Abstract
Longitudinal profile of an asphalt concrete pavement in a cold region was measured weekly during winter using inertial profiler and the International Roughness Index, IRI, was calculated to analyze its seasonal changes.
The IRI of segments including cuts was greatly increased during winter and decreased to the same level as fall, when spring came. The frost penetration depth reached the subgrade at the beginning of Febrauary. The dates of the maximum IRI concentrated in the period when the maximum frost penetration depth was observed. This indicated that the IRI's increase in winter was affected by frost heave. The IRI increased with freezing index in the segments where the IRI increased largely and the IRI in the cut sections of these segments became sevral times that in fall.
