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1. SCOPE
This specification covers the quality of fine aggregate and coarse aggregate for use in the manufacture of portland cement concrete.
2. QUALITY
Aggregate shall conform to the requirements of ASTM Specification C 33 for the specified sizes. Aggregates that fail to meet any requirement may be accepted only when: (1) the specified alternate conditions of acceptance can be proven prior to the use of the aggregates on the job and within a period of time such that no work under the contract will be delayed by the requirements of such proof; or, (2) the specification for concrete expressly contains a provision of special mix requirements to compensate for the effects of the deficiencies.
3. REACTIVITY WITH ALKALIES
The potential reactivity of aggregates with the alkalies in cement shall be evaluated by petrographic examination and, where applicable, the chemical method of test, ASTM Designation C 289, or by the results of previous tests or service records of concrete made from similar aggregates from the same source. The standards for evaluating potential reactivity shall be as described in ASTM Specification C 33, Appendix A1.
Aggregates indicated by any of the above to be potentially reactive shall not be used, except under one of the following conditions:
a. Applicable test results of mortar bar tests, made according to ASTM Method C 227, are available which indicate an expansion of less than 0.10 percent at six (6) months in mortar bars made with cement containing not less than 0.8 percent alkalies expressed as sodium oxide; or
b. Concrete made from similar aggregates from the same source has been demonstrated to be sound after three (3) years or more of service under conditions of exposure to moisture and weather similar to those anticipated for the concrete under these specifications.
Aggregates indicated to be potentially reactive, but within acceptable limits as determined by mortar bar test results or service records, shall be used only with "low alkali" cement, containing less than 0.60 percent alkalies expressed as sodium oxide.
4. STORING AND HANDLING
Aggregates of each class and size shall be stored and handled by methods that prevent segregation of particle sizes or contamination by intermixing with other materials.
Specification Date 10/98