Dynamic Properties of Expansive Soil-Rubber under Freeze-Thaw Cycles

Soils mixed with recycled waste rubbers have been widely used in geotechnical and geoenvironmental engineering. However, the research on rubber-soil mixtures in deep seasonally frozen regions is relatively lacking, so the application and dynamic properties of expansive soil-rubber (ESR) undergoing freeze-thaw (FT) cycles need further investigation. This study investigated the dynamic properties of ESR undergoing freeze-thaw cycles in terms of confining pressure and frequency using temperature-controlled dynamic triaxial tests. The results show that (1) shear stress and dynamic shear modulus with 5% and 10% rubber content (RC) are similar under freeze-thaw cycles, and both decrease and then increase with the number of cycles; (2) shear stress and dynamic shear modulus are positively correlated with confining pressure and frequency for the same number of cycles; (3) ESR damping ratio decreases with increasing shear strain, with a maximum reduction of 50.65%; (4) variations in ESR damping ratio under the influence of freeze-thaw cycles, confining pressure, and frequency are significant; and (5) ESR damping ratio is optimal when FT=12 and RC=10%, and is 29.76% higher than that of plain expansive soil.

Automated summary

This study investigated the dynamic properties of expansive soil-rubber (ESR) undergoing freeze-thaw cycles using temperature-controlled dynamic triaxial tests. The results showed that shear stress and dynamic shear modulus decreased and then increased with increasing number of cycles. Shear stress and dynamic shear modulus were positively correlated with confining pressure and frequency. The damping ratio of ESR decreased with increasing shear strain, and the influence of freeze-thaw cycles, confining pressure, and frequency on the damping ratio was significant. The optimal ESR damping ratio was achieved when FT=12 and RC=10%, which was 29.76% higher than that of plain expansive soil.