TM 5-822-11/AFP 88-6, Chap. 7
reaction with asphalt, which is also derived from
(c) During the storage of two component
petroleum.
sealants, the accelerating agent, typically a powder
(2) JFR sealants are usually made from a tar
in suspension, can settle to the bottom of the
based material modified with suitable resins or
sealant container. The settlement can be mini-
polymers. These sealants are most widely used on
mized by turning the containers upside down at
PCC pavement subjected to fuel spillage or lubri-
regular intervals, such as 1-week intervals. Even
cant leaks. JFR sealants should be used for park-
when this procedure is followed, the accelerator
ing aprons, maintenance areas, and refueling ar-
should be thoroughly remixed before being placed
eas. Most tar is produced from coal which gives it
in the application equipment. The mixing can be
a different chemical makeup than asphalt, render-
accomplished using any suitable hand held device,
ing the tar based sealant less affected by the
such as a drill equipped with a mixing paddle, that
spillage of petroleum based materials. Federal
mixes horizontally and vertically to ensure the
Specification SS-S-1614A covers field-poured hot-
curing agent is lifted off of the bottom of the
applied JFR sealants. These sealants may be
container and resuspended into the liquid.
damaged by synthetic hydraulic fluids.
(2) Single component non-JFR cold applied
c. Field-Poured Cold Applied Sealants.
sealants, such as silicone and nitrile rubber based
(1) Two-component polymer type cold-
materials can be used in both bituminous and PCC
applied JFR sealants used in PCC pavements are
pavements not subjected to fuel spillage unless
covered in Federal Specification SS-S-200E,
they are specifically tested for fuel resistance.
under Type H or Type M. These polymer-type
d. Preformed elastomeric (compression) seals
sealants are tar, polyurethane, or polysulfide based
are solid at the time of installation and therefore
materials modified with suitable elastomeric
must be sized for a given joint. Not all preformed
polymers or resins. One of the two components
seals are fuel resistant; therefore, their use in
contains the polymer in liquid form, and the other
areas where fuel spillage is expected must be
component contains the chemical that solidifies the
restricted to only those fabricated from fuel
polymer. These sealants are used in areas that are
resistant materials.
subjected to fuel spillage and jet blast. Although
e. Preformed elastomeric compression seals
the sealant is not completely jet blast resistant, it
have been made of bituminous-impregnated foam
is more resistant to the heat from jet blast than the
rubber, cork, or extruded polychloroprene. The
sealants in Federal Specification SS-S-1614A.
polychloroprene seal is used more often than the
Some one-component materials are being
others and is a labyrinth or webbed type seal
produced that claim to meet the performance
referred to as the elastomeric compression seal.
requirements of Federal Specification SS-S-200E.
ASTM D 2628 is the specification used in
The sealant material must be tested to ensure
selecting appropriate seals. A lubricant/adhesive is
specification conformance before its use is
required when installing the preformed seal into
approved.
the joint. The lubricant coats the seal to allow
(a) Federal Specification SS-S-200E, Type
easier installation of the seal. Once the seal is in
H. Type H two-component sealants are designed
place, solvent evaporates from the lubricant and it
for hand-mixing. Type H sealants are generally
becomes a very weak adhesive. The specification
used for small projects and spot repairs of deterio-
requirements for the lubricant/adhesive are given
rated sealant in areas where fuel spillage and/or
in ASTM D 2835. Since the preformed seals must
heat blast are expected. Type H sealants are
remain in compression in the joint at all times to
normally not used for major sealing projects; how-
function properly, it is necessary to properly size
ever, some Type H sealants are manufactured for
the seal. Guidance for sizing preformed compres-
areas that are on steep inclines such as embank-
sion seals is provided in appendix C. Some pre-
ment areas. The steep slopes would make it diffi-
formed seals are not compression seals. Instead,
cult to use sealant application equipment, and
they are applied in the joint with an adhesive
therefore, a hand-mix sealant would be desirable.
which maintains the seal's bond with the concrete.
(b) Federal Specification SS-S-200E, Type
The selected width of the noncompression seal is
M. Type M two-component sealants are designed
equal to the width of the joint. The adhesive is
to be machine-mixed in a one-to-one ratio by
applied to the joint faces and to the seal. The seal
volume
using
the
appropriate
sealant
is inserted into the joint and pressurized until the
mixing/application equipment described later.
adhesive cures. The adhesive used for this type of
Machine-mixed sealants are normally used for
seal is much stronger than the ones which conform
large sealing projects in areas where fuel spillage
to ASTM D 2835.
and/or heat blast are expected.
2-3
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