Evaluation of strength properties of clay treated by nano-SiO2 subjected to freeze-thaw cycles

Stabilisation by nanoparticles can be considered as an efficient method for enhancing the mechanical properties of clay exposed to the freeze-thaw cycles. The laboratory tests were conducted to understand the effects of various freeze-thaw cycles on clay treated with different percentages of nano-SiO2. In this paper, unconfined compressive strength (UCS) and shear resistance of soil, as well as the influencing mechanism of nano-SiO2 was evaluated.The results showed that nano-SiO2 leads to improve and prevent the resistance reduction of clay due to the freeze and thaw processes. After 9 cycles, the UCS and shear strength of clay treated with 1.0% nano-SiO2 were 16% and 21% more than natural clay which was not subjected to the freeze-thaw cycles. Scanning electron microscopy (SEM) images represent that nano-SiO2 produces whiskers under thermal stresses caused by freeze-thaw cycles. The whisker phenomenon leads to a significant increase in the mechanical properties of clay by creating filamentary networks.