MIL-HDBK-1011/1
Dissimilar Metals. To attenuate the galvanic action of dissimilar
3.7.4
metals when galvanized metal is proposed for use, take one of the following
two alternative steps:
a) Eliminate the dissimilar metal condition by providing either
all galvanized or all non-galvanized ferrous items, or ensure that all
galvanized items are separated or insulated from all non-galvanized items
before placing of concrete; or
b) Use epoxy-coated reinforcing steel. This alternative is
recommended for extremely corrosive marine environments.
3.8
Concrete Curing. Timely and appropriate curing procedures are
critical factors for quality control of concrete. Do not use seawater or
brackish water for curing reinforced concrete. Do not use chemical additives.
3.9
Structural Precast Concrete. These paragraphs cover precast
concrete, both prestressed and reinforced, including non-stressed decorative
panels and precast items such as manholes and covers. Prestressed concrete
includes pre-tensioned and post-tensioned structural members.
3.9.1
Prestressed Concrete Members. The use of prestressed concrete for
structural members in tropical environments is recommended. However, the
project design and specifications must contain adequate quality control
provisions to assure proper construction and protection against corrosion.
3.9.2
Problem Areas. Consider the several major problem areas before
choosing precast and prestressed concrete.
Corrosion of steel.
a)
b) Water infiltration through construction joints.
c) Shrinkage and temperature cracks which can occur if proper care
is not taken when designing end connectors.
d) Transportation of precast items.
e) Field erection tolerance control and difficulty of field
modifications to correct out-of-tolerance items.
3.9.3
Materials.
Coat reinforcing steel, including tie wires, in precast
concrete panels with fusion-bonded epoxy as well as all steel accessories.
The use of admixtures is encouraged to provide the most workable concrete mix
with the minimum water to cement ratio.
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