Study on the Mechanical Properties of Fiber Reinforced Concrete Composite to Cryogenic Temperatures

Abstract

This paper investigates the mechanical properties of steel-polypropylene hybrid fiber-reinforced concrete (HFRC) at low temperatures, including 20 ℃, − 40 ℃, − 80 ℃, − 120 ℃, and − 165 ℃. The compressive strength, tensile strength, flexural strength, and stress-strain relationships of the material under these conditions were tested and analyzed. The results indicate that the compressive strength, tensile strength, peak stress, elastic modulus, and flexural strength of HFRC are improved under low temperatures, while the peak strain decreases. Additionally, the mechanical properties and flexural toughness of HFRC are better than normal concrete (NC). Among specimens with different fiber compositions, the HFRC specimen containing 0.5% steel fibers (SF) and 0.1% polypropylene fibers (PF) exhibited optimal mechanical properties. Finally, the test results were used to develop a calculation model for determining the compressive, tensile, and flexural strengths of HFRC. By modifying the parameters of existing stress-strain models, a stress-strain model for HFRC under low-temperature conditions was established.