Strain‐Based Constitutive Model with Mixed Evolution Rules for Concrete

Abstract

The theories of continuum damage mechanics and plasticity are combined in a strain‐based phenomenological approach to yield an effective constitutive model for plain concrete. The model reproduces the majority of the typical behavior exhibited by plain concrete: anisotropic stiffness evolution, pressure‐dependent ductility and strength, postpeak dilation, recovery of stiffness upon reverse loading, and permanent deformations. The proposed combination of continuum damage mechanics and plasticity theory is unique in that: (1) A strain‐based formulation is used; (2) a separate “inelastic” surface is postulated for the tensile regime and the compressive regime; (3) the inelastic surfaces are used for both damage evolution and permanent deformation; and (4) an isotropic evolution law is used for compression and a kinematic law for tension. The model requires a modest number of material constants (10). Strain‐softening considerations are discussed, relative to implementation of the model into numerical methods for solution of boundary value problems; however, only laboratory data from tests on small specimens are evaluated. The model's effectiveness is shown through comparisons with three sets of experimental data.