Air permeability of reinforced concrete damaged by Internal Swelling Reactions (ISR) ; Perméabilité à l’air du béton armé endommagé par des Réactions de Gonflement Interne (RGI)

The work described in this manuscript is part of research programs dedicated to the study of the aging of nuclear civil engineering structures, initiated by the Institut de Radioprotection et de Sûreté Nucléaire (IRSN) and conducted within the Laboratoire Matériaux et Durabilité des Constructions (LMDC) in Toulouse. This research falls within the framework of a project aimed at extending the operational lifespan of French nuclear power plants. The objective of this study is to contribute to the acquisition of knowledge related to the impact of the development of certain internal pathologies within irreplaceable components of nuclear power plants, such as containment structures, on the transport characteristics of concrete. It is worth noting that the behavior of these materials at the containment level is of crucial importance in the assessment of the safety of nuclear installations, as containment structures represent the third and final barrier of protection against any potential release of radioactive products into the environment. Professionals responsible for concrete durability tests face a major challenge: evaluating the transport characteristics of concrete affected by Internal Swelling Reactions (ISR). These pathologies are generally associated with two types of chemical reactions: Delayed Ettringite Formation (DEF) and Alkali-Aggregate Reaction (AAR). When these reactions develop, tensile stresses appear in the concrete, leading to the formation of cracks in structures affected by these pathologies. In this context, the research conducted as part of this thesis focuses on two main aspects: measuring the air permeability of concrete subjected to internal swelling reactions, covering a range of saturation levels from partially saturated (80% Sr) to completely dry. Furthermore, all nuclear civil engineering structures are reinforced with passive and active reinforcements, so this study takes into account the presence of reinforcements in various arrangements. The data collected in this study allow for the ...