Effect of the addition of polypropylene fibers on the rheological behaviour of fresh fluid cementitious materials

Polypropylene fibers are accepted in the literature as an efficient preventative measure for concrete spalling due to fire. Use of the high dosage of fibers enhances this effect but drastically reduces the workability of concrete. A lack of the literature on the rheological behavior of fresh cementitious materials with flexible fibers prevents from the identification of an optimal fiber dosage and geometry. This work is aimed at studying the influence of fiber dosage and geometry on the rheological behavior of fresh fluid cementitious materials. Slump flow tests conducted on cement pastes containing fibers allowed to determine the influence of fiber dosage and geometry on the yield stress of fresh cement pastes. It is concluded that the rheology of cement pastes with flexible fibers is more complex in comparison to the rheology of cement pastes with rigid fibers due to their bending.