High-efficiency thermal insulation for an embankment dike in Yakutsk

High-efficiency thermal insulation materials are widely used in permafrost engineering for the thermal protection of ice-rich structures (dams, levees, storage facilities, airfields, roads, etc.) and for controlling natural and anthropogenic cryogenic processes and hazards (e.g., icings, seasonal freeze-thaw cycles). Investigating these processes is highly relevant task for Arctic and Subarctic regions. From 1982 to 1986, a full-scale field experiment was conducted on a dyke adjacent to the Permafrost Institute in Yakutsk. The objective was to create an impermeable frozen core within its embankment and foundation using a combination of thermosyphons and high-efficiency thermal insulation (PVC-1 foam). In 2024, a PVC-1 foam sample was retrieved from the crest of the dyke to assess its residual thermophysical properties after 40 years of service. The investigation employed thermal analysis, two-probe measurements, and steady-state technique evaluations using a Netzsch HFM 436 Lambda apparatus. The results demonstrate that the material has maintained its structural integrity and insulating performance remarkably well, confirming that PVC-1 foam constitutes a reliable and durable insulating layer under the climatic conditions of Yakutia. This finding suggests that more advanced insulating materials used to maintain foundation soils in a frozen state or to form frozen dam cores can potentially achieve a very long service life (exceeding 50 years).