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:
  AFM Asphalt Mixes Asphalt Mixtures Asphalt Pavements Asphalt Binders Bituminous Binders RAP Blending RAS Reclaimed Asphalt Pavements Recycled Asphalt Pavements Recycled Materials Shingles

  More +
• 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
  
  
• Format:
  PDF
• Funding:
  SJN 135143
• Collection(s):
  US Transportation Collection
• Main Document Checksum:
  urn:sha-512:10514418f25db97a0bc2241a55f67ee5242c37e45a494b39d04dec9e06ebe7e75702b45b4e267c0aa2e9617eab64800da8f34b60200eb16fc31d2c9f8b151a27
• Download URL:
  https://rosap.ntl.bts.gov/view/dot/32786/dot_32786_DS1.pdf
• File Type:
  [PDF - 12.66 MB ]