FACTORS AFFECTING THE DETERMINATION OF DENSITY AND MOISTURE BY NUCLEAR RADIATION TECHNIQUES

This report contains a laboratory investigation of various factors that influence the determination of density and moisture by nuclear radiation techniques that utilize the backscatter principle. A total of five materials were tested in the research program. These materials were subsequently divided into two material groups. This was done as an aid in employing different procedures of testing to the groups. For one group, a system of built-up material layers was tested for a given type. The last group of tests were performed on several gradings of a crushed limestone and a siliceous gravel. It was concluded that material type is a factor which influences nuclear density determinations. For the moisture unit, material type had no effect upon count readings for all materials tested. Grain size distribution influenced nuclear density readings for a given material type. Effect of moisture in the substrate material upon density readings was considered negligible for the range in moisture quantities studied. Generally, instrument stability was a function of the instrument in question. Adverse effects of temperature were negligible for density and moisture self-standards for Instrument A, while Instrument B was found to be inoperative at a temperature of 0 degrees F. Instrument A deviations in density counts per minute were considered to be adverse for battery supply voltage conditions, however the use of a count ratio procedure eliminated this deviation. It was found that extreme care must be taken to insure that physical conditions surrounding the density gages are the same when taking self-standard readings at different times. If this is not observed, validity of results obtained are questioned even though a count ratio procedure is used to analyze the data. The introduction of a leveling course had greater effect on the density results obtained on the open graded materials than on those for the finer crushed materials.

• Supplemental Notes:
  • Joint Highway Research Project
• Corporate Authors:

  Purdue University

  Executive Building
  Lafayette, IN  United States  47907
• Authors:
  • Witczak, M
• Publication Date: 1963-7

Language

• English

Media Info

• Features: Appendices; Figures; References; Tables;
• Pagination: 99 p.

Subject/Index Terms

• TRT Terms: Backscattering; Crushed limestone; Gravel; Instruments for measuring density; Measuring instruments; Nuclear density gages; Nuclear radiation; Soils by density; Soils by moisture content or potential
• Subject Areas: Geotechnology; Highways; I41: General Soil Surveys;

Filing Info

• Accession Number: 00770528
• Record Type: Publication
• Report/Paper Numbers: 18
• Files: TRIS
• Created Date: Oct 19 1999 12:00AM