Fatigue performance assessment of recycled tire rubber modified asphalt mixtures using viscoelastic continuum damage analysis and AASHTOWare pavement ME design

Improving fatigue cracking resistance of asphalt mixtures is an important issue that concerns roadway agencies, public and industry. There are various, well-established methods for improving the material characteristics, such as polymer modification methods. Recycling/reusing scrap tire rubber in asphalt pavements has also been an interest of engineers. As such, many different methods of scrap tire rubber (herein called crumb rubber) modification alternatives are being developed. This study focused on a comparative evaluation of the fatigue cracking resistance of various base and recycled tire rubber modified asphalt mixtures, including the relatively new and innovative devulcanized rubber (DVR), crumb rubber terminally blend (CRTB), crumb rubber wet process (CRWET), original/base PG58-28 and softer PG58-34 binders, by using Push-Pull Viscoelastic Continuum Damage (PP-VECD) analysis and AASHTOWare Pavement Mechanistic Empirical Design (Pavement ME) software. The results of the study revealed that rubberized asphalt mixtures provided better fatigue lives than the base and softer binders did. Especially, DVR mixtures outperformed at high strain levels, implying they can be used for heavy traffic roads to enhance the fatigue life of asphalt pavements. Both PP-VECD and Pavement ME produced results that showed similar trends. (C) 2020 Elsevier Ltd. All rights reserved.