Oxidative Aging and Physical Hardening of Conventional and Polymer Modified Binders

摘要

The long-term performance of bituminous materials is influenced by, among other things, oxidative aging and physical hardening. Time-related hardening is one of the principal factors contributing to deterioration of asphalt pavements. This paper presents results of a study on oxidative aging and physical hardening of various conventional and polymer modified binders. Five bitumens of different source/grade were selected for investigation. Polymer modified binders were prepared by blending the base bitumens with different types of elastomers and plastomers at contents of 3, 6 and 9% (by weight). Laboratory aging of binders was performed using TFOT, RTFOT and modified RTFOT. Effects of aging on binder composition and viscoelastic properties were investigated by means of Fourier transform infrared spectroscopy, chromatography and rheological analysis using a dynamic shear rheometer. Based on aging index, relationships between the aging methods were examined. Physical hardening was studied using a bending beam rheometer at different low temperatures and during different times of isothermal storage. Effects of bitumen characteristics and polymer modification on physical hardening were investigated.