TM 5-822-9/AFM 88-6, Chap.10
edge or joint replacement areas, concrete removal
working cracks, the cracks must be maintained like
should have a bottom slope not exceeding 30 de-
a working joint. A different approach is required
grees. The minimum depth of the concrete removal
because rigid temporary inserts cannot be used. In
will depend on the maximum depth of the spalled or
this case a bond-breaking medium must be used to
damaged area. The concrete should be removed to
prevent bonding the epoxy concrete to the concrete
a sufficient depth to expose sound concrete in the
adjacent to the spall area which could possibly
entire patching area. The removal depth should be
result in further spalling. One bond-breaking
at least 2 inches, except where interior slab spalls,
medium uses polyethylene foam strips cut to fit the
such as popouts, are to be repaired. In this case, the
entire working face adjacent to the spall and an
minimum depth should be 1 inch.
appropriately sized flexible polyethylene backing
b. Surface preparation. All newly exposed sur-
rod which is temporarily embedded to provide a
faces are to be cleaned by sandblasting. Dust and
groove for the joint-sealing material. Another bond-
other debris resulting from the removal of deterio-
breaking medium involves coating the working face
rated surfaces or contaminants must be removed.
adjacent to the spall area with a bond-breaking
Cleaning may be accomplished by jetting the sur-
medium, such as grease, and temporarily
face with compressed air, thorough washing with
embedding a backing rod for groove-forming as in
high-pressure water jets, or by use of a high-suction
the previous case. With either of the suggested
vacuum. The vacuum method should only be used
methods, the backing rod must be removed after
when other procedures cannot be employed. All
the epoxy concrete hardens.
e. Repair of spalls within working cracks.
equipment for providing compressed air must have
oil and water traps in the air supply lines.
Where working cracks continue through areas to be
c. Maintaining the working joint. The regular
patched, the crack should be maintained as a joint
working joint may be maintained by the use of a
through the freshly placed epoxy resin concrete.
fiberboard coated with a polyethylene film, poly-
After removal of the unsound concrete and cleaning
ethylene foam strips, or other suitable material. The
of the prepared spall area, a polyethylene foam
separating medium should be approximately inch
sheet should be cut to fit along the alignment of the
thick cut to closely fit the pattern of the cavity
crack within the prepared cavity. The concrete
along the adjacent slab (see fig. 2). If fiberboard is
surface along the alignment of the crack should not
used, it should be coated with a polyvinyl film or
be excessively irregular which would produce voids
vinyl duct tape to prevent epoxy from binding to
greater than 1/4 inch deep below the sheet when
the board. If necessary, the irregular surface treated
placed over the crack. A small chipping hammer
at the crack of the pavement joint should be coated
equipped with a - to 1-inch-wide blade may be
with a suitable bond-breaking medium. A flexible
used to remove high spots along the crack to form
latex caulking compound may be used to fill any
a regular surface. When placing the epoxy resin
voids underneath the sheet material. The insert
concrete, placements need to be carefully made
should be removed after the epoxy resin concrete
around the joint filler sheet to prevent tilting or
hardens, or it may be cut out with a concrete saw to
misalignment of the sheet. Maintaining an active
form the joint sealant reservoir. The formed joint is
crack through an area being repaired is shown in
later sealed with an acceptable joint-sealant
figures 3 and 4.
f. Placement of epoxy resin concretes and mor-
material. Oils, waxes, greases, or silicones should
tars. In scheduling the placement of epoxy resin
not be used on the insert since these substances
prevent bonding of the joint-sealant materials.
concretes and/or mortars, the correct type and
d. Spalls along working cracks. For spalls along
classification of epoxy resin system should be
procured, pavement and materials temperatures
should be carefully considered, and appropriate
operational conditions and procedures established.
(1) Prior to the placement of epoxy resin
concrete or mortars, the surface of the cavity
(except for the face of the working joint) shall be
primed with the binder. The primer should be
applied in a relatively thin coat (15 to 20 mils) and
briskly scrubbed into the concrete surface with a
stiff bristle brush or roller. Placement of the epoxy
resin concrete or mortar should begin immediately
after application of the prime coat.
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