TY - JOUR A1 - Spilker, A. A1 - Stelzner, Ludwig A1 - Weise, Frank A1 - Wieland, M. T1 - Analyse der thermischen Dehnung von Fahrbahndeckenbetonen aus dem BAB-Netz N2 - Die Kenntnis von Materialeigenschaften spielt bei der Entwicklung oder Optimierung von Betonen und Bauweisen für den Straßenbau sowie der Qualitätssicherung eine bedeutende Rolle. Gleichermaßen bilden physikalische Materialkennwerte die Grundlage für die rechnerische Dimensionierung und die Restsubstanzbewertung von Betonfahrbahndecken. Eine relevante Kenngröße bei der Untersuchung thermisch induzierter Spannungs- und Verformungszustände stellt der thermische Ausdehnungskoeffizient dar. Im Zuge der systematischen Weiterentwicklung der rechnerischen Dimensionierung, aber auch im Zusammenhang mit der gezielten Verbesserung der Gebrauchseigenschaften von Betonfahrbahndecken gilt es zu hinterfragen, ob lastunabhängige Formänderungseigenschaften der verwendeten Betone aktuell ausreichend Beachtung finden, ob allgemeine Literaturwerte für die heutigen Fahrbandeckenbetone stets Gültigkeit besitzen und ob deren Implementierung in numerische Modelle zu realitätsnahen Vorhersagen führt. Für eine empirische Herangehensweise ist die Verfügbarkeit adäquater Prüfverfahren von entscheidender Bedeutung. In Deutschland existiert aktuell jedoch kein standardisiertes oder genormtes Verfahren für die prüftechnische Bestimmung des thermischen Ausdehnungskoeffizienten von Beton. Daher wurden unter Beachtung straßenbauspezifischer Gesichtspunkte zwei Prüfansätze entwickelt, die in diesem Beitrag vorgestellt sowie hinsichtlich möglicher Messunsicherheiten und Messungenauigkeiten diskutiert werden. Außerdem werden ausgewählte Ergebnisse aus Analysen an Bestandsbetonen aus dem BAB-Netz dargestellt. Im Ergebnis sollen die Untersuchungen einen Beitrag zur Schaffung der prüftechnischen Voraussetzungen für eine abgesicherte Quantifzierung der thermischen Dehnung von Fahrbahndeckenbetonen leisten. KW - Betonfahrbahndecken KW - Materialkennwerte KW - Thermischer Ausdehnungkoeffizient KW - Prüfverfahren PY - 2020 DO - https://doi.org/10.1002/best.202000044 VL - 116 IS - 1 SP - 26 EP - 34 PB - John Wiley & Sons AN - OPUS4-54967 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Scharf-Wildenhain, R. A1 - Hälsig, A. A1 - Schröpfer, Dirk A1 - Wandtke, Karsten A1 - Kannengießer, Thomas T1 - Wire Arc Additive Manufacturing (WAAM) mit hochfesten Feinkornbaustählen N2 - Die additive Verarbeitung hochfester Feinkornbaustähle mittels Wire Arc Additive Manufacturing (WAAM) ist ein komplexes, aber zugleich auch effizientes Verfahren, bei dem Werkstoff, Bauteilgeometrie und Schweißprozess gezielt aufeinander abgestimmt sein müssen. Ziel dieser Studie war es, einen Zusammenhang zwischen den Prozessparametern und der generierten Schichtgeometrie zu ermitteln. Dazu wurden definierte Referenzkörper mit einem robotergestützten Schweißsystem additiv gefertigt und hinsichtlich Schichthöhe, Wandstärke und Mikrostruktur analysiert. Fokus der Untersuchung waren sowohl konventionelle als auch für die WAAM-Fertigung speziell entwickelte hochfeste Schweißzusatzwerkstoffe. Die geometrischen Eigenschaften additiv gefertigter Bauteile lassen sich insbesondere durch die Faktoren Drahtvorschubgeschwindigkeit und Schweißgeschwindigkeit gezielt einstellen. Jedoch können diese Parameter nicht beliebig variiert werden, auch aufgrund der rheologischen Eigenschaften der Zusatzwerkstoffe. Zu hohe Streckenenergien führen zu lokalen Überhitzungen und Fehlstellen in der generierten Schicht. Undefinierte Fließ- und Erstarrungsvorgänge im überhitzten Bereich erschweren die maßhaltige Fertigung. Deshalb wird bei speziellen WAAM-Schweißdrähten das Fließverhalten gezielt modifiziert, sodass es über einen größeren Temperaturbereich hinweg konstant ist. Erst die Kenntnis über die komplexen Zusammenhänge zwischen den Prozessparametern und der Bauteilgeometrie ermöglicht die Erzeugung exakter Schichtmodelle für die additive Fertigung. Dies bildet die Grundlage für die Bearbeitung weiterer Fragestellungen auf dem Gebiet der additiven Fertigung mit hochfesten Zusatzwerkstoffen und insbesondere deren Anwendung in modernen hochfesten Bauteilen. T2 - 41. Assistentenseminar Fügetechnik CY - Magdeburg, Germany DA - 03.09.2020 KW - Additiver Fertigung KW - MSG-Schweißen KW - Eigenspannungen KW - Hochfester Stahl KW - Kaltrisssicherheit PY - 2020 AN - OPUS4-56690 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - van Beek, F. A1 - Kuijper, P. A1 - Voskuilen, J. A1 - Hean, S. A1 - Recknagel, Christoph A1 - Mookhoek, S. D. A1 - van Vliet, D. T1 - Guidlines for flexible joint transition systems RTD 1007-4:2020 N2 - Flexible joint transition systems in the form of bituminous joint transitions, type 4.1a according to RTD1007-1, have been used in the Netherlands with varying success. The lifespan in practice was found to vary greatly: between 1 and 5 years. This is too short a lifespan in relation to the lifespan of the layers of asphalt pavement. Ideally, the replacement of these bituminous joint transitions should take place simultaneously as the maintenance of the asphalt layers. In the meantime, research has been carried out nationally and internationally into improving the life span of bituminous joint transitions. In Germany and Switzerland, the regulations have been shown to lead to a life span of more than 10 years. On this basis, ETAG032-3 was established in the context of EOTA in 2013. In a competition "Silent sustainable joint transitions" held by the Dutch Directorate-General for Public Works and Water Management in the period 2007-2012, three flexible bituminous joint transitions have already been tested, two of which were ultimately found to be suitable. These have been included in the multi-choice matrix (RTD 1007-1) as concept 4.1b (anchored bituminous joint transition) and 4.1c (unanchored bituminous joint transition with stretch-spreading inlay and poured asphalt edge beams). Monitoring these joint transitions in practice over the past 8 years has shown that the desired life span is achievable with these improved joint transitions. It is expected that the improvement in life span achieved abroad can also be realised in the Netherlands if several aspects specific to the Netherlands are taken into account:  For large parts of the Dutch main road network, the traffic intensity of 500,000 heavy vehicles per year assumed in the ETAG032-3 is insufficient. This is a factor 4 to 5 higher on the busiest main roads in the Netherlands.  On 90% of the Dutch main road network, in contrast to countries such as Germany and Switzerland, an open layer (ZOAB (zeer open asfaltbeton [very open asphalt concrete])) is used.  In the Netherlands, in contrast to countries such as Germany and Switzerland, bridges and viaducts are made on a large scale of prefabricated beams and 'floating' support systems that consist entirely of rubber supports that can be deformed all-round. Such constructions have a less favourable, high-frequency deformation behaviour under traffic load.  In Germany and Switzerland, a minimum joint mass temperature of -20 °C is assumed to test bituminous joint transitions. For the Netherlands, -15 °C is assumed, which has a favourable effect. The present second version of RTD 1007-4 is a guideline for the development and realisation of a new generation of more durable flexible joint transitions with a minimum design life of 10-15 years and is a guideline for contractors to demonstrate that a flexible joint transition system meets the requirements as set out in the Directorate-General for Public Works and Water Management guideline RTD 1007-2. KW - Technical rule KW - Approval requirements KW - Extension joints KW - Highway pavements PY - 2020 VL - Version 2.0 SP - 1 EP - 77 CY - Rijkswaterstaat AN - OPUS4-54599 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - RPRT A1 - Denkler, Tilman T1 - Comparison of the Operation of Accreditation Bodies in Europe - Final Report 2nd Round N2 - In 2019 the Bundesanstalt für Materialforschung und –prüfung (BAM) conducted a benchmarking to compare the operations of European accreditation bodies and to identify best practices, with the aim of improving key processes in accreditation. Ten European accreditation bodies attended the comparison, four of which had already taken part in the pilot phase of the benchmarking project, which was conducted in 2017 by the German accreditation body Deutsche Akkreditierungsstelle GmbH (DAkkS) and BAM. The study, designed to examine and compare the operation of accreditation bodies in Europe, used a management tool called Process Maturity Benchmarking Tool, which was especially elaborated and validated for this purpose in the pilot phase, in order to determine the values of indicators, thus enabling a comparison of the accreditation bodies despite different operational processes and organizational forms. The management tool is based on the analysis of selected processes with high relevance for the operation of accreditation bodies. The processes are derived from a process map designed for accreditation bodies in a universally applicable way. The indicators used to characterize the processes come from two sources: The first source relates to data already available from internal databases, reports, financial audits, and others. The second source is derived from the self-evaluation of process maturity performed by the accreditation bodies. The criteria for evaluating process maturities were designed by applying the criteria of the EFQM excellence model 2013 of the European Foundation for Quality Management (EFQM) to the processes identified in the process map. The results of the analysis were presented to and discussed with representatives of the ten accreditation bodies at a Results-Workshop that took place at BAM on 21/22 January 2020. KW - Akkreditierung KW - Accreditation KW - Benchmarking KW - EFQM Excellence Modell KW - Quality Infrastructure KW - Total Quality Management PY - 2020 SP - 1 EP - 70 AN - OPUS4-54712 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR ED - Stawski, Tomasz ED - Van Driessche, A. E. S. T1 - Special issue "Formation of sulfate minerals in natural and industrial environments" N2 - Sulfate is abundant in the environment and, as a result, sulfate-containing minerals constitute a large and important focus of research. These minerals play an important role in many geochemical and industrial processes, including the sulfur cycle, the construction industry (e.g., plaster of Paris), fault tectonics, acid mine drainage, and even rare biominerals. Important to note are the abundant amounts of sulfate (minerals) located on the surface of Mars, and in meteorites, extending the relevance of this mineral group beyond the realm of our planet. In geological systems, sulfate minerals such as barite are also important for indicating certain sedimentation environments. In this regard, sulfate deposits can be used to evaluate the redox state of ancient oceans during early Earth time periods. KW - Calcium sulfate KW - Sulfates PY - 2020 UR - https://www.mdpi.com/journal/minerals/special_issues/FSMNIE SN - 2075-163X VL - 10(9)-12(3) SP - 10-812-1 EP - 12-299-3 PB - MDPI CY - Basel AN - OPUS4-54700 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Steger, Simon A1 - Stege, H. A1 - Bretz, S. A1 - Hahn, Oliver ED - Tomasin, P. T1 - Disclosing glittering and sparkling effects in 20th-century reverse glass paintings: a study of metallic pigments and metal foils by means of in situ XRF and DRIFTS analysis N2 - This work presents a spectroscopic study of metallic pigments and metal foils used in reverse glass paintings that were created between 1912 and 1954. Metallic pigments induce a notable sparkling effect by means of the lateral incidence of light, whereas metal foils enhance the gloss and create a glittering effect when the painting is viewed in reflected light. Both effects were desired features especially in modern reverse paintings on glass and applied by artists in manifold creative manner. The paper gives an overview on the composition of the metalfoils and metal pigments in 14 works as determined in situ by X-ray spectrometry. Metal foils made of tin, brass, aluminium and silver were found in nine paintings. Gold imitating Cu-Zn pigments in different hues and with various Cu/Zn net intensity ratios were recorded for six paintings. Silvery pigments were identified mainly as Al pigments, but also as Cu-Zn-Ni alloy in one case. Other uncommon metallic pigments were detected in Arlequin vindicatif (c. 1925) by Floris Jespers, who used not only Cu-Zn and Al pigments, but also brownish Cu and Cu-Zn-Sn pigments. Non-invasive diffuse reflectance infrared Fourier-transform spectroscopy (DRIFTS) was used to classify the binding media of the metallic pigments. Drying oil and natural resin probably mixed with oil were the most common binding media. A polysaccharide-based binder was found in the silvery Cu-Zn-Ni pigment of Ohne Titel (1954) by Marianne Uhlenhuth. KW - Archaeometry KW - Non-invasive analysis KW - Reverse paintings on glass PY - 2020 DO - https://doi.org/10.1016/j.culher.2020.11.008 SN - 1296-2074 VL - 48 SP - 196 EP - 204 PB - Elsevier Masson SAS CY - Amsterdam AN - OPUS4-54428 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Zancajo, V. M. R. A1 - Lindtner, T. A1 - Eisele, M. A1 - Huber, A. J. A1 - Elbaum, R. A1 - Kneipp, Janina T1 - FTIR Nanospectroscopy Shows Molecular Structures of Plant Biominerals and Cell Walls N2 - Plant tissues are complex composite structures of organic and inorganic components whose function relies on molecular heterogeneity at the nanometer scale. Scattering-type near-field optical microscopy (s-SNOM) in the mid-infrared (IR) region is used here to collect IR nanospectra from both fixed and native plant samples. We compared structures of chemically extracted silica bodies (phytoliths) to silicified and nonsilicified cell walls prepared as a flat block of epoxy-embedded awns of wheat (Triticum turgidum), thin sections of native epidermis cells from sorghum (Sorghum bicolor) comprising silica phytoliths, and isolated cells from awns of oats (Avena sterilis). The correlation of the scanning-probe IR images and the mechanical phase image enables a combined probing of mechanical material properties together with the chemical composition and structure of both the cell walls and the phytolith structures. The data reveal a structural heterogeneity of the different silica bodies in situ, as well as different compositions and crystallinities of cell wall components. In conclusion, IR nanospectroscopy is suggested as an ideal tool for studies of native plant materials of varied origins and preparations and could be applied to other inorganic–organic hybrid materials. KW - Cells KW - Plants KW - Organic polymers KW - Silica KW - Infrared light PY - 2020 DO - https://doi.org/10.1021/acs.analchem.0c00271 SN - 0003-2700 VL - 92 IS - 20 SP - 13694 EP - 13701 PB - ACS Publications AN - OPUS4-54445 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Baer, Wolfram T1 - Detection and understanding of the chunky graphite degeneration in ferritic spheroidal graphite cast iron materials with respect to fatigue N2 - CHG is very different compared to other graphite degenerations or defects; Filigree, multi-branched string-like, 3d interconnected structure; Morphology and volumetric amount of CHG cannot be accessed by stereological interpretation of 2d section data; Field-tested, technically established method to quantify CHG in components not available; Fatigue: CHG causes substantial reduction in fatigue limit and significant increase in crack growth rate; Therefore: Avoid or exclude CHG! T2 - 4th International Symposium on Fatigue Design and Material Defects CY - Online meeting DA - 26.05.2020 KW - Ductile cast iron KW - Chunky graphite degeneration KW - Fatigue KW - Correlation microstructure to properties PY - 2020 AN - OPUS4-54409 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Liehr, Sascha T1 - ANNforPAT - Artificial Neural Networks for Process Analytical Technology N2 - This code accompanies the paper "Artificial neural networks for quantitative online NMR spectroscopy" published in Analytical and Bioanalytical Chemistry (2020). KW - Artificial neural networks KW - Automation KW - Online NMR spectroscopy KW - Process industry KW - Real-time process monitoring PY - 2020 UR - https://github.com/BAMresearch/ANNforPAT PB - GitHub CY - San Francisco AN - OPUS4-54481 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Yusenko, Kirill T1 - Single-source precursors strategy to access refractory high-entropy alloys for electrocatalytic applications N2 - High-entropy alloys containing up to 6 platinum group metals can be prepared by thermal decomposition of single-source precursors non requiring high temperature. We prepare the first example of a single-phase hexagonal high-entropy alloy. Heat treat- ment up to 1500 K and compression up to 45 GPa do not result in phase changes, a record temperature and pres- sure stability for a single-phase high-entropy alloy. The alloys show pronounced electrocatalytic activity in methanol oxidation, which opens a route for the use of high-entropy alloys as materials for sustainable energy conversion. T2 - HEA2020: first international virtual workshop on high-entropy alloy and complex solid solution nanoparticles for electrocatalysis CY - Online meeting DA - 06.10.2020 KW - High-entropy alloys KW - Single-source precursors PY - 2020 AN - OPUS4-54013 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -