NONDESTRUCTIVE MONITORING OF CHLORIDE IN BRIDGE DECKS WITH A MOBILE NEUTRON-GAMMA SPECTROMETER

A mobile, self-contained instrument for rapid, nondestructive monitoring of chloride content at the reinforcing-bar level in portland cement concrete bridge decks has been developed to field prototype stage and tested on a range of concrete specimens and on five bridge decks in Texas. The instrument uses the technique of neutron-induced gamma-ray spectrometry with a 400-mug californium-252 sealed neutron source. Two measuring heads provide the capability for depth discrimination and enable chloride contents to be measured at the reinforcing-bar depth irrespective of surface washout, salt encrustation, the presence of overlays or membranes, and different depth distributions of chloride content. The sensitivity to chloride obtained depends on the required depth discrimination and speed of measurement but is normally sufficient to detect chloride concentrations below the corrosion threshold of approximately 300 mg/kg (1.2 lb/cube yds). (Author)

• Record URL:
  • http://onlinepubs.trb.org/Onlinepubs/trr/1981/821/821-016.pdf
• Record URL:
  • https://scholar.google.com/scholar_lookup?title=NONDESTRUCTIVE+MONITORING+OF+CHLORIDE+IN+BRIDGE+DECKS+WITH+A+MOBILE+NEUTRON-GAMMA+SPECTROMETER&author=J.+Rhodes&publication_year=1981
• Availability:
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• Supplemental Notes:
  • Publication of this paper sponsored by Committee on Instrumentation Principles and Applications. Distribution, posting, or copying of this PDF is strictly prohibited without written permission of the Transportation Research Board of the National Academy of Sciences. Unless otherwise indicated, all materials in this PDF are copyrighted by the National Academy of Sciences. Copyright © National Academy of Sciences. All rights reserved
• Authors:
  • Rhodes, J R
• Conference:
  • 60th Annual Meeting of the Transportation Research Board
  • Location: Washington District of Columbia, United States
  • Date: 1981-1-12 to 1981-1-16
• Publication Date: 1981

Media Info

• Media Type: Print
• Features: Figures; Photos; References; Tables;
• Pagination: pp 88-94
• Monograph Title: Bituminous mixes, concrete pavements and structures, testing and construction prices
• Serial:
  • Transportation Research Record
  • Issue Number: 821
  • Publisher: Transportation Research Board
  • ISSN: 0361-1981

Subject/Index Terms

• TRT Terms: Bridge decks; Chloride content; Material reinforcement; Monitoring; Neutron activation analysis; Nondestructive tests; Portable equipment; Portland cement concrete; Spectrometers
• Uncontrolled Terms: Mobile equipment
• Subject Areas: Bridges and other structures; Geotechnology; Highways; Materials; I35: Miscellaneous Materials;

Filing Info

• Accession Number: 00348710
• Record Type: Publication
• ISBN: 0309032638
• Files: TRIS, TRB
• Created Date: Jun 30 1982 12:00AM