A large number of road structures are subjected to seasonal freezing and thawing in Canada. Low
volume (secondary) roads in frost-prone regions are susceptible to loss of structural capacity
during thaw season. During freezing season, ice lenses form in the subgrade soil. Melting of
these ice lenses during thawing season is deemed to be the main cause of losing structural
capacity. There are several suggested empirical methods in the literature for predicting the onset
and duration of thawing condition in the subgrade soil. Generally, transportation agencies use the
outcome of these prediction models to apply limitations on maximum allowable loads of trucks
passing on the vulnerable roads which is known as Spring Load Restriction (SLR) or Spring
Road Ban (SRB).
As part of an ongoing research on the Integrated Road Research Facility (IRRF)’s test road
constructed in August 2012 which is a new access road to Edmonton Waste Management Center
(EWMC), the temperature data were recorded over the winter of 2013 using thermometers
installed across the depth of the pavement structure in order to monitor the temperature variation
through different layers (Hot Mix Asphalt (HMA), Granular Base Course (GBC) and subgrade.)
This research is a comparative study between 4 different methods to evaluate their credibility in
determining the imposition date of SLR using the recorded field temperature data. It was found
that all models were able to accurately predict the onset of thawing through the pavement.
