Numerical Investigation on Effects of Steel Fibers Content on Flexural Behavior of UHPCC

Abstract

Ultra-High Performance Cementitious Composites (UHPCC) is a kind of concrete with specific characteristics that has lesser drawbacks in term of tensile strength and breakage. One of the methods for improving the mechanical properties of concrete is adding fibers. This study numerically investigates the effect of steel fiber with different volume fractions (Vf) on flexural behavior of UHPCC using nonlinear finite element method (NLFEM). For this purpose, hooked ended fibers with five different Vf of fibers (0%, 0.5%, 1%, 1.5% and 2%) and aspect ratio length to diameter 80 (L/D=80) are used in four-point bending tests. The modeling of the nonlinear region of three-dimensional (3D) model of concrete is based on concrete damage plasticity model (CDPM). Type and size of the suitable element are chosen based on mesh sensitivity analysis. The interaction mechanism between steel fibers and concrete considered the embedded region algorithm. Finite element modeling of the compressive specimen is validated by comparing the stress-strain curve of the numerical model with that of the experimental study. Results showed that the addition of steel fibers with different Vf caused 6% to 33% improvement in flexural behavior.