Thermal Segregation

Details

• Creators:
  Gilbert, Kim
• Corporate Creators:
  Colorado. Department of Transportation
• Corporate Contributors:
  United States. Department of Transportation. Federal Highway Administration
• Subject/TRT Terms:
  • Hot mix asphalt
  • Compaction
  • Density
  • Aggregate gradation
  • Aggregate segregation
  • Asphalt pavements
  • Binders
  • Cameras
  • Coarse aggregates
  • Infrared analysis
  More +
• Publication/ Report Number:
  CDOT-DTD-R-2005-16
• Resource Type:
  Tech Report
• Geographical Coverage:
  United States ; Colorado
• Edition:
  Final Report
• Corporate Publisher:
  Colorado. Department of Transportation
• Description:
  The purpose of this study was to detect thermal segregation and its resulting effect on pavement density. Thermal segregation can be caused by material cooling and not being thoroughly remixed or by segregation of the hot mix asphalt (HMA). If the HMA segregates, it is expected that the coarse aggregate will cool more quickly than will the fine aggregate. This study identified areas of thermal segregation, either by cooling or by material segregation. A thermal camera was used to quickly identify areas with a 25º F or greater temperature difference. An infrared temperature gun was also used in an attempt to locate temperature segregation with a less costly device. Segregated areas were located for nuclear density testing following rolling of the HMA. The area that was 25º F or more cooler than the surrounding mat was tested for relative compaction. An adjacent area that was a minimum of 25º F warmer was also tested for relative compaction. Information was gathered about mix nominal maximum aggregate size, binder type, paver type, truck type, delivery system, etc. to determine if a change in some factors could aid in decreasing segregation. The study showed that grading S mixes temperature segregate at three times the rate than do the finer gradation SX mixes. End dump trucks used without Material Transfer Devices are prone to temperature segregation. Also, windrow elevators appear to work as well as do Material Transfer Devices.
• Format:
  PDF
• Funding:
  10.35
• Download URL:
  https://rosap.ntl.bts.gov/view/dot/93182/dot_93182_DS1.pdf
• File Type:
  [PDF - 267.62 KB]
• Collection(s):
  US Transportation Collection
• Main Document Checksum:
  urn:sha-512:33b6546779863e36f24a93883933682d6593818fa64e8e9c6db77a309be8be607ae8a1e1aa6cabab69c6690edff9ebe67ed2d58e9bd63848f1a29d29f683e6d7