Rheological and Structural Evolution of Rubberized Asphalts under Weathering

Abstract

Rubberized asphalt has been widely used for extending the service life of pavement. Understanding the weathering mechanism of rubberized asphalt is useful for selecting appropriate rubberized asphalt. This paper examines the weathering process of two typical rubberized asphalts composed of crumb rubber modified asphalt (CRMA) and terminal blend rubber asphalt (TB) by characterizing the rheological and structural evolution of the aged asphalt. Dynamic shear rheometer analysis, infrared spectroscopy, and gel permeation chromatography are used to analyze this evolution. The results show that significant changes occur in the chemical structures and rheological properties of the two rubberized asphalts throughout the weathering process. Although the stiffness of CRMA and TB obviously increases during weathering, their increasing trends are distinct from each other. The chemical evolutions of CRMA and TB during the weathering process differ significantly in terms of variations in molecular weight and carbonyl index.