Grant: Alliance Grants

Unpaved roads account for 60% of roads in Canada and 80% of roads worldwide. Freeze-thaw is a major cause of road failures in Canada. The geosynthetics such as geocells and geogrids are normally placed in the base courses or between base courses and subgrade in roads to enhance the road performance. However, the mechanisms of geocell or geogrid reinforcement to roads under the freeze-thaw cycles are not well understood, and the relevant design methods have not been established. This research project aims to investigate the use of geocell and geogrid to mitigate the freeze-thaw damages to unpaved roads through both laboratory model tests and field tests. The outcomes of this project are (1) development of a large-scale cyclic freeze-thaw and plate loading (FTPL) model test apparatus in laboratory, (2) trafficking load tests of full-scale unpaved road sections in field after seasonable freeze-thaw cycles, (3) development of design methods for freeze-thaw affected geocell- or geogrid- reinforced unpaved roads, and (4) an improved understanding of the benefits of geocell and geogrid reinforcement and the underlying reinforcing mechanisms under freeze-thaw cycles. The results of this research will advance the design of unpaved roads affected by freeze-thaw cycles and facilitate recommendations to stakeholders with respect to sustainable and cost-effective solutions to construction of durable unpaved roads in Canada.