30 June 2001
recycled concrete shall meet all other applicable requirements specified below. Recycled concrete to be
exposed to sulfates in the ground or water must be checked for sulfate resistance. Contact MAJCOM for
AGGREGATE BASE COURSES FOR ARMY AND AIR FORCE RIGID PAVEMENT.
a. General. Drainage layers generally serve as aggregate base courses under rigid pavements
and must meet the requirements of EI 02C202/AFJMAN 32-1016. A minimum aggregate base-course
thickness of 102 millimeters (4 inches) will be required over subgrades that are classified as CH, CL,
MH, ML, and OL (ASTM D 2487) for protection against pumping except in arid climates where
experience has shown that there is no need for the aggregate base course to prevent pumping. In
certain cases of adverse moisture conditions (high water table or poor drainage), SM and SC soils may
also require aggregate base courses to prevent pumping. Engineering judgment must be exercised in
the design of aggregate base-course drainage to ensure that water is not trapped directly beneath the
pavement, which invites the pumping condition that the base course is intended to prevent. In addition,
aggregate base courses in inlay sections should be constructed to drain toward the outside edge.
Daylighting of the aggregate base course may also be required. Care must also be exercised when
selecting aggregate base-course materials to be used with slipform construction of the pavement.
Generally, slipform pavers will operate satisfactorily on materials meeting aggregate base-course
requirements. However, cohesionless sands, rounded aggregates, etc., may not provide sufficient
stability for slipform operation and should be avoided if slipform paving is to be a construction option.
The designer should consider extending the aggregate base course 1.5 to 3.0 meters (5 to 10 feet)
outside the edge of the pavement to provide a working platform for construction equipment.
b. Material Requirements. A complete investigation will be made to determine the source, quantity,
and characteristics of available materials. The aggregate base course may consist of natural materials
or processed materials, as discussed for flexible pavements. In general, the unbound aggregate base
material will be a well-graded, high-stability material. All aggregate base courses to be placed beneath
airfield rigid pavements will conform to the following requirements in addition to those requirements in
base course guide specifications (sieve designations are in accordance with American Society for
Testing and Materials (ASTM E 11):
Well-graded, coarse to fine.
Not more than 85 percent passing the 2.0-millimeter (No. 10) sieve.
Not more than 15 percent passing the 0.075-millimeter (No. 200) sieve.
PI not more than 8 percent.
However, when it is necessary for the base course to provide drainage, the requirements set forth in
EI 02C202/AFJMAN 32-1016 will be followed.
AGGREGATE BASE COURSES FOR NAVY AND MARINE CORPS RIGID PAVEMENTS.
a. General. The main structural support element in a rigid pavement is the portland cement
concrete slab. The most important function of the aggregate base-course material in a rigid pavement is
to provide uniform long-term support to the slab with adequate drainage to prevent pumping and loss of
support. The aggregate base course must be constructed of quality material and properly designed to
ensure a good foundation. If pumping and loss of support occur, the performance of the concrete slab
will be reduced.