Civil Engineering Reference
In-Depth Information
coating.
Failure modes of coatings applied solo included cracking, continued
leakage, continued corrosion and deteriorated concrete. Where failed
coatings were over patches it is not clear whether failure originated in the
patch or the coating.
Case histories of failed repairs, for an underpass, a bridge and a lift tower,
are illustrated in
Figures 14.12
to
14.14.
The repair failure shown in
Figure 14.12
was caused by the pressure of salt
crystallisation causing cracks and debonding of the coating. It was concluded
that the repair had been incorrectly designed and the wrong repair material
was used. Moreover, the back of the wing wall had not been waterproofed.
The bowstring bridge shown in
Figure 14.13
had deteriorated due to
AAR. The repair failure was caused by access of water to the concrete which
encouraged continued AAR. It was concluded that the problem had been
incorrectly diagnosed and the wrong repair system was used.
