Behaviour of reinforced concrete panels under impact loading after cryogenic freeze-thaw cycles

Abstract

Concrete structures are widely used in modern constructions including energy storage system such as all concrete liquefied natural gas (ACLNG) storage tanks. In ACLNG tanks, concrete structure is exposed to cryogenic temperatures and freeze-thaw (FT) cycles. Cryogenic temperatures and FT cycles are recognized to influence the mechanical characteristics of concrete. To ensure safety of the critical energy infrastructure, it is crucial to explore the concrete structural response under the combined cryogenic FT cycles and accidental impact loading. This study aims to numerically examine the damage caused by impact loading on reinforced concrete panels after exposure to cryogenic FT cycles. A plasticity based continuous surface cap model was adopted to simulate concrete. The material modulus, uniaxial and triaxial strength surface as well as damage parameters were updated to incorporate the effect of cryogenic FT cycles. A numerical model was established to forecast the impact resistance of the reinforced concrete panels after various cryogenic FT cycles. Through the numerical simulation, it was evident that FT cycles exerted detrimental effects on the impact resistance of reinforced concrete panels. With an escalation in the number of FT cycles, there was a pronounced increase in the size of the crater formed on the top surface, accompanied by a corresponding rise in the penetration depth of the panel. The results of this research offer insights into the impact resistance of reinforced concrete structures following cryogenic FT cycles. Such insights are vital for the design and maintenance of critical structures like liquefied natural gas (LNG) storage tanks and other cryogenic facilities.