Numerical simulation on time-dependent mechanical behavior of concrete under coupled axial loading and sulfate attack

This paper numerically simulates time-dependent mechanical behaviors, such as stress redistribution and bearing capacity degradation, of concrete subjected to the coupled axial loading and sulfate attack. Based on Fick's law and chemical reaction kinetics, a diffusion-reaction model was proposed to obtain the spatial and time-dependent concentration distribution of sulfate ion, gypsum and ettringite. From previous study, a chemical damage, characterized by the volumetric expansion from ettringite formation, is introduced to reflect the influence of sulfate attack on concrete performance. Furthermore, using the plasticity theory and damage mechanics, a coupled chemo-mechanical damage constitutive model was determined by introducing the chemical damage. Finally, a concrete prism is regarded as a research object, to investigate the time-dependent stress and bearing capacity degradation of concrete structures subjected to the coupled axial compression and sulfate attack.