Determination of total fracture energy for fiber-reinforced concrete

The influence of fiber-reinforcement in concrete is most apparent after cracking has begun propagating through the fiber-reinforced concrete (FRC). The size-independent "initial" or specific fracture energy is defined as the energy per unit area to create a new crack surface; while the "total" fracture energy can be defined as the size- and geometry dependent amount of energy per unit area required for a specimen to exhibit complete separation failure at which negligible traction occurs across the new surface. While the initial fracture energy is used to define un-reinforced concrete, the total fracture energy parameter has been successfully utilized for characterizing the benefit of lowvolume fractions of fiber-reinforcement for pavement and slab applications. This paper summarizes the main issues associated with using total fracture energy for FRC relate to the methodology for obtaining and interpreting the fiber component contribution as well as understanding the test methods and modeling options available.