Local Calibration of “C-Values” for Common Idaho Soil Types for Use in Mechanistic-Empirical Pavement Design

This project will collect C-Value data from Idaho Transportation Department (ITD) projects over time. The C-Value is a ratio utilized by AASHTOware software to correlate laboratory-established resilient moduli with moduli back-calculated from field tests. There are three hierarchal levels of data accuracy for pavement mechanistic-empirical (ME) roadway design methodology, which is currently used by ITD. Level 1 is site or project-specific. Level 2 is based on local data. Currently, ITD uses Level 3 C-Values, which are a best estimate for a global default value. Developing a database of C-values within a dedicated stand-alone project would be cost prohibitive due to the costs of labor, traffic control, drilling, testing, and data processing involved. However, if C-values are leveraged from projects that are already planned or in process over the course of three years, a reliable database of C-Values can be created and maintained in a more cost-effective manner. Establishing this database of accurate C-values will allow for more specific and reliable data available to project designers. The main objectives of this project include collecting C-Value data from ITD projects over a three-year period and incorporating those values into a database for use by ITD, LHTAC, local highway districts, and Idaho municipalities.


  • English


  • Status: Completed
  • Funding: $36000
  • Contract Numbers:

    RP 289

  • Sponsor Organizations:

    Idaho Transportation Department

    P.O. Box 7129, 3311 West State Street
    Boise, ID  United States  83707-1129
  • Project Managers:

    Coy, Tyler

  • Performing Organizations:

    Shannon & Wilson

    5260 W Chinden Blvd.
    Boise, ID  United States  83714
  • Principal Investigators:

    Crawforth, Stanley

    Kassem, Emad

  • Start Date: 20200423
  • Expected Completion Date: 20220430
  • Actual Completion Date: 20220430

Subject/Index Terms

Filing Info

  • Accession Number: 01759897
  • Record Type: Research project
  • Source Agency: Idaho Transportation Department
  • Contract Numbers: RP 289
  • Files: RIP, STATEDOT
  • Created Date: Dec 10 2020 2:40PM