Evolution of the characteristic grain size over time at four heliocentric distances. Curves display the mass-dominating size R^m (dashed) and surface-area-dominating grain size R^A (solid). After an initial phase of efficient coagulation (marked by R^m and R^A increasing similarly), the creation of fragments in disruptive collisions acts to lower R^A and halt growth altogether as a steady state is reached towards the end of the local simulations (shown as open white circles).