MIL-HDBK-1011/1
When conventional aggregates are not available locally, coral
aggregate has been proven acceptable. Ensure the specific gravity of the
coralline material is not less than 2.40. Fine aggregate may be washed,
natural beach sand, manufactured sand, or a combination of beach and
manufactured sand. Sand shall be devoid of salt to the maximum extent
possible; the salt content shall never exceed 0.7 percent by weight. Specify
washing with fresh water.
4.4.3
Design Requirements. The weight of masonry units for general
construction in a tropical environment is not important except as it affects
porosity. Direct design and production of masonry units towards reducing
shrinkage, porosity, and absorption. Proper vibration and autoclave curing
provide for better quality units. Admixtures to densify units are
recommended.
Specify load-bearing type masonry units.
a) Incorporate weep holes in exterior CMU walls to drain each
ungrouted CMU cell. Provide weep holes over bond beams and other solid
precast members. Indicate how to prevent inadvertent sealing of such weep
holes with mortar droppings during the construction of the wall. Include
field tests to ensure compliance in the specifications.
b) Galvanize embedded steel items except reinforcing bars, and
closely monitor all construction to prevent steel corrosion. Separate
galvanized and non-galvanized ferrous items to preclude the galvanic action
when mortar is placed.
c) Use hot-dip galvanized embedded ferrous metals wherever
possible. Follow the hot-dip galvanizing by dipping in a chromate bath. This
requirement also applies to embedded ferrous pipes and conduits which must be
covered with a bituminous or other protective coating before being embedded in
concrete. Do not embed aluminum items in masonry construction.
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