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Thermodynamic Modeling and Experimental Validation of Acetic Acid Attack on Hardened Cement Paste: Effect of Silica Fume

Berger, Felix ; Bogner, Andreas ; Hirsch, Astrid ; Ukrainczyk, Neven ; Dehn, Frank ; Koenders, Eduardus (2022)
Thermodynamic Modeling and Experimental Validation of Acetic Acid Attack on Hardened Cement Paste: Effect of Silica Fume.
In: Materials, 15 (23)
doi: 10.3390/ma15238355
Artikel, Bibliographie

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Kurzbeschreibung (Abstract)

Concrete structures are increasingly becoming exposed to organic acid attack conditions, such as those found in agriculture and food-related industries. This paper aims to experimentally verify the thermodynamic modeling of cement pastes under acetic acid attack. For this, a modeling approach implemented in IPHREEQC via Matlab is described, and results are compared with measured pH and compositions of equilibrated solutions (MP-AES) as well as unreacted/precipitated solids (XRF, XRD and STA) for a wide range of acid concentrations. The 11% replacement of cement by silica fume (SF) led to a 60 or 70% reduction (measured or modeled, respectively) of Portlandite content in the hardened cement paste due to the pozzolanic reaction resulting in higher content of CSH phases, which has effects on the progression of dissolution processes and a resulting pH with increased acid concentrations. Considering that no fitting parameter was used, the model predictions showed good agreement with measured values of pH, dissolved ion concentrations and composition of the remaining (degraded) solids overall. The discrepancies here were more pronounced at very high acid concentrations (equilibrium pH < ~4), i.e., after the full dissolution of hydrate phases due to limitations in the model used to describe Al-, Si- and Fe-gel phases and/or identified experimental challenges in precipitation of calcium and aluminum acetate hydrates.

Typ des Eintrags: Artikel
Erschienen: 2022
Autor(en): Berger, Felix ; Bogner, Andreas ; Hirsch, Astrid ; Ukrainczyk, Neven ; Dehn, Frank ; Koenders, Eduardus
Art des Eintrags: Bibliographie
Titel: Thermodynamic Modeling and Experimental Validation of Acetic Acid Attack on Hardened Cement Paste: Effect of Silica Fume
Sprache: Englisch
Publikationsjahr: 2022
Ort: Darmstadt
Verlag: MDPI
Titel der Zeitschrift, Zeitung oder Schriftenreihe: Materials
Jahrgang/Volume einer Zeitschrift: 15
(Heft-)Nummer: 23
Kollation: 22 Seiten
DOI: 10.3390/ma15238355
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Kurzbeschreibung (Abstract):

Concrete structures are increasingly becoming exposed to organic acid attack conditions, such as those found in agriculture and food-related industries. This paper aims to experimentally verify the thermodynamic modeling of cement pastes under acetic acid attack. For this, a modeling approach implemented in IPHREEQC via Matlab is described, and results are compared with measured pH and compositions of equilibrated solutions (MP-AES) as well as unreacted/precipitated solids (XRF, XRD and STA) for a wide range of acid concentrations. The 11% replacement of cement by silica fume (SF) led to a 60 or 70% reduction (measured or modeled, respectively) of Portlandite content in the hardened cement paste due to the pozzolanic reaction resulting in higher content of CSH phases, which has effects on the progression of dissolution processes and a resulting pH with increased acid concentrations. Considering that no fitting parameter was used, the model predictions showed good agreement with measured values of pH, dissolved ion concentrations and composition of the remaining (degraded) solids overall. The discrepancies here were more pronounced at very high acid concentrations (equilibrium pH < ~4), i.e., after the full dissolution of hydrate phases due to limitations in the model used to describe Al-, Si- and Fe-gel phases and/or identified experimental challenges in precipitation of calcium and aluminum acetate hydrates.

Freie Schlagworte: cementitious materials, acid attack, silica fume, pozzolanic reaction, thermodynamic modeling, IPHREEQC, solid-liquid phase equilibration experiments
Zusätzliche Informationen:

This article belongs to the Special Issue Mathematical Modeling of Building Materials

Sachgruppe der Dewey Dezimalklassifikatin (DDC): 600 Technik, Medizin, angewandte Wissenschaften > 620 Ingenieurwissenschaften und Maschinenbau
600 Technik, Medizin, angewandte Wissenschaften > 690 Hausbau, Bauhandwerk
Fachbereich(e)/-gebiet(e): 13 Fachbereich Bau- und Umweltingenieurwissenschaften
13 Fachbereich Bau- und Umweltingenieurwissenschaften > Institut für Werkstoffe im Bauwesen
Hinterlegungsdatum: 02 Aug 2024 12:46
Letzte Änderung: 02 Aug 2024 12:46
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