Microstructure-based identification of bitumen performance

ABSTRACT Motivated by recent progress in both experimentation and the micromechanical description of the behavior of multi-composed materials, a multiscale model for asphalt is currently developed at the Christian Doppler laboratory for “Performance-Based Optimization of Flexible Pavements” at Vienna University of Technology. This model allows us to relate macroscopically observable asphalt properties to finer-scale information. Since the mechanical properties of asphalt and the influence of environmental conditions (temperature, aging) originate from the binder properties, a proper characterization of bitumen is essential for the predictive capability of the anticipated multiscale model. In this paper, the characterization of bitumen, comprising the bitumen chemistry, its microstructure, and its viscoelastic properties, is presented for two types of bitumen (standard and polymer-modified bitumen) considering the unaged and aged state. The obtained results provide new insight into the durability behavior of binders, explained by changes of the chemical composition, the microstructure, and the micromechanical properties of bitumen. KEYWORDS: multiscalebitumenmicrostructureIatroscanscanning electron microscopynanoindentation