Simulation of the rheological behaviour of UHPC

The demands on properties of cementious suspensions in the hardened stage have been steadily increasing. Ultra High Performance Concrete (UHPC) is a good example for this development. The paper presents a simulation supported characterization of the rheology of UHPC. A simple time independent yield stress fluid model with shear rate dependent viscosity was implemented within the fully three dimensional flow solver CoR heoS of the Fraunhofer Institute for Industrial Mathematics (ITWM), Kaiserslautem. The model was calibrated at the University of Kaiserslautem using a combination of rheological measurements with a rotational rheometer and slump flow tests. Not only the spread but also the time scale of the slump flow could be reproduced by the simple rheological model.