Study on the Impact Compression Strength Variation of Carbon Fiber-reinforced Concrete after Freeze-thaw Cycles

Abstract

To study the variation in the strength of carbon fiber-reinforced concrete (CFRC) under impact loading after freeze-thaw cycles, we conducted a split Hopkinson pressure bar impact compression test on CFRC subjected to freeze-thaw cycles. Dynamic stress-strain curves of CFRC subjected to different numbers of freeze-thaw cycles (0, 50, 100, and 150 cycles) under impact loading (at strain rates of 55 s^-1, 110 s^-1 and 165 s^-1). The results show that even after freeze-thaw cycles, CFRC has a significant strain rate effect, with the peak stress increasing with the strain rate. Meanwhile, the peak stress of CFRC gradually decreased as the number of freeze-thaw cycles increased. The mechanisms of the effects of freeze-thaw cycles and strain rate on the peak stress of CFRC were analyzed from an energy transformation perspective. A damage factor was defined through the dynamic elastic modulus, and the freeze-thaw cycle damage evolution of the CFRC was analyzed based on the Weibull probability distribution. A predictive model for the impact compressive strength of CFRC was developed considering freeze-thaw cycle damage and strain rate. This model accurately predicts the impact compressive strength of CFRC after freeze-thaw cycles, providing a reference for predicting CFRC strength under impact loading after freeze-thaw cycles.