  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 with regular and random aggregate arrangements 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
length, 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), increases crack width and consequently
greatly increases permeability.
