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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, 2022, 15 (23)
doi: 10.26083/tuprints-00022970
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Item Type: Article
Type of entry: Secondary publication
Title: Thermodynamic Modeling and Experimental Validation of Acetic Acid Attack on Hardened Cement Paste: Effect of Silica Fume
Language: English
Date: 19 December 2022
Place of Publication: Darmstadt
Year of primary publication: 2022
Publisher: MDPI
Journal or Publication Title: Materials
Volume of the journal: 15
Issue Number: 23
Collation: 22 Seiten
DOI: 10.26083/tuprints-00022970
Corresponding Links:
Origin: Secondary publication DeepGreen
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.

Uncontrolled Keywords: cementitious materials, acid attack, silica fume, pozzolanic reaction, thermodynamic modeling, IPHREEQC, solid-liquid phase equilibration experiments
Status: Publisher's Version
URN: urn:nbn:de:tuda-tuprints-229700
Additional Information:

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

Classification DDC: 600 Technology, medicine, applied sciences > 620 Engineering and machine engineering
600 Technology, medicine, applied sciences > 690 Building and construction
Divisions: 13 Department of Civil and Environmental Engineering Sciences > Institute of Construction and Building Materials
Date Deposited: 19 Dec 2022 12:42
Last Modified: 14 Nov 2023 19:05
SWORD Depositor: Deep Green
URI: https://tuprints.ulb.tu-darmstadt.de/id/eprint/22970
PPN: 50324256X
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