Climate change: potential impacts on frost–thaw conditions and seasonal load restriction timing for low-volume roadways

Low-volume roads constitute a major percentage of roadways around the world. Many of these are located in seasonal frost areas where agencies increase and decrease the allowable weight limits based on seasonal fluctuations in the load carrying capacity of the roadway due to freeze–thaw conditions. As temperatures shift due to changing climate, the timing and duration of winter freeze and spring thaw periods are likely to change, potentially causing significant impacts to local industry and economies. In this study, an ensemble of 19 climate models were used to project future temperature changes and the impact of these changes on the frost depth and timing of seasonal load changes across five instrumented pavement sites in New England. The study shows that shifts of up to 2 weeks are projected at the end of the century and that moderate variability was observed across the study region, indicating that local conditions are important for future assessments depending on the desired level of accuracy. From 1970 to 1999, the average freezing season lasted between 9 and 13 weeks in the study region. By 2000–2029, the frozen period shortens by approximately 10 days over baseline duration (10–20% reduction). By the end of the century under RCP 4.5, frozen periods are typically shorter by 4 weeks or a 30–40% reduction. However, RCP 8.5 results indicate that four out of the five sites would have no frozen period during at least six winters from 2060 to 2089.