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 - 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 - 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 - GEN A1 - Habel, Wolfgang A1 - Hofmann, Detlef A1 - Gutmann, Toivo A1 - Basedau, Frank A1 - Molter, M. A1 - Hegger, J. ED - Inaudi, D. T1 - Characterization of bond performance of textiles in cement matrices using fiber optic sensors T2 - Smart structures and materials 2002 - Smart sensor technology and measurement systems CY - San Diego, CA, USA DA - 2002-03-18 KW - Textile reinforced concrete KW - Fibers KW - Concrete KW - Bond KW - Fiber-optic sensors PY - 2002 SN - 0-8194-4442-1 DO - https://doi.org/10.1117/12.472626 SN - 1605-7422 N1 - Serientitel: SPIE proceedings series – Series title: SPIE proceedings series IS - 4694 SP - 253 EP - 258 PB - SPIE CY - Bellingham, Wash. AN - OPUS4-1458 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 - 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 - 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 - 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 - 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 - 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 -