TM 5-822-9/AFM 88-6, Chap.10
require that the random crack be widened with a
proportions specified by the producer without
rotary-type grooving tool and sealed with a joint
additional fillers and/or aggregate.
sealer so as to function as the working joint, and
11. Field mixing and batch size. Small
the existing nonworking joint be filled with an
mechanical mixers of the drum type and mortar
epoxy resin mortar. The vertical faces of the joint
mixers have been used successfully for mixing
groove should be free of oils, greases, residual fines
epoxy resin concrete and mortars. Small batches of
from sawing operation, or other coatings. All fillers
approximately 0.1 cubic foot (1 gallon) can be
and joint sealant material should be removed from
hand-mixed using a spatula or trowel. The
the joint. Oils and greases will rarely be present, but
maximum batch size will be limited by the ability to
if inspection indicates areas of even minor traces of
thoroughly mix the epoxy resin system and
oil and grease, these areas shall be cleaned by
aggregate. Experience has demonstrated that the
sandblasting. Inspection of joints or other small
maximum batch size will range from 200 to 300
openings can be facilitated by using a small mirror
pounds (1.5 to 2.0 cubic feet). Prior to starting
to reflect light into the opening. Residual fines from
operations, the immediate on-site availability of all
sawing operations or sandblasting should be
materials and the suitability and adequacy of the
removed by the use of high-pressure water jet
mixing and placing tools shall be carefully checked.
followed by an air jet to dry the concrete before
Several 2- to 5-gallon plastic graduated buckets
applying the epoxy resin system. A moderately rich
have been found to be satisfactory for
epoxy resin mortar should be used for filling joint
proportioning by volume. The mixing procedure of
grooves and other small openings where it may be
an epoxy resin system must produce a uniform and
difficult to hand-fill and compact a lean mix.
homogeneous mix. The components of the epoxy
However, care should be exercised to ensure that
resin system are mixed by stirring or agitation to
the epoxy resin mortar is not so rich that the
effectively put them into solution. For mixing epoxy
material flows. The epoxy resin mortar batch size
resin systems in small containers (1 quart), a
should be adjusted so that the personnel available
spatula, palette knife, or similar device can be used.
can complete all placing and finishing operations
For larger volumes, the epoxy resin system shall be
before the epoxy resin mortar starts to gel. The
mechanically mixed in plastic buckets. A paint
batching operations will follow the same sequence
mixing paddle driven by a low-speed electric drill
as that for trial batches. The epoxy resin system is
may be used for the mixing. After mixing the epoxy
prepared first and the fine aggregate gradually
components, the mixture should be immediately
added while continuing mixing until all particles are
transferred to the mixing pan (small mixes) or the
coated. After the joint or crack has been filled with
mechanical mixer (large mixes) and the aggregates
the epoxy mortar, the surface should be neatly
immediately added. Delays in adding the aggregate
finished, flush with the pavement surface, using
to the mixed epoxy resin system can result in a loss
appropriate hand tools. Excess material shall be
of the binder due to the accelerated chemical
carefully removed and not thinly spread on the
reaction. In mixing epoxy resin concrete, the large
adjacent concrete.
aggregate should be added to the mixed epoxy resin
13. Procedure for condition 3. Repair of this
binder first, followed by the fine aggregate. This
type of condition requires that the area within the
order of addition will help prevent the tendency of
broken corner (fig. 1) be removed and replaced
the mix to "ball." The mechanical mixers should be
with new PCC. The new concrete will be bonded to
cleaned immediately after usage to prevent the
the old concrete with an epoxy resin system at the
epoxy compounds from curing in the mixers. High-
prepared vertical faces of the patch area. The
pressure water can be used to remove the uncured
vertical face of the joint must be maintained to
epoxy if used shortly after the application. The
prevent the new PCC from bonding to the adjacent
most widely used cleaning method is to immerse
slab. If the joint is not properly maintained, the
the tools and wash the mixers with solvents such as
concrete patch will break loose due to slab move-
methyl-ethyl-ketone or methylene chloride. Mineral
ment caused by variations in temperature.
spirits or toluene may also be used with greater
a. Preparation of repair area. The area to be
safety although they are not as efficient as the
repaired should be outlined using a concrete saw.
previously mentioned solvents. If the epoxy resins
The saw cut lines should be located at least 2 inches
have hardened on the tools or mixers, strippers,
outside the crack in sound concrete, and not
mechanical abrasion, or burning will be necessary to
extend past the joint into the adjacent slab. The
remove the cured epoxies.
depth of the saw cut should be at least 2 inches.
12. Procedures for conditions 1 and 2.
Remove the broken corner and the remaining
Conditions of pavements, as described in this
concrete inside the saw cut to the full depth of the
manual, are shown in figure 1. Conditions 1 and 2
4
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