Deformational characteristics of subgrade soils and subbase materials with freeze-thaw

An Anti-freezing layer is not present when there is no frost heaving in subgrade soils with a low water table. In this case, such subgrade soils and subbase materials were shown to have experience in freeze-thaw cycles when an external water supply was not present. Deformational characteristics of subgrade soils and subbase materials in Korea were determined by IR tests under a closed freeze-thaw cycle system, where no external water supply was introduced during testing. There was a very small difference in the modulus between before and after freeze-thaw cycles for all tested subgrade soils and subbase materials. This means that the thawweakening of subgrade soils and subbase materials did not occur under a closed water supply system. This indicates that it is not necessary to consider the thaw-weakening of subgrade soils when subgrade soils are freezing without frost heaving. Furthermore, the damping ratio was slightly increased at the start of freezing and then rapidly decreased during freezing process. This same pattern was established for all samples and trials that were conducted. Additionally, the damping ratio at thawing stage increased slightly more than the before freezing stage, while the damping ratio decreased and established almost the same value before freezing.