Page 321 - Planning and Design of Airports

Structural Design of Airport Pavements 279

1/4" (6 mm) radius Sealant material 1/4"–3/8"
or chamfer (6–10 mm) below surface
Detail 1
3/4"±1/8" (19±3 mm)
Isolation joint Rod backup material
Non-extruding premolded compressible
material ASTM D-1751 or 1752
3/4"±1/8" (19±3 mm)
Sealant material 1/4"–3/8"
(6–10 mm) below surface
W
T/4"±1/4" (±6 mm)
Detail 2
Contraction joint D 1 1/4" (32 mm) minimum
T/4 +/– 1/4" (6 mm)
Rod backup material

Optional (all joints) Sealant material 1/4"–3/8"
1/4" × 1/4" chamfer (6–10 mm) below surface
W
Detail 3
Construction joint
D 1 1/4" (32 mm) minimum
Rod backup material
Construction joint between slabs
Longitudinal joint type C or E
Bar length varies
Plan view-position of dowels 12" (305 mm) minimum
at edge of joint type C or E
Bar length varies
10" (254 mm) minimum Transverse joint
type C or E
NOTES:
1. Sealant reservoir sized to provide proper shape factor, W/D. Field poured and preformed sealants require different
shape factors for optimum performance.
2. Rod backup material must be compatible with the type of sealant used and sized to provide the desired shape factor.
3. Recess sealant 3/8"–1/2" for joints perpendicular to runway grooves.
4. Chamfered edges are recommended when pavements are subject to snow removal equipment of high traffic
volumes.
FIGURE 7-11 Rigid pavement joint structure details.

Dowels are load transfer devices which permit joints to open by
which prevent differential vertical displacement. Usually dowels are
solid, round steel bars, although pipe may also be used. Several dif-
ferent analyses have been proposed for the design of dowels. The
spacing of dowels depends on the thickness of the pavement, modu-
lus of subgrade reaction, and the size of the dowel. Table 7-7 contains
recommendations for dowel sizes and spacings.

Continuously Reinforced Concrete Pavements
A continuously reinforced concrete pavement (CRCP) is one in
which transverse joints have been eliminated (except where the
pavement intersects or abuts existing pavements or structures) and
the longitudinal reinforcing steel is continuous throughout the
length of the pavement. Other than the design of the embedded