A new elastoplasticity model of Prandtl–Reuss type which can accurately simulate tension–compression asymmetry and stiffness degradation of high-performance concrete

Purpose This study proposes a new constitutive model to accurately capture the nonlinear, path-dependent strength degradation of high-performance concrete within an efficient computational framework. Design/methodology/approach An elastoplastic model is developed based on an extended Prandtl–Reuss formulation. A generalized invariant is introduced to decouple tension–compression asymmetry, while energy dissipation and non-elastic recovery are explicitly accounted for. Uniaxial stress–strain relations are derived to describe all through hardening–softening response. Model predictions are validated against multiple experimental datasets. Findings The model accurately captures the asymmetric hardening–softening response under monotonic loading and the path-dependent stiffness degradation during unloading, using only a limited set of physically interpretable parameters without introducing explicit damage or crack-tracking variables. Numerical comparisons confirm its predictive accuracy. Originality/value The formulation introduces a novel invariant for generalized tension–compression decoupling. Unloading stiffness degradation emerges intrinsically rather than from ad hoc assumptions. The model achieves physical clarity and computational efficiency, advancing simulation of concrete inelastic response.