Research progress of the thermophysical and mechanical properties of concrete subjected to freeze-thaw cycles

• Effects of freeze-thaw cycles on thermophysical and mechanical properties of concrete are reviewed. • Freeze-thaw damage theories, damage identification methods, and numerical models are summarized. • Gaps and limitations in freeze-thaw deterioration models under the multi-factor actions at various scales are discussed. • Future research directions are recommended for the damage mechanism of concrete under multi-factor actions. In cold regions, concrete structures such as pavements, bridges, and tunnels can undergo freeze-thaw conditions, which may significantly deteriorate the performance of concrete and further pose a threat to the structures’ safety and shorten their service life. This paper displays a comprehensive review of the effects of freeze-thaw cycles (FTCs) on the thermophysical and mechanical properties of concrete, which include the mass loss, specific heat capacity, thermal conductivity, coefficient of thermal expansion, compressive strength, splitting tensile strength, flexural strength, elastic modulus, and stress-strain relationship. Meanwhile, the influences of water/binder ratio, air content, number of FTCs, saturation degree, and multiple factors are analyzed and discussed in detail. In addition, changes in the microstructure and constituents, available theories, test methods, and damage identification/evaluation methods to characterize the freeze-thaw damage are summarized. Accordingly, recommendations are proposed for future investigations to be carried out. The discussion indicates that multiple factors and multiple fields should be comprehensively considered to reveal the micromechanism of the freezing and thawing damage on concrete in real complex environments. Also, existing freeze-thaw damage theories and test methods are supposed to be considered to develop the multiscale models and corresponding techniques.