Flexible pavements in cold regions: a geotechnical perspective

Abstract

This paper summarizes recent research on the behaviour of flexible pavements in cold regions. One of the major objectives is to show that basic geotechnical engineering principles can be extremely useful for the analysis of pavement structures subjected to freezing and thawing. The frost susceptibility of subgrade soils should be analyzed for three distinct zones: (i) unsaturated zone, (ii) zone saturated by capillary action, and (iii) zone below the water table. Field observations on instrumented highway sections suggest the existence of a swelling mechanism during thaw in subgrade soils well below the maximum frost penetration. The magnitude of strength reduction associated with this swelling phenomenon depends on the frost susceptibility and the swelling index of the subgrade soil.Key words: frost susceptibility, subgrade, saturation, swelling, strength, field observations.