TM 5-822-5/AFM 88-7, Chap. 1
face. Some of these special joints or junctures are as
edge was provided at the free edge of the existing
follows:
pavement, but neither met the design requirements
a. Slip-type joints. At the juncture of two pave-
for the new pavement.
ment facilities, expansion and contraction of the
(3) For transverse contraction joints, when re-
concrete may result in movements that occur in
moving and replacing slabs in an existing pavement.
different directions. Such movements may create
(4) For longitudinal construction joints, when
detrimental stresses within the concrete unless
removing and replacing slabs in an existing pave-
provision is made to allow the movements to occur.
ment if the existing load-transfer devices are dam-
At such junctures, a thickened-edge slip joint shall
aged during the pavement removal.
be used to permit the horizontal slip- page to occur.
(5) Any other location where it is necessary to
The design of the thickened-edge slip joint will be
provide load transfer for the existing pavements.
similar to the thickened-edge construction joint (see
The special joint design may not be required if a
fig 15-6). The bond-breaking medium will be either
new pavement joins an existing pavement that is
a heavy coating of bituminous material not less than
grossly inadequate to carry the design load of the
1
/16 inch in thickness when joints match or a normal
new pavement or if the existing pavement is in poor
nonextruding-type expansion joint material not less
structural condition. If the existing pavement can
than inch in thickness when joints do not match.
carry a load that is 75 percent or less of the new
The 1/16-inch bituminous coating may be either a
pavement design load, special efforts to pro- vide
low penetration (60 to 70 grade asphalt) or a clay-
edge support for the existing pavement may he
type asphalt-base emulsion similar to that used for
omitted and the alternate thickened-edge joint used
roof coating (see Military Specification MIL-R-
(fig 15-4h); however, if omitted, accelerated failures
3472) and will be applied to the face of the joint by
in the existing pavement may be experienced. The
hand brushing or spraying.
new pavement will simply be designed with a
b. Joints between new and existing pavements.
thickened edge at the juncture. Any load-transfer
A special thickened-edge joint design (see fig 15-4f)
devices in the existing pavement should be used at
will be used at the juncture of new and existing
the juncture to provide as much support as possible
pavements for the following conditions:
to the existing pavement. Drilling and grouting
(1) When load-transfer devices (keyways or
dowels in the existing pavement for edge support
dowels) or a thickened edge was not provided at
may he considered as an alternate to the special
the free edge of the existing pavement.
joint; however, a thickened-edge design will be used
(2) When load-transfer devices or a thickened
for the new pavement at the juncture.
15-18
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