates KW - Debonding KW - Voids PY - 2006 SN - 0-947644-59-8 SP - 1(?) EP - 17(?) PB - Engineering Technics Pr., CY - Edingburgh AN - OPUS4-13794 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Helmerich, Rosemarie A1 - Milmann, Boris A1 - Wöstmann, Jens A1 - Feistkorn, S. ED - Barros, J. ED - Sena-Cruz, J. T1 - Durability of CFRP-laminate strengthening N2 - First bridge structures have been strengthened by means of Carbon-Fiber-Reinforced-Polymer (CFRP)-laminates extemally glued to the concrete surface in the last two decades. At present there is no Information about the durability of these Systems after having been in Service for more than ten years. The paper presents laboratory tests and case studies with automated non-destructive testing to analyse the current bond condition of extemally bonded CFRP-laminates to concrete structures, strengthened about ten years ago. The paper presents the feasibility and the limitations of ultrasonic inspection of selected areas of CFRP-laminate-strengthened structures co-funded by the German Center of Competence in Civil Engineering (DIBt) in a national project. Areas of interest were the end region of laminates or areas with educated doubts about their bond integrity selected and marked in the inspection records during main inspections. In a feasability study, the functionality of the ultrasonic test for bond evaluation below CFRP-laminates without any surface protection measure, was confirmed by testing a CFRP-laminate strengthened slab with artificial voids in a blind laboratory test with an accuracy of + 1 cm. The accuracy depends on the step width, line interspace and the distance between ultrasonic transducer and receiver. This accuracy suits a measuring grid of 1 cm. The case studies consider flexural strengthening and repair of prestressed concrete structures as well as longitudinal and transverse strengthening of bridge slabs with simple reinforcement. Both alternatives were considered, covered with mineral surface protection layer and without. The measurement results of automated scanned surfaces is presented in color-codes images. In the tested areas with no or thin surface protection the non-destructive inspection did not uncover severe defects or Deterioration processes. None the less, proposals for further research is given, in testing of the acceptable bond defects and in advancing the ultrasonic test including the devlopment of sensors for this application. T2 - FRPRCS-11 - 11th International symposium on fiber reinforced polymer for reinforced concrete structures CY - Guimaraes, Portugal DA - 26.06.2013 KW - CFRP-Laminate KW - Debonding KW - Flexural strengthening KW - Bridge KW - NDT KW - Durability test KW - Inspection PY - 2013 SN - 978-972-8692-84-1 SP - 41 EP - 42 (Session 6.5) AN - OPUS4-28859 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -