TM 5-822-11/AFP 88-6, Chap. 7
CHAPTER 3
DETERMINING SEALING NEEDS
3-1.
General. The information provided in
(5) Splitting of the sealant material or cohe-
this chapter can be used to help determine the
sion failure.
sealing requirements of an existing pavement. TM
(6) Lack or absence of sealant in the joint.
5-826-6/AFR 93-5 provides definitions of terms
(7) Sealant placed too low in the joint.
used in pavement evaluation. The steps to deter-
(8) Uncured sealant.
mine if a pavement should be resealed and the
c. Severity Levels. The description of severity
sealant and procedures that are used in resealing
levels listed below are discussed in TM 5-826-
are explained in the following paragraphs.
6/AFR 93-5 and are given in general terms below
for each sample unit and individual joints. The
3-2.
Factors to be Considered. There are
types of joint seal damage were previously pre-
many factors that should be considered when
sented in figures 2-6 and 2-7.
answering the "to seal or not to seal" question.
(1) Low Severity. The joint sealant is
Once this question has been answered, there are
generally in good condition throughout the
other factors that need to be considered in select-
section. The sealant is performing well with only
ing the best sealant and the proper installation
a minor amount of any of the above types of
procedures for a project. A brief discussion of
damage present. For individual joints being
each factor is presented in the general order in
examined, low severity is when the sealant is in-
which they should be considered. The relative
place, but has no incompressible material intrusion
importance of these factors will vary from site to
and little loss of bond, cracking, splitting, or slip
site and from feature to feature.
down that would allow water infiltration. No other
distresses have occurred.
a. Purpose of a Sealant. A sealant which must
(2) Medium Severity. The joint sealant is
prevent both water infiltration and incompressible
generally in fair condition over the entire surveyed
intrusion must be in better condition than a sealant
section with one or more of the above types of
which is only required to prevent incompressible
damage occurring to a moderate degree. The seal-
intrusion. If the pavement is in an area with high
ant will need replacing within 2 years. For indi-
annual rainfall or has a moisture susceptible
vidual joints, the medium severity level has a
subgrade, the sealant is needed to minimize water
small amount of debris retention or incompressible
intrusion. If the pavement is in an area with low
material intrusion, a moderate amount of extru-
annual rainfall or has a fast draining subbase, the
sion, twisting, slip down, cracking, splitting, or
sealant may be needed more to prevent intrusion
loss of resiliency has occurred.
of incompressibles.
(3) High Severity. The joint sealant is gener-
b. Sealant Condition. The most important
ally in poor condition over the entire surveyed
factor in evaluating pavement sealant requirements
section with one or more of the above types of
is the existing sealant condition. TM 5-826-6/AFR
damage occurring to a severe degree. The sealant
93-5 defines joint seal damage as any condition
needs immediate replacement. High severity for
that enables soil or rocks to accumulate in the
individual joints means that some joint sealant is
joints or allows significant infiltration of water.
missing from the joint, a considerable amount of
Accumulation of incompressible materials that
debris retention is present, and incompressible
prevent the slabs from expanding any may result
intrusion occurs which has caused spalling or
in buckling, shattering, or spalling. A pliable joint
allowed the free inflow of water.
sealant, bonded to the edges of the slabs, prevents
(4) Joints with no Defects. If none of the
the collection of incompressibles and the seepage
listed damage types have occurred, the sample unit
of water into the joint weakening the foundation
is not rated as having a severity level which means
that is supporting the slab. Typical types of joint
that the joint and sealant are in excellent condi-
seal damage include:
tion.
(1) Extrusion of the joint sealant.
d. Variation of Sealant Condition. The sealant
(2) Growth of vegetation in the joints.
condition may vary throughout the pavement fea-
(3) Hardening or oxidation of the sealant.
ture. This will be noted by variance in the joint
(4) Loss of bond between the sealant and
seal condition for the sample units in the pavement
pavement or adhesion failure.
feature. This variance is important in deter-
3-1
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