Comparison of properties of RAP aggregates extracted by ignition and centrifuge methods

Subhash C. Thakur, Jie Han, Wai Kiong Chong, Robert L. Parsons

Research output: Chapter in Book/Report/Conference proceedingConference contribution

4 Scopus citations


Recycled Asphalt Pavement (RAP) is one of the most recycled materials in the United States. Due to rapid increase in the price of asphalt, engineers have tried to increase the percentage of RAP in new mixes. Different agencies suggest determining physical and consensus properties of RAP aggregate before selecting the percentage of RAP to be incorporated in the new mix. Ignition and centrifuge methods of extraction are two widely used methods to recover the aggregate from RAP. The recovered RAP aggregate is often tested for physical and consensus properties for evaluation. The properties of RAP aggregate also depend upon the method used for extraction of aggregate. In this study, an NCAT ignition tester was used for the ignition method of extraction and Trichloroethylene (TCE) was used as a solvent for the centrifuge method of extraction. The objective of this research was to evaluate and compare binder content, gradation, specific gravity, and absorption of the aggregates, fine aggregate angularity (FAA), coarse aggregate angularity (CAA), flat and elongated particles (F&E), and Los Angeles (LA) abrasion value. The test results did not show significant difference in coarse aggregate angularity, bulk specific gravity of fine aggregate, and gradation obtained by the centrifuge and ignition methods of extraction for the RAP. However, fine aggregate angularity and Los Angeles abrasion value were found higher in the ignition method of extraction than those in the centrifuge method. The bulk specific gravity of coarse aggregate was found to be higher using the centrifuge method of extraction than that using the ignition method of extraction.

Original languageEnglish (US)
Title of host publicationGeo-Frontiers 2011
Subtitle of host publicationAdvances in Geotechnical Engineering - Proceedings of the Geo-Frontiers 2011 Conference
Number of pages10
Edition211 GSP
StatePublished - 2011
Externally publishedYes
EventGeo-Frontiers 2011: Advances in Geotechnical Engineering - Dallas, TX, United States
Duration: Mar 13 2011Mar 16 2011

Publication series

NameGeotechnical Special Publication
Number211 GSP
ISSN (Print)0895-0563


OtherGeo-Frontiers 2011: Advances in Geotechnical Engineering
Country/TerritoryUnited States
CityDallas, TX


  • Aggregates
  • Asphalt pavements
  • Centrifuge
  • Recycling

ASJC Scopus subject areas

  • Civil and Structural Engineering
  • Architecture
  • Building and Construction
  • Geotechnical Engineering and Engineering Geology


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