Fracture Characteristics of Asphalt Mixtures Containing Incinerator Bottom Ash Aggregate

The documented results form part of a larger research program to study the mechanical and environmental properties of asphaltic mixtures containing incinerator bottom ash aggregate (IBAA). The fracture characteristics of four mixtures containing 0%, 30%, 60%, and 80% IBAA by weight were investigated under monotonic and cyclic semi-circular bending conditions. The linear elastic fracture mechanics (LEFM) approach was used to evaluate crack resistance of the tested mixtures with the aim of investigating the effect of IBAA content on these properties. LEFM led to the determination of the stress intensity factor, the J-integral, fracture energy, and Paris law parameters. Crack propagation was monitored with a digital camera, and a program developed in-house was adopted in interpreting crack growth. In addition, a new approach was presented to obtain asphalt fatigue damage parameters from fracture tests. Results showed a benefit to be gained in adding IBAA up to a certain amount, beyond which cracking properties become close to those of the control mix.