It is essential that all unsound
concrete be removed. The use of a hammer
will be necessary to sound tight areas, and the use of a sounding chain will
speed up deck sounding. The practice of
removing additional sound concrete after the deteriorated material is removed
helps to ensure a stable surface to pour against.
Pay special attention to the
locations at the edges of the patch where the reinforcing steel enters the
sound concrete. In many cases, during
the removal process, the reinforcing steel is vibrated or impacted, which
causes cracking around the reinforcing steel penetration point. If this occurs, the Contractor will have to
“chase” the cracks to make sure all fractured concrete is removed.
It is very difficult to get
proper consolidation of a vertical patch.
It may be necessary for the Contractor to utilize a “pencil” vibrator
and/or externally vibrate the forms to assist in consolidation. In all cases, the Contractor is responsible
to provide a well consolidated patch.
Make sure all form ties and
form attachment points in both the new concrete and the existing sound concrete
are repaired after formwork removal.
1. Document the patch depth of 4 inches (10 cm) for
horizontal patches and the patch depth of 3 inches (8 cm) for vertical patches
as per 519.03.
2. Patch area thoroughly cleaned with water, compressed
air, etc.
3. Concrete testing data and batch tickets for Class S or
QC-2 concrete, as specified in the plans.
4. Exposed area of patch given a rubbed finish and cured
as per 511.14.
5. Sound patches before final acceptance.
6. Measure length and width for pay.