DEVELOPMENT OF NUCLEAR METHODS FOR QUALITY CONTROL OF HIGHWAY EMBANKMENT CONSTRUCTION

THE EXTENSIVE LABORATORY AND FIELD TESTING CONDUCTED IN AN EFFORT TO PROPERLY DESIGN, CALIBRATE, AND USE THE NUCLEAR METHOD FOR COMPACTION CONTROL IN MICHIGAN IS DESCRIBED. THE STUDY INCLUDES INVESTIGATION OF ALL BASIC METHODS OF USING NUCLEAR DENSITY GAGES: BACKSCATTER, DIRECT TRANSMISSION, AIR-GAP, AND DIRECT READING, AND RECORDING CHART READOUT TECHNIQUES. ALSO INCLUDED IS AN INVESTIGATION OF THE APPLICABILITY OF RANDOM SAMPLING AND STATISTICAL CONTROL OF COMPACTION. FIELD TESTING OF THE GAGE WAS PERFORMED BOTH UNDER CAREFULLY CONTROLLED CONDITIONS AND UNDER NORMAL FIELD CONDITIONS BY ASSIGNING GAGES DIRECTLY TO CONSTRUCTION PERSONNEL. THE BASIC CONCLUSIONS ARE: (1) ALTHOUGH THE BASIC PRINCIPLES OF NUCLEAR RADIATION USED IN THE GAGES ARE SOUND, AS EVIDENCED BY RESULTS OF CAREFULLY CONTROLLED LABORATORY TESTS, THE GAGE HAS NOT BEEN SATISFACTORY WHEN USED UNDER FIELD CONDITIONS. THE PRIMARY PROBLEM APPEARS TO BE THE SENSITIVITY OF THE GAGE TO THE SURFACE LAYERS UPON WHICH IT IS PLACED. THIS NOT ONLY TENDS TO GIVE FALSE DENSITY MEASUREMENTS BUT CAN NEGATE ATTEMPTS TO OBTAIN BY CONVENTIONAL DENSITY MEASURING METHODS. SURFACE EFFECTS HAVE BEEN LESS APPARENT WHEN TESTING UNIFORM SANDS. (2) WHEN SPECIAL SURFACES WERE PREPARED FOR THE GAGES THE TIME REQUIRED PERTEST APPROACHED THAT REQUIRED FOR THE CONVENTIONAL TEST, NOW THAT THE SPEEDY MOISTURE METER IS USED IN THE LATTER METHOD. WITH LITTLE OR NO TIME SAVINGS, THE HIGH INITIAL AND OPERATING COST OF THE EQUIPMENT CANNOT BE JUSTIFIED. AND (3) EVEN WHEN USING NEW EQUIPMENT, CONSIDERABLE MAINTENANCE WAS REQUIRED RESULTING IN SERIOUS CONSTRUCTION DELAYS. /AUTHOR/

  • Corporate Authors:

    Michigan Department of State Highways

    State Highways Building, PO Drawer K
    Lansing, MI  USA  48904

    Bureau of Public Roads /US

    400 7th Street, SW
    Washington, DC  USA  20590
  • Authors:
    • Mainfort, R C
  • Publication Date: 1970-9

Subject/Index Terms

Filing Info

  • Accession Number: 00215936
  • Record Type: Publication
  • Source Agency: Bureau of Public Roads /US
  • Report/Paper Numbers: 61 E-22
  • Files: TRIS, STATEDOT
  • Created Date: Sep 28 1970 12:00AM