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 DO - 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 - 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 DO - 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 - 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 - 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 - JOUR A1 - Beutel, R. A1 - Reinhardt, H.-W. A1 - Grosse, C.U. A1 - Glaubitt, A. A1 - Krause, Martin A1 - Maierhofer, Christiane A1 - Algernon, Daniel A1 - Wiggenhauser, Herbert A1 - Schickert, M. T1 - Comparative performance tests and validation of NDT methods for concrete testing N2 - Validation of non-destructive testing methods is necessary to create a common basis where different systems can be compared and their applications and limitations be identified. This can be achieved through comparing the measurements taken by several systems used for a common diagnostic purpose under practical but controlled testing conditions. Well-designed small and large laboratory or field specimens promise such conditions. The special concrete specimen (LCS) at BAM was constructed for validation purposes, in particular, to be used for evaluating the performance of echo methods. The thickness of the specimen is varying and it contains carefully designed built-in faults, such as voids, honeycombs and tendon ducts with various degrees of grouting defects. Since the geometry and condition of the defects are known, it can be used to compare the performance of radar, ultrasonic, impact-echo. The research was conducted within the Research group FOR384, sponsored by the German Research Society DFG. KW - Performance demonstration KW - Non-destructive testing KW - Concrete KW - Radar KW - Ultrasound KW - Impact-echo PY - 2008 DO - https://doi.org/10.1007/s10921-008-0037-1 SN - 0195-9298 SN - 1573-4862 VL - 27 IS - 1-3 SP - 59 EP - 65 PB - Plenum Press CY - New York, NY AN - OPUS4-17925 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 - TY - CHAP A1 - Maierhofer, Christiane ED - Maierhofer, C. ED - Reinhardt, H.-W. ED - Dobmann, G. T1 - Planning a non-destructive test programme for reinforced concrete structures KW - Non-destructive testing KW - Concrete KW - On-site assessment KW - Method validation KW - Quality assurance PY - 2010 SN - 978-1-84569-950-5 VL - 2 IS - Chapter 1 SP - 3 EP - 13 PB - Woodhead Publ. AN - OPUS4-22610 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 - GEN A1 - Krankenhagen, Rainer A1 - Kervalishvili, Guram N. A1 - Maierhofer, Christiane T1 - Influence of air-gaps on the thermal behaviour of the plaster-concrete bonds N2 - The delamination of a plaster layer, which covers a concrete structure, can be detected by active thermography. In this paper, a systematic series of measurements is described, where the gap between plaster and concrete was varied. These investigations were compared to FEM-simulations. The experimental and simulated data were in good agreement. It was found that the used experimental setup yields only marginal differences between fixed and lose plaster in the thermal behavior. However, significant characteristics within the temperature decays could be resolved, which are clearly related to the air gap. T2 - QIRT 10 - 10th International conference on Quantitative InfraRed Thermography CY - Québec, Canada DA - 2010-07-27 KW - Active thermography KW - Plaster KW - Concrete KW - Temperature decay PY - 2010 UR - http://qirt.gel.ulaval.ca/archives/qirt2010/papers/QIRT%202010-067.pdf SN - 978-2-9809199-1-6 IS - QIRT 2010-067 SP - 1 EP - 5(?) AN - OPUS4-21956 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Kohl, Christoph A1 - Maierhofer, Christiane A1 - Krause, Martin A1 - Streicher, Doreen A1 - Wiggenhauser, Herbert ED - Mazal, P. T1 - Data fusion of complementary NDT methods applied in civil engineering T2 - 2nd International Workshop of NDT Experts CY - Prague, Czech Republic DA - 2003-10-06 KW - Non-destructive testing in civil engineering KW - Data fusion KW - Radar KW - Ultrasonics KW - Concrete PY - 2003 SN - 80-2142475-3 SP - 1 EP - 11(?) PB - Univ. of Technology CY - Brno AN - OPUS4-3054 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -