TABLE 13
Minimum Percent Voids in Mineral Aggregate (VMA)
+)))))))))))))))))))))))))))))0))))))))))))))))))))))))))))))))))),
* Nominal Max. Aggregate Size *Minimum Voids in Mineral Aggregate *
*
*
*
(inches)
(percent)
/)))))))))))))))))))))))))))))3)))))))))))))))))))))))))))))))))))1
* 3/8.........................*
*
16
* 1/2.........................*
*
15
* 3/4.........................*
*
14
* 1.0.........................*
*
13
.)))))))))))))))))))))))))))))2)))))))))))))))))))))))))))))))))))-
c. Penetration Macadam. Penetration macadam surfacings are satisfactory for
low-volume roads and for pavements in remote locations and low yardage. They
should not be used for areas subjected to tracked vehicles. For recommended
aggregate gradations, see Table 15. Recommended types of bitumen are given in
Table 10.
d. Bituminous Surface Treatments. Bituminous surface treatments may be used
on sound, strong base courses or on asphalt surfacings. The total thickness of
the surface treatment should be less than 1 inch. Use surface treatments for
temporary paved areas and where traffic volumes are light. Do not use surface
treatments on pavements subjected to tracked vehicles or heavy trucks.
Gradation and bitumen requirements are contained in Bituminous Surface
Treatment, NAVFAC TS-02677.
stabilize in-place subgrade soils for use as temporary roads or as an
intermediate surfacing in a program of stage construction. A subgrade soil may
be suitable for stabilization if it contains less than approximately 25
percent by weight passing the No. 200 sieve and has a PI less than 8.
Preference should be given to the use of emulsified asphalts for this form of
stabilization.
(1) Stabilization With Asphalt Emulsion. Provide sufficient bitumen to
thoroughly coat the soil particles and yield a stable, durable mass. Table 16
provides an estimate of the required emulsion content for various soil
gradations. Confirm these quantities with laboratory tests prior to a final
determination. Emulsion mixes require a brief period of aeration prior to
compaction in order to support compaction equipment and gain stability.
27
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