TM 5-822-9/AFM 88-6, Chap.10
required, and the test procedures are given in
60 to 100 degrees F prior to mixing with a
appendix B. If epoxy resin concretes are to be used,
mechanical stirring device. Although adequate
samples of fine aggregate and coarse aggregate
uniformity of the mixture might be obtained at
should be submitted for testing. The contractor is
lower temperatures by a prolonged mixing time
required to supply the testing laboratory the
when epoxy resin concretes or mortars are being
proportions of aggregate used by weight or vol-
prepared, an overly "rich" mixture (a mixture
ume.
containing excess epoxy resin) could occur due to
the reduced wetting capability.
epoxy resin concretes. Variations in aggregate
d. "Triggering" curing chemical reaction. To
grading and particle shape may affect the propor-
expedite resumption of traffic over a repair area for
tions required to obtain an economical mixture that
low pavement and atmospheric temperature
has satisfactory placing and finishing characteristics.
conditions, the early hardening rate of the epoxy
Small laboratory trial batches shall be prepared and
binders can be appreciably accelerated. This may be
tested prior to the start of field placement
accomplished by warming the aggregates before the
operations. The quantity of epoxy resin system
aggregates are added to the epoxy resin.
prepared for use in these trial batches should be at
Aggregates may be warmed by storing in a heated
least 300 grams. The labels on the shipping
building, by burners, or by radiation. Care must be
containers will specify the manufacturer*s
taken not to heat aggregates excessively because
recommended mixing proportions. A polyethylene
such heating can limit the working life of the epoxy
container having a hemispherical (convex) bottom
mortars and epoxy concretes. Aggregate
should be used as the mixing vessel. The
temperatures above 120 degrees F shall be avoided.
recommended proportions of the two components
8. Aggregates for epoxy resin concretes
are added to the mixing vessel and mixed until a
and mortars. a. Concretes. The aggregates used
uniform mixture is obtained. The rate of stirring
for epoxy resin concretes should be clean, dry,
should be such that the amount of entrapped air is
washed gravel or crushed stone, 3/8-inch or -inch
minimized. Hand-mixing is usually unsatisfactory
maximum size, well graded from coarse to fine, and
and a powerdriven (air or spark-proof), propeller-
of the same quality as those used for PCC and
type blade should be used. The mixed epoxy resin
bituminous mixtures. Fine aggregate and coarse
system must be uniform and homogeneous. Mixing
aggregate of indicated sizes meeting the require-
may require 2 to 5 minutes depending on the
ments of ASTM C 33 should be specified for epoxy
viscosity and density of the epoxy resin. Epoxy
resin concrete mixtures.
resin concrete proportions by weight may vary from
6 to 10 parts aggregate to 1 part epoxy resin
resin mortars is required to conform to either
binder, which is equivalent to a ratio of approxi-
ASTM C 144 or ASTM C 33. The aggregate
mately 4 to 7 parts aggregate to 1 part epoxy resin
should be well graded from coarse to fine with a
binder by volume. The aggregate mixture (fine and
minimum amount of material passing the No. 100
coarse aggregate) should contain 55 5 percent
sieve. The maximum size required will depend on
fine aggregate by weight. The epoxy resin mortars
the intended use of the mortar. For example, in the
may vary from 4 to 7 parts aggregate by weight to
filling of saw kerfs, the normal width of the cut
1 part epoxy resin binder, which is equivalent to a
requires the use of an aggregate with 100 percent
ratio of approximately 3 to 5 parts aggregate to 1
passing the No. 8 sieve. In general, for both epoxy
part epoxy resin binder by volume. The proportions
resin concrete and mortar, the maximum size
suggested are applicable only to aggregates in the
aggregate should not exceed one-third of the
2.60 to 2.80 specific gravity range. Aggregates
thickness of the layer being placed nor one-third of
having specific gravities above or below these
the width of the opening being filled.
values will probably require adjustment of the
9. Sampling and testing epoxy resins. All
suggested proportions. The trial batch procedure
epoxy resins proposed for use should be tested for
will assist field personnel in obtaining the proper
compliance with the requirements of the applicable
proportions of aggregate and binder in preparing
specification. The manufacturer*s certificates of
the larger field batches.
compliance with the requirements will not be
b. Epoxy resin system and epoxy resin grout.
accepted in lieu of tests for large jobs. The US
Trial batches are not required when using an epoxy
Army Engineer Waterways Experiment Station and
resin system as a bonding medium between plastic
the South Pacific Division Laboratories, US Army
and hardened PCC or when using epoxy resin grout
Corps of Engineers, have been designated to
for filling cracks and/or placing dowels. The two
conduct the required tests for acceptance of epoxy
components of a grout will usually be mixed in the
resins. The method of sampling, amount of sample
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