15 Février – Séminaire Prof. Stefano DAL PONT
17 h ENSAM - Amphi C
Better understanding the spalling mechanisms in concrete at high temperature: a combined approach based on numerical tools and neutron tomography
When a structural element is exposed to high temperature, concrete is prone to spalling. The latter exposes the reinforcement and may lead to premature failure of the structural element putting at risk the safety of concrete structures. The evolution of moisture content is believed to be one of the processes directly related to this phenomenon. Numerical models found in literature for studying the behavior of concrete at high temperature follow the theory of heat and mass transfer in porous media. The validation of these numerical models is usually based on experiments as in measuring temperature and pressure inside a heated concrete specimen. However, pressure measurements are not always reliable since the pressure can be influenced by the sensors or by cracks.
In this study, the evolution of moisture content obtained from neutron imaging of high-performance concrete at high temperature are compared with results from a state-of-the-art in-house developed numerical model implemented in the finite element code Cast3M. The water loss measured experimentally and the numerical results suggest that some commonly adopted constitutive laws need to be reconsidered.