This paper presents the results of a study carried out to monitor the structural
behaviour of a flexible pavement in cold regions, which is significantly affected by the
environmental factors and traffic loads. In this study, a heavy vehicle simulator is used to
simulate the traffic load and provide the necessary cooling and heat energy required to create
the freeze-thaw environment. The mechanical response of the typical Quebec flexible
pavement structure during freeze and thaw was investigated using this research tool. The
results show that the changes of moisture content and matric suction for unbound materials
have a good correlation with the frost state of surrounding materials. The mechanical
responses, including strains, stress and surface deflection, experience a regular variation
along with the increase of frost penetration and thaw depth.