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 - 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 - 09.07.2012 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 -