A 3D visco-elasto-plastic damage constitutive model of concrete under long-term loads

The present paper proposes a 3D coupled elasto-plastic damage model of concrete, incorporating long-term effects at the meso-scale. The model is able to capture permanent deformations, stiffness reduction and creep characteristics of concrete in a unified manner, including local confinement effects and stress concentrations of the cement matrix at the meso-scale. The modelling aspect related to plasticity is based on the pressure-dependent Menétrey–Willam plastic surface, extended to include a scalar damage variable accounting for the reduction in size of the elastic domain as concrete undergoes damage. The modelling aspect related to damage, on the other side, is inspired by the formulation of the isotropic damage by Mazars. Specifically, in the proposed formulation a stress-dependent damage variable is introduced to account for crack closure effects. The long-term effects are taken into account via the B3 creep model by Bažant and Baweja. Some challenging aspects related to the numer...