This report describes the final phase of the design, construction and evaluation of a prototype automated vehicular carried nuclear moisture-density backscatter gage. Gage development was based upon resarch and analysis of several factors that affect gage performance. Those studies indicated that the prototype backscatter gage measurements were approximately equivalent to measurements obtained by commercial transmission gages. The implication of this research finding is the possibility of a backscatter test method as a valid, reliable, and expedient procedure for determining in-situ soil conditions. Field comparisons between the prototype gage and a commerical nuclear backscatter gage showed a 20% improvement in performance by the prototype. During Phases I and II the prototype gage was installed on a motor vehicle together with a hydraulically operated mechanism that automatically positions the gage for testing. The vehicle gage unit, or Autoprobe, can determine in-situ moisture and density values in about three minutes. Phase III activities largely involved refining of the Autoprobe and the gage positioning mechanism based upon data developed by Phases I and II. The auto probe is now ready for use by the department for investigational and quality control purposes. /FHWA/

  • Supplemental Notes:
    • Sponsored by the California Department of Transportation. Conducted in cooperation with the Department of Transportation, Federal Highway Administration.
  • Corporate Authors:

    California Department of Transportation

    Transportation Laboratory
    5900 Folsom Boulevard
    Sacramento, CA  United States  95819
  • Authors:
    • Champion, F C
    • Lister, B
    • HANNON, J B
    • Forsyth, R A
  • Publication Date: 1978-12

Media Info

  • Pagination: 60 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00195610
  • Record Type: Publication
  • Source Agency: Federal Highway Administration
  • Report/Paper Numbers: FHWA-CA-78-35 Final Rpt.
  • Contract Numbers: F-4-8
  • Created Date: Sep 15 1979 12:00AM