specifications and design assumptions must be
modified. It is imperative that all aggregate be
investigated for problems related to
alkali-aggregate reactions.
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2.2.1
Aggregate Sources
2.2.1.1
Durability
**************************************************************************
NOTE: Use first option for Army and Air Force;
second option is for Navy projects only.
**************************************************************************
Aggregate shall have a satisfactory service record in freezing and thawing
of at least 5 years successful service in three concrete paving projects.
The service record shall include a condition survey of the existing
concrete and a review of the concrete-making materials, including coarse
and fine aggregates, cement, and mineral admixtures. This review should
consider the previous aggregate source and test results, cement mill
certificate data, mineral admixture chemical and physical composition, and
the mix design (cement factor and water-cementitious material ratio).
Aggregate not having a satisfactory demonstrable service record shall have
a durability factor of 50 or more when subjected to freezing and thawing in
concrete in accordance with COE CRD-C 114. Fine and coarse aggregates to
be used in all concrete shall be evaluated and tested by the contractor for
durability in accordance with ASTM C 88. Results shall not show more than
18 percent loss when subjected to 5 cycles using Magnesium Sulfate. If
Sodium Sulfate is used, results shall not show more than 12 percent loss
when subjected to 5 cycles.
2.2.1.2
Alkali-Silica Reactivity
**************************************************************************
NOTE: Use options a, b, and c for Navy projects;
use options a and b for Army and Air Force.
**************************************************************************
Fine and coarse aggregates to be used in all concrete shall be evaluated
and tested by the Contractor for alkali-aggregate reactivity in accordance
with ASTM C 1260. Both coarse aggregate size groups shall be tested if
from different sources. The fine and coarse aggregates shall be evaluated
separately and in combination, which matches the Contractor's proposed mix
design proportioning, utilizing the modified version of ASTM C 1260. Test
results of the combination shall have a measured expansion equal to or less
than 0.08 percent at 16 days after casting. Should the test data indicate
an expansion of greater than 0.08 percent, the aggregate(s) shall be
rejected or additional testing, using a modified version of ASTM C 1260
shall be performed using one of the following options:ASTM C 1260 shall be
modified as follows to included one of the following options:
a. Utilize the Contractor's proposed low alkali portland cement and
Class F fly ash or Class N pozzolan in combination with the proposed
aggregate percentage for the test proportioning. Class F fly ash or
Class N pozzolan shall be used in the range of 25 percent to 40 percent
of the total cementitious material by mass. The quantity shall be
determined that will meet all the requirements of these specifications
and that which will lower the expansion equal to or less than 0.08
SECTION 02753
Page 35
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