Urban roadway pavement rutting, particularly at signalized intersections, is a significant issue and a challenge for those responsible for municipal pavement infrastructure. Agencies have, in recent years, been proactive in trying new strategies for dealing with this problem. These strategies have included premium hot mix asphalt (HMA) surfacing materials including the use of polymer modified or performance grade asphalt binder, stone matrix asphalt (SMA), Superpave mix types, sulfur extended asphalt modifier, and asphalt rubber mixes. The Cities of Calgary and Lethbridge have recently installed various types of pavement surfacing materials with the objective of assessing performance under in-service conditions. The limited experience with these types of hot mix asphalt materials has made it necessary for the municipal agencies to adopt available methods to provide some indication of their performance prior to their widespread use in construction. The Asphalt Pavement Analyzer (APA) has been shown to be a useful tool for the assessment of the permanent deformation (rutting) resistance of HMA materials. This paper describes how APA testing was used for the assessment of HMA materials within the context of projects undertaken by the Cities of Lethbridge and Calgary, in 2003 and 2004. In some cases the APA testing was used to validate and/or optimize HMA mixture designs. This means of accelerated testing was also used to evaluate the rut resistance performance of constructed pavements, with the objective of assessing the different materials and construction strategies. Guidance regarding the use of APA results, including benefits as well as limitations, is provided.
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