Performance of silty sand reinforced with aqueous solution of polyvinyl alcohol subjected to freeze-thaw cycles

Abstract This study aimed to examine the change in the mechanical properties of the silty sand reinforced with an aqueous solution of polyvinyl alcohol (PVA) subjected to freeze-thaw cycles. A series of unconsolidated undrained triaxial compression tests were conducted to determine the compressive strength, resilient modulus, cohesion, and internal friction angle. Experimental samples were prepared by adding aqueous solutions of different PVA concentrations (5%, 7.5%, and 10% of the weight of the water) into silty sand. The numbers of freeze-thaw cycle (0, 5, 10, 15, 20) were realized in a closed system. A comparison of reinforced and unreinforced samples of silty sand showed that the addition of an aqueous solution of PVA can significantly affect the mechanical properties of silty sand. It was experimentally proven that the positive impact on the mechanical properties of soil increases with increasing concentration of PVA in the solution and with increasing number of freeze-thaw cycle. When a 10% aqueous solution of PVA was added into the soil, the strength of the samples after 20 freeze-thaw cycles increased by 8.5% compared with the strength before freezing. The resilient modulus of unreinforced samples after 20 cycles decreased by 16.1%, while that of reinforced samples after 20 cycles increased by 30.2%. According to the results, the reinforcing additive has a significant effect on the cohesions of soil both before and after the freezing process.