Freeze–Thaw Effects on Mechanical Behavior of Geocell-Reinforced Sands from Element and Model Tests

Freeze–thaw (F–T) cycles are a major cause of pavement distress in seasonal frost regions. It has been demonstrated in practical applications that geocell-reinforced roads are effective in resisting F–T damage. However, this beneficial effect has not been quantified, and the underlying mechanisms are not well appreciated either. To address these questions, this study carried out two types of laboratory-scale tests, namely element tests (single geocell) and model tests (multiple geocells) to investigate the mechanical properties (stiffness and ultimate bearing pressure) of geocell-reinforced sands subjected to various freeze–thaw cycles. The experimental results showed that although the poorly graded sands used in this study were classified as frost insusceptible, both mechanical properties (stiffness and ultimate bearing pressure) of the sands were reduced up to 20% after five F–T cycles. The mechanical properties of both unreinforced and reinforced sands were decreased with the increased F–T cycles. At different F–T cycles, geocells improved the mechanical properties by 30–110%. The test results showed high variability at a small number of F–T cycles in the element tests, but the variability diminished at a higher number of F–T cycles. The discrepancy of test results between element tests and model tests might be due to scale difference that resulted in different soil conditions prepared and thus different water distributions inside the soils.