4.3—Typical selection problems
High chloride content, misplaced reinforcing steel, poorquality
concrete, and carbonation are some of the factors that
contribute to corrosion. Every attempt should be made to
minimize the affect of these factors on a repair program. An
appropriate protective system should be designed into the
repair program. This minimizes the effect of any detrimental
existing conditions and anticipated factors that could result in
a failure of the repairs or contribute to other concrete deterioration.
When developing the protection system for a
project, all of the factors affecting the performance of the
completed repairs should be evaluated. More than one potential
problematic condition usually should be addressed before
selecting the protection system. The following are some of
the more common problems that should be considered in a
repair program.
4.3.1 Poor-quality or inadequate concrete cover—The
performance of any concrete structure is in part a function of
the quality and cover of concrete in that structure. Good
quality, durable, properly consolidated concrete with adequate
cover placed with minimal honeycombing and cracks
provides an environment that should protect the embedded
reinforcing steel for years without any protection system
before repairs, if ever, are required. Conversely, poor-quality
concrete with deficiencies such as excessive internal cracking,
internal voids, lack of consolidation, inadequate entrained
air-void system, or otherwise substandard conditions,
contribute to the corrosion of the reinforcing steel as well as
to other forms of deterioration of the structure. It is best to
remove any deficient concrete as part of a repair program,
when and where possible. A properly selected protection
system can improve the long-term durability of poor-quality
concrete, enhance the performance of good concrete, and
extend the life of any repair.
4.3.2 Misplaced reinforcing steel—Misplaced reinforcing
steel is a major contributing factor to corrosion. This
commonly occurs at reveals on walls or columns, in slabs
with variable thickness at the edge bars along exposed slabs,
and at hooked bars perpendicular to exposed concrete slab
edges, if placed too close to the surface. The repair program
should provide for the lack of cover on the reinforcement.
This can be accomplished with buildouts, where appropriate.
Barrier coatings on the reinforcing steel or concrete surface,
probably in combination with other techniques, provides added
4.3—Typical selection problemsHigh chloride content, misplaced reinforcing steel, poorqualityconcrete, and carbonation are some of the factors thatcontribute to corrosion. Every attempt should be made tominimize the affect of these factors on a repair program. Anappropriate protective system should be designed into therepair program. This minimizes the effect of any detrimentalexisting conditions and anticipated factors that could result ina failure of the repairs or contribute to other concrete deterioration.When developing the protection system for aproject, all of the factors affecting the performance of thecompleted repairs should be evaluated. More than one potentialproblematic condition usually should be addressed beforeselecting the protection system. The following are some ofthe more common problems that should be considered in arepair program.4.3.1 Poor-quality or inadequate concrete cover—Theperformance of any concrete structure is in part a function ofthe quality and cover of concrete in that structure. Goodquality, durable, properly consolidated concrete with adequatecover placed with minimal honeycombing and cracksprovides an environment that should protect the embeddedreinforcing steel for years without any protection systembefore repairs, if ever, are required. Conversely, poor-qualityconcrete with deficiencies such as excessive internal cracking,internal voids, lack of consolidation, inadequate entrainedair-void system, or otherwise substandard conditions,contribute to the corrosion of the reinforcing steel as well asto other forms of deterioration of the structure. It is best toremove any deficient concrete as part of a repair program,when and where possible. A properly selected protectionsystem can improve the long-term durability of poor-qualityconcrete, enhance the performance of good concrete, andextend the life of any repair.4.3.2 Misplaced reinforcing steel—Misplaced reinforcingsteel is a major contributing factor to corrosion. Thiscommonly occurs at reveals on walls or columns, in slabswith variable thickness at the edge bars along exposed slabs,and at hooked bars perpendicular to exposed concrete slabedges, if placed too close to the surface. The repair programshould provide for the lack of cover on the reinforcement.This can be accomplished with buildouts, where appropriate.Barrier coatings on the reinforcing steel or concrete surface,probably in combination with other techniques, provides added
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