A regular triangular lattice of beam elements is used to model fracture processes in concrete. Heterogeneity is introduced by projecting the planar lattice network onto a computer generated image of the mesostructure. During fracture, lattice element properties are systematically modified to simulate three-dimensionality of the material and fracture process.
An adaptive meshing procedure is used for analyzing fracture in concrete CT specimens of significantly differing scale, while keeping the lattice mesh density constant. The model resolves the distributions of damage and energy consumption within the fracture process zone. The distribution of fracture events about the macrocrack centerline compares well with acoustic emission source distributions obtained from testing. Correlations between FPZ size and local fracture energy consumption are examined and it is shown that specific fracture energy and specific peak load are dependent on specimen scale, in accordance with test results.