TM 5-822-5/AFM 88-7, Chap. 1
rigid overlay of a rigid base pavement with no bond,
The longitudinal and transverse cold joints for each
according to the guidance in chapter 14.
lift should always coincide. All sawed joints should
he sealed.
c. Construction joints. Currently, there are two
17-5. Joint Types for RCC.
types of construction joints in RCC paving-fresh
a. Expansion joints. Expansion joints, within an
and cold. When fresh concrete can he placed and
area paved with RCC, will not be required except to
compacted against in-place concrete prior to initial
protect facilities located within the paved area.
set (usually within 90 minutes), the juncture or joint
b. Contraction joints. Generally, longitudinal
will he considered to he a fresh joint and no special
contraction joints will not he required in RCC
treatment will be required. For the construction of
pavements. However, most RCC pavement to date
a fresh joint, the edge of the in-place concrete is left
has been allowed to crack naturally in the transverse
uncompacted and rolled after the adjoining concrete
direction. These cracks usually occur randomly at
has been placed. When the in-place RCC has
40- to 70-foot spacings, and have performed well,
stiffened significantly before the adjoining fresh
with little raveling or faulting. The natural cracks
concrete can he placed (usually around 90 minutes),
are typically not sealed; however, it is
the resulting juncture will be considered a cold
recommended that all cracks be routed and sealed
construction joint. The in-place concrete must be
in areas where the pavement may be susceptible to
fully compacted and then the edge trimmed back to
frost damage. Sawing of contraction joints is
solid concrete to form a near vertical face. If the
recommended at spacings of 50 to 75 feet,
required density or smoothness is not obtained, then
providing the sawing can be accomplished in the
the in-place concrete must be removed. Immediately
first 24 hours without excessive raveling. The opti-
prior to placement of the adjoining concrete, the
mum time for sawing and optimum transverse joint
vertical edge should be dampened. After placement
spacing should be determined during the test section
of the fresh concrete, the excess which spills onto
construction. Depth of sawcut should be one-third
the compacted material should he pushed back to
of the pavement thickness. For multilift pavements,
the edge of the fresh concrete before rolling. No
the sawcut should be made one-third the pavement
effort will be made to achieve load transfer at the
depth if full bond conditions are used. If partial
cold joint. Every effort should be made to keep cold
bond or no bond conditions are used, the sawcuts
longitudinal construction joints spaced at least 50 to
should be made in each lift in coinciding locations
75 feet.
to one-third the lift thickness (the sawcuts in the
lower lifts may be made 1 hour after compaction).
17-2
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