Abstract
Rubber modification of asphalt leads to improvement in certain asphalt mixture properties in lab studies, and extension of service life has been reported in a number of field studies. However, modern laboratory cracking tests often produce conflicting results in terms of the expected cracking performance of rubber-modified asphalt mixtures. To better understand cracking/toughening mechanisms in rubber modified asphalt materials, a fracture mechanics based test was devised for various unmodified and modified binder systems (unmodified control, polymer- and rubber-modified at various treatment levels). The results of this testing showed that unmodified and polymer-modified specimens failed in a brittle fashion, while the rubber-modified specimens displayed increasing ductile-type failures as the rubber modification level increased. Analysis of the fractured faces of the specimens under a Scanning Electron Microscope also revealed the presence of characteristic tails and cavities in the rubber-modified specimens associated with a crack-pinning-type toughening mechanism.
Disclosure statement
No potential conflict of interest was reported by the author(s).