Roughness degradation models of flexible pavements subjected to seasonal frost action

In cold regions, flexible pavements are constantly submitted to the effects of repeated traffic loads combined with the climate effect. The frost heave of the subgrade soils due to formation of ice segregation is among the main mechanism involved in the high deterioration rate of flexible pavement. This paper presents developments of flexible pavement damage models, developed through a multiple linear regression (MLR) analysis, associating long-term roughness performance to degradation mechanisms, such as, among others, frost heave. Those models would be essential to assess the advantages or consequences to have a frost heave lower, equal or higher than the allowable threshold values established by the Ministry of Transportation of Quebec (MTQ) according to the roads functional classification. One of the models developed uses the cracking performance index as a direct quantification of cracking and the other one uses indirect cracking quantification using thickness and age of pavement. This research illustrates that a notable increase in long-term IRI deterioration rate of pavement is usually caused by frost heave, variable subgrade soil and traffic. Obtaining the flexible pavement damage models with the various degradation mechanisms will help to predict and reduce the residual distortions that affect the structural and functional capacities of cold region’s road network.