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Title: BENEFITS OF USING HALF-CELL POTENTIAL MEASUREMENTS IN CONDITION SURVEYS OF CONCRETE BRIDGE DECKS
Accession Number: 00625274
Record Type: Component
Availability: Find a library where document is available Abstract: The benefits of using half-cell potential measurements in condition surveys of concrete bridge decks were examined using data collected from several decks by visual inspection, sounding with chain draggings, and measurement of half-cell potentials. Half-cell potentials on a deck were found to fluctuate from survey to survey, likely in response to seasonal fluctuations of temperature, oxygen, chloride, and moisture content in the concrete. Consequently, in contrast to ASTM interpretation guidelines (ASTM C-876), the numerical value of each measured half-cell potential by itself would be a poor indicator of the condition of rebars. Instead, the potential measured at each location should be considered relative to potentials measured in the surrounding concrete. When the potentitals were plotted on an iso-potential contour map, the locations of active rebar corrosion and corrosion-induced damage in the concrete were associated with high negative potential gradients. Because of the localized nature of rebar corrosion, the recommended grid spacing of 4.0 ft (ASTM C-876) for surveys of bridge decks was found to be too large to allow location of existing active corrosion and the associated damage to concrete. It was determined that a grid spacing of no more than 2.0 ft should be used. If a half-cell potential survey is performed on a sufficiently small grid and the collected measurements are plotted on contour maps of iso-potential lines, the locations of existing active rebar corrosion and corrosion-induced damage in the concrete will be indicated with a high degree of accuracy by areas of relatively high potential gradients. When combined with the other inspection techniques, such a survey would be extremely useful in estimating necessary repair.
Supplemental Notes: This paper appears in Transportation Research Record No. 1347, Maintenance of Highway Structures. 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
Monograph Title: Monograph Accession #: 01405025
Language: English
Authors: Clemena, Gerardo GJackson, Donald RCrawford, Gary CPagination: p. 46-55
Publication Date: 1992
Serial: ISBN: 0309052130
Features: Figures
(12)
; References
(15)
TRT Terms: Old TRIS Terms: Subject Areas: Bridges and other structures; Design; Highways; Maintenance and Preservation; I24: Design of Bridges and Retaining Walls; I61: Equipment and Maintenance Methods
Files: TRIS, TRB
Created Date: Nov 3 1993 12:00AM
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