- Verlag Bau + Technik
- Eintrag
Brechsand als Zementhauptbestandteil
Leitlinien künftiger Anwendung im Zement und Beton
Müller, Christoph / Severins, Katrin / Spanka, Gerhard
Klimaschutz und Ressourceneffizienz sind zwei wesentliche Themen der umweltpolitischen Agenda. Sie werden zweifelsohne auch das Bauen mit Zement und Beton weiterhin beeinflussen. Der Einsatz von Recyclingbrechsand im Zementwerk trägt dazu bei, mineralische Stoffkreisläufe weiter zu schließen. Seine Verwendung als Hauptbestandteil bietet eine Möglichkeit, den Anteil des Portlandzementklinkers zu reduzieren und somit CO2-Emissionen zu senken. Allerdings muss hierzu ein kontinuierlicher, gleichmäßiger Stoffstrom von entsprechender Qualität zwischen Aufbereitern und Zementwerk gegeben sein. Zudem wäre eine allgemeine bauaufsichtliche Zulassung/Zustimmung im Einzelfall notwendig. Ausgehend von aktuell geltenden Regelwerken werden im Folgenden Ergebnisse aus dem Forschungsvorhaben „R-Beton“ (www.r-beton.de) vorgestellt sowie Vorschläge zur Herstellung ressourcenschonender Zemente mit gemahlenem Recyclingbrechsand als Hauptbestandteil abgeleitet. Im Projekt „R-Beton“ wurden die brechsandhaltigen Zemente als „R-Zemente“ bezeichnet. Das Projekt wurde mit Mitteln des Bundesministeriums für Bildung und Forschung (BMBF) gefördert.
Crushed sand as a main cement constituent – guidelines for future use in cement and concrete
The use of recycled crushed sands contributes to closing the material cycles in the building materials industries that process nonmetallic minerals. The potential that arises from the processing of mineral demolition waste for the production of resource-conserving concretes was investigated in the “R-Beton” joint research project. Investigations by VDZ gGmbH showed that the production and use of clinker-efficient cements that contain finely ground crushed sand as a main cement constituent can represent an alternative recycling route. Crushed sand from railway sleepers, railway ballast, crushed concrete, bricks, tiles and masonry was used in the project. In Germany, the recycling of crushed sand in this way involves proof of usability in accordance with building regulations law. In addition to the environmental compatibility of the crushed sands and the technical performance of the cements containing crushed sand as specified in DIN EN 197-1 it also is necessary to comply with the approvalrelevant durability for the concretes to be produced with these cements (so-called R-cements) and fulfil building inspectorate requirements. The investigations in the project have shown, for example, that concretes made with R-cements containing 10 or 30 mass % crushed masonry with a high brick/tile content can pass all the durability tests safely, in contrast to cements made with crushed sand of different origin. When the results obtained in the project are considered as a whole it can be stated that R-cements made with up to 30 mass % crushed sand could, at least, be used for internal component concretes but external components in building construction also appear to be possible. The investigations carried out on crushed sands with respect to their effects on soil and water have shown that the environmental analysis requirements for solids and eluates as specified in DIN 4226-101 can be fulfilled.
Crushed sand as a main cement constituent – guidelines for future use in cement and concrete
The use of recycled crushed sands contributes to closing the material cycles in the building materials industries that process nonmetallic minerals. The potential that arises from the processing of mineral demolition waste for the production of resource-conserving concretes was investigated in the “R-Beton” joint research project. Investigations by VDZ gGmbH showed that the production and use of clinker-efficient cements that contain finely ground crushed sand as a main cement constituent can represent an alternative recycling route. Crushed sand from railway sleepers, railway ballast, crushed concrete, bricks, tiles and masonry was used in the project. In Germany, the recycling of crushed sand in this way involves proof of usability in accordance with building regulations law. In addition to the environmental compatibility of the crushed sands and the technical performance of the cements containing crushed sand as specified in DIN EN 197-1 it also is necessary to comply with the approvalrelevant durability for the concretes to be produced with these cements (so-called R-cements) and fulfil building inspectorate requirements. The investigations in the project have shown, for example, that concretes made with R-cements containing 10 or 30 mass % crushed masonry with a high brick/tile content can pass all the durability tests safely, in contrast to cements made with crushed sand of different origin. When the results obtained in the project are considered as a whole it can be stated that R-cements made with up to 30 mass % crushed sand could, at least, be used for internal component concretes but external components in building construction also appear to be possible. The investigations carried out on crushed sands with respect to their effects on soil and water have shown that the environmental analysis requirements for solids and eluates as specified in DIN 4226-101 can be fulfilled.
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beton 9/2020 ab Seite 336
Herausgeber des Artikels:
beton
bis beton 4/2022: Verlag Bau+Technik GmbH
ab beton 5/2022: Concrete Content UG
Wuppertal / Schermbeck
Tel: +49 (0) 2 02 7 69 92 69
Fax: +49 (0) 2 02 7 69 92 70
beton
bis beton 4/2022: Verlag Bau+Technik GmbH
ab beton 5/2022: Concrete Content UG
Wuppertal / Schermbeck
Tel: +49 (0) 2 02 7 69 92 69
Fax: +49 (0) 2 02 7 69 92 70