Ultra-low temperature effects on tensile stress-strain relationships in reactive powder concrete

To address the pressing need for reliable material data in the design of cryogenic structures, this study characterizes the tensile mechanical properties of Reactive Powder Concrete (RPC) for Liquefied Natural Gas (LNG) storage tank applications. This study investigates the tensile mechanical properties of steel fiber-reinforced RPC from 20^oC to −165^oC. A total of 21 axial tensile tests were performed on standard RPC specimens at various temperature levels. The effects of temperature and steel fibers on the tensile stress-strain relationship of RPC were evaluated from 20^oC to −165^oC. The results indicated that the average tensile strength of RPC within this temperature range reaches approximately 2.22 times that of ordinary concrete (typically 2−4 MPa). At −120 °C, both the tensile strength and toughness of RPC reach their peak values of 9.47 MPa and 135,145 MPa·μɛ, respectively, representing improvements of 48% and 211% compared to room temperature conditions(6.41 MPa and 64,096 MPa·μɛ). Simultaneously, RPC began to approach the ductile-brittle transition temperature, and the enhancing effect of low temperature on its toughness gradually diminished. Additionally, an effective predictive model has been established for the axial tensile stress-strain behavior of RPC under cryogenic conditions. The study provides the fundamental data and theoretical underpinning necessary for applying RPC to full-capacity LNG storage tanks.