MIL-HDBK-1011/1
2.4.3
Steel Piles. Steel piles are often used for waterfront facilities
in remote locations where concrete piles are not readily available. Since
steel piles have a better capacity to weight ratio and can easily be spliced
to longer lengths by welding, they are the preferred pile foundation system
when high load bearing capacities and long pile lengths are required in
isolated locations. Corrosion is a serious problem in the tropics,
particularly if the steel is in contact with coralline soils. In such cases,
protective coating and cathodic protection are required.
2.4.4
Cast-in-Place Piles. Cast-in-place piles are suitable for use in
the tropic regions. They have similar qualities and construction constraints
as driven concrete piles.
Paving. High precipitation, low subgrade strength, the limited
2.5
choice of construction aggregate, and long distance transportation of
materials and equipment, are factors which must be considered in pavement type
selection as well as pavement design.
2.5.1
Coral as Construction Aggregate. Coral aggregate, with proper
gradation, is a good subbase and base course material for roadway pavements.
However, it may not have sufficient soundness and abrasion resistance for use
as base course for flexible airfield runways. For concrete pavement, ensure
that a coral base does not come into contact with wire mesh or other metal
reinforcing unless the aggregate is washed prior to placement.
Coral aggregate is sometimes used in asphaltic concrete and
portland cement concrete pavement. In general, coral aggregate has lower
soundness, higher absorption, and lower abrasion resistance than other rock
aggregate. These drawbacks can sometimes be compensated for in pavement
design by slight increases in total pavement thickness and in asphalt or
cement contents.
Exposed coral aggregate on the asphaltic concrete pavement surface
is susceptible to abrasion. The skid resistance decreases with time, making
the pavement surface slippery to traffic when it is wet. Correct this
condition by pavement grooving or overlaying a new friction course on top of
the pavement.
2.5.2
Pavement Repair and Recycling. Climatic influences cause asphaltic
concrete pavements in the tropics generally to have a shorter service life.
Consider more frequent pavement repair and resurfacing in the life cycle cost
analysis during planning. In remote island facilities, a viable alternative
to pavement resurfacing is pavement recycling. Pavement recycling requires a
pavement grinder to remove the in-place asphaltic concrete and then crush it
to proper aggregate size for reuse. Pavement recycling can often produce
savings in time, cost, and energy.
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