Tensile Behavior of UHPFRC Under Uniaxial And Biaxial Conditions

The representative characterization of the tensile behavior of strain hardening Ultra High Performance Fiber Reinforced Cementitious Composite (UHPFRC) remains a challenge. Currently, the uniaxial methods (direct tensile test and 4-point bending test) are commonly applied, although the biaxial tensile condition has been widely recognized in most of the UHPFRC applications, e.g. thin UHPFRC element as external reinforcement layer or bridge deck slab. In this paper, the ring-on-ring test on circular slab-like specimens has been developed to determine the equal-biaxial tensile response by means of inverse analysis using 3D finite element method (FEM) models. In addition, direct tensile test (DDT) using dumbbell specimens cut from large square plates and 4PBT (4-point-bending-test) cast in molds were carried out. The representative tensile response from 4PBT was derived through inverse analysis using 2D FEM models. Finally, the corresponding results from different tests under either uniaxial or biaxial stress condition were analyzed and compared in terms of tensile parameters, tensile material law, cracking pattern and energy absorption capacity. The main objective is to examine the tensile performance under uniaxial and biaxial stress conditions, and to propose the most appropriate test method for a given UHPFRC application.