RADIOISOTOPE X-AND GAMMA-RAY METHODS FOR FIELD ANALYSIS OF WET CONCRETE QUALITY-PHASE II, INSTRUMENT DESIGN AND OPERATION

THE RESULTS OF AN INITIAL FEASIBILITY STUDY, (COVERED IN DETAIL BY AN EARLIER REPORT ARE REVIEWED, AND THE DESIGN AND OPERATION OF A PROTOTYPE INSTRUMENT FOR THE FIELD DETERMINATION OF CEMENT IN WET (PLASTIC) PORTLAND CEMENT CONCRETE ARE DESCRIBED. GAMMA-RAY SCATTERING TECHNIQUES ARE USED IN A PROBE OF SUBMERSIBLE DESIGN. TWO RADIOISOTOPE SOURCES ARE EMPLOYED WITH A SINGLE SCINTILLATION COUNTER DETECTOR. THE ELECTRONIC UNIT SIMULTANEOUSLY REGISTERS THE TWO INTENSITIES AND THE CEMENT CONTENT IS INTERPRETED FROM A CALIBRATION CURVE. THE MEASUREMENT IS COMPENSATED FOR BULK DENSITY AND WATER CONTENT VARIATION AND IS INSENSITIVE TO AGGREGATE PARTICLE SIZE. COMPENSATION FOR AGGREGATE TYPE IS DISCUSSED. THE INSTRUMENT IS PORTABLE, RUGGED AND SIMPLE TO OPERATE. THE METHOD APPEARS SOUND FOR CONCRETE MIXES CONTAINING AGGREGATES WHICH ARE PREDOMINANTLY SILICEOUS IN NATURE. ALTHOUGH APPLICABLE TO AGGREGATE MIXES WHICH CONTAIN SOME LIMESTONE, ACCURACY DECLINES RAPIDLY WITH INCREASING LIMESTONE CONTENT AS A RESULT OF THE REDUCTION IN THE INTRINSIC, SENSITIVITY TO CEMENT FACTOR AND THE INCREASE IN THE BULK DENSITY INFLUENCE. /AUTHOR/

  • Corporate Authors:

    Texas State Department of Highways & Public Transp

    11th and Brazos Streets
    Austin, TX  United States  78701

    Nuclear-chicago Corp, Des Plaines Ill

    ,    

    Federal Highway Administration

    1200 New Jersey Avenue, SE
    Washington, DC  United States  20590
  • Authors:
    • Berry, P F
  • Publication Date: 1970-9-30

Subject/Index Terms

Filing Info

  • Accession Number: 00212099
  • Record Type: Publication
  • Source Agency: Federal Highway Administration
  • Report/Paper Numbers: P. O. -9-1-0266
  • Files: TRIS, USDOT, STATEDOT
  • Created Date: Aug 8 1971 12:00AM