Effect of Freeze–Thaw Action on Mesostructure of Ecological Fiber Reinforced Loess

Traditional chemical additives inevitably pollute, damage, and destroy the ecological environment and natural resources while simultaneously addressing the requirements of engineering construction in loess areas. Additionally, freeze–thaw cycles exert a substantial influence on the long‐term durability of engineering structures located in areas with loess deposits. Thus, it is a considerable benefit to identify and utilize materials that are beneficial to the environment and which will augment the engineered performance and freeze–thaw resistant capacity of loess. The purpose of this research is to evaluate the impact of freezing and thawing cycles on the mesostructural attributes using loess reinforced with lignin fiber and to elucidate an effect of varying fiber doses in relation to the response of loess to freezing and thawing. The findings illustrate that the incorporation of fiber effectively eliminates the presence of overhead pores in the loess. Furthermore, the freeze–thaw action induces the formation of long‐narrow pores along the fiber surface in the reinforced loess. Adding the fiber reduces the characteristic parameters of the loess mesostructure. On the other hand, the freezing and thawing action increases the apparent void ratio, the mean pore area, and the area probability distribution index of the reinforced loess, while decreasing the probability entropy and bringing the fractal dimension very close. Freeze–thaw has the least effect on the apparent void ratio and microfine pore area ratio of 1% fiber loess. The filling and bridge effects of lignin fiber serve as the primary means of enhancing the strength of loess. Through its control of water, fiber bears the influence of some loess particles and pores, thus improving the freeze–thaw resistant capacity of loess.