THE NUCLEAR ASPHALT CONTENT GAUGE

Improper mix designs and amounts of asphalt cement are major causes of premature failure in pavement structures. There are three major methods for determining asphalt content: solvent extraction, nuclear asphalt content gauge, and metering methods. This article discusses one specific indirect test, the nuclear test, in an effort to provide accurate information on its abilities and its limitations and to encourage its use. It describes the equipment and its operation, in addition to licensing, safety, and economic factors that support its use. It also addresses the gauge's more favorable environmental operation over traditional methods. There are three gauges currently on the market, consisting of a control unit, sample chamber, and specimen pan. Neutrons are transmitted into the asphalt mix, and their movement through the material is influenced by the hydrogen composing or surrounding the aggregate. During the calibration process, the nuclear gauge "counts" the neutrons influenced by the hydrogen as they pass through the sample, establishing the hydrogen versus neutron count relationship. Correlating these counts to asphalt content using mathematical regression techniques permits the evaluation of asphalt content for any sample having the same mix design. Environmental concerns are making chemical methods increasingly costly and imposing additional regulations on solvents. The nuclear gauge method is accurate, cost-effective, environmentally clean, and quick to perform.

• Record URL:
  • http://www.fhwa.dot.gov/publications/publicroads/95winter/p95wi8.cfm
• Availability:
  • Find a library where document is available. Order URL: http://worldcat.org/oclc/1586080
• Corporate Authors:

  Federal Highway Administration

  1200 New Jersey Avenue, SE
  Washington, DC  United States  20590
• Authors:
  • Black, K N
• Publication Date: 1995

Language

• English

Media Info

• Features: Figures; Photos; References; Tables;
• Pagination: p. 8-13
• Serial:
  • Public Roads
  • Volume: 58
  • Issue Number: 3
  • Publisher: Federal Highway Administration
  • ISSN: 0033-3735
  • Serial URL: https://www.fhwa.dot.gov/publications/publicroads/
• Publication flags:

  Open Access (libre)

Subject/Index Terms

• TRT Terms: Aggregates; Asphalt cement; Asphalt concrete pavements; Asphalt content; Asphalt mixtures; Asphalt pavements; Calibration; Cost effectiveness; Environmental protection; Hydrogen; Licensing; Mix design; Neutrons; Nondestructive tests; Nuclear gauges; Regression analysis; Safety; Solvents; Test procedures; Testing equipment
• Subject Areas: Data and Information Technology; Design; Environment; Geotechnology; Highways; Pavements; Safety and Human Factors; I22: Design of Pavements, Railways and Guideways; I23: Properties of Road Surfaces;

Filing Info

• Accession Number: 00781712
• Record Type: Publication
• Files: TRIS, USDOT
• Created Date: Jan 16 2000 12:00AM