Innovative Air Convection Embankment for Cold/Arctic Region Low-Volume Roads

Roadbed thaw settlement is a unique challenge for the durability of low-volume roads (LVRs) in permafrost regions. Air convection embankment (ACE) is an effective technique that acts as a semi-heat-transfer system to control temperature variation and reduce the thaw depth of subsoil. However, limited by the shortage of the necessary crushed rocks within a short distance, building an ACE in Alaska, U.S., is prohibitively expensive. Previous studies identified the feasibility of using cellular concrete for ACE and determined the optimized thickness of the cellular concrete aggregate interlayer for ACE. However, the economic efficiency and thermal and mechanical performance of the optimized, innovative cellular concrete aggregate ACE need further investigation. Therefore, two innovative cellular concrete ACEs with reasonable heights for cold/Arctic region LVRs were evaluated in this study. A thermal-mechanical coupling model was created using ANSYS Fluent and ANSYS Mechanical to evaluate the thermal and mechanical stability of the two optimized innovative cellular concrete aggregate ACEs by comparing them with a typical Alaskan flexible pavement, a silty sand/gravel embankment, and a conventional crushed-rock ACE. The fatigue damage was predicted using the elastic-based Alaska Flexible Pavement Design (AKFPD) program. A life-cycle cost analysis was conducted using AKFPD to evaluate the overall long-term economic efficiency of the cellular concrete ACEs. The results showed that cellular concrete ACE could achieve better thermal and mechanical performance with much lower embankment height than crushed-rock ACE. The cost analysis showed that the proposed cellular concrete ACEs had a significant cost advantage over the conventional crushed-rock ACE.