FINE
COARSE
PROPERTY
AGGREGATE
AGGREGATE
TEST
[Petrographic
Examination
Every 6 months
Every 6 months
ASTM C 295]
[Chert, less
than 2.40
specific
gravity
Every 6 months
Every 6 months
ASTM C 123]
[Coal and
Lignite, less
than 2.00
gravity
Every 6 months
Every 6 months
ASTM C 123]
b. Corrective Action for Aggregate Quality - If the result of a
quality test fails to meet the requirements for quality immediately
prior to start of concrete placement, production procedures or
materials shall be changed and additional tests shall be performed
until the material meets the quality requirements prior to proceeding
with either mixture proportioning studies or starting concrete
placement. After concrete placement commences, whenever the result of
a test for quality fails the requirements, the test shall be rerun
immediately. If the second test fails the quality requirement, the
fact shall be reported to the Contracting Officer and immediate steps
taken to rectify the situation.
3.7.2.4
Scales
a. Weighing Accuracy - The accuracy of the scales shall be checked by
test weights prior to start of concrete operations and at least once
every 3 months for conformance with the applicable requirements of
paragraph BATCHING EQUIPMENT. Such tests shall also be made as
directed whenever there are variations in properties of the fresh
concrete that could result from batching errors.
b. Batching and Recording Accuracy - Once a week the accuracy of each
batching and recording device shall be checked during a weighing
operation by noting and recording the required weight, recorded weight,
and the actual weight batched. The Contractor shall confirm that the
calibration devices described in paragraph BATCH PLANT for checking the
accuracy of dispensed admixtures are operating properly.
c. Scales Corrective Action - When either the weighing accuracy or
batching accuracy does not comply with specification requirements, the
plant shall not be operated until necessary adjustments or repairs have
been made. Discrepancies in recording accuracies shall be corrected
immediately.
3.7.2.5
Batch-Plant Control
The measurement of all constituent materials including cementitious
materials, each size of aggregate, water, and admixtures shall be
continuously controlled. The aggregate weights and amount of added water
shall be adjusted as necessary to compensate for free moisture in the
aggregates. The amount of air-entraining agent shall be adjusted to
control air content within specified limits. A report shall be prepared
SECTION 03301A
Page 48
Previous Page
