Table 5 Assessment standard of extreme freeze-thaw days in cold regions
From: Analysis methodology and assessment indices of vulnerability for asphalt pavement in cold regions
Assessment Index | Micro | Mild | Moderate | Severe | Extreme |
|---|---|---|---|---|---|
Freeze-thaw days (d) | < 54 | 54 ~ 60 | 60 ~ 66 | 66 ~ 72 | ≥72 |
The frequency of blizzard | < 0.2 | 0.2 ~ 0.4 | 0.4 ~ 0.6 | 0.6 ~ 0.8 | ≥0.8 |
Permafrost temperature (°C) | <−3 | − 3 ~ −1.5 | −1.5 ~ −0.5 | − 0.5 ~ 0 | > 0 |
Ice content of permafrost | S, D, F | S, D, F | S, D, F | S, D, F | B, H |