UFC 3-260-02
30 June 2001
Table 12-7
Recommended Spacing of Transverse Contraction Joints
Pavement Thickness, millimeters (inches)
Spacing, meters (feet)
Less than 230 (9)
3.8 to 4.6 (12.5 to 15)
230 to 305 (9 to 12)
4.6 to 6 (15 to 20)
Over 305 (12)1
6 (20 max)
1
6-meter (20-foot) maximum spacing for Army and Air Force pavements.
(5) Spacing of longitudinal contraction joints. Contraction joints will be placed along the
centerline of paving lanes that have a width greater than the determined maximum spacing of transverse
contraction joints in Table 12-7. Contraction joints may also be required in the longitudinal direction of
overlays, regardless of overlay thickness, to match joints existing in the base pavement unless a bond-
breaking medium is used between the overlay and base pavement or the overlay pavement is
reinforced.
(6) Doweled contraction joints. Dowels will be required in the last three transverse contraction
joints back from the ends of all runways to provide positive load transfer in case of excessive joint
opening due to cumulative shrinkage of the pavement. Similar dowel requirements may be included in
the transverse contraction joints at the end of other long paved areas, such as taxiways or aprons where
local experience indicates that excessive joint opening may occur. In rigid overlays in Air Force and
Army Type A traffic areas, longitudinal contraction joints that would coincide with an expansion joint in
the base pavement will be doweled. Dowel size and spacing will be as specified in Table 12-8.
(7) Aggregate Interlock. Aggregate interlock can provide adequate load transfer across joints
when the pavement is originally constructed during hot weather. However, as joint movements due to
temperature variation and load applications increase and the joint begins to open, aggregate interlock is
lost and load transfer is greatly reduced. The effectiveness of aggregate interlock may be improved by
increasing base strength and the angularity of coarse aggregate and shorter spacing of joints.
b. Construction Joints. Centerline longitudinal construction joints should be used on runways and
taxiways.
(1) General. Construction joints may be required in both the longitudinal and transverse
direction. Longitudinal construction joints (generally spaced 6 meters (20 feet) apart but may be more
than one lane wide depending on construction equipment capability) will be required to separate
successively placed paving lanes. Transverse construction joints will be installed when it is necessary to
stop concrete placement within a paving lane for a length of time that will allow the concrete to start to
set. All transverse construction joints will be located in place of other regularly spaced transverse joints
(contraction or expansion types) and will normally be doweled butt joints. There are several types of
construction joints available for use as shown in Figure 12-32 and as described below. The selection of
the type of construction joint will depend on such factors as the concrete placement procedure (formed
or slipformed), airfield type, adjacent existing pavement, and foundation conditions.
12-21
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