INSPECTION, MAINTENANCE, AND REPAIR - Prestressed Concrete Transmission Pole Structures - page 106

remove all remaining dust and other foreign particles and then allowed
to dry. The repair area should now be clean, open, and textured. If internal
steel reinforcement has been exposed, the steel should be cleaned of all
contaminates and corrosion and then coated, usually with an epoxy, and
allowed to dry. A thin coat of the bonding agent should be applied to the
area to be patched and allowed to dry. Next, the fi ll material should be
prepared as specifi ed by the Purchaser. Typical fi ll materials include
mortar mixes, grout mixes, a low viscosity epoxy, or grout/bonding agent
compounds. All mixes and compounds should be prepared in accordance
with the product manufacturer's specifi cations. The fi ll material should
be carefully applied to the prepared patch area. The outside surface of the
patch should be leveled, usually with a steel trowel or sponge fl oat, and
possibly sanded smooth after curing. The resulting patch should follow
the contours of the pole's appearance prior to the damage. Poles with
cavities larger than the foregoing should be brought to the Purchaser's
attention for review and assignment of a satisfactory repair.
Major concrete repairs also may include fi berglass resin wraps around
the damaged zone of the pole to further protect and reinforce the affected
section.
Repair of Cracks: Cracks that exist after the pole is installed and
propagate through the pole to the interior steel should be monitored and
possibly repaired. A tapered grinding cone is commonly used to bevel the
crack for the full length. All unsound material should be removed. Next,
the area should be thoroughly cleaned and washed with water to remove
all remaining dust and other foreign particles and then allowed to dry. If
internal steel reinforcement has been exposed, the steel should be cleaned
of all contaminates and corrosion and coated, usually with an epoxy, and
allowed to dry. The crack is then fi lled with a structure epoxy that has
approximately the same thermal expansion coeffi cients as the parent con-
crete. Major cracks should be reported to the Purchaser and the pole
Manufacturer to determine the extent of damage to the pole and the type
of repair required.
Repair Finish: The pole repaired area should have a smooth appear-
ance. Sharp or rough edges should be tooled until they are smooth. The
outside surface along the length of the structure should be leveled with a
steel trowel or sponge fl oat until all projections, depressions, and irregu-
larities have been removed, and the entire surface has a smooth texture
with neat lines. At times, it may be necessary to sand the cured repaired
surface to achieve the desired fi nish.
Repair Compounds: Special patching compounds, bonding agents,
and repair procedures are normally available from the concrete pole