Modified the smeared crack constitutive model of fiber reinforced concrete under uniaxial loading

Abstract The addition of randomly distributed short fiber in the plain concrete can significantly improve the compressive and tensile properties. Herein, a modified smeared crack constitutive model for the fiber reinforced concrete (FRC) is proposed for the simulation of the mechanical behavior under uniaxial loading. In this model, the two-phase composite law is introduced to modify the elastic stiffness matrix. For the conditions of compression, the FRC is considered as the simple composite which follows the two-phase composite law and the smeared crack model. When the tensile crack occurs, the fiber-bridging plays an important role in the post-cracking behavior. The model considers the plastic deformation as the interfacial slip displacement of the fiber, and employs the bond-slip model to simulate interfacial debonding and fiber pullout. The constitutive model is achieved by the Fortran code in the user subroutines (Umat) of the finite element software Abaqus. The comparison between the numerical simulation results and experimental data under uniaxial loading shows that the model simulates the mechanical properties behavior of FRC with good accuracy.