A new paradigm in rutting evaluation: The concept of rutting tolerance temperature (RuTT) for asphalt mixtures

Abstract

Rutting is a primary distress in flexible pavements caused by excessive traffic loads and high temperatures leading to permanent deformation along wheel paths. Ensuring rutting resistance requires careful selection of asphalt binder, aggregate type, and aggregate structure. While SUPERPAVE high-temperature performance grading (PG) selects binders based on stiffness (G*/sin δ), binder properties alone are insufficient as aggregate characteristics also significantly influence mixture performance. Evaluating rutting at a single temperature provides only comparative performance and does not determine the mixture's tolerance under field conditions. This study introduces the Rutting Tolerance Temperature (RuTT) as a comprehensive metric integrating binder and aggregate properties to assess rutting resistance. Four binders (VG30, VG40, PMB40, CRMB60) and three aggregates (Dolomite, Granite, Sandstone) were used. Binder performance was assessed via high PG test, while aggregate effects were evaluated through uncompacted void content (UVC) and angle of repose (AoR). Asphalt mixtures were tested using IDEAL-RT, Hamburg wheel tracking (HWTT), and high-temperature indirect tensile strength (HT-IDT). RuTT was established from IDEAL-RT and validated with HWTT and HT-IDT results. Polymer-modified binders demonstrated superior rutting resistance while Dolomite with higher angularity and surface texture outperformed Granite and Sandstone. RTindex values increased with UVC and AoR highlighting the role of aggregate interlocking. RuTT results revealed that the same binder exhibited different tolerance temperatures with different aggregates; for example, VG30 (PG 58) showed RuTT values of 52°C, 58°C, and 46°C for Dolomite, Granite, and Sandstone. The study confirms RuTT as a reliable parameter for screening and selecting asphalt mixtures based on actual temperature conditions. Copyright © 2025. Published by Elsevier Ltd.