Flow Simulation of Fresh Concrete under a Slipform Machine

ABSTRACT This paper deals with the numerical simulation of fresh concrete flow in the laying of a concrete pavement. After a recall of present state-of-the-art in the fields of fresh concrete rheology and flow simulation, a full scale experiment is described, dealing with the construction of a thin, continuously reinforced layer of high-performance concrete. Difficulties in the control of evenness and the lack of consolidation in some particular areas of the pavement were identified. Simulations could explain the latter through dead zones in the concrete flow, in which concrete was subject to early stiffening permitted by the material thixotropy. Also simulations suggest directions to control the evenness, by the control of the concrete height ahead of the machine, and the choice of a long enough slipform table. Through this example, the potential of a scientific approach to help practitioners is demonstrated.