Comparative study of lightweight aggregates

  • Lightweight aggregates (LWA) are mixtures of porous grains of mineral origin characterised by particle bulk densities less than 2000 kg/m³ or loose bulk densities less than 1200 g/m³. They are used in concrete, mortar and grout in buildings, roads and civil engineering works. LWA are commonly produced by thermal treatment of natural raw materials such as clay, shale and other clayey or igneous rocks at temperatures between 1000 °C and 1300 °C. Expanded clay, expanded shale, vermiculite and expanded perlite are well-known aggregates used in the construction industry today. But porous LWA can also be manufactured from mineral residues, such as waste glass or masonry rubble, by thermal expending process. The source materials must satisfy two conditions. First, their chemical composition must be in balance between fluxing agents, silica and alumina to reach pyroplastic conditions at an economically viable temperature to develop sintering and melting phases of proper viscosity. Second, theLightweight aggregates (LWA) are mixtures of porous grains of mineral origin characterised by particle bulk densities less than 2000 kg/m³ or loose bulk densities less than 1200 g/m³. They are used in concrete, mortar and grout in buildings, roads and civil engineering works. LWA are commonly produced by thermal treatment of natural raw materials such as clay, shale and other clayey or igneous rocks at temperatures between 1000 °C and 1300 °C. Expanded clay, expanded shale, vermiculite and expanded perlite are well-known aggregates used in the construction industry today. But porous LWA can also be manufactured from mineral residues, such as waste glass or masonry rubble, by thermal expending process. The source materials must satisfy two conditions. First, their chemical composition must be in balance between fluxing agents, silica and alumina to reach pyroplastic conditions at an economically viable temperature to develop sintering and melting phases of proper viscosity. Second, the material should contain some components, which ensure gas release during the partial melting, to form expanded porous particles. Lightweight aggregates usually show a heterogeneous and macroporous pore structure. Their solid skeleton is continually opened by large bulky pores whereas the skeletal walls contain many small pores. Additionally, the grains consist of partly melted areas. The specific microstructural and morphological characteristics of different LWA are strongly influenced by the great variety of source materials and the particular manufacturing conditions. Recycling granules (RC granules), which are lightweight aggregates made from masonry rubble containing about 50 % brick material, are already described in terms of manufacturing process, engineering properties and microstructure in. The objective of this study is to compare the chemical, physical, mineralogical and microstructural characteristics of RC granules with those of commercially produced expanded clay aggregates. Results of the ICP optical emission spectrometry, X-ray diffraction, thermal analysis, fusibility tests, particle shape analysis, porosity measurements, mercury intrusion porosimetry und environmental scanning electron microscopy are presented. The microstructural characteristics are correlated with engineering properties of the lightweight aggregates, such as water absorption and particle strength. The study was part of two research projects that were supported by the Federal Ministry of Education and Research in the framework of the funding initiative “r2-Innovative Technologies for Resource Efficiency - Resource-Intensive Production Processes” and the Bundesministerium für Wirtschaft und Energie in the framework of the Central Innovation Programme for SMEs.zeige mehrzeige weniger

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Metadaten
Autor*innen:Katrin RübnerORCiD
Koautor*innen:S. Hempel, Mathias Lindemann, Burkhard Peplinski, Nico VoglerORCiD, Annett Zimathies
Dokumenttyp:Posterpräsentation
Veröffentlichungsform:Präsentation
Sprache:Englisch
Jahr der Erstveröffentlichung:2017
DDC-Klassifikation:Technik, Medizin, angewandte Wissenschaften / Ingenieurwissenschaften / Ingenieurbau
Technik, Medizin, angewandte Wissenschaften / Ingenieurwissenschaften / Sanitär- und Kommunaltechnik; Umwelttechnik
Freie Schlagwörter:Composition and pore structure; Expanded clay; Lightweight aggregates (LWA); Recycling granules
Veranstaltung:11th International Symposium on the Charcterization of Porous Solids (COPS-XI)
Veranstaltungsort:Avignon, France
Beginndatum der Veranstaltung:14.05.2017
Enddatum der Veranstaltung:17.05.2017
Verfügbarkeit des Dokuments:Datei im Netzwerk der BAM verfügbar ("Closed Access")
Datum der Freischaltung:13.02.2018
Referierte Publikation:Nein
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