In-situ neutron tomography and 3D numerical modeling of moisture distribution in concrete at high temperature

Abstract

One of the drawbacks of high performance concrete is its vulnerability to high temperature manifested in the form of spalling. The latter exposes the reinforcement and may lead to the premature failure of structures such as tunnels, high rise buildings, nuclear plants etc. In this communication, the first 3D measurements of moisture content in heated concrete, which is believed to be one of the processes directly related to spalling, have been performed using in-situ neutron tomography. In order to follow the fast dehydration process of concrete, one 3D scan per minute was captured thanks to the world leading flux at the Institute Laue Langevin in Grenoble France. The influence of the aggregate size on the moisture distribution is presented. A fully coupled thermo-hydro-mechanical model has been implemented and used in this study for predicting the temperature and moisture distribution measured experimentally. In addition, a mesoscopic approach is
adopted in the model for investigating the effect of aggregates on the drying front.