TY - JOUR A1 - Maierhofer, Christiane A1 - Brink, Arne A1 - Röllig, Mathias A1 - Wiggenhauser, Herbert T1 - Detection of shallow voids in concrete structures with impulse thermography and radar N2 - New thermography systems enable the application of active investigation techniques, i.e. the observation of the cooling down process after heating the surface of a structure under investigation. Defects like voids in concrete having a different thermal diffusivity in comparison to the bulk material are visualised by different surface temperatures. The differences between temperature transient curves above sound regions and above inhomogeneities are expected to include information about the defect parameters. Experimental investigations with impulse thermography and radar on a concrete test specimen containing voids were analysed. Radar was used to determine the depth of the voids. The influence of size and depth of the voids on the temperature transient curves was studied for different heating times. The transient curves were also fitted with a simple semi-empirical model. KW - Impulse thermography KW - Radar KW - Non-destructive testing KW - Concrete KW - Civil engineering PY - 2003 SN - 0963-8695 VL - 36 IS - 4 SP - 257 EP - 263 PB - Butterworth-Heinemann CY - Oxford AN - OPUS4-11867 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schubert, F. A1 - Wiggenhauser, Herbert A1 - Lausch, Regine T1 - On the accuracy of thickness measurements in impact-echo testing of finite concrete specimens - numerical and experimental results N2 - In impact-echo testing of finite concrete structures, reflections of Rayleigh and body waves from lateral boundaries significantly affect time-domain signals and spectra. In the present paper we demonstrate by numerical simulations and experimental measurements at a concrete specimen that these reflections can lead to systematic errors in thickness determination. These effects depend not only on the dimensions of the specimen, but also on the location of the actual measuring point and on the duration of the detected time-domain signal. KW - Impact-echo testing KW - Concrete KW - Thickness measurements KW - Time-domain simulations PY - 2004 DO - https://doi.org/10.1016/j.ultras.2004.01.076 SN - 0041-624x VL - 42 IS - 1-9 SP - 897 EP - 901 PB - Elsevier CY - Amsterdam AN - OPUS4-11050 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kääriäinen, H. A1 - Rudolph, Michael A1 - Schaurich, Dieter A1 - Tulla, K. A1 - Wiggenhauser, Herbert T1 - Moisture measurements in building materials with microwaves N2 - The method requires two parallel boreholes in the specimen in which two microwave antennae can be moved. The moisture content in the material can be calculated from the microwave intensity transmitted between the two boreholes. Moisture profiles along the boreholes can be obtained by moving the antennae in steps along the length of the boreholes and taking measurements at each step. The microwave frequencies used in the laboratory measurements ranged from 8 to 16.5 GHz in steps of 0.5 GHz. The diameters of the antennae were between 7 and 9 mm, and of the boreholes between 8 and 12 mm. The microwave method produced measurement uncertainties between 0 and 2% by volume for all the materials studied in this report. KW - Construction materials KW - Moisture transport KW - Moisture meter KW - Microwaves KW - Concrete KW - Sand KW - Wood PY - 2001 SN - 0963-8695 VL - 34 IS - 6 SP - 389 EP - 394 PB - Butterworth-Heinemann CY - Oxford AN - OPUS4-11049 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Van Gemert, D. A1 - Czarnecki, L. A1 - Maultzsch, Matthias A1 - Schorn, H. A1 - Beeldens, A. A1 - Lukowski, P. A1 - Knapen, E. T1 - Cement concrete and concrete-polymer composites: Two merging worlds. A report from 11th ICPIC Congress in Berlin, 2004 N2 - The search for durable and sustainable construction materials inspires the developments in the world of cement concrete, as well as in the world of concrete–polymer composites. Both worlds recognize, strive for and accept each other’s contribution to the synergetic effects that are realized by the combination of classical building materials and polymers. A better knowledge of materials behaviour, especially in the field of admixtures, and a better understanding of curing processes allowed the development of highly performing mineral or modified mineral concretes, mortars and grouts. CPC-science becomes an invaluable element in the development of sustainable construction materials. ICPIC brings together practitioners and scientists, dealing with concrete–polymer composites in all industrial fields, but with emphasis on construction industry. The 11th International ICPIC Congress took place in Berlin, 2–4th June 2004. New trends and evolutions have been presented and discussed. The highlights of the Congress, and the synergies for the construction world that emerge from this congress on polymers in concrete in combination with cement concrete, are presented. KW - Concrete KW - Polymer KW - Cement KW - Composites KW - Synergy PY - 2005 DO - https://doi.org/10.1016/j.cemconcomp.2005.05.004 SN - 0958-9465 SN - 1873-393X VL - 27 IS - 9-10 SP - 926 EP - 933 PB - Elsevier CY - Barking, Essex AN - OPUS4-10864 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Müller, Urs A1 - Rübner, Katrin ED - Hughes, J. ED - Leslie, A. ED - Walsh, A. T1 - The micro texture of concrete made with municipal waste incinerator bottom ash as an aggregate component T2 - 10th Euroseminar on Microscopy Applied to Building Materials CY - Paisley, UK, Scottland DA - 2005-06-21 KW - MSWI bottom ash KW - Concrete KW - Durability KW - Aluminium KW - Micro texture PY - 2005 SN - 1-903978-21-1 SP - 85 EP - 86 PB - University of Paisley CY - Paisley AN - OPUS4-7647 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 DO - 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 - Arndt, Ralf A1 - Maierhofer, Christiane A1 - Röllig, Mathias A1 - Weritz, Friederike A1 - Wiggenhauser, Herbert T1 - Structural investigation of concrete and masonry structures behind plaster by means of pulse phase thermography T2 - 7th International Conference on Quantitative Infrared Thermography (QIRT 2004) CY - Rhode-St-Genese, Belgien DA - 2004-06-05 KW - Pulse phase thermography KW - Nondestructive testing in civil engineering KW - Plaster KW - Concrete KW - Masonry KW - Delaminations KW - Voids PY - 2004 SP - I.3.1 EP - I.3.6 PB - Karman Institute for Fluid Dynamics CY - Rhode-St-Genese AN - OPUS4-4397 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Kühne, Hans-Carsten A1 - Maultzsch, Matthias A1 - Wolff, L. A1 - Meng, Birgit A1 - Raupach, M. ED - Maultzsch, M. T1 - Long-term performance of surface protection systems for concrete T2 - 11th International Congress on Polymers in Concrete (ICPIC `04) CY - Berlin, Germany DA - 2004-06-02 KW - Surface protection system KW - Concrete KW - Weathering KW - Water uptake KW - Freezethaw resistance KW - Chloride ingress KW - Carbonation KW - Hydrophobic treatment PY - 2004 SN - 3-00-013706-8 SP - 417 EP - 428 PB - BAM CY - Berlin AN - OPUS4-3602 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Brink, Arne A1 - Wedler, Gerd A1 - Maierhofer, Christiane A1 - Röllig, Mathias A1 - Weritz, Friederike A1 - Wiggenhauser, Herbert T1 - Active infrared thermography in civil engineering - quantitative analysis by numerical simulation N2 - The cooling-down process of building structures after heating-up with an external radiation source was analysed to detect voids inside and below the surface. Quantitative results of concrete test specimen containing voids with different sizes at various depths will be presented here. The experimental results were compared to numerical simulations performed with a Finite Difference program developed at BAM. 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 - Acitve thermography KW - Concrete KW - Voids KW - Numerical SImulation KW - Finite differences PY - 2003 UR - http://www.ndt.net/article/ndtce03/papers/p024/p024.htm SN - 3-931381-49-8 SP - 1 EP - 8(?) PB - DGZfP CY - Berlin AN - OPUS4-3403 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Maierhofer, Christiane A1 - Brink, Arne A1 - Röllig, Mathias A1 - Wiggenhauser, Herbert T1 - Quantitative Impulse-Thermography as Non-Destructive Testing Method in Civil Engineering - Experimental Results and Numerical Simulations N2 - Impulse-thermography is an active method for quantitative investigation of the near surface region of various structures which has recently been applied to civil engineering. It is well suited for the detection of voids and honeycombing in concrete up to concrete covers of 10 cm and more. For quantitative analysis, a computer program for numerical simulation of the heating up and cooling down processes was developed based on Finite Differences. With this program parameter studies have been performed for investigating the influence of environmental conditions, material parameters and geometry on the thermal behaviour. The comparison between experimental and simulated results enables the Inverse Solution. KW - Impulse-thermography KW - Numerical simulation KW - Non-destructive testing KW - Concrete KW - Civil engineering PY - 2005 SN - 0950-0618 VL - 19 IS - 10 SP - 731 EP - 737 PB - Elsevier CY - Oxford AN - OPUS4-3162 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 - 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 - TY - JOUR A1 - Schickert, M. A1 - Krause, Martin A1 - Müller, W. T1 - Ultrasonic Imaging of Concrete Elements Using Reconstruction by Synthetic Aperture Focusing Technique N2 - Ultrasonic reconstruction by the synthetic aperture focusing technique (SAFT) has a great potential to image concrete elements and detect embedded objects. Its algorithm focuses ultrasonic signals received at many aperture points by coherent superposition, yielding a high-resolution image of the region of interest. Using this approach, several problems caused by the strongly inhomogeneous structure of concrete are diminished, where scattering of transmitted pulses leads to disturbing phenomena such as attenuation and structural noise. This contribution is intended to review the work of the writers on the application of SAFT reconstruction to concrete testing. First, consequences of scattering of ultrasonic waves in concrete are qualitatively explained. Then the use of SAFT is discussed in comparison to traditional A-scan and B-scan techniques. Different reconstruction algorithms and implementations are presented for one-, two-, and three-dimensional SAFT. Pulse-echo measurement systems are described, which are able to acquire large sets of data on linear and planar apertures employing single transducer, transducer array, and scanning laser Doppler vibrometer arrangements. To illustrate the application of the SAFT techniques, examples from laboratory and field experiments are described comprising imaging of back walls, tendon ducts containing faults, layers, and reinforcement in concrete elements. KW - Imaging techniques KW - Concrete KW - Acoustic detection PY - 2003 DO - https://doi.org/10.1061/(ASCE)0899-1561(2003)15:3(235) SN - 0899-1561 SN - 1943-5533 IS - May/June SP - 235 EP - 246 PB - American Society of Civil Engineers CY - New York, NY AN - OPUS4-2752 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Popovics, J. S. A1 - Wiggenhauser, Herbert ED - Smyth, A. W. T1 - Non-Contact Laser Vibrometer Wave Sensing on Concrete N2 - Rapid and accurate non-destructive evaluation (NDE) techniques are needed to assess the in-place condition of concrete structures. However the time and effort required to perform NDE tests using conventional surface-mounted contact sensors hinder rapid evaluation of full-scale structures. The authors are cooperating in research to develop rapid and robust methods that collect mechanical wave signals from concrete structures and to characterize defects in concrete using that signal data. The suitability of surface waves and laser-based, non-contact wave detection techniques for this purpose are examined here. After a brief introduction to non-contact sensing, an experimental set-up is described and results from experimental tests are presented. Mechanical surface waves in a concrete slab specimen are generated with several different conventional sources. The ability of a laser vibrometer to detect wave propagation from concrete that does not have any reflective treatment (normal concrete surface) is demonstrated, allowing the generation of ultrasonic images. Test results from a concrete specimen containing a subsurface defect are then presented. The obtained ultrasonic images illustrate some limitations of using surface waves to detect subsurface defects in concrete, although approaches to improve the results are proposed. T2 - 15th ASCE Engineering Mechanics Conference ; 15th EM 2002 CY - New York, NY, USA DA - 2002-06-02 KW - Concrete KW - Imaging KW - Laser KW - Surface Waves KW - Ultrasound KW - Vibrometer PY - 2002 SP - 1(?) EP - 7(?) AN - OPUS4-2215 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Meinhold, Uwe A1 - Mellmann, Günter A1 - Maultzsch, Matthias ED - Malhotra, V. M. T1 - Performance of high-grade concrete with full substitution of aggregates by recycled concrete N2 - On the background of the need for reuse of building rubble and the saving of natural resources, a European Union research project was performed covering concrete technology and durability aspects. A very special precondition was the use of large-scale processed building rubble with unknown origin and the total replacement of aggregates above 2 mm. Comprehensive tests were carried out on the properties of the starting material from different processing plants and fresh concrete, particularly the interdependence of water addition and wor ability. Investigations on hardened concrete properties included strength devel-opment, creep and shrinkage, modulus of elasticity, capillary absorption, freezing and thawing resistance, and carbonation behavior over a long period. The results demonstrate that the industrial production of a high-grade, durable concrete is possible. The project is a promising contribution for sustainable development. T2 - Third CANMET/ACI International Symposium on Sustainable Development of Cement and Concrete CY - San Francisco, CA, USA DA - 16.09.2001 KW - Aggregates KW - Compressive strength KW - Concrete KW - Creep KW - Modulus of elasticity KW - Recycled concrete KW - Shrinkage PY - 2001 SN - 0-87031-041-0 N1 - Serientitel: ACI SP – Series title: ACI SP IS - SP 202 SP - 85 EP - 96 PB - American Concrete Institute (ACI) CY - Farmington Hills, Mich. AN - OPUS4-1933 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Colla, Camilla A1 - Krause, Martin A1 - Maierhofer, Christiane A1 - Höhberger, H.-J. A1 - Sommer, H. T1 - Combination of NDT techniques for site investigation of non-ballasted railway tracks N2 - Today's civil engineering NDT needs are for quantitative, fast to apply and easy to interpret methods. They are required on site both for evaluation of existing structures/infrastructure and for quality control in new construction. With this purpose, BAM has carried out in-situ feasibility studies, using radar, impact-echo and ultrasonic-echo methods. Two examples are given of their combined application on different railway slab–track constructions, using high frequency radar, scanning impact-echo and ultrasonic array methods. The aim was to evaluate limitations and advantages, comparability and complementarity of these methods. The on-site measurements demonstrated the possibility to investigate, with good accuracy via NDT, the bonding conditions between sleepers and slab, to locate voids and measure layer thickness. The acoustic and electromagnetic methods used, were found to be complementary. KW - Concrete KW - NDT KW - Impact echo KW - Ultrasonics KW - Radar KW - Railway PY - 2002 DO - https://doi.org/10.1016/S0963-8695(01)00033-0 SN - 0963-8695 VL - 35 SP - 95 EP - 105 PB - Butterworth-Heinemann CY - Oxford AN - OPUS4-1858 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Maierhofer, Christiane A1 - Brink, Arne A1 - Röllig, Mathias A1 - Wiggenhauser, Herbert ED - Binda, L. T1 - Transient thermography for non-destructive investigation of building structures in the near surface region T2 - RILEM TC 177-MDT Workshop on On-Site Control and Non-Destructive Evaluation of Masonry Structures CY - Mantova, Italy DA - 2001-11-12 KW - Non-destructive testing KW - Masonry KW - Concrete KW - Impulse thermography KW - Plaster KW - Laminates PY - 2003 SN - 2-912143-34-9 N1 - Serientitel: RILEM proceedings – Series title: RILEM proceedings IS - 26 SP - 251 EP - 261 PB - RILEM Publications CY - Bagneux, France AN - OPUS4-1829 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Maierhofer, Christiane A1 - Kind, Thomas ED - Koppenjan, S. K. T1 - Application of impulse radar for non-destructive investigation of concrete structures N2 - The application of impulse radar for structural investigation of concrete elements has been increased during the last years related to technical developments, i. e. of high frequency antennas. In this paper, case studies will be presented related to the location of reinforcing bars, tendon ducts and repaired concrete areas in concrete bridges, anchors and dowels in concrete highways and delaminations of layered structures as they are used for non-ballasted railway tracks. It is shown that impulse radar can be applied in case of regular inspection and for searching the cause of damages but also for quality assessment in civil engineering. T2 - 9th GPR 2002 ; 9th International Conference on Ground Penetrating Radar CY - Santa Barbara, CA, USA DA - 2002-04-29 KW - Non-destructive testing KW - Radar KW - Polarisation KW - Civil engineering KW - Concrete KW - Reinforcement KW - Voids KW - Quality assurance PY - 2002 UR - http://cat.inist.fr/?aModele=afficheN&cpsidt=14182375 SN - 0-8194-4522-3 SN - 1605-7422 N1 - Serientitel: SPIE proceedings series – Series title: SPIE proceedings series IS - 4758 SP - 382 EP - 387 PB - SPIE, the International Society for Optical Engineering CY - Bellingham, Wash. AN - OPUS4-1825 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Maierhofer, Christiane A1 - Brink, Arne A1 - Röllig, Mathias A1 - Wiggenhauser, Herbert T1 - Transient thermography for structural investigation of concrete and composites in the near surface region KW - Impulse thermography KW - Non-destructive testing KW - Quantitative analysis KW - Concrete KW - Composites KW - Civil engineering KW - Simulation KW - Finite differences PY - 2002 SN - 1350-4495 VL - 43 SP - 271 EP - 278 PB - Pergamon Press CY - Oxford AN - OPUS4-1759 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Bäßler, Ralph A1 - Klinghoffer, O. A1 - Goltermann, P. ED - Casas, J. R. T1 - Smart Structures - Embeddable Sensors for Use in the Integrated Monitoring Systems of Concrete Structures T2 - 1st International Conference on Bridge Maintenance, Safety and Management ; 1st IABMAS '02 CY - Barcelona, Spain DA - 2002-07-14 KW - Monitoring KW - Concrete KW - Deterioration KW - Corrosion KW - Chloride KW - Carbonation and Moisture PY - 2002 SN - 84-95999-05-6 SP - 1 EP - 8 PB - International Center for Numerical Methods in Engineering (CIMNE) CY - Barcelona AN - OPUS4-1619 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -