TY - CONF A1 - Weimann, Karin A1 - Müller, A. A1 - Linß, E. A1 - Schulz, T. A1 - Adamczyk, Burkart ED - Jones, M.R. ED - Newlands, M.D. ED - Halliday, J.E. ED - Csetenyi, L.J. ED - Li, Z. ED - McCarthy, M.J. ED - Dyer, T.D. T1 - Reducing sulphates in crushed concrete: improving the building material properties of recycled concrete aggregates N2 - The material properties of recycled concrete aggregates (RCA) are correlated to the sorting accuracy of the former demolition waste. Impurities like wood, clay bricks or gypsum can lead to inferior building material properties. Harmful substances like heavy metals or organic pollutants should be minimised as well. Hence the non-concrete materials have to be separated from the concrete material stream. This can be done during the demolition process by using selective dismantling techniques. Alternatively a variety sorting and classifying techniques to purify the crushed concrete can be utilized. A research project, funded by the Federal Ministry for the Environment, Nature Conservation and Nuclear Safety, investigated the possibilities of gaining recycled concrete aggregates of a high quality for the reuse in the production of concrete. The work focuses especially on how gypsum respectively sulphates in the crushed concrete can be reduced. Sulphates can impair the setting behaviour of concrete and also damage set concrete by causing expansion. Therefore the content of sulphates in RCA is restricted by guidelines and standards in Germany. Generally, gypsum in construction waste originates from interior fittings like gypsum walls, floor screeds, plaster boards and also plaster. Most of these materials can be reconstructed using selective dismantling techniques. This can be achieved either by manual labour or by using mechanical equipment e.g. to remove floor screeds by milling. Depending on the specific deconstruction site it can be more effective and/or more environmentally compatible to remove sulphates by treating the crushed concrete. Applicable treatments for sulphate reduction include dry processes like manual sorting of gypsum wall blocks as well as wet treatments e.g. jigging. In addition this research project an environmental performance evaluation was undertaken to assess different techniques for reducing sulphates in recycled concrete aggregates. T2 - Tagung 'Cocrete in the low carbon era' CY - Dundee, Great Britain DA - 2012-07-09 KW - Building material properties KW - Environmental performance evaluation KW - Gypsum KW - Recycled concrete aggregates KW - Sulphates PY - 2012 SN - 978-0-9573263-0-9 SP - 687 EP - 698 AN - OPUS4-26211 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - RPRT A1 - Weimann, Karin A1 - Matyschik, Jan A1 - Adam, Christian A1 - Schulz, T. A1 - Linß, E. A1 - Müller, A. T1 - Optimierung des Rückbaus/Abbruchs von Gebäuden zur Rückgewinnung und Aufbereitung von Baustoffen unter Schadstoffentfrachtung (insbes. Sulfat) des RCMaterials sowie ökobilanzieller Vergleich von Primär- und Sekundärrohstoffeinsatz inkl. Wiederverwertung N2 - Aufgrund der großen Massenströme ist das Recycling von Baurestmassen von besonderer Bedeutung für die Schonung von natürlichen Ressourcen. Eine wichtige Voraussetzung für ein hochwertiges Recycling, wie z.B. eine Wiederverwertung von aufbereitetem Bauschutt/Altbeton als rezyklierte Gesteinskörnung im Hochbau, ist die Einhaltung von Grenzwerten für Stör- und Schadstoffe. Dabei steht der Sulfatgehalt im Eluat von Bauschutt besonders im Fokus. In der vorliegenden Studie wird untersucht, wie durch die Optimierung von Abbrucharbeiten und Bauschuttaufbereitung hochwertige Gesteinskörnungen aus Altbeton gewonnen werden können. Anhand von Literatur- und Datenrecherchen werden zunächst Sulfatquellen in Gebäuden sowie verfügbare Abbruch- und Aufbereitungstechniken zusammengestellt. Am Beispiel von unterschiedlichen Gebäudetypen werden Szenarien für selektiven und nicht selektiven Abbruch (Schwerpunkt: Sulfatentfachtung) in Hinblick auf ihre Umweltwirkungen ökobilanziell bewertet. Ergänzt werden diese Bewertungen durch Untersuchungen an realen Bauschuttmaterialien und Abbruchprojekten. Auf dieser Basis werden Handlungsempfehlungen für die Gewinnung von hochwertigen RC-Gesteinskörnungen erarbeitet und diskutiert.----------------------------------------------------------------------------------------- Due to the large-scale mass flow of construction and demolition wastes, the recycling of those residues is of particular importance for the conservation of natural resources. An important requirement for recycling on a high level, like the reuse of crushed concrete as recycled concrete aggregate, is the observation of limits for hazardous substances and impurities. This study is focusing on the reduction of sulphates in the eluate of crushed concrete. An investigation of possibilities to optimize demolition and dismantling as well as treatment of crushed concrete with the objective of gaining recycled concrete aggregates of high quality. Based on a literature research and a data review the origins of sulfates in buildings and also the availability of techniques for demolition and treatment of crushed concrete are listed and evaluated. Using the examples of different building types scenarios for selective dismantling and non-selective demolition (focused on reducing suphates) are evaluated in terms of affecting the environment. In addition samples from real demolition construction sites and plants for treatment of construction rubble were investigated. Based on these results recommendations for the production of high quality recycled concrete aggregates are worked out. KW - Bauschuttaufbereitung KW - Abbruch KW - Ökobilanzielle Bewertung KW - RC-Beton KW - Gips KW - Abbruchverfahren KW - Hochwertiges Recycling KW - Ökobilanzielle Betrachtung KW - Sulfatentfachtung KW - Demolition/dismantling KW - Treatment of C&D wastes KW - High-grade recycling KW - Environmental LCA KW - Reduction of sulphates PY - 2012 UR - http://www.umweltbundesamt.de/publikationen/optimierung-des-rueckbausabbaus-von-gebaeuden-zur SN - 1862-4804 SP - 1 EP - 227 PB - Umweltbundesamt CY - Dessau-Roßlau AN - OPUS4-26999 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bütefisch, S. A1 - Weimann, T. A1 - Busch, I. A1 - Danzebrink, H.-U. A1 - Gross, Thomas A1 - Unger, Wolfgang A1 - Wirth, Thomas T1 - New reference material for imaging XPS (X-ray photoelectron spectroscopy) instrument characterization N2 - Reference materials without variations in topography are essential for the characterization of imaging XPS (X-ray Photoelectron Spectroscopy) Instruments. Therefore a new fabrication process for this kind of zero-topography reference material was developed at PTB and resulted in first prototypes. The fabrication process and first measurement results will be presented in this paper. T2 - Sensor 2015 - 17th International conference on sensors and measurement technology CY - Nuremberg, Germany DA - 19.05.2015 KW - Imaging XPS KW - Reference material KW - Topography free KW - Micro technology PY - 2015 SN - 978-3-9813484-8-4 DO - https://doi.org/10.5162/sensor2015/P7.1 SP - Chapter P7, 821 EP - 825 AN - OPUS4-33837 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Weimann, Karin A1 - Adam, Christian A1 - Schulz, T. A1 - Linsz, E. T1 - Environmental evaluation of different ways to produce recycled concrete aggregates N2 - Due to the great quantities of construction and demolition waste in Europe, the reuse of building material waste as secondary raw materials is of particular importance. A recycling of building materials can meet the requirements of sustainability in several aspects: the extended time availability of primary raw materials and the related protection of natural resources as well as the saving of landfill sites. In recent years sulphates originating from gypsum in secondary building materials, made of construction and demolition waste, received growing attention. Sulphates are unwanted in secondary building materials for concrete production as well as for other use e.g. in unbounded layers. The content of gypsum resp. sulphates in secondary aggregates can be reduced by different methods. Depending on the type of material different steps for selective dismantling can be used to separate gypsum containing residues from concrete rubble. Furthermore some steps for the processing of building rubble are suitable for the reduction of sulphates in the produced aggregates. An environmental evaluation of different ways for the production of recycled concrete aggregates was performed with regard to a reduction of sulphates in the secondary building material. The use of techniques for selective dismantling was environmentally advantegous for the deconstruction of three investigated model houses. T2 - SUM2014 - 2nd Symposium on urban mining CY - Bergamo, Italy DA - 19.05.2014 KW - Recycling KW - Concrete aggregates KW - Building waste KW - Construction PY - 2014 SN - 9788862650311 SP - Session C 6, 1 EP - 8 AN - OPUS4-30825 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Unger, Wolfgang A1 - Stockmann, Jörg M. A1 - Senoner, Mathias A1 - Weimann, T. A1 - Bütefisch, S. A1 - Passiu, C. A1 - Spencer, N. D. A1 - Rossi, A. T1 - Introduction to lateral resolution and analysis area measurements in XPS N2 - Imaging and small-spot (small area) XPS have become increasingly important components of surface chemical analysis during the last three decades, and its use is growing. Some ambiguity in the use of terminology, understanding of concepts, and lack of appropriate reference materials leads to confusing and not always reproducible data. In this paper, it is shown that by using existing knowledge, appropriate test specimens, and standardized approaches, problems of comparability and such reproducibility issues recently observed for XPS data reported in the scientific literature can be overcome. The standardized methods of ISO 18516:2019, (i) the straight-edge, (ii) the narrow-line, and (iii) the grating method, can be used to characterize and compare the lateral resolution achieved by imaging XPS instruments and are described by reporting examples. The respective measurements are made using new test specimens. When running an XPS instrument in the small-spot (small area) mode for a quantitative analysis of a feature of interest, the question arises as to what contribution to the intensity originates from outside the analysis area. A valid measurement approach to control the intensity from outside the nominal analysis area is also described. As always, the relevant resolution depends on the specific question that needs to be addressed. The strengths and limitations of methods defining resolution are indicated. KW - Imaging XPS KW - Lateral resolution KW - Analysis area measurements KW - Small-spot XPS PY - 2020 DO - https://doi.org/10.1116/6.0000398 VL - 38 IS - 5 SP - 053206 AN - OPUS4-51394 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Stockmann, Jörg M. A1 - Radnik, Jörg A1 - Bütefisch, S. A1 - Busch, I. A1 - Weimann, T. A1 - Passiu, C. A1 - Rossi, A. A1 - Unger, Wolfgang T1 - A new test specimen for the determination of the field of view of small-area X-ray photoelectron spectrometers N2 - Small-area/spot photoelectron spectroscopy (SAXPS) is a powerful tool for the investigation of small surface features like microstructures of electronic devices, sensors or other functional surfaces, and so forth. For evaluating the quality of such microstructures, it is often crucial to know whether a small signal in a spectrum is an unwanted contamination of the field of view (FoV), defined by the instrument settings, or it originated from outside. To address this issue, the d80/20 parameter of a line scan across a chemical edge is often used. However, the typical d80/20 parameter does not give information on contributions from the long tails of the X-ray beam intensity distribution or the electron-optical system as defined by apertures. In the VAMAS TWA2 A22 project “Applying planar, patterned, multi-metallic samples to assess the impact of analysis area in surface-chemical analysis,” new test specimen was developed and tested. The here presented testing material consists of a silicon wafer substrate with an Au-film and embedded Cr circular and square spots with decreasing dimensions from 200 μm down to 5 μm. The spot sizes are traceable to the length unit due to size measurements with a metrological SEM. For the evaluation of the FoV, we determined the Au4f intensities measured with the center of the FoV aligned with the center of the spot and normalized to the Au4f intensity determined on the Au-film. With this test specimen, it was possible to characterize, as an example, the FoV of a Kratos AXIS Ultra DLD XPS instrument. T2 - ECASIA 2019 CY - Dresden, Germany DA - 15.09.2019 KW - Field of view KW - Reference material KW - Selected area XPS KW - Small-area XPS KW - Small-spot XPS PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-509902 DO - https://doi.org/10.1002/sia.6831 SN - 1096-9918 VL - 52 IS - 12 SP - 890 EP - 894 PB - John Wiley & Sons Ltd AN - OPUS4-50990 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -