Structural and mechanical evolution of the multiphase asphalt rubber during aging based on micromechanical back-calculation and experimental methods

Asphalt rubber (AR) is a sustainable paving material composed of bitumen and crumb modifier (CRM) recycled from waste tires. The interaction between CRM re-distributes the fractions creates multiphase internal structure AR. Although superior aging resistance AR has been acknowledged, mechanism remains unclear due to limited understanding on behaviors different phases during aging. This study aims investigate structural mechanical evolution binder through micromechanical back-calculation experimental tests. A series separation methods were used disintegrate system at four conditions. properties obtained frequency sweep tests their volumetric as input for back-calculation, which yielded accurate prediction complex modulus swelling but failed that undissolved rubber, so further chemical characterization was conducted estimate its evolution. results indicated process in structures changed simultaneously with properties. All subphases became stiffer influences overall property variated after