Developing Performance-Based Specifications for Heavy-Duty Asphalt Mixes in Southern Ontario

Approach intersections in road sections face more intense loading due to static, accelerating, and decelerating traffic, which can diminish their service life. York Region has experienced reduced durability in approach intersections with high truck traffic volumes. To address this issue, a resilient pavement design is required. Traditional volumetric design approaches may not fully capture the behavior of asphalt mixes under heavy traffic loading. Performance-related specifications offer a potential solution, allowing for the production of high-performing asphalt mixes with increased service life. To investigate this hypothesis, six Stone Mastic Asphalt (SMA) mixes were produced with varying performance grade (PG) asphalt binders (PG70-28, PG76-28, and PG82-28) and nominal maximum aggregate sizes (NMAS) of 9.5 mm and 12.5 mm. Laboratory tests were conducted to evaluate the low-temperature cracking resistance (Disk-Shaped Compact Tension Test), intermediate temperature cracking resistance (Illinois Flexibility Index Test), and shear resistance (Hamburg Wheel Tracking Test) of the asphalt mixes. A comparison was made with a plant-produced asphalt mix (WMA SP12.5FC2-PG70-28) commonly used in York Region. A preliminary performance-based specification for heavy-duty asphalt mixes was developed based on the research findings, specifically for their application in Southern Ontario.