Dynamic Response of Carbon Fiber-Reinforced Clay Under Freeze–Thaw Cycles

Annual freeze–thaw (F–T) cycles can cause significant damage to soil structures, particularly roads. This study explored the effectiveness of adding carbon fibers (CF) to clay to enhance its performance during F–T cycles. The CF were mixed with clay at varying rates, ranging from 0.1 to 0.4%, based on the weight of the dry soil. Dynamic tests were conducted on unreinforced and reinforced samples after subjecting them to 0, 3, 6, and 9 F-T cycles under 100 kPa and 300 kPa confining pressure. The findings revealed that the inclusion of CF led to an increase in both the shear modulus and damping ratio. Specifically, the sample containing 0.3% CF demonstrated a significant 30% increase in shear modulus compared to the pure sample at the same cyclic stress level. Moreover, while the shear modulus decreased with the number of F–T cycles, this reduction was less pronounced in samples reinforced with CF compared to pure samples.