Thermodynamics between RAP/RAS and virgin aggregates during asphalt concrete production : a literature review.

Details

• Creators:
  Hossain, Mohammad Imran ; Veginati, Varun ; Krukow, Justin
• Corporate Creators:
  Bradley University. Department of Civil Engineering and Construction
• Corporate Contributors:
  United States. Federal Highway Administration ; Illinois. Department of Transportation. Bureau of Materials and Physical Research
• Subject/TRT Terms:
  • Hot mix asphalt
  • Reclaimed asphalt pavements
  • Recycled materials
  • Asphalt concrete
  • Mix design
  • Thermal analysis
  • Aggregates
  • Literature reviews
• Publication/ Report Number:
  FHWA-ICT-15-015
• Resource Type:
  Tech Report
• Geographical Coverage:
  United States
• Corporate Publisher:
  Illinois Center for Transportation
• Abstract:
  In hot-mix asphalt (HMA) plants, virgin aggregates are heated and dried separately before being mixed with ; RAP/RAS and virgin asphalt binder. RAP/RAS materials are not heated or dried directly by a burner to avoid ; burning of aged binder coating on the materials so they are heated and dried indirectly by the hot virgin ; aggregates. A literature review shows that virgin aggregate temperature has been predicted for drying and ; heating RAP at batch plants only. In this study, thermodynamics and heat transfer principles are used to predict ; virgin aggregate temperature for drying and heating RAP/RAS at a drum plant. Among many results, it was ; shown that virgin aggregates become superheated (more than 1000°F) when both virgin aggregate and RAP ; moisture content were in the range of 3% to 5% and the material proportions were in the range of 30% to 50%. ; The size of virgin aggregates and RAP/RAS, the moisture content of virgin aggregates and RAP/RAS, and the ; mix proportion of virgin aggregates and RAP/RAS were the major contributing parameters in predicting virgin ; aggregate temperature in the drum plant. The plant’s moisture content data indicate that virgin coarse ; aggregates hold a lower amount of moisture compared with virgin fine aggregates. However, in comparing same-size virgin aggregates and RAP, RAP contained a higher amount of moisture. The reason might be that the aged ; binder coating of RAP holds moisture better than virgin aggregates do. Also, RAS contains a higher amount of ; moisture compared with RAP of the same size.
  More +
• Format:
  PDF
• Funding:
  R27-SP29
• Download URL:
  https://rosap.ntl.bts.gov/view/dot/29561/dot_29561_DS1.pdf
• File Type:
  [PDF - 3.64 MB]
• Collection(s):
  US Transportation Collection
• Main Document Checksum:
  urn:sha-512:6f698d246a5894d270844cb2626a02b5ca6aed7137273deb50a490ba8556a46b95a46443c40ce7821c1ac893513cd97dd7703ee54553be2eb50d938b06f605a6