Continuum damage-healing constitutive modeling for concrete materials through stress spectral decomposition

Self-healing concrete materials have the capability to recover a part of the weakened mechanical properties induced by damage. In this paper, a constitutive model is proposed to investigate damage and healing phenomena in concrete materials. In order to consider the different behavior of concretes in tension and compression, a spectral decomposition of the stress is utilized. In addition, employing the Clausius-Duhem inequality and considering the irreversible thermodynamics, conjugate forces of the damage and healing are expressed. The Gibbs potential energy is decomposed into three parts: elastic, damage and healing. In this regard, damage and healing behavior are distinguished from the elastic behavior via the damage and healing surfaces (F-d(+/-),F-h(+/-)). Evolution equations of damage and healing variables are proposed based on these surfaces. Validity of the proposed model is shown in uniaxial tension and compression loading conditions compared to the experimental data available in the literature. Finally, parametric studies are applied on the healing parameters to show the response of the self-healing concrete materials in tension and compression.