Provide load-bearing units for exterior walls, foundation walls,
load-bearing walls, and shear walls.
b.
Hollow Non-Load-Bearing Units: ASTM C 129, Type I or II, made
with lightweight [or medium weight] [or normal weight] aggregate.
Load-bearing units may be provided in lieu of non-load-bearing
units.
c.
Solid Load-Bearing Units: ASTM C 90, Type I or II, lightweight
[or medium weight] [or normal weight] units. Provide solid units
[for masonry bearing under structural framing members] [as
indicated].
2.4.1
Aggregates
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NOTE: Where sufficient evidence based on previous
construction experience indicates concrete masonry
units manufactured from aggregate from a specific
source may be subject to excessive popouts and/or
staining, contract specifications may be written to
exclude such aggregate.
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Lightweight aggregates and blends of lightweight and heavier aggregates in
proportions used in producing the units, shall comply with the following
requirements when tested for stain-producing iron compounds in accordance
with ASTM C 641: by visual classification method, the iron stain deposited
on the filter paper shall not exceed the "light stain" classification.
2.4.2
Kinds and Shapes
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NOTE: Bullnose units will be specified only in
cases where sharp corners are considered
objectionable, such as in heavy traffic areas. If
bullnose units are specified, the locations of use
will be detailed on the drawings and/or listed in
this paragraph.
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Units shall be modular in size and shall include closer, jamb, header,
lintel, and bond beam units and special shapes and sizes to complete the
work as indicated. In exposed interior masonry surfaces, units having a
bullnose shall be used for vertical external corners except at door,
window, and louver jambs. Radius of the bullnose shall be 25 mm 1 inch.
Units used in exposed masonry surfaces in any one building shall have a
uniform fine to medium texture and a uniform color.
2.4.2.1
Architectural Units
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NOTE: Where architectural units are used, local
sources should be checked to determine available
shapes, sizes, patterns, and colors. Desired unit
pattern should be clearly shown on the drawings.
Delete integral coloring if units will be painted or
if natural color is satisfactory. CMU veneer wythes
should be solid units to minimize trapping water
SECTION 04200
Page 20
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