Rheological Behaviour of Flexible Fiber-Reinforced Cementitious Materials
Résumé
Polypropylene fibers are accepted in many studies as an effective preventative measure against concrete spalling due to fire exposure. A high dosage of the fibers enhances this effect but reduces the flowability of fresh concrete. Due to a lack of literature, it is hard to identify optimal fiber dosage and geometry. This paper is aimed at understanding the influence of polypropylene fibers on the rheology of fresh cementitious materials. Slump flow tests that ensure an isotropic flow of the material are conducted in order to assess the yield stress of cement pastes containing flexible fibers. The results present the influence of fiber dosage and geometry (fiber length and diameter) on the yield stress of fresh cementitious materials. Using predictive scheme for the yield stress of the cementitious materials with rigid fibers, it is seen that the rheology of cement pastes with flexible fibers is more complex compared to the rheology of paste with rigid fibers.