Interactions between hydrated cement pastes and aggressive ammonium: experimental batches characterization

Agricultural and food industries concrete facilities face chemically aggressive conditions that can damage their microstructure and reduce their lifespan. They are particularly exposed to ammonium-rich environments from natural microbial activity. The poorly crystalline mineralogy of hydrated cement...

Ausführliche Beschreibung

Gespeichert in:
Bibliographische Detailangaben
Veröffentlicht in:MATEC web of conferences 2022, Vol.364, p.5010
Hauptverfasser: Giroudon, Marie, Roosz, Cédric, Bista, Mehdi, Peyre Lavigne, Matthieu, Lacarrière, Laurie, Bertron, Alexandra
Format: Artikel
Sprache:eng
Schlagworte:
Online-Zugang:Volltext
Tags: Tag hinzufügen
Keine Tags, Fügen Sie den ersten Tag hinzu!
Beschreibung
Zusammenfassung:Agricultural and food industries concrete facilities face chemically aggressive conditions that can damage their microstructure and reduce their lifespan. They are particularly exposed to ammonium-rich environments from natural microbial activity. The poorly crystalline mineralogy of hydrated cement pastes, the compositional variability of the phases and their reactivity make the geochemical behaviour of such materials difficult to investigate and predict over both large periods of time and wide variety of chemical compositions. This work aims (i) to assess the stability of the cement phases involved in ammonium-rich conditions as well as to identify the alteration products, and (ii) to understand the mechanisms and intensity of alteration. To do this, experiments were carried out both on OPC paste powder and on monolithic OPC pastes, degraded by an ammonium nitrate solution in semi-batch conditions. The powder was gradually added to the aggressive solution while the monoliths were immersed for 16 weeks in regularly renewed solution. The pH and the concentration of the chemical elements in solution were monitored over the experiments. The microstructural, chemical and mineralogical changes of the samples were analysed by scanning electron microscopy, electron probe micro-analysis and X-Ray diffraction and showed phenomena of dissolution, leaching and carbonation.
ISSN:2261-236X
2274-7214
2261-236X
DOI:10.1051/matecconf/202236405010