  In this paper, the influence of aggregate size and volume fraction on
shrinkage induced micro-cracking and permeability of concrete and mortar was
investigated. Nonlinear finite element analyses of model concrete and mortar
specimens were performed. The aggregate diameter was varied between 2 and 16
mm. Furthermore, a range of volume fractions between 0.1 and 0.5 was studied.
The nonlinear analyses were based on a 2D lattice approach in which aggregates
were simplified as monosized cylindrical inclusions. The analysis results were
interpreted by means of crack width and change of permeability. The results
show that increasing aggregate diameter (at equal volume fraction) and
decreasing volume fraction (at equal aggregate diameter) greatly increases
permeability.
