Mechanical characterization and modelling of Ultra High Performance Fiber Reinforced Concrete

In the last two decades the use of Ultra High Performance Fiber Reinforced Concrete (UHPFRC) for the construction of structural and non-structural elements has increased, but there is still a strong need to establish a complete method for its mechanical characterization, especially of its tensile behavior. In this paper, a mechanical investigation carried out on four UHPFRC specimens with a fiber volume fraction of 3.3% is presented. The fiber content resulted to be sufficient to cause strain hardening behavior, characterized by a multicracking phase. The tensile constitutive law provided by Model Code 2010 for the inverse analysis from bending tests is hereby discussed. In particular, the size of the mul-ticrack diffusion zone is investigated with vision-based measurement tools and used as a characteristic length.