Effect of fiber content on mechanical and fracture properties of ultra high performance fiber reinforced cementitious composites

This study investigated the mechanical properties of ultra high performance fiber reinforced cementitious composites (UHPFRCC) with four different fiber volume fractions (Vf = 1%, 2%, 3%, and 4%) within an identical mortar matrix. The higher amount of fiber resulted in an improvement of load carrying capacity and elastic modulus in compression up to 3 vol.% of fibers. A higher pullout strength was obtained from the inclusion of fibers in the matrix, and 2 vol.% of fibers provided the best performance in all aspects of fiber pullout behavior including average and equivalent bond strengths and pullout energy. The flexural strength was pseudo-linearly increased with increase in fiber volume fraction, despite an insignificant difference in the first cracking load. Furthermore, a bi-linear softening curve for UHPFRCC was suggested based on the result of inverse analysis, and it was verified through comparison with the experimental data.