Fundamental evaluation of the interaction between RAS/RAP and virgin asphalt binders.

Details

• Creators:
  Nazzal, Munir D. ; Kim, Sang Soo ; Abbas, Ala R. ; Qtaish, Lana Abu ; Holcombe, Evan ; Hassan, Yazeed Abu
• Corporate Creators:
  Ohio University. Department of Civil Engineering
• Corporate Contributors:
  Ohio. Dept. of Transportation ; United States. Federal Highway Administration
• Subject/TRT Terms:
  • Bituminous binders
  • Reclaimed asphalt pavements
  • Asphalt mixtures
  • Recycled materials
  • Shingles
  • Asphalt pavements asphalt binders
  • AFM
  • RAP blending
  • RAS
  • Asphalt Mixes
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• Publication/ Report Number:
  FHWA/OH-2017-24
• Resource Type:
  Tech Report
• Geographical Coverage:
  Ohio;United States
• Corporate Publisher:
  Ohio. Dept. of Transportation
• Abstract:
  A comprehensive laboratory testing program was conducted in this research project to examine the blending between reclaimed asphalt ; pavement (RAP)/recycled asphalt shingles (RAS) and virgin asphalt binders and to evaluate the factors that may affect fatigue and lowtemperature ; cracking as well as moisture-induced damage in asphalt mixtures prepared using these materials. This project included two ; parts: a binder study and a mixture study. In the binder study, atomic force microscopy (AFM) was utilized to characterize the micromechanical ; properties of the interfacial zone that develops between the RAP/RAS binders and the virgin asphalt binders. Three virgin ; asphalt binders with different performance grades (PG 58-28, PG 64-28, and PG 64-22), three RAP sources, as well as manufacturing ; waste and tear-off RAS were used in this project. A new sample-preparation procedure was developed to simulate the blending between ; the RAS/RAP and the virgin asphalt binders that occurs during asphalt mixture production. The micro-structure, stiffness and the adhesive ; properties along the blending zone were evaluated for different combinations of RAP/RAS binders and virgin binders. In the mixture ; study, several asphalt mixtures were used to evaluate the effect of the incorporation of RAP and/or RAS on the mix performance, ; including a control mixture (no RAP or RAS), a mixture containing 30% RAP, a mixture containing 5% tear-off RAS, and a mixture ; containing 20% RAP and 3% tear-off RAS. All mixtures were designed to meet ODOT specifications for Item 442 (Superpave) Type A ; for heavy traffic intermediate course asphalt mixes. The resistance of the asphalt mixtures to fatigue cracking was evaluated using the ; semi-circular bend (SCB) and the indirect tensile strength (IDT) tests. The SCB test was performed using the Illinois Method and the ; Louisiana Method. In addition the potential for low-temperature cracking was evaluated using the asphalt concrete cracking device ; (ACCD), and the susceptibility of the asphalt mixtures to moisture-induced damage was evaluated using the AASHTO T 283 (modified ; Lottman) test. ; The AFM test results indicated that blending occurred to a varying degree between the RAP binders and the virgin binders for all RAPvirgin ; binder combinations. The average modulus of the blending zone depended on the properties of the RAP and the virgin binders. For ; all binders, a reduction in the adhesive bonding energy was also observed in the blending zone due to the presence of RAP. However, the ; adhesive properties of the blending zone were significantly higher than those in the RAP binders. Statistical analysis also indicated that the ; stiffness of the interface blending zone is affected by the properties of the RAP and virgin asphalt binders, while the adhesive properties of ; the interface blending zone is primarily affected by those of virgin binder used. A linear regression model was developed to predict the ; modulus and adhesive bonding energy of the blending zone in terms of RAP and virgin binder properties. The validation of the regression ; models suggested that these models can serve as a viable tool in selecting the virgin binder to be used in a RAP mixture based on the ; properties of the RAP binder. Finally, the AFM imaging and force spectroscopy experiments revealed very limited to no blending between ; manufacturing waste or tear-off RAS materials and the virgin binders considered. The asphalt mixture test results also showed that the use ; of tear-off RAS in intermediate asphalt mixes significantly reduced their resistance to low-temperature and fatigue cracking as well as ; moisture damage, which can be attributed to the limited blending observed in the AFM experiments between the RAS and the virgin asphalt ; binders
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• Format:
  PDF
• Funding:
  SJN 135143
• Download URL:
  https://rosap.ntl.bts.gov/view/dot/32786/dot_32786_DS1.pdf
• File Type:
  [PDF - 12.66 MB]
• Collection(s):
  US Transportation Collection
• Main Document Checksum:
  urn:sha-512:10514418f25db97a0bc2241a55f67ee5242c37e45a494b39d04dec9e06ebe7e75702b45b4e267c0aa2e9617eab64800da8f34b60200eb16fc31d2c9f8b151a27