A large portion of Canada’s highway network is low traffic volume roads with thin pavement structures.
Currently, no generally accepted design method is available for these roads. As such, pavement design
and/or construction methods vary widely among the jurisdictions. The AASHTO 1993 guide recommends the same design approach for thin asphalt (0.98) were observed between the AC layer thickness and the
predicted IRI as well as between the AC layer thickness and the predicted total rutting. Overall, these trial
results indicated that PMED software can be used to design pavements with a minimum AC thickness of
approximately 100 mm (4 in.) considering all type of distresses. However, considering only the IRI and
total rutting criteria and ignoring small irregularities in the trends of predicted IRI and total rutting in
pavement designs for low traffic volume roads, an AC thickness of as low as 50 mm could be used when using the PMED software.
