Abstract Manager

Based on network level asset management data, cracking is the most prevalent asphalt pavement distress observed on Saskatchewan’s provincial highway network. Thermal transverse cracks typically reflect through new paved asphalt mats within two years of repaving, and in some cases as early as after the first winter. Applying preservation treatments on newly rehabilitated asphalt pavements takes funds away from other roads and impacts the overall level of service of the pavement network. In 2019, the Saskatchewan Ministry of Highways (ministry) implemented the use of polymer-modified asphalt binders for highways with high truck traffic, with the objective of using softer grade base asphalt to help mitigate cracking of newly constructed asphalt pavements. In addition, polymer-modified asphalt binders were mandated on repaving projects for higher volume highways.

This paper compares the cracking performance of asphalt concrete pavement test sections constructed on Highway 7 rehabilitation project in 2019, with dense-graded asphalt mixes using 150-200A binder and PG 58-37P binder, both containing 1% hydrated lime. Visual crack assessments were conducted, and automated cracking data collected with a laser crack measuring system (LCMS) was compared over time. LCMS data was also compared over selected segments of the pavement outside the official test sections for a more comprehensive analysis. Further assessment included laboratory testing of pavement cores from the test sections for evaluation of cracking resistance of the asphalt mixes using the I-FIT test (AASHTO TP 124) and the Indirect tensile cracking test, IDT Nflex (AASHTO TP 141).