numerical homogenization of concrete microstructures without explicit meshes

life management of electric hydro or nuclear power plants requires to estimate long-term concrete properties on facilities, for obvious safety and serviceability reasons. decades-old structures are foreseen to be operational for several more decades. as a large number of different concrete formulations are found in edf facilities, empirical models based on many experiments cannot be an option for a large fleet of power plant buildings. to build predictive models, homogenization techniques offer an appealing alternative. to properly upscale creep, especially at long term, a rather precise description of the microstructure is required. however, the complexity of the morphology of concrete poses several challenges. in particular, concrete is formulated to maximize the packing density of the granular skeleton, leading to aggregates spanning several length scales with small inter particle spacings. thus, explicit meshing of realistic concrete microstructures is either out of reach of current meshing algorithms or would produce a number of degrees of freedom far higher than the current generic fem codes capabilities.