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Innovative Preservation Treatments to Address Premature Pavement Roughness on a Swelling Clay Subgrade in Alberta


In the early 2000s, Alberta Transportation (AT) twinned a portion of Highway 43 east of Grande Prairie in a staged sequence. The new westbound lanes exhibited premature roughness shortly after final paving. The observed roughness so early in the life of the pavement was extremely unusual and unexpected. Detailed investigation was carried out to determine the factors that were causing the premature roughness and to identify potential treatments that could be installed to restore ride quality or mitigate the recurrence of similar roughness. The assessment included a review of the as-built and historical information, a field trenching and drilling and a laboratory testing program, and field observations under winter and summer conditions. Profile data of the outer travel lane was collected during the summer/fall season of 2003 through 2008. In addition, data was collected in the winter of 2008 to assess seasonal effects and on the shoulder to assess the difference in roughness between the travel lanes and the shoulders. The analyses indicated that the roughness was characterized by heaving of the pavement surface in the vicinity of thermal induced cracks overlying a clay subgrade material with a high swell potential. The IRI has increased every year, and further increased in the winter. The road shoulders were smoother than the driving lanes. A mechanism that provided an explanation for the observed roughness was developed. Seven different treatment alternatives with different pre-overlay crack repairs were installed in 2009. This paper describes the comprehensive assessment activities, development of innovative treatments, and early performance.

Conference Paper Details

Session title:
Mohammad Karim
Dave Palsat
Art Johnston
Trent McLaughlin