Investigating Binder Flushing of SP-2 Mixes

Mix bleeding, or binder flushing, is migration of the bitumen to the surface of the flexible pavement, with or without fines. Krishnan and Rao indicated that migration can happen by means of two mechanisms: first, by the diffusion of asphalt into the air voids when it is subjected to temperature exceeding its softening point and second by the movement of asphalt due to pressure gradient developed in asphalt. The development of this pressure gradient is due to the reduction of air voids under traffic loads. Both mechanisms can occur simultaneously and the contribution of each depends very much on the temperature-stiffness relationship of the binder, the air voids distribution in the mix and the traffic loads to which the pavement is subjected to. Literature lists mix segregation and binder contamination during the construction process as possible causes of binder flushing. The objective of this study is to analyze available data on early flushing sections of Superpave mixes in Nebraska and to have a better understanding of the possible causes.

Record URL:
Corporate Authors:
University of Nebraska, Lincoln

National Bridge Research Organization, College of Engineering and Technology
Lincoln, NE United States 68588-0531

Nebraska Department of Roads

1500 Highway 2, P.O. Box 94759
Lincoln, NE United States 68509
Authors:
- Abdelrahman, Magdy A
Publication Date: 2005-9

Language

English

Media Info

Media Type: Print
Edition: Final Report
Features: Appendices; Figures; References; Tables;
Pagination: 84p

Subject/Index Terms

TRT Terms: Air voids; Asphalt mixtures; Binders; Bleeding (Pavements); Flexible pavements; Stiffness; Superpave; Traffic loads
Geographic Terms: Nebraska
Subject Areas: Highways; Materials; I31: Bituminous Binders and Materials;

Filing Info

Accession Number: 01153198
Record Type: Publication
Report/Paper Numbers: Research Project Number P559
Files: TRIS, STATEDOT
Created Date: Mar 24 2010 1:50PM