ABSTRACT
Concrete is subject to the alternate action of positive and negative temperatures of the environment frequently in cold regions. The freeze-thaw cycle causes the spalling of concrete surface. In view of this, the investigation of the changes of fluid migration and icing in concrete during the temperature change process were carried on, the critical pore radius of frozen pore at different temperatures was determined based on the thermodynamic law. Then, considering the thermal deformation of all constituents, the deformation induced by the micro-cryosuction process and the deformation caused by the phase change of water-ice during the freeze-thaw cycle, the internal pore stress of a representative volume element is analyzed. Finally, considering the effect of the phase change of water ice, a numerical model of concrete freeze-thaw failure under the coupling of thermal-water-mechanical filed is established. It is found that, influenced by the temperature, the concrete will shrink first and then expand under the freeze-thaw effect. The stress during freezing process of the concrete surface is higher than that of thawing process and the concrete will be more prone to spalling damage.
