To investigate the mechanical properties of SFRC (Steel Fiber Reinforced Concrete) in low-temperature environments, a 3D mesoscale model approach was employed to simulate the mechanical behavior of SFRC specimens at cryogenic temperatures. The model considers SFRC a multiphase material composed of mortar, aggregate, ITZ (Interface Transition Zone), and steel fiber. Using the mesoscale modelling, the damage pattern, stress-strain curve, load-deformation curve, dissipated energy, strength under compressive and splitting-tensile loadings, strength prediction formula as well as the flexural toughness of SFRC specimens with different steel fiber content at low temperatures were obtained and analyzed. The results show that the compressive/splitting tensile strength significantly increases with the decrease in temperature. The splitting tensile strength, the peak deformation as well, and the dissipated energy increase in the case of a greater steel fiber volume fraction while the improvement effect of fiber content is weaker with the decrease in temperature. A prediction formula that considers the coupling effect of fiber volume fraction and temperature on the tensile strength of concrete was proposed. The effect of steel fiber on compressive strength is not obvious regardless of temperature. The flexural toughness index of SFRC increases significantly with increased steel fiber content but is insensitive to temperature changes.

为了研究低温环境下 SFRC（钢纤维增强混凝土）的力学性能，采用 3D 介观模型方法来模拟 SFRC 试件在低温下的力学行为。该模型认为 SFRC 是一种由砂浆、骨料、ITZ（界面过渡区）和钢纤维组成的多相材料。利用细观建模，得到了不同钢纤维含量的钢纤维混凝土试件在低温下的损伤模式、应力-应变曲线、载荷-变形曲线、耗散能、压、劈拉载荷下的强度、强度预测公式以及弯曲韧性。获得并分析温度。结果表明，随着温度的降低，抗压/劈裂拉伸强度显着增加。随着温度的降低，钢纤维体积分数较大时，劈裂抗拉强度、峰值变形和耗散能均增大，而纤维含量的改善效果较弱。提出了考虑纤维体积分数和温度耦合效应对混凝土抗拉强度的预测公式。无论温度如何，钢纤维对抗压强度的影响都不明显。SFRC的弯曲韧性指数随着钢纤维含量的增加而显着增加，但对温度变化不敏感。