Evaluation of aggregate subgrade materials used as pavement subgrade/granular subbase.

Details

• Creators:
  Kazmee, Hasan ; Tutumluer, Erol
• Corporate Creators:
  Illinois Center for Transportation
• Corporate Contributors:
  United States. Federal Highway Administration ; Illinois. Dept. of Transportation
• Subject/TRT Terms:
  • Subgrade materials
  • Subgrade (Pavements)
  • Aggregates
  • Granular bases
  • Image analysis
  • Ground penetrating radar
  • Recycled materials
  • Pavement performance
  • Specifications
  • Ruts (Pavements)
  More +
• Publication/ Report Number:
  FHWA-ICT-15-013;UILU-ENG-2015-2016
• Resource Type:
  Tech Report
• Geographical Coverage:
  Illinois
• Corporate Publisher:
  Illinois Center for Transportation
• Abstract:
  With recent focus on sustainable construction practices and the ever-increasing transportation costs and scarcity of ; natural resources, integration of large-size and marginally acceptable aggregates and recycled materials (e.g., ; reclaimed asphalt pavement RAP) with current construction specifications is becoming imperative. As an incentive, ; the Illinois Department of Transportation has been using large-size rocks, popularly known as aggregate subgrade. ; However, adequate scientific knowledge about material performance is largely unknown. To this end, a research ; study was undertaken at the Illinois Center for Transportation to evaluate the adequacy and field performances of ; IDOT’s new aggregate subgrade specifications. A state-of-the-art image analysis technique was used to characterize ; the size and shape as well as the texture and angularity properties of selected aggregate subgrade materials. For ; field evaluation, 24 combinations of pavements were constructed over subgrade with controlled low immediate ; bearing value (IBV) or unsoaked California bearing ratio (CBR) strength properties. Construction quality control was ; achieved through in-place density and modulus measurements on aggregate layers using a nuclear gauge, ; lightweight deflectometer, and soil stiffness gauges. Periodic rut measurements were carried out on the pavement ; surface throughout the accelerated loading process using an Accelerated Transportation Loading Assembly ; (ATLAS). Contributions of the underlying pavement layers to the total rut accumulation were evaluated through ; innovative applications of ground-penetrating radar (GPR), a lightweight variable-energy penetrometer device, known ; as the PANDA, and a geo-endoscopy probe. Layer intermixing and material migration at the aggregate subgrade– ; subgrade interface improved the foundation layer stiffness properties and pavement performance results ; significantly. RAP-capped construction platforms consistently exhibited a higher magnitude of rutting. Performances ; of flexible pavement sections were governed by the as-constructed HMA thicknesses, which varied considerably ; during the paver operation because of RAP subbase sinkage and the weak subgrade. Adequate validation and ; potential revisions to current IDOT specifications were recommended.
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• Format:
  PDF
• Funding:
  R27-124
• Download URL:
  https://rosap.ntl.bts.gov/view/dot/29384/dot_29384_DS1.pdf
• File Type:
  [PDF - 12.28 MB]
• Collection(s):
  US Transportation Collection
• Main Document Checksum:
  urn:sha-512:1793bc1311fb6c983d820b857a06e0cb89accae64f1798518779740bbce03fd8b06de92cfd084edd63ca16b1a36679fa814e48851fbd1397db6d771d7de350ac