Aurora

About the research

An increase in freeze-thaw events will result in detrimental impacts on pavement systems. However, the impacts of recent climate changes on freeze-thaw cycles have not been well studied, although they are of interest to a broad number of transportation agencies. In this study, the number of freeze-thaw events at typical air temperature sensor level (e.g., 6 feet above the earth’s surface) as well as at different pavement layers and critical sub-pavement locations such as saturated subgrade within the active zone were quantified.

In response to global warming, current work resulted in rigorously quantified freeze-thaw events rooted in climate data from 1941 to 2020. Results indicated that in the recent 40 years (i.e., 1981–2020), Minnesota winters have become warmer by 1–2ºF daytime and 2–5ºF nighttime temperatures. With a decrease in freezing temperatures, the yearly number of freeze-thaw cycles tended to decrease at shallow pavement depths (<6 in.), whereas remained sporadic at deeper pavement layers. The decreases in freeze-thaw events at shallower depths were significant during the early and late winter months. However, the annual freeze-thaw events at the air temperature sensor level were randomly distributed throughout the analysis period.