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Materials and Structures

, Volume 32, Issue 10, pp 719–726 | Cite as

Thermo-mechanical properties of Penly reactor envelope at temperatures up to 200°C

  • I. Janotka
  • T. Nürnbergerová
Scientific Reports
  • 73 Downloads

Abstract

This paper reports on an experimental investigation conducted to study the effects of high temperatures of up to 200°C on the phase composition, pore structure development and physico-mechanical properties of concrete at the PENLY nuclear power plant (France). The concrete specimens were manufactured under laboratory conditions from identical materials used at the construction site in PENLY, and then stored at 20°C/100% R.H. for 28 days and exposed to temperatures of 40°C, 60°C, 100°C, 200°C, and 20°C/60%R.H., respectively.

Test results revealed that an intense structural integrity degradation of PENLY concrete occurs between 100°C and 200°C due both to a loss of water bound in hydrated cement minerals and to subsequent air void formation. This phenomenon is related to an increase in the median pore radius and total porosity values, as well as to a decrease in the dynamic and static moduli of PENLY concrete. The reduction in volume of the hydrate phase is believed to be the reason behind the rapid expansion, over a short time interval, due to a time-limited moistening of the specimen by released water with a sudden rise in temperature, followed by a stabilised period of shrinkage and creep.

Keywords

Compressive Strength Silica Fume Ettringite Concrete Specimen Dynamic Modulus 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Résumé

Cet article traite d’une recherche expérimentale sur les effets de températures allant jusqu’à 200°C sur la composition de phase, le développement de la structure poreuse et les propriétés physicomécaniques du béton sur le site de la centrale nucléaire de PENLY (France). Les échantillons de béton ont été préparés dans les conditions de laboratoire à partir des matériaux identiques à ceux utilisés dans la construction du site de PENLY, maintenus pendant 28 jours à 20°C et 100% d’humidité relative, puis exposés respectivement à des températures de 40°C, 60°C, 100°C, 200°C et de 20°C, pour une humidité relative de 60%.

Les résultats de ces essais ont révélé qu’une intense dégradation de l’intégrité structurelle du béton de PENLY a lieu entre 100°C et 200°C en raison d’une perte de l’eau liée dans les minéraux hydratés du ciment, et de la formation ultérieure de vides d’air. Ce phénomène s’avère étroitement lié à l’augmentation du rayon moyen des pores et à celle de la porosité totale du volume de la phase hydratée, ainsi qu’à la diminution des modules dynamiques et statiques du béton de PENLY. La réduction du volume de la phase hydratée est la cause supposée de l’expansion rapide sur une période courte, en raison de l’cau dégagée suite à l’élévation soudaine de la température, phénomène suivi d’une période stabilisée de retrait et de fluage.

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Copyright information

© RILEM 1999

Authors and Affiliations

  • I. Janotka
    • 1
  • T. Nürnbergerová
    • 1
  1. 1.Institute of Construction and ArchitectureSlovak Academy of SciencesBratislavaSlovak Republic

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