1.3.6.1 General—Experience shows that concrete repair
work requires much greater attention to details and good
practice than new construction. The contractor should follow
specifications and use proper procedures and techniques to
achieve the desired results. On any repair project, unexpected
or concealed conditions may be revealed as work progresses.
1.3.6.2 Shoring/work sequences—The repair process,
including concrete removal and reinforcing repair, may alter
the force and load distribution within and between reinforced
concrete members. It is essential that the contractor, in
conjunction with the engineer, determine the extent and
sequence of shoring and repair that satisfies structural safety
and force distribution.
1.3.6.3 Concrete removal—The removal of deteriorated,
damaged, or defective concrete requires special attention to
the identification and extent of unsound and sound concrete to
be removed, the type of removal techniques, and the protection
of existing reinforcing during removal. These factors should
be addressed to maintain structural integrity and avoid damage
to the structure while implementing the repairs.
1.3.6.4 Surface preparation—The success of the repair is
highly dependent on adequate surface preparation before repair
material installation. The surface preparation required depends
on the concrete removal technique and the type of repair
being undertaken. Surface preparation includes the repair,
replacement, and installation of supplemental reinforcement.
1.3.6.5 Repair techniques and material installation—The
proper repair techniques and material selection and installation
are essential for a successful project that is capable of
providing the serviceability and durability of any repair.
1.3.6.6 Protective systems—Protective systems, such as
coatings, sealers, and membranes, may be incorporated into
the repair process to extend the service life of the repairs and
reduce and minimize further deterioration in the structure.
Protective systems provide varying types of protection to the
repair and structure and should be selected to satisfy project
serviceability requirements.
1.3.7 Quality control— All of the best efforts in designing
a repair and specifying the optimum materials are at risk if
the implementation lacks the appropriate quality control
measures to ensure a successful installation. ACI 311.4R
provides guidance on setup of quality control, inspection,
and testing procedures. A written quality plan should be
prepared and presented to the engineer for approval. ACI
311.1R (SP-2) and ACI 311.5R provide guidance on
inspection and testing.
1.3.7.1 Performance objectives—A clear understanding
forms the basis for a successful repair. The repair documents
should define the structural, environmental, aesthetic, and
protection objectives to be achieved. Mockups are recommended
where appropriate, such as in those instances where
the color or texture must meet the surrounding concrete (ACI
311.1R, 311.4R, and 311.5R).
1.3.7.2 Quality control procedures during the repair—
The successful completion of the repair procedure can be
verified by continuing quality control measures during the
course of the work.
• Such measures include the appropriate safety measures
to ensure the safety of all personnel and the structure
being repaired throughout the course of the work;
• Periodic reviews by the engineer and implementation
of all testing and inspection requirements are essential
to meeting the performance objectives established by
the engineer;
• Adequate supervision by the contractor should include
daily monitoring of temperature, humidity, and weather
conditions that may affect the repair procedure;
• The contractor should pay attention to the specification
requirements for appropriate shoring, repair preparation,
material installation, and subsequent curing; and
• Accurate record keeping should include repair locations,
repair modifications, quantities installed, site visits by
the engineer, weather conditions, changes to the
engineering documents, and periodic progress reports.
1.3.7.3 Testing or inspection agency qualifications—This
agency should meet the requirements of ASTM E 329.
Personnel should be ACI certified as technicians or inspectors
as appropriate.
1.3.8 Maintenance after completion of repairs—Lack of
adequate maintenance may result in premature failure of the
repair or surrounding areas. Therefore, appropriate maintenance
procedures after completion of a concrete repair
project is recommended, including the following:
• Warranty documentation should be obtained, when
applicable, upon completion of the repair project;
• Warranty conditions should be adhered to ensure warranty
coverage is maintained, such as periodic inspections or
recoating of membranes or sealers;
• All plan and specification documents from the repair
project along with the original building plans and
specifications (when available) should be maintained;
• Performance of repairs should be monitored by documenting
subsequent changes of the concrete repairs or
surface applied systems;
• Proactive monitoring systems, such as acoustic monitoring
for post-tensioned structures, should be activated
and maintained where applicable; and
• Continued evaluation of the structure by periodic
engineering reviews should be programmed.