There is an ongoing collaboration between SCK-CEN and UAntwerp on thermo-hydro-mechanical behaviour of concrete at higher temperatures. In this context, there is a specific interest to pursue innovative work in the field of continuum damage mechanics of concrete, given its importance in nuclear engineering applications such as nuclear containment buildings, nuclear waste disposal, etc.
Concrete is a highly heterogeneous material. Interpreting its micro-structure as stiff particles randomly distributed in a soft matrix, is a common first idealization. Deformation behaviour of concrete is usually described by classical continuum theories which rely eventually on the representative volume element (RVE) concept. The latter fails, if length characteristics of phenomena to be modelled are close to micro-structural length properties, like, for instance, the mean particle distance. Examples are strong gradients in applied traction loads, damage and fracture processes, etc.
As long as a continuum approach is still preferred to describe these kind of phenomena, generalized continuum theories, such as strain gradient theories, have to be used. Although a theoretical framework is already available, a number of problems are still unresolved, which prevents the usage of corresponding concepts for practical design purposes.