High-performance concrete for liquid hydrogen storage: Cryogenic stability, transport resistance, and microstructural response

Seasonal variability in renewable energy generation necessitates large-scale and long-duration energy storage solutions, among which liquid hydrogen (LH 2 ) represents a promising option for stationary applications. Concrete, which has been successfully applied in liquefied natural gas (LNG) storage tanks, offers a potentially cost-effective alternative to conventional metallic materials for stationary LH 2 containment. This study evaluates the feasibility of an optimised high-performance concrete (HPC) designed according to cryogenic performance principles—including a low water-to-binder ratio, optimised particle gradation, and fibre reinforcement, for application under extreme cryogenic temperatures and cyclic thermal loading. An integrated experimental programme was conducted to assess HPC performance in terms of microstructural compactness, mechanical integrity, transport-related behaviour, and thermal performance. The results indicate that the optimised HPC exhibits a highly dense microstructure with extremely low oxygen diffusivity and permeability below the detection limit. Mechanical performance was generally retained following the short-duration cryogenic thermal cycles investigated, although the first-peak flexural strength of fibre-reinforced specimens decreased after repeated cycling. Microstructural observations revealed only limited microcracking following cryogenic cycling. In addition, the thermal conductivity of HPC remained approximately one order of magnitude lower than that of conventional metallic containment materials, indicating its potential contribution to reducing heat transfer while providing structural capacity. This material represents a promising and cost-effective material option for large-scale, stationary LH 2 storage applications under cryogenic conditions.