Durability of Reinforced Concrete Structure Repaired by Desalination

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Desalination is an electrochemical method aimed at removing chlorides from reinforced concrete structures. In this study, influences of applying desalination on durability and load-carrying capacity of RC structures were investigated.The results obtained in this study can be summarized as follows.(1) As results of the pull-out test, maximum bond stress of treated specimens was found to be smaller than that of non-treated specimens. The decrease due to desalination became larger with an increase in the amount of premixed chlorides or an increase in the total current density, because soft layers were formed around the steel bars due to passing of electric current.(2) According to the results of flexural test of beams containing 8.0 kg/m3 of C1, the change in the ultimate load was slight and the capacity of deflection increased at 8 weeks treatment.(3) In the case of flexural failure type beams, maximum crack width at the reinforcing steel level of specimens receiving 4 weeks treatment was less than that of non-treated ones. However, in some specimens treated for 8 weeks, maximum crack width at the reinforcing steel level was greater than the permissible crack width. Moreover, by applying desalination, the number of cracks was decreased and crack distribution became deteriorated.(4) Slow strain rate tensile tests on prestressing steel removed from treated PC prism specimens indicated no change in elastic behavior nor strength-related properties but the fracture behavior was altered by the absorbed hydrogen. For example, the falling branch in stress-strain curves was shortened and the contraction rate of fractured steel section decreased as compared with non-treated specimens.(5) As results of flexural loading tests on treated PC beams, the rupture of prestressing steel due to hydrogen embrittlement were not observed, and both load-displacement performance was not reduced by desalination, compared with the non-treated specimens.