The Flexural Creep Behavior and Creep Compliance Prediction of Basalt Fiber Composites Under Freeze–Thaw Cycles

ABSTRACT With the wide application of fiber reinforced composites in cold‐region civil engineering, it is necessary to investigate the influence of freeze–thaw (F–T) cycles on mechanical properties of composites. In this paper, basalt fiber‐reinforced polymer (BFRP) composite was manufactured by vacuum‐assisted resin infusion and exposed to 50, 100, and 200 F–T cycles in water. Flexural and creep properties of F–T exposure were evaluated. Additionally, microstructural and chemical changes were characterized by scanning electron microscopy and Fourier‐transform infrared spectroscopy at the fiber and matrix scales. The results show progressive degradation in flexural and creep behavior with increased F–T cycles. The flexural strength decreased by 24% after 200 F–T cycles, while the flexural modulus increased after 50 F–T cycles and then decreased. The F–T exposure accelerated the creep strain, leading to an earlier onset of tertiary creep. The modified Findley model incorporating F–T influence functions was modified to predict the creep compliance after different F–T cycles. The observed mechanical degradation was primarily due to matrix cracking, interfacial deterioration, and the accumulation of microstructural damage. This paper quantifies the influence of F–T cycles on the flexural and creep behavior and provides valuable guidance for the rational design of FRP composites.