TM 5-822-5/AFM 88-7, Chap. 1
CHAPTER 12
PLAIN CONCRETE PAVEMENT DESIGN
tained from the design chart presented in figure 12-
12-1. General.
1 for roads and streets. Figure 12-2 is used to
Rigid pavements for roads, streets, and open stor-
determine the thickness of parking and storage
age areas at military installations will be plain
areas except that the thickness of roller-compacted
(nonreinforced) concrete except for those condi-
concrete parking and storage areas will be designed
tions listed in chapter 13 or unless otherwise ap-
using figure 12-1. These design charts are graphical
proved by HQUSACE (CEMP-ET), or the
representations of the interrelation of flexural
appropriate Air Force Major Command.
strength, modulus of subgrade reaction k, pavement
thickness, and repetitions (design index) of the basic
12-2. Roller-Compacted Concrete Pavements.
18,000-pound single-axle loading. These design
Roller-compacted concrete pavements (RCCP) are
charts are based on the theoretical analyses of
plain concrete pavements constructed using a zero-
Westergaard (New Formulas for Stresses in
slump portland cement concrete mixture that is
Concrete Pavements of Airfields, ASCE
placed with an AC paving machine and compacted
Transactions), supplemented by empirical modifi-
with vibratory and rubber-tired rollers. The design
cations determined from accelerated traffic tests and
of RCCP is presented in chapter 17.
observations of pavement behavior under actual
service conditions. The design charts are entered
12-3. Design Procedure.
using the 28-day flexural strength of the concrete.
For convenience in determining design require-
A horizontal projection is then made to the right to
ments, the entire range of vehicle loadings and
the design value for k. A vertical projection is then
traffic intensities anticipated during the design life
made to the appropriate design-index line. A second
of pavements for the various classifications of mili-
horizontal projection to the right is then made to
tary roads and streets has been expressed as an
intersect the scale of pavement thickness. The
equivalent number of repetitions of an 18,000-
dashed line shown on curves is an example of the
pound single-axle loading. To further simplify the
correct use of the curves. When the thickness from
design procedure, the range of equivalent repeti-
the design curve indicates a fractional value, it will
tions of the basic loading thus determined has been
be rounded up to the next -inch thickness. All
designated by a numerical scale defined as the
plain concrete pavements will be uniform in cross-
pavement design index. This index extends from 1
sectional thickness. Thickened edges are not
through 10 with an increase in numerical value
normally required since the design is for free edge
indicative of an increase in pavement design
stresses. The minimum thickness of plain concrete
requirements. Values for the design index are de-
for any military road, street, or open storage area
termined using the procedure in chapter 3. Once the
will be 6 inches.
design index has been determined the required
thickness of plain concrete pavement is then ob-
12-1
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