Use of H2Ri Wicking Fabric to Prevent Frost Boils in the Dalton Highway Beaver Slide Area, Alaska

INE/AUTC 12.2

Application of wicking fabric to reduce damage in Alaskan pavements

Thesis (M.S.) University of Alaska Fairbanks, 2016Beaver Slide is located near kilometer 177.8 (mile 110.5) on the Dalton Highway. The road is sloped downhill when heading north. The road gradient is approximately 11%, and the road prism is on a side hill. Each year, soft spots usually appear in the pavement structure in late April and remain all summer. These soft spots have been called “frost boils”. The “frost boils” have resulted in extremely unsafe driving conditions and frequent accident occurrences. Conventional repair methods have not worked. A newly developed geosynthetic wicking fabric was installed in the road structure in August 2010. The fabric has a high specific surface area (consequently high wettability and high capillary action) and high directional permittivity. Test results over the initial two year period proved the effectiveness of the wicking fabric to mitigate “frost boils” and the subsequent road softening issue. Data collected during the past four years were analyzed to evaluate the long-term performance of the wicking fabric. A scanning electron microscope (SEM) was used to explore the interaction between the wicking fabric and in situ soils, and to determine the condition of the fabric five years after installation

Long-Term Performance of Wicking Fabric in Alaskan Pavements

Beaver Slide is near 177.8 km (110.5 mi) on the Dalton Highway and the road gradient is approximately 11%, built on a hill side. Each year, soft spots, also commonly named as frost boils, were observed starting from late April and lasting for the entire summer. The frost boils have resulted in an extremely unsafe driving condition and frequent accident occurrences. Conventional repair methods cannot effectively solve this issue. A newly developed geotextile, which has high specific surface area, was installed in the selected test section to mitigate the frost-boil issue in August 2010. This type of geotextile can provide high wettability and relatively high suction (capillary force), consequently be able to laterally transport water (a high-directional transmissivity) under unsaturated conditions. Test results over the initial 2 years had proved the effectiveness of the geotextile to alleviate frost heave and the subsequent thaw-weakening issue. However, there were still some concerns regarding its long-term performance, such as clogging of the microscopic drainage channels and mechanical failures. The data collected during the past 5 years were used to analyze and evaluate the effectiveness of the wicking fabric. A scanning electron microscope was used to explore the interaction between the wicking fabric and in situ soils, and to determine the condition of the fabric 5 years after the installation