Modelação da anisotropia do comportamento à tração do UHPFRC

Abstract

The tensile behaviour of ultra-high performance fibre reinforced cementitious composites (UHPFRC) is decisive for many applications of this type of materials and strongly depends on the fibre orientation. This leads to an anisotropic tensile behaviour that needs to be characterized. Moreover, the fibre orientation varies throughout the structural element, being influenced by the casting procedure, by the rheology of the material and by the shape of the element to be cast. Therefore, the "in-structure" tensile response of the UHPFRC can differ significantly from that characterized in laboratory test specimens. A meso-mechanical model is presented for determining the uniaxial tensile stress-deformation curve of UHPFRC based on a minimal number of parameters with clear physical meaning. The mathematical formulation describing the fibre orientation and the directional variation of the fibre orientation factor are presented. The model is validated with experimental results.