with clay, silt, or sand. It commonly occurs as dull, earthy
particles, homogeneous concretionary masses, or hard-shell particles
with soft interiors. Other names commonly used for clay ironstone are
"chocolate bars" and limonite concretions.
e. Chert is defined as a rock composed of quartz, chalcedony or opal,
or any mixture of these forms of silica. It is variable in color. The
texture is so fine that the individual mineral grains are too small to
be distinguished by the unaided eye. Its hardness is such that it
scratches glass but is not scratched by a knife blade. It may contain
impurities such as clay, carbonates, iron oxides, and other minerals.
Cherty stone is defined as any type of rock (generally limestone) that
contains chert as lenses and nodules, or irregular masses partially or
completely replacing the original stone.
f. Claystone, mudstone, or siltstone, is defined as a massive
fine-grained sedimentary rock that consists predominantly of indurated
clay or silt without laminations or fissility. It may be indurated
either by compaction or by cementation.
g. Shaly limestone is defined as limestone in which shale occurs as
one or more thin beds or laminae. These laminae may be regular or very
irregular and may be spaced from a few inches down to minute fractions
of an inch. Argillaceous limestone is defined as a limestone in which
clay minerals occur disseminated in the stone in the amount of 10 to 50
percent by weight of the rock; when these make up from 50 to 90
percent, the rock is known as calcareous (or dolomitic) shale (or
claystone, mudstone, or siltstone).
h. Testing shall be performed in accordance with the referenced test
methods, except that the minimum sample size shall be as specified in
Paragraph: Testing Deleterious Materials-Airfields Only.
2.2.2.5
Testing Sequence
Deleterious Materials -- Airfields Only
**************************************************************************
NOTE: Contact TSMCX for guidance on available
petrographers in USACE. Use first option for Navy
projects; second option applies to Army and Air
Force.
**************************************************************************
The Contractor will not be entitled to any extension of time or additional
payment due to any delays caused by the testing, evaluation, or personnel
requirements. Sample sizes shall be in accordance with the referenced test
methods. The size of the sample shall be at least 90 kg 200 pounds for the
19 to 37 mm 3/4 to 1-1/2 inch size and 12 kg 25 pounds for the 4.75 to 19
mm No. 4 to 3/4 inch coarse aggregate and 5 kg 10 pounds for the fine
aggregate. The Contractor shall provide facilities for the ready
procurement of representative test samples. The testing procedure on each
sample of coarse aggregate for compliance with limits on deleterious
materials shall be as follows:
Step 1: Test full sample for material finer than the 0.075 mm No. 200
sieve. Discard material finer than the 0.075 mm No. 200 sieve.
Step 2: Test remaining full sample for clay lumps and friable
particles and remove.
SECTION 02753
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