Civil Engineering Reference
In-Depth Information
Failed repair material
14.6 Causes of repair failure
In some cases the respondents admitted that the cause of failure was not
known and in others the comments were rather vague. This is not altogether
surprising as non-destructive testing was applied in only 15 per cent of the
cases so that diagnoses were based on visual inspections alone. The main
causes of failure were given as follows:
• Incorrect design of the repair, for example repairs to AAR which failed
to address the root cause.
• Use of incorrect material, for example a patch composed of material that
was much stronger than the substrate, selection of aesthetic coatings for
application in aggressive conditions.
• Poor workmanship, including failure to follow manufacturer's
instructions.
• Incorrect diagnosis of the underlying problem, for example dealing
with corroded reinforcement but failing to stop leakage that caused the
problem in the first place.
• Other causes included vandalism, the repairer failing to follow
instructions, excess economy and extremes of weather during the repair
work.
