Durability of concrete repairs - Concrete Repair - page 246

unsuitable weather in order to avoid expensive delays. In many cases the
causes of repair failure given by respondents could have been avoided if
the financial pressures were less and good practice had been followed more
closely.
There were no cases where the quality of materials was considered to be
a cause of failure but there were many where it was considered that material
selection had been incorrect. Repair materials should be compatible with
the substrate particularly in relation to ductility. In many cases there has
been undue emphasis on the strength of the repair material and inadequate
attention to ductility.
The case histories have shown that there are benefits from the application
of coatings on repairs as the success rate for patches was increased from 30
to 50 per cent and for crack injection from 70 to 80 per cent.
The performance of CP is encouraging as 60 per cent of the installations
were reported to be wholly successful compared with 50 per cent for all
repair methods. However, it is important for owners of structures to be
aware that installations require regular inspection to ensure that they are in
working order, and to be aware that they are susceptible to vandalism.

Abbreviations
AAR Alkali-aggregate reaction

C Inj Crack injection

C Inj+C Crack injection plus coating

CP Cathodic protection

Patch+C Patch plus coating

X constr. Faulty construction

References
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