  A meso-scale analysis is performed to determine the fracture process zone of
concrete subjected to uniaxial tension. The meso-structure of concrete is
idealised as stiff aggregates embedded in a soft matrix and separated by weak
interfaces. The mechanical response of the matrix, the inclusions and the
interface between the matrix and the inclusions is modelled by a discrete
lattice approach. The inelastic response of the lattice elements is described
by a damage approach, which corresponds to a continuous reduction of the
stiffness of the springs. The fracture process in uniaxial tension is
approximated by an analysis of a two-dimensional cell with periodic boundary
conditions. The spatial distribution of dissipated energy density at the
meso-scale of concrete is determined. The size and shape of the deterministic
FPZ is obtained as the average of random meso-scale analyses. Additionally,
periodicity of the discretisation is prescribed to avoid influences of the
boundaries of the periodic cell on fracture patterns. The results of these
analyses are then used to calibrate an integral-type nonlocal model.
