ABSTRACT
The addition of strong, ductile, discontinuous fibers with high aspect ratio to concrete or mortar results in Fiber Reinforced Concrete (FRC) or Fiber Reinforced Mortar (FRM), which, when compared to the plain material, exhibits superior ductility, failure toughness, strength, impact resistance, and fatigue strength. Laboratory tests show these improved properties are a result of the randomly distributed fibers which act as crack arrestors. Currently, an adequate numerical approach does not exist for the analysis of structures composed of FRC or FRM. In this paper, a recently developed constitutive model for the pre-peak response of FRC/FRM is presented and then extended to the post-peak regime using a nonlocal approach. The existing, local model is based loosely within the theory of mixtures; for the plain concrete or mortar, an anisotropic, strain-based, continuum damage/plasticity model is used. To represent the effect of the fibers, a simplified model that accounts for both the resistance of the fibers and the enhanced resistance of the matrix is employed. In the Finite Element implementation of the model, the nonlocal approach is shown to lessen mesh sensitivity and to improve the predictions of energy dissipation. The results of the Finite Element Model are shown to compare well with the experimental results from two separate test programs.
