Relating Dynamic Shear Modulus (G*) of Performance Grade (PG) Asphalt Binders to Nanoindentation Stiffness (E)

Asphalt concrete's dynamic modulus (E*) is one of the key input parameters for structural design of asphalt/flexible pavements according to the new Pavement Mechanistic Empirical (ME) Design software. This software uses asphalt binder shear modulus, G*-based equation to estimate E* of asphalt concrete (AC) from mix volumetric information and binder properties. Use of shear modulus, G* of liquid asphalt to estimate E* of solid asphalt concrete (AC) sample is not justified and has been questioned by asphalt researchers for long time. Because liquid binder is not a part of AC, rather thin film of asphalt binder, mastic, and aggregate are the parts of a solid AC sample. Not only that, AC's E* testing is performed in uniaxial compression mode, whereas asphalt binder's G* test is performed in shear mode. Due to equipment and discovery limitations, over the past years, asphalt industry has performed asphalt binder tests that are limited to rheology and bulk volume of liquid. Asphalt industry has not come up yet with equipment and/or method that can be used on binder film or mastic or aggregate phase of a solid AC sample. Recently, nanoindentation has created an opportunity to determine the stiffness (E) of asphalt binder, mastic, and other phases while they are being integral parts of an AC sample and also, under compression (indentation) loading. This project proposes to conduct dynamic shear modulus (G*) and nanoindentation stiffness (E) testing of selected performance grade (PG) asphalt binders, examine possible correlation between G* and E, and possibly replace the existing G*-based equation with E-based equation for pavement design. This proposed study may dramatically improve the way our asphalt pavements being designed using the new Pavement ME Design software.


  • English


  • Status: Completed
  • Funding: $152000.00
  • Contract Numbers:


  • Sponsor Organizations:

    Department of Transportation

    Office of the Assistant Secretary for Research and Technology
    1200 New Jersey Avenue, SE
    Washington, DC  United States  20590
  • Principal Investigators:

    Tarefder, Rafiquel

  • Start Date: 20140910
  • Expected Completion Date: 20150909
  • Actual Completion Date: 20160930
  • Source Data: RiP Project 37022

Subject/Index Terms

Filing Info

  • Accession Number: 01541229
  • Record Type: Research project
  • Source Agency: Center for Advanced Transportation Education and Research (CATER)
  • Contract Numbers: DTRT-13-G-UTC55
  • Files: UTC, RIP
  • Created Date: Oct 21 2014 1:01AM