TY - JOUR A1 - Weritz, Friederike A1 - Arndt, Ralf A1 - Röllig, Mathias A1 - Maierhofer, Christiane A1 - Wiggenhauser, Herbert T1 - Investigation of concrete structures with pulse phase thermography N2 - The applicability of pulse phase thermography (PPT) for the investigation of structures is studied systematically on concrete test specimens and on a plastered sandstone column. In the test specimens, voids and delaminations are implemented in different depths and with different sizes, modelling real voids, honeycombing and debonding. Delaminations of plaster in concrete and masonry and behind tiles on concrete are investigated. PPT is based on the frequency analysis of the cooling down process of actively heated surfaces. Therefore, it is contactless and thus completely non-destructive (if overheating of the surface is prevented), fast and allows the inspection of large surface areas. The interpretation of amplitude and phase images gives semi-quantitative information about the observed defects. The phase images provide a deeper probing up to 10–15 cm in relation to the interpretation of the thermograms and to the amplitude images. In addition, the influence of surface inhomogeneities and non-uniform heating is reduced. KW - Pulse phase thermography KW - Impulse thermography KW - Concrete KW - Voids KW - Honeycombing PY - 2005 U6 - https://doi.org/10.1007/BF02481657 SN - 1359-5997 SN - 1871-6873 VL - 38 IS - 9 SP - 843 EP - 849 PB - Springer CY - Dordrecht AN - OPUS4-12300 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Maierhofer, Christiane A1 - Zacher, Gerhard A1 - Kohl, Christoph A1 - Wöstmann, Jens ED - Christian U. Grosse, T1 - Radar and Fusion for Concrete Elements KW - NDT-CE KW - Concrete KW - Concrete bridge KW - Reinforcement bars KW - Radar KW - Ultrasonic KW - Data fusion PY - 2007 SN - 978-3-540-72447-6 SP - 631 EP - 638 PB - Springer CY - Heidelberg AN - OPUS4-15990 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Maierhofer, Christiane A1 - Zacher, Gerhard A1 - Kohl, Christoph A1 - Wöstmann, Jens T1 - Evaluation of Radar and Complementary Echo Methods for NDT of Concrete Elements N2 - Non-destructive testing (NDT) of concrete structures plays an increasing role in civil engineering. This paper presents the results of systematic measurements carried out in the laboratory at BAM and on-site at several bridges using reconstructed and fused radar and ultrasonic echo data sets. For investigating the influence of concrete mixture, radar and ultrasonic measurements were performed at test specimens consisting of concrete mixtures with different pore content and distribution as well as with steel fibres. Further, it is demonstrated how the fusion of data sets recorded with different methods at the same structure (here: concrete bridges) enhances the information content in the fused data set. Different approaches for data fusion algorithms are discussed. The results of these investigations show the high potential of reconstruction and data fusion for the improvement and simplification of the interpretability of large data sets measured with impulse-echo methods. The presented results are based on the research project FOR384 funded by the DFG (Deutsche Forschungsgemeinschaft). KW - Radar KW - Ultrasonic KW - Data fusion KW - Pixel level KW - Evidence theory KW - Concrete KW - Bridges KW - Reinforcement KW - Pores KW - Steel fibres PY - 2008 U6 - https://doi.org/10.1007/s10921-008-0030-8 SN - 0195-9298 SN - 1573-4862 VL - 27 IS - 1-3 SP - 47 EP - 57 PB - Plenum Press CY - New York, NY AN - OPUS4-17711 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Maierhofer, Christiane A1 - Wiggenhauser, Herbert A1 - Brink, Arne A1 - Röllig, Mathias T1 - Quantitative numerical analysis of transient IR-experiments on buildings N2 - Impulse-thermography has been established as a fast and reliable tool in many areas of non-destructive testing. In recent years several investigations have been done to apply active thermography to civil engineering. For quantitative investigations in this area of application, finite difference calculations have been performed for systematic studies on the influence of environmental conditions, heating power and time, defect depth and size and thermal properties of the bulk material (concrete). The comparison of simulated and experimental data enables the quantitative analysis of defects. T2 - 7th International Workshop on Advanced Infrared Technology and Applications ; 7th AITA Conference CY - Pisa, Italy DA - 2003-09-09 KW - Impulse-thermography KW - Numerical simulation KW - Non-destructive testing KW - Concrete KW - Civil engineering PY - 2004 U6 - https://doi.org/10.1016/j.infrared.2004.03.022 SN - 1350-4495 VL - 46 IS - 1-2 SP - 173 EP - 180 PB - Pergamon Press CY - Oxford AN - OPUS4-4984 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Maierhofer, Christiane A1 - Röllig, Mathias A1 - Arndt, Ralf A1 - Kreutzbruck, Marc ED - Thompson, D. O. ED - Chimenti, D. E. T1 - Influence of surface properties on the detection and quantification of voids in concrete structures using active thermography N2 - Impulse thermography is an active method for quantitative investigations of the near surface region of various structures. It has recently been applied and optimized to applications in civil engineering. For quantitative analysis of data recorded on the building site, the problems are manifold. Here, the influence of the different surface properties on the detection and characterization of voids and honeycombing simulated by polystyrene cubes and cubes prepared of porous concrete are demonstrated. T2 - 35th Annual Review of Progress in Quantitative Nondestructive Evaluation CY - Chicago, IL, USA DA - 2008-07-20 KW - Active thermography KW - Pulse phase thermography KW - Surface properties KW - Emissivity KW - Concrete KW - Voids KW - Honeycombing PY - 2009 SN - 978-0-7354-0629-2 SN - 0743-0760 SN - 0094-243X N1 - Serientitel: AIP conference proceedings – Series title: AIP conference proceedings IS - 1096 SP - 1505 EP - 1511 PB - American Institute of Physics CY - Melville, NY AN - OPUS4-19438 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CHAP A1 - Maierhofer, Christiane A1 - Röllig, Mathias T1 - Application of active thermography to the detection of safety relevant defects in civil engineering structures T2 - IRS² 2009 - 11th International conference on infrared sensors & systems CY - Nürnberg, Germany DA - 2009-05-26 KW - Non-destructive testing KW - Active thermography KW - Pulse-phase thermography KW - Concrete KW - Voids KW - Cracks KW - CFRP delaminations PY - 2009 SN - 978-3-9810993-6-2 IS - Chapter 2.2 SP - 215 EP - 220 AN - OPUS4-19873 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Maierhofer, Christiane A1 - Krause, Martin A1 - Wöstmann, Jens A1 - Röllig, Mathias A1 - Arndt, Ralf A1 - Streicher, Doreen A1 - Kohl, C. ED - L. Binda, ED - M. di Prisco, ED - R. Felicetti, T1 - Influence of concret properties on the calibration of radar, ultrasonics and active thermography T2 - 1st International RILEM Conference, on Site Assessment of Concrete, Masonry and Timber Structures (SACoMaTiS 2008) CY - Varenna, Italy DA - 2008-09-01 KW - Concrete KW - Radar KW - Ultrasonics KW - Active thermography KW - Velocity calibration PY - 2008 SN - 978-2-35158-062-2 VL - 1 IS - PRO 59 SP - 15 EP - 24 PB - RILEM Publications AN - OPUS4-18033 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Maierhofer, Christiane A1 - Krause, Martin A1 - Niederleithinger, Ernst A1 - Wiggenhauser, Herbert T1 - Non-destructive testing methods at BAM for damage assessment and quality assurance in civil engineering N2 - The structural safety, durability and performance of the infrastructure is of primary interest in every country. An efficient system for early and regular structural assessment as well as for quality assurance during and after the construction of new structures and of reconstruction processes is urgently required. At BAM, NDT methods to be applied in civil engineering are developed and their application improved. From the experience of on-site assessments, quality assurance systems and methodologies for regular inspections are elaborated. This work is mainly performed in the frame of externally funded research projects. T2 - 6th International Symposium Non-Destructive Testing in Civil Engineering (NDT-CE) CY - Berlin, Germany DA - 2003-09-16 KW - Non-destructive testing in civil engineering KW - Radar KW - Ultrasonics KW - Impact-echo KW - Impulse thermography KW - Concrete KW - Masonry PY - 2003 UR - http://www.ndt.net/article/ndtce03/papers/v068/v068.htm SN - 3-931381-49-8 PB - DGZfP CY - Berlin AN - OPUS4-3160 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Maierhofer, Christiane A1 - Krankenhagen, Rainer A1 - Myrach, Philipp A1 - Meinhardt, J. A1 - Kalisch, U. A1 - Hennen, C. A1 - Mecke, R. A1 - Seidl, T. A1 - Schiller, M. ED - Toniolo, L. ED - Boriani, M. ED - Guidi, G. T1 - Monitoring of cracks in historic concrete structures using optical, thermal and acoustical methods N2 - Cracks are a major issue in the field of cultural heritage. In order to evaluate the significance of a crack, a long term monitoring of the damaged region is required. However, there is a lack of easy to operate tools for such monitoring measures. Therefore, new or existing methods for other applications have to be optimised for cultural heritage investigation. The paper describes the application of such crack observation methods on a historic concrete sculpture. Beside conventional methods, like mapping by hand and ultrasonic depth profiling, a novel tracking system is presented. Furthermore, the suitability of active thermography for the investigation of cracks was investigated. The results show promising prospects for these non-destructive techniques. KW - Crack monitoring KW - Concrete KW - Thermography KW - Crack mapping PY - 2015 SN - 978-3-319-08532-6 SN - 978-3-319-08533-3 U6 - https://doi.org/10.1007/978-3-319-08533-3 SN - 2198-7300 SN - 2198-7319 SP - Part II, 93 EP - 102 PB - Springer AN - OPUS4-33851 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CHAP A1 - Maierhofer, Christiane A1 - Kohl, Christoph A1 - Wöstmann, Jens ED - Maierhofer, C. ED - Reinhardt, H.-W. ED - Dobmann, G. T1 - Combining the results of various non-destructive evaluation techniques for reinforced concrete: data fusion KW - Non-destructive testing KW - Concrete KW - Data fusion KW - Radar KW - Ultrasonic techniques PY - 2010 SN - 978-1-84569-950-5 VL - 2 IS - Chapter 5 SP - 95 EP - 107 PB - Woodhead Publ. AN - OPUS4-22607 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -