Comparison of Various Methods to Determine Bulk Specific Gravity of Cores: An Investigation of High Values Using AASHTO T 275 – Paraffin-Coated Method

A report from a Missouri Department of Transportation (MoDOT) asphalt paving project was that unexpected results were obtained when adhering to the standard for determination of bulk specific gravity of compacted asphalt mixture (Gmb) specimens, AASHTO T 166. The test method requires specimens with water absorption greater than 2.0 percent be retested according to either AASHTO T 275, bulk gravity using paraffin-coated specimens, or T 131, bulk gravity using the automatic vacuum sealing method (CoreLok.) The contractor chose to perform T 275 and obtained bulk specific gravities of the cores higher than originally obtained. A limited investigation into the method was performed. The result of this investigation confirmed the contractor’s results and a recommendation that specimens dipped in paraffin be prohibited as an allowable test method. It was determined that paraffin entering the pore structure of the cores resulted in falsely high bulk specific gravity values.


  • English

Media Info

  • Media Type: Web
  • Edition: Final Report
  • Features: Figures; Photos; Tables;
  • Pagination: 15p

Subject/Index Terms

Filing Info

  • Accession Number: 01448616
  • Record Type: Publication
  • Report/Paper Numbers: CMR 13-002
  • Created Date: Oct 5 2012 11:17AM