In this paper, aggregate migration patterns during fluid concrete
castings are studied through experiments, dimensionless approach and
numerical modeling. The experimental results obtained on two beams show
that gravity induced migration is primarily affecting the coarsest
aggregates resulting in a decrease of coarse aggregates volume fraction
with the horizontal distance from the pouring point and in a puzzling
vertical multi-layer structure. The origin of this multi layer structure
is discussed and analyzed with the help of numerical simulations of free
surface flow. Our results suggest that it finds its origin in the non
Newtonian nature of fresh concrete and that increasing casting rate
shall decrease the magnitude of gravity induced particle migration. (C)
2012 Elsevier Ltd. All rights reserved.