Comprehensive Evaluation of the Long-Term Performance of Rubberized Pavement: Phase II: The Influence of Rubber and Asphalt Interaction on Mixture Durability

This project investigated the long-term performance of hot asphalt mixes containing crumb rubber modifiers (CRM) added in dry or wet processes. A total of eight asphalt mixtures—four Porous European Mixtures (PEMs) and four Stone Matrix Asphalts (SMAs)—were designed with performance-grade (PG) 76-22 modified with CRM, which was added in either a dry or wet process. These mixtures were compared to control mixtures using a styrene-butadiene-styrene (SBS)-modified PG 76-22. Mixtures incorporating a “hybrid”-modified PG 76-22 were also evaluated. First, the samples were weathered in the Georgia Weathering Asphalt Device (GWAD) for 1,000 hrs and 3,000 hrs and tested to determine their dynamic modulus, fatigue life, rutting, and Cantabro. Binders extracted from the weathered samples were then evaluated using a dynamic shear rheometer (DSR), gel-permeable chromatography (GPC), and Fourier transform infrared spectroscopy (FTIR). Second, the interactions of dry- and wet-processed CRM with asphalt binder were compared during storage and paving. Results indicated: 1) adding transpolyoctenamer (TOR) to the CRM binder improved PG grade and separation resistance; 2) the dynamic modulus, |E*|, of both rubberized PEM and SMA in dry process did not differ significantly from that of the control mixtures or mixtures using the “hybrid”- modified binders before and after weathering; 3) the fatigue life (Nf) of unaged rubberized PEM and SMA in the dry process was similar to that in wet process, although lower than that of control SBS; 4) after 3000-hrs aging, the fatigue life of the dry-processed rubberized SMA is similar to that of the wet-processed but lower than that of hybrid and SBS SMA, regardless of strain and stress levels or test temperatures; 5) the rutting and Cantabro loss of the rubberized PEM and SMA in dry process were higher than those of control SBS after weathering; 6) CRM and asphalt binder interact during the production and paving stages based on DSR, GPC, FTIR, and atomic force microscopy (AFM) results. The effect of weathering on the properties of the asphalt binders in rubberized, dry-processed PEMs and SMAs was similar to that in the wet-processed mixtures but greater than that in the control SBS.

• Record URL:
  http://g92018.eos-intl.net/eLibSQL14_G92018_Documents/12-29.pdf
• 
• Supplemental Notes:
  • Title page date: January 2015
• Corporate Authors:

  Georgia Southern University, Statesboro

  College of Engineering and Information Technology
  Statesboro, GA  United States 

  Georgia Department of Transportation

  Office of Research, 15 Kennedy Drive
  Forest Park, GA  United States  30297-2534

  Federal Highway Administration

  1200 New Jersey Avenue, SE
  Washington, DC  United States  20590
• Authors:
  • Shen, Junan
  • Xie, Zhaoxing
  • Li, Bo
• Publication Date: 2014-12

Language

• English

Media Info

• Media Type: Digital/other
• Edition: Final Report
• Features: Figures; Photos; References; Tables;
• Pagination: 171p

Subject/Index Terms

• TRT Terms: Asphalt mixtures; Asphalt rubber; Bituminous binders; Crumb rubber; Durability; Dynamic modulus of elasticity; Evaluation; Fatigue limit; Mix design; Pavement performance; Rutting; Weathering
• Subject Areas: Design; Highways; Materials; Pavements; I22: Design of Pavements, Railways and Guideways; I31: Bituminous Binders and Materials; I33: Other Materials used in Pavement Layers;

Filing Info

• Accession Number: 01577100
• Record Type: Publication
• Report/Paper Numbers: FHWA-GA-12-1229, No.12-29
• Files: TRIS, ATRI, USDOT, STATEDOT
• Created Date: Sep 28 2015 9:10AM