Durability of cement pastes exposed to external sulfate attack and leaching : Physical and chemical aspects

The unfortunate recent collapse of the Morandi bridge in Genoa has reminded us of the importance of the degradation of concrete and cement with time. For example, cement is attacked by sulfate ions in seawater or underground, leading to expansion, strength loss and eventually the catastrophic loss of structures such as bridges. Cement expansion is usually related to ettringite and gypsum precipitation. However, despite numerous studies and expertise, the exact degradation mechanisms remain unclear and controversial. We have thus conducted a study of this mechanism in collaboration with a private company, Bouygues, and an academic partner, IFSTTAR. It aimed to characterize the possible altered zone and to identify the mechanisms of degradation under sulfate attack. The analysis of the physical and chemical aspects of this phenomenon shows that two modes of transfer occur : transfer of sulfate ions to the cement matrix and leaching of calcium ions to the external solution. The analysis of the chemical composition of the affected material highlights the progressive consumption of portlandite at the surface, the decalcification of C-S-H and the formation of AFt from both Afm and aluminum incorporated in C-S-H.

If you want to know more
O. OmikrineMetalssi, F. Barberon, J.-M. Torrenti, N. Roussel, L. Divet, J.-B. d’Espinose de Lacaillerie, Durability of cement pastes exposed to external sulfate attack and leaching : Physical and chemical aspects, Cement and Concrete Research, 116, pages 134-145 (2019)

https://doi.org/10.1016/j.cemconres.2018.11.006


Haut de page



À lire aussi...

Microalgae as Soft Permeable Particles

For non-motile microalgae, colloidal surface interactions are the only factor modulating their distribution in space. This is not a totally (…) 

> Lire la suite...

Effets mémoire en frottement : au coeur du contact

Dans un article récemment publié dans les Proceedings of the Royal Society A, nous apportons un éclairage nouveau sur les effets mémoire mis en (…) 

> Lire la suite...

 

Informations Pratiques

Sciences et Ingénierie de la Matière Molle - UMR 7615

10 rue Vauquelin
75231 PARIS CEDEX 05

  • Directeur : J.B. d’Espinose
  • Comité de direction : A. Chateauminois, Y. Tran, B. Bresson
  • Pôle gestion : F. Decuq, D. Kouevi Akoe, S. Diakite
  • Communication : A. Hakopian et M. Ciccotti
  • Systèmes d’information : A. Hakopian
  • Assistant prévention : F. Martin et M. Hanafi

Comment venir ?
Mentions légales