The boom of liquified natural gas (LNG) trade has increased the demand for LNG tanks. The replacement of 9% nickel steel with concrete can build 'full concrete' LNG tanks. This strategy will reduce the costs by 46% and decrease the construction period by 33% and improve the durability of the structure. Thus it has great economic and scientific significance. The temperature fluctuations (-40℃ to -165℃) and freeze-thaw (ambient temperature to -170℃) cycles are the main challenges for the safety services of LNG tanks. However, the failure mechanism of concrete at cryoge-nic temperature (-40℃ to -197℃) is still unclear. The freezing of water in the pores at cryogenic temperature can cause a lot of changes in the pore structure, thermal conductivity, thermal strain, permeability, and energy release behavior of the concrete during failure. The evolution mechanism of the properties of concrete at cryoge-nic temperature is still in the early stage of research. Using advanced characterization techniques and efficient research methods to explore the relationship between the icing of water in pores and the evolution of macroscopic properties of concrete from multiple angles is an effective strategy to clarify the deterioration mechanism of concrete at cryogenic temperature. In this paper, the characterization technologies (nuclear magnetic resonance (NMR), X-ray computed tomography (μ-CT), differential scanning calorimeter (DSC), low-temperature scanning electron microscope (LTSEM), acoustic emission (AE), and laser flash analysis (LFA)) and research methods (thermal strain test and permeability test) of concrete at cryogenic temperature were reviewed. Moreover, the performance of ultra-high-performance concrete (UHPC) at cryogenic temperature was summarized. NMR and DSC can be used to in-situ study the freezing behavior of water in pores of concrete at cryogenic temperature. NMR can study the evolution of the state of water in pores; DSC can quantitatively characterize the volume of ice in pores based on the heat flow data. The μ-CT technique can explore the 3D shape of pores and cracks before and after freeze-thaw cycles. LTSEM can acquire the micromorphology of ice in pores. The combination of thermal strain test and AE technology can clarify the correlation between thermal deformation and energy release of concrete during failure. UHPC has excellent cryogenic temperature resistance based on the removal of coarse aggregate and the reduction of porosity and moisture content. At present, the thermal conductivity and permeability of concrete at cryogenic temperature are still lacking in comprehensive research, LFA is an effective technique to investigate the thermal conductivity of concrete at cryogenic temperature. This paper systematically summarizes the characterization techniques and research methods of concrete at cryogenic temperature, which is helpful to deeply understand the failure mechanism of concrete at cryogenic temperature and develop high-durability 'full concrete' LNG storage tanks. © 2021, Materials Review Magazine. All right reserved.
