Investigation on Chloride Threshold for Reinforced Concrete by a Test Method combining ANDT and ACMT

Chloride threshold (Cth) of reinforced concrete structures in tidal zone of marine environment has been experimentally investigated. A new test method combining artificial-natural diffusion test (ANDT) and accelerated chloride migration test (ACMT) was proposed to simulate the marine environment and accelerate the chloride diffusion. Different definitions and expressions of Cth were discussed and Cth was defined as the chloride content required for activating the depassivation of steel bar and maintaining the aggressive pitting corrosion in present work. The effects of concrete cover thickness and steel type were then investigated. The results show that Cth decreases as concrete cover thickness increases and then remains steady. Moreover, ribbed bars can survive in a higher chloride concentration than plain ones. In view of the design parameters of reinforced concrete structures in tidal zone, Cth for hooping bar (plain bar) and longitudinal tensile bar (ribbed bar) is suggested to be 0.2% and 0.3% (total chloride content by weight of concrete), respectively. Also, a concept of critical pH was mentioned and a value of 11.0 may indicate a high risk of steel bar corrosion. Compared to the results in other field studies, this test method can be expected to be convincing and time-saving.

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  • English

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  • Accession Number: 01708969
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Apr 27 2019 3:07PM