running through the blocks. Each block shall be penetrated by a cable that
allows articulation of the blocks, but restrains removal of individual
blocks. Void filler shall be placed to inhibit lateral movement, cover the
geotextile, and increase hydraulic stability. [Articulating concrete
block, cables, and fittings shall be fabricated into mattresses at the
manufacturer's plant.]
2.1.4
Structural requirements
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NOTE: Freeze-thaw Testing - The specifier should
edit this paragraph based on the project's location.
The default values correspond to the default values
in ASTM C 1372, Segmental Concrete Retaining Wall
Units. The freeze thaw requirements for retaining
wall blocks are referenced since they are similar
products, ACB blocks can be produced by similar
manufacturing methods, and retaining walls have been
the subject of more freeze thaw durability research.
The number of seasonal freeze thaw cycles for
typical ACB's is likely less than for retaining
walls. Chloride from deicing salts or sea water
increases saturation of the concrete, and thus has a
very pronounced affect on freeze thaw degradation.
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Articulating concrete block shall be wet cast using concrete as specified
herein, or dry-cast by a vibratory block forming machine. The blocks shall
be manufactured to the following requirements:
a. The minimum compressive strength shall be 28 MPa 4000 psi for an
average of 3 units, and 24 MPa 3500 psi for an individual unit.
Compressive strength shall be determined by ASTM C 42/C 42M for wet
cast blocks, or by ASTM C 140 for dry cast blocks.
b. The maximum water absorption for dry cast units shall be 145 kg/m3
9 pcf for an average of 3 units, and 195 kg/m3 12 pcf for an individual
unit. Water absorption shall be determined by ASTM C 140.
[c. The minimum saturated surface-dry density shall be [140] [_____]
for average of 3 units, and [140] [_____] for an individual unit.]
[d. Wet cast concrete shall be air entrained to contain between 4 and
7 percent total air.]
[e. For freeze-thaw durability tested in accordance with ASTM C 1262,
specimens shall comply with either of the following: (1) the weight
loss of each of 5 specimens after 100 cycles shall not exceed 1
percent; or (2) the weight loss of each of 5 specimens after 150 cycles
shall not exceed 1.5 percent.]
2.2
GEOTEXTILE
**************************************************************************
NOTE: The AASHTO M 288 table provides survivability
requirements. Class 1 is recommended for harsh or
severe installation conditions where there is a
potential for vehicular traffic, or where irregular
sections may require removal and replacement of
SECTION 02382
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