Use of binder stress relaxation parameters and mixture IDEAL-CT for the control of pavement cracking: A case study from a Highway 655 trial in northeastern Ontario, Canada

• Aging reduces binder stress relaxation, varying by composition. • Polymer-modified mixtures resist cracking when unaged but degrade after aging. • PET fibers counter aging effects via crack-deflection and bridging. • IDEAL-CT poorly ranks field resistance but helps identify weak designs. The longevity of asphalt pavements in cold regions is primarily determined by their resistance to cracking which ultimately causes structural failure. Accurately controlling this distress through laboratory tests on binders and mixtures remains a significant challenge. This study aims to analyze asphalt binder and mixture test feasibility in predicting and ranking asphalt pavement trial section cracking performance. Seven binders used in adjacent trial sections were assessed for phase angle master curves and stress relaxation attributes, while the indirect tensile asphalt cracking test (IDEAL-CT) was performed on corresponding mixtures. Accelerated aging in the laboratory reduces stress relaxation ability in major ways depending on binder composition. Unaged polymer modified mixtures demonstrated good cracking resistance in the IDEAL-CT at intermediate temperatures. However, their performance decreased considerably after irreversible oxidative and thermo-reversible aging at low temperatures. In contrast, polyethylene terephthalate (PET) fibers were able to largely offset the negative effects of binder aging through crack-deflection and crack-bridging mechanisms in mixtures made with straight Cold Lake, Alberta binder. While the IDEAL-CT did poorly at ranking field cracking resistance, practical mixture cracking tests remain useful for identifying and rejecting inferior designs with low benefit/cost ratios. This study highlights the importance of comprehensive testing to ensure long lives and sustainability for asphalt pavements in cold regions.