TM 5-822-13/AFJMAN 32-1018
CHAPTER 7
CONCRETE PAVEMENTS
7-1. Application.
In general, all concrete pavements for roads, streets, and open storage areas on military installations will be
plain concrete unless otherwise approved by Headquarters, Department of the Army (CEMP-ET), Washington,
DC 20314-1000, or the appropriate Air Force Major Command. Roller-compacted concrete pavements (RCCP)
are plain concrete pavements constructed using a zero-slump PCC mixture that is placed with an asphalt con-
crete paving machine and compacted with vibratory and rubber-tired rollers. Most of the engineering and mate-
rial properties of RCCP are similar to those of conventional concrete. Pavements constructed using RCCP have
been approved for use in parking and storage areas and for road and street classes where vehicle speed does not
exceed 45 miles per hour.
7-2. Design Procedure.
The design of a concrete pavement for mixed vehicular loads and traffic levels is based on Minor's hypothesis. It
involves selecting a thickness of the PCC slab in which the maximum tensile stress does not exceed a certain
value. This tensile stress is calculated using the JULEA computer program, and the limiting stress criteria are
based on equations 5-1 and 5-2. Since traffic loads travel near the pavement (free) edges, load transfer is not
considered in the design for roads and streets but is considered for parking and storage areas.
a. Select several concrete slab thicknesses and compute the maximum tensile stresses under each design
axle load using the layered elastic method. The concrete thickness required using the conventional design proce-
dure may be used as a starting point. The computed maximum stresses should be multiplied by 1.33 for roads
and streets.
b. Based on the computed stresses, determine the allowable coverages Ni using equation 5-1 for each thickness.
c. Compute the damage which is equal to the sum of the ratios of the design coverage ni to the allowable
coverage Ni, where i varies to account for each design axle load. For instance, if there are three different axle
loads involved in the design, i varies from 1 to 3.
d. Select the thickness at a damage of 1.
e. Select the slab thickness for the damage value of 1 from the relationship between the damage and slab
thickness.
f. The selection of an unbound granular base or a stabilized base under the concrete slab is a matter of
engineering judgment depending on many factors such as cost, material availability, frost protection require-
ment, pumping, and subgrade swell potential. Subgrade soil may be stabilized to gain strength or modified to
increase its workability and reduce swell potential.
g. All plain concrete pavements will be uniform in cross-sectional thickness. The minimum thickness of con-
crete will be 6 inches. The computed thickness will be rounded to the next full or half-inch thickness.
7-3. Design Procedures for Stabilized Foundations.
a. Soil stabilization or modification. Soils that have been treated with additives such as cement, lime, flyash,
or bitumen are considered to be either stabilized or modified. A stabilized soil is one that shows improvement in
load-carrying capability and durability characteristics. A modified soil is one that shows improvement in its
construction characteristics but which does not show an increase in the strength of the soil sufficient to qualify
as a stabilized soil. The principal benefits of soil modification or stabilization include a stable all-weather con-
struction platform, a reduction of concrete pavement thickness requirements, and when applicable, a reduction
of swell potential and susceptibility to pumping and strength loss due to moisture.
b. Requirements. The design of the stabilized or modified layers will follow TM 5-822-4/AFM 88-7, Chap. 4,
and TM 5-822-5/AFM 88-7, Chap. 3. To qualify as a stabilized layer, the stabilized material must meet the uncon-
fined compressive strength and durability requirements in TM 5-822-14/AFJMAN 32-1019; otherwise, the layer
is considered to be modified.
7-1
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