Advanced techniques for studying damage mechanisms of cementitious matrices affected by sulfate attack
- Cementitious materials, in particular concrete, are durable materials if prepared appropriately and the Service life of concrete structures is now often required to last 120 years or more. Concrete durability depends strongly on intrinsic (e.g. composition, porosity) and exterior factors (e.g. moisture condition and composition, frost cycles, load pattem). Deleterious actions leading to concrete degradation are often created by the environment. Extemal sulfate attack is one of the more spectacular damage scenarios for concrete structures caused by the ingress of sulfate ions into the pore System of the material and successive formation of expanding phases. Though in recent years well studied there are still many questions remaining conceming the mechanisms of sulfate attack. In particular over the last ten years, with the increased utilization of blended cements, new questions arose concerning the sulfate resistance of those binder Systems. In the presented study therefore a method wasCementitious materials, in particular concrete, are durable materials if prepared appropriately and the Service life of concrete structures is now often required to last 120 years or more. Concrete durability depends strongly on intrinsic (e.g. composition, porosity) and exterior factors (e.g. moisture condition and composition, frost cycles, load pattem). Deleterious actions leading to concrete degradation are often created by the environment. Extemal sulfate attack is one of the more spectacular damage scenarios for concrete structures caused by the ingress of sulfate ions into the pore System of the material and successive formation of expanding phases. Though in recent years well studied there are still many questions remaining conceming the mechanisms of sulfate attack. In particular over the last ten years, with the increased utilization of blended cements, new questions arose concerning the sulfate resistance of those binder Systems. In the presented study therefore a method was developed to analyze the changes of the phase composition within the micro structure due to sulfate attack. The analytical method was based on pX-Ray diffraction (pXRD) using Synchrotron radiation in Debye-Scherrer (transmission) geometry. The spatial resolution of the method is ca. 10 pm and allows the characterization of phase transformations in the wake of damaging processes in more detail compared to other techniques. Furthermore, the experimental setup provides the possibility for analyzing the phase assemblage of a given sample without destroying the micro structure. This is possible because the specimens for phase analysis consists of thick sections, which can be used for further microscopic analysis of the micro structure and micro chemistry (e.g. by SEM-EDX). Samples containing supplementary cementitious materials were measured in comparison and to reconstruct the influence of the degradation process in detail. Additionally, reaction ffonts within the samples were localized by micro x-ray fluorescence analysis (MXRF).…
Autor*innen: | Urs Müller, Moritz-Caspar Schlegel, Franziska EmmerlingORCiD |
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Dokumenttyp: | Beitrag zu einem Tagungsband |
Veröffentlichungsform: | Verlagsliteratur |
Sprache: | Englisch |
Titel des übergeordneten Werkes (Englisch): | EMABM 2011 - 13th Euroseminar on microscopy applied to building materials (Proceedings) |
Jahr der Erstveröffentlichung: | 2011 |
Herausgeber (Institution): | ZAG, Slovenian National Building and Civil Engineering Institute |
Erste Seite: | 1 |
Letzte Seite: | 9 |
Freie Schlagwörter: | Concrete; Phase analysis; Sulfate attack; Synchrotron; XRD |
Veranstaltung: | EMABM 2011 - 13th Euroseminar on microscopy applied to building materials |
Veranstaltungsort: | Ljubljana, Slovenia |
Beginndatum der Veranstaltung: | 14.06.2011 |
Enddatum der Veranstaltung: | 18.06.2011 |
ISBN: | 978-961-90366-7-9 |
Verfügbarkeit des Dokuments: | Datei im Netzwerk der BAM verfügbar ("Closed Access") |
Datum der Freischaltung: | 19.02.2016 |
Referierte Publikation: | Nein |