Modelling of heated concrete

This paper presents the basic principles and details of the physical, mathematical and numerical models forming the main structure of the numerical analysis of the thermal, hydral and mechanical behaviour of normal, high-performance and ultra-high performance concrete structures subjected to heating. A fully coupled non-linear formulation is designed to predict the behaviour and potential for spalling, of heated concrete structures for fire and nuclear reactor applications. Concrete is considered as a multiphase material consisting of a solid phase, two gas phases and three water phases. The physical model is described with emphasis being placed upon the real processes occurring in concrete during heated based on tests carried out in several major laboratories around Europe as part of the wider HITECO research programme. Examples of preliminary outputs are presented in the form of isoline diagrams compared with those obtained from experiment.