Enhancing the performance of crumb rubber-modified binders through varying the interaction conditions

Abstract

Traditional crumb rubber-modified (CRM) binders produced with coarse particles according to the McDonald method, the wet process, raise engineering as well as environmental concerns for their suitability in Superpave applications. This paper investigates the possibility of producing high-performance terminal blending CRM binders suitable for Superpave applications through the wet process. This paper re-examines the asphalt–rubber interaction mechanism and focuses on controlling the swelling of crumb rubber particles through varying the interaction conditions. This study considers parameters such as time, temperature, shearing speed and the addition of polymer modifiers to enhance the binder performance properties to meet the requirements of Superpave mixes. Rubber-modified terminal blends are very different from the McDonald-type binders and so are the conditions required for each binder type. The binder properties of interest are those related to performance and compatibility.

Keywords:

• asphalt rubber
• modified binder
• CRM
• superpave application
• terminal blend

Acknowledgements

The authors would like to acknowledge the NDSU Civil Engineering Department for its support of this research. Nebraska Department of Roads is greatly appreciated for its contributions.