Structural build-up of rigid fiber reinforced cement-based materials

The structural build-up of rigid fiber reinforced cement-based materials is studied. It has recently been shown that the behaviour of fiber reinforced concrete depends on the orientation of the fibers that has to be optimized during casting. As a result, there is a great interest to study the rheology of fiber reinforced concrete. One of the most important characteristics of modern fresh concretes is the structural build-up which is involved in many recent issues of concrete casting. This characteristic depends on the cement pastes chemical activity. This present work shows that structural build-up modelling used for common concretes can be generalized to fiber reinforced concretes. It can be shown that, if the inclusions percolation threshold is not reached, the structural build-up rate A (thix) is amplified by the addition of fibers and aggregates. Finally, this amplification of the structuration is estimated using modelling initially developed for spherical inclusions and aggregates.