Abstract:
Based on theory of mixtures, a coupled thermo-hygro-mechanical damage model for concrete subjected to high temperatures was presented. Concrete was considered as a mixture composed of solid skeleton, liquid water, water vapor, dry air and dissolved air. The Macroscopic balance equations of the model consisted of the mass conservation equations of each component, the momentum and energy conservation equation of the whole medium mixture. The state equations and constitutive model used in the model were given. Four final governing equations were given in term of four primary variables, i.e. displacement components of soil skeleton, gas pressure, capillary pressure and temperature. The processes involved in the coupled model included evaporation, dehydration, heat and mass transfer, etc. Through the process of deformation failure and energy properties, mechanics damage evolution equations were established based on the principle of conversation of energy and Lemaitre equivalent strain assumption, and then the influence of thermal damage on mechanical property and mechanics damage evolution equations were considered.
