Concrete Permeability Testing – Part 1

This article describes and discusses ponding and electrical tests that are used to measure, directly or indirectly, the penetrability of chloride ions into concrete. These tests are required as part of the surveillance of chloride-induced corrosion of reinforcement of concrete bridges, the primary durability problem that these bridges face. The tests include the salt ponding methods of AASHTO T 259 and ASTM C1543 and the electrical methods of AASHTO T 277, AASHTO TP 64, and ASTM C1202 for rapid assessment of concrete’s resistance to chloride ion penetration. The author notes that, with the advent of service-life prediction models, the emphasis has been placed on methods that measure the more fundamental properties of concrete such as chloride diffusion (ASTM C1556) and water sorptivity (ASTM C1585). Tests on diffusion and sorptivity will be covered in Part II of this series. The author describes the salt ponding tests, including their methodology, rationale, sampling, and analysis. The next section describes the rapid chloride permeability test (RCPT), which is an electrical test designed to provide analysis more quickly than the length of time required with ponding tests (typical range of 28 to 42 days). One table provides an example of performance limits based on the RCPT. Another test is also described: AASHTO TP 64, the rapid migration test (RMT), operates under the same principle as the RCPT, but is designed to actually drive chloride ions into the concrete specimen so their depth of penetration can be measured. For both of these tests, the author describes methodology, test apparatus, rationale, and implications. The major differences between the RMT and the RCPT are that a higher (10% versus 3%) concentration sodium chloride solution is used in the RMT; the voltage across the electrodes is adjusted to one of three levels based on the conductivity of the specimen and decreases with increasing conductivity; and the test duration is 18 hours rather than 6 hours. The author concludes that these electrical test results have been reported to correlate well with long-term ponding tests.

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  • English

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  • Accession Number: 01148127
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Jan 8 2010 7:41AM