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Reducing sulphates in crushed concrete: improving the building material properties of recycled concrete aggregates

  • 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 ofThe 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.zeige mehrzeige weniger

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Metadaten
Autor*innen:Karin Weimann, A. Müller, E. Linß, T. Schulz, Burkart Adamczyk
Persönliche Herausgeber*innen:M.R. Jones, M.D. Newlands, J.E. Halliday, L.J. Csetenyi, Z. Li, M.J. McCarthy, T.D. Dyer
Dokumenttyp:Beitrag zu einem Tagungsband
Veröffentlichungsform:Verlagsliteratur
Sprache:Englisch
Titel des übergeordneten Werkes (Englisch):Tagung 'Cocrete in the low carbon era'
Jahr der Erstveröffentlichung:2012
Herausgeber (Institution):University of Dundee
Erste Seite:687
Letzte Seite:698
Freie Schlagwörter:Building material properties; Environmental performance evaluation; Gypsum; Recycled concrete aggregates; Sulphates
Veranstaltung:Tagung 'Cocrete in the low carbon era'
Veranstaltungsort:Dundee, Great Britain
Beginndatum der Veranstaltung:2012-07-09
Enddatum der Veranstaltung:2012-07-11
ISBN:978-0-9573263-0-9
Verfügbarkeit des Dokuments:Physisches Exemplar in der Bibliothek der BAM vorhanden ("Hardcopy Access")
Bibliotheksstandort:Sonderstandort: Publica-Schrank
Datum der Freischaltung:19.02.2016
Referierte Publikation:Nein
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