Producing Bio-Modified Rubber (BMT) Asphalt; A Sustainable and Bio-Based Alternative for Petroleum-Based Asphalt
The contract for this project has just been signed. This follow-on project will explore and establish technical and scale-up feasibility and market viability of bio-modified rubber (BMR) asphalt (developed in an earlier IDEA Project NCHRP-171) as a sustainable bio-based alternative to petroleum-based asphalt and test it in the field. Work in Stage 1 will focus on designing and building a prototype to perform thermochemical liquefaction of swine manure, followed by filtration and vacuum distillation to produce an amide-enriched bio-modifier. This modifier will be blended with crumb rubber to activate the rubber surfaces. During blending (at 175ºC with 20 minutes residence time), molecules of bio-modifier will cleave polysulfidic crosslinks of swollen vulcanized crumb rubber in the absence of oxygen to promote interaction between the rubber surface and the amide groups in bio-modifier molecules. Amide-type organic compounds have a polar end and a non-polar hydrocarbon tail. When BMR is added to the asphalt binder, the polar end attaches to the rubber (polar surfaces) and the tail attaches to asphalt (non-polar) promoting interaction between BMR and the asphalt matrix. This reduces the propensity of rubber segregation within the asphalt blend and enhances asphalt rheological properties. In addition, the prototype unit will be able to produce sufficient BMR for laboratory and field evaluation. Work in Stage 2 will focus on experimental evaluation of BMR asphalt, alone and within the paving mixture. Superpave PG grading will be conducted for three selected BMRs. In addition, a comprehensive analysis at both binder and mixture levels will be performed. At the binder level, chemical and rheological characteristics of bio-asphalt before and after short-term and long-term aging (RTFO and PAV) will be investigated At the mixture level, Superpave mixtures will be prepared using three different BMRs for both intermediate and low temperature performance. Tests to be performed will include a low temperature cracking test [disk-shaped compact tension (DCT) test following ASTM D7313]. Stiffness will be investigated by measuring the dynamic modulus and flow number (AASHTO TP79). Moisture resistance will be investigated using a Hamburg wheel-track tester (AASHTO T324). Finally, the compounds that leach out from each of the mixtures will be analyzed and compared with ground water standards. The best performing BMR asphalt mixture will be selected for a trial field section. The trial section will use two rubber modified asphalts -- one with BMR (surface treated rubber) and the other with un-treated rubber. Field work will be done in collaboration with the industry partner and the North Carolina DOT. The mixing temperature and level of agitation for both asphalts as well as the number of roller compaction passes will be monitored to compare the ease of application of the two mixtures. In addition, field samples will be collected before and after compaction to conduct performance testing following North Carolina DOT specifications.
- Record URL:
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Supplemental Notes:
- The project was terminated. No final report is available.
Language
- English
Project
- Status: Terminated
- Funding: $99931
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Contract Numbers:
Project 20-30, IDEA 194
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Sponsor Organizations:
National Cooperative Highway Research Program
Transportation Research Board
500 Fifth Street, NW
Washington, DC United States 20001American Association of State Highway and Transportation Officials (AASHTO)
444 North Capitol Street, NW
Washington, DC United States 20001Federal Highway Administration
1200 New Jersey Avenue, SE
Washington, DC United States 20590 -
Project Managers:
Jawed, Inam
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Performing Organizations:
North Carolina State University, Raleigh
Institute for Transportation Research and Education
Campus Box 8601
Raleigh, NC United States 27695-8601 -
Principal Investigators:
Parast, Mahour
Fini, Elham
- Start Date: 20170107
- Expected Completion Date: 20181231
- Actual Completion Date: 20181231
- Source Data: RiP Project 41385
Subject/Index Terms
- TRT Terms: Asphalt mixtures; Asphalt rubber; Crumb rubber; Moisture content; Petroleum; Specifications; Superpave; Sustainable development
- Identifier Terms: North Carolina Department of Transportation
- Subject Areas: Highways; Materials; Pavements;
Filing Info
- Accession Number: 01622201
- Record Type: Research project
- Source Agency: Transportation Research Board
- Contract Numbers: Project 20-30, IDEA 194
- Files: TRB, RIP
- Created Date: Jan 8 2017 10:26AM