Assessment of Flexible Pavement Response during Partial Thawing Conditions Using Accelerated Pavement Testing

Damage to flexible pavements is known to be greatly influenced by climatic factors. Among them, partial thawing conditions encountered during winter warming periods, as well as in the early period of spring thaw, are reported as critical conditions for flexible pavement structures in cold regions. Experimental research was conducted using a laboratory test pit and a heavy vehicle simulator in order to document flexible pavement response during these critical conditions. Freezing of a typical experimental pavement was induced at-10°C. Thawing at 20°C was initiated afterwards from the surface downward. Pavement response and conditions were monitored using a thermistor string, as well as stress and strain sensors in all the pavement layers. The pavement response was measured regularly throughout thawing. It was more specifically documented for asphalt concrete temperatures of 10°C, 0°C, and-5°C when thaw depths reached 300, 600, 900, and 1,200 mm. The paper documents the pavement response for various partial thaw and temperature conditions. Weakening was found to be moderate in the pavement structural layers but reached a maximum for the subgrade soil once the pavement was completely thawed.