Diagnosis and Repair Method for Corrosion of Reinforcing Bar by Salt Injury
Jun TAKATA, Takahiko SASAKI, Hidenobu TATEMATSU
Corrosion of reinforcing bar by salt injury is one of the serious issues for
concrete because it damages durability and strength of concrete structure.
Not any effective means has been developed so far, for non-destructive testing
and repair of corroded reinforcing bars. We re-examined a rest potential method
which has been generally applied for diagnosis of the corrosion. We revealed that
the rest potential could be influenced by some properties of covering concrete
since the rest potential of the reinforcing bar was normally measured across the
covering, and we proposed a new potential correction procedure taking the properties
of covering into account. At the same time, we synthesized an anion adsorbent that
could adsorb excess amount of chlorine ion in concrete which caused the salt injury,
releasing nitrite ion which suppressed the reinforcing bar corrosion. We also developed
an inorganic repair material which contained the adsorbent. Based on the effectiveness
of the new material for suppressing the reinforcing bar corrosion, we propose a new
repair method named Suppressing Salt Injury method (SSI method).