TY - JOUR A1 - Kruschwitz, Sabine A1 - Oesch, T. A1 - Mielentz, Frank A1 - Meinel, Dietmar A1 - Spyridis, P. T1 - Non-Destructive Multi-Method Assessment of Steel Fiber Orientation in Concrete JF - Applied Sciences N2 - Integration of fiber reinforcement in high-performance cementitious materials has become widely applied in many fields of construction. One of the most investigated advantages of steel Fiber reinforced concrete (SFRC) is the deceleration of crack growth and hence its improved sustainability. Additional benefits are associated with its structural properties, as fibers can significantly increase the ductility and the tensile strength of concrete. In some applications it is even possible to entirely replace the conventional reinforcement, leading to significant logistical and environmental benefits. Fiber reinforcement can, however, have critical disadvantages and even hinder the Performance of concrete, since it can induce an anisotropic material behavior of the mixture if the fibers are not appropriately oriented. For a safe use of SFRC in the future, reliable non-destructive testing (NDT) methods need to be identified to assess the fibers’ orientation in hardened concrete. In this study, ultrasonic material testing, electrical impedance testing, and X-ray computed tomography have been investigated for this purpose using specially produced samples with biased or random Fiber orientations. We demonstrate the capabilities of each of these NDT techniques for fiber orientation measurements and draw conclusions based on these results about the most promising areas for future research and development. KW - Spectral induced polarization KW - Steel fiber reiniforced concrete KW - Fiber orientation KW - Non-destructive testing KW - Micro-computed tomography KW - Ultrasound PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-543520 DO - https://doi.org/10.3390/app12020697 VL - 12 IS - 2 SP - 1 EP - 14 PB - MDPI CY - Basel Switzerland AN - OPUS4-54352 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ulbricht, Alexander A1 - Gollwitzer, Christian A1 - Kupsch, Andreas A1 - Léonard, Fabien A1 - Müller, Bernd R. A1 - Oesch, Tyler A1 - Onel, Yener A1 - Thiede, Tobias A1 - Zscherpel, Uwe ED - Puente León, F. ED - Zagar, B. T1 - Moderne Methoden der CT-gestützten Strukturanalyse T1 - Modern techniques of CT based structure analysis JF - tm - Technisches Messen N2 - Durch den großflächigen Einsatz der Computertomographie (CT) in unterschiedlichen Industriebereichen steigen auch die Anforderungen an die quantitative Bildanalyse. Subjektive Bildwahrnehmung muss durch objektive Algorithmen ersetzt werden. In diesem Artikel stellt die Bundesanstalt für Materialforschung und -prüfung (BAM), die seit den 1980er Jahren an der Entwicklung der industriellen CT beteiligt ist, anhand ausgewählter Beispiele den aktuellen Stand ihrer Analysemethoden an verschiedenen Anwendungsbeispielen der CT vor. N2 - The increasing use of computed tomography (CT) in various industrial sectors requires more sophisticated techniques of quantitative image analysis. Subjective image perception needs to be replaced by objective algorithms. The German Federal Institute for Materials Research and Testing (BAM) has been involved in the development of industrial CT since the 1980s. This paper summarizes the current status of quantitative 3D image analysis techniques based on selected examples. KW - Computed tomography KW - Computertomographie KW - Röntgen-Refraktion KW - X-Ray refraction KW - Schadensanalyse KW - Damage analysis KW - Normung KW - standardization PY - 2020 DO - https://doi.org/10.1515/teme-2019-0125 SN - 0171-8096 SN - 2196-7113 VL - 87 IS - 2 SP - 81 EP - 91 PB - de Gruyter CY - Berlin AN - OPUS4-50337 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Munsch, Sarah Mandy A1 - Strangfeld, Christoph A1 - Kruschwitz, Sabine T1 - Application of 1H proton NMR relaxometry to building materials - A review JF - Journal of magnetic resonance open N2 - Since nuclear magnetic resonance with focus on 1H protons is highly sensitive to pore filling fluids, it is nowadays often applied for the investigation of porous media. Mainly in materials research and especially in the field of non-destructive testing in civil engineering it is increasingly used. Scientific questions about and based on NMR meanwhile cover a broad spectrum. To give an overview, we have reviewed various studies dealing with the determination of moisture contents and parameters such as the pore-size distribution, surface relaxivity, porosity, etc. In some papers, the monitoring of moisture transport in connection with degradation processes or admixtures was the main objective. In other papers, NMR was used for pore space analysis or even applied on site to assess the state of conservation of cultural heritage. Building materials that have been investigated in the presented studies are for example cement, concrete, woods, sandstones etc. In this paper, short descriptions and the significant results of the reviewed articles are summarized and their measurement problems and discrepancies are pointed out. A special feature of this review article is the concise tabular compilation of determined 𝑇1 and 𝑇2 relaxation times, as well as of surface relaxivity values for various materials and components. Finally, relevant aspects are summed up and conclusions about the increasing potential of NMR relaxometry for investigations of porous building materials are drawn, followed by an outlook about future applications and the need for technical development. KW - NMR relaxometry KW - Building materials KW - Natural stones KW - Relaxation times KW - Surface relaxivities KW - Moisture KW - Pore space characterization PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-521888 DO - https://doi.org/10.1016/j.jmro.2021.100012 N1 - Geburtsname von Munsch, Sarah Mandy: Nagel, S. M. - Birth name of Munsch, Sarah Mandy: Nagel, S. M. VL - 6-7 SP - 100012 PB - Elsevier Inc. CY - Amsterdam AN - OPUS4-52188 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Millar, Steven A1 - Gottlieb, Cassian A1 - Sankat, Nina A1 - Wilsch, Gerd A1 - Kruschwitz, Sabine T1 - Chlorine determination in cement-bound materials with Laser-induced Breakdown Spectroscopy (LIBS) – A review and validation JF - Spectrochimica Acta Part B-Atomic Spectroscopy N2 - The determination of chloride is still one of the main tasks for the evaluation of reinforced concrete structures. The corrosion of the reinforcement induced by the penetrating chlorides is the dominant damage process affecting the lifetime of concrete structures. In the recent years different research groups demonstrated that LIBS can be a fast and reliable method to quantify chlorine in cement-bound materials. Because chlorine in concrete can only occur as solved ions in the pore solution or bound in salts or hydrated cement phases, the detected emission of chlorine can be correlated with the chloride concentration determined e.g. with potentiometric titration. This work inter alia describes the production of reference samples and possible side effects during the production process. Due to transport processes in the porous matrix of the cement a misinterpretation of the concentrations is possible. It is shown how to overcome these effects and higher precisions of the single measurements can be realised. Using the calibration method, blank sample method and noise method, three different ways of calculating the limit of detection (LOD) and limit of quantification (LOQ) are compared. Due to the preparation of the reference samples a precision of the whole calibration model of sx0 = 0.023 wt% is determined. The validation of the model is based on different test sets, which are varying in their composition (different Cl-salts, water-to-cement ratios and additives). The determined mean error of the validation is 0.595 ± 0.063 wt%, which is comparable to standardised methods like potentiometric titration, direct potentiometry or photometry (0.40 ± 0.06 wt%) [1]. KW - LIBS KW - Chlorine KW - Cement KW - Calibration KW - Validation PY - 2018 DO - https://doi.org/10.1016/j.sab.2018.05.015 SN - 0584-8547 VL - 147 IS - September SP - 1 EP - 8 PB - Elsevier B.V. CY - Amsterdam AN - OPUS4-46558 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Millar, Steven A1 - Kruschwitz, Sabine A1 - Wilsch, Gerd T1 - Determination of total chloride content in cement pastes with laser-induced breakdown spectroscopy (LIBS) JF - Cement and Concrete Research N2 - The presented work discusses the accuracy of Laser Induced Breakdown Spectroscopy (LIBS) in determining the total chloride content in cement pastes. LIBS as an emission spectroscopy method is used to detect simultaneously several elements present in cement-based materials. By scanning surfaces the variability in the spatial distribution of elements can be visualised. However, for a quantification of the results, studies are necessary to characterise possible influences due to the wide variation of the chemical compositions in which cement can occur. It is shown how the calibration can be done, how the calibration samples were produced, and which statistical parameters are necessary to describe the precision of the regression. The performance of LIBS is estimated by detecting chloride in validation samples. Therefore, 55 samples and 7 ets with changing mix ompositions were produced. The presented study deals with possible influences of different mix compositions, ncluding different cations of chloride, varying w/c-ratios and the artial replacement of Portland cement with last furnace slag (50% BFS) and limestone (30% LS). Comparing the LIBS results with otentiometric titration, n accuracy of±0.05 wt%/total has been determined. KW - Spectroscopy KW - LIBS KW - Chloride KW - Quantification KW - Cement PY - 2019 DO - https://doi.org/10.1016/j.cemconres.2018.12.001 SN - 0008-8846 VL - 117 IS - March SP - 16 EP - 22 PB - Elsevier CY - Amsterdam AN - OPUS4-47059 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -