The complex coupling relationship between liquid sodium and concrete materials affects both the sodiumfire characteristics and concrete properties through heat and chemical erosion. In this study, experimentson direct and indirect (separated by a steel plate) contact of the columnar sodium fire with theconcrete surface were performed. It was found that the combustion efficiency of liquid sodium in directcontact with concrete was significantly enhanced and accompanied by intermittent explosions andsplashing of small concrete fragments. The sodium fire on the surface of the concrete considerablyincreased the internal temperature, pore size, and distribution density of the concrete. In addition, thedepth of influence on the loosening of the concrete structure was also greatly extended. The contact ofliquid sodium with the concrete substantially affected its permeability resistance. The water absorptionof the concrete surface was increased by more than 70% when liquid sodium directly impacted the bareconcrete surface. However, the change in water absorption in the centre of the concrete was primarilyaffected by the duration of the external heat