TM 5-822-11/AFP 88-6, Chap. 7
mining whether routine sealing by in-house main-
maintenance and repair needs of a pavement. If
tenance personnel will suffice.
the PCI is 40 to 60 or lower, the pavement has
e. Joint and Crack Condition. The condition of
deteriorated to the point where it may need major
the joint or crack affects how the sealant will
repair in the near future. Resealing should always
perform in the future and also indicates the
be included as part of any major repair work. PCI
relative need for joint repair before sealing. Sev-
prediction programs available in PAVER and
eral distress types such as spalling, faulting, set-
Micro-PAVER should be used to determine if
tlement or heave, corner spalls, and keyway fail-
resealing the joints will raise the PCI of the
ure may have to be repaired before effectively
pavement feature enough to justify the cost deter-
resealing the joint or crack. In extreme cases, it
mined from a life-cycle cost analysis (see app D).
may be necessary to completely rebuild the joint
h. Joint and Slab Design. The joint sealant
before it can be successfully sealed. For example,
reservoir and the pavement slab size must be
joints with keyway failures or spalling require the
considered when resealing, especially in selecting
failure to be repaired before it is resealed. The
the type of sealant and determining the amount of
repair will reduce the potential for FOD and
preparation required before resealing. The amount
reduce the susceptibility of debris retention in the
of horizontal movement at a joint (the working
joint. The incompressible materials and debris in
range of the joint) depends upon several factors
a joint create nonuniform, high-compressive
such as the size of the slab, the seasonal tempera-
stresses on the joint faces as the joint tries to
ture changes, friction between the slab and under-
close. The compressive stresses can cause spalls,
lying material, and the type of joint (transverse or
blowups, or slab shoving. Joints that have only
longitudinal). Therefore, longer slabs and greater
minor spalling or widening due to intrusion of
seasonal temperature changes cause more horizon-
incompressibles require only cleaning and then
tal joint movement. The working range of the
resealing. The joint condition also influences the
sealant, which is controlled by the sealant proper-
selection of the sealant to be used when resealing.
ties and the width of the joint reservoir, must be
A liquid (field- poured) sealant can perform
larger than the working range of the joint. A
satisfactorily in a joint that has small spalls or
sealant is more likely to fail in a narrow joint
other joint shape irregularities while a preformed
sealant reservoir than a wider one as described in
compression seal cannot. The difference in
chapter 2. It may be necessary to widen a joint
performance results from the method each seal
sealant reservoir before resealing to obtain ade-
uses to bond with the joint faces. The preformed
quate width and depth for satisfactory sealant
compression seal must have a uniform joint shape.
performance. Appendix C provides the working
Otherwise, uneven pressures will be placed on the
range calculations for joints and sealants.
seal and force it out of the joint (see fig 2-5), and
i. Current and Future Mission of the Pavement
a field-poured sealant will take the shape of the
Feature. The type of traffic and pavement use
existing joint.
must be considered when determining the need to
f. Moisture Accelerated Distress Types. The
reseal and the type of sealant to use. The amount
infiltration of water through joints or cracks into
of allowable FOD depends upon the type of
a moisture susceptible subbase or subgrade can
aircraft or other traffic using the pavement. The
cause or accelerate moisture related distresses. In
pavement use will determine the expected amount
concrete pavement, the moisture related distresses
of fuel, hydraulic, and other fluid spillages which
may be indicated by pumping, corner breaks,
the sealant must withstand. Any expected changes
settlement or faulting, or cracking caused by
in either type of traffic or pavement use may
subgrade volume change. In bituminous pavement,
require a different type of sealant to be used
the moisture related distresses include medium- to
instead of the type indicated by present conditions.
high-severity alligator cracking, depressions and
j. Performance of Previous Sealant. Hot- and
swells, and medium- to high-severity transverse
cold-applied sealants meeting current specifica-
and longitudinal cracking. If a significant amount
tions should last 4 to 6 years, and preformed
of these distress types occur, resealing should be
elastomeric compression seals should last 10 to 15
done immediately before the distress develops in
years. Some improved liquid sealants have lasted
other areas of the pavement. The damaged pave-
much longer than the 4- to 6-year time frame and
ment area should be removed and replaced to
some have failed in less than 1 year. The age of
maintain the load-carrying capability of the pave-
the existing sealant should be determined, and if it
ment.
failed rapidly, the cause of deterioration should be
g. Overall Pavement Condition. The pavement
determined. If possible, the cause of deterioration
surface condition is measured using the pavement
should be eliminated before resealing. Failure to
condition index (PCI). It is directly related to the
remedy the problem will probably cause the new
3-2
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