Test
Specifications
ASTM C 88-99a
Apparatus
- Sieves
- Containers
- Weighing Balance
- Oven
Related
Theory
This test method covers the testing of aggregates to estimate
their soundness when subjected to weathering action in concrete or other
applications. This is accomplished by repeated immersion in saturated solutions
of sodium or magnesium sulfate followed by oven drying to partially or
completely dehydrate the salt precipitated in permeable pore spaces. The
internal expansive force derived from the rehydration of the salt upon
re-immersion simulates the expansion of water on freezing.
Procedure
- Immerse the sample in the prepared solution of sodium sulfate or magnesium sulfate for not less than 16 h nor more than 18 h in such that solution covers them to a depth of at least 0.5 in.
- Cover the container to protect from external substances and extra evaporation.
- Maintain temperature between 21 ± 1 oC
- After submersion of 16h let the sample drain for 15 min and the keep in oven for drying at temperature 110 ± 5 oC
- Let the sample dry until constant weight has been achieved. Constant weight will be considered to have been achieved when weight loss is less than 0.1 % of sample weight in 4 h of drying.
- Repeat above steps for number of times.
- After completion of final cycle wash the sample and Sieve the fine aggregate over the same sieve on which it was retained before the test Weigh the material retained on each sieve and record each amount. The difference between each of these amounts and the initial weight of the fraction of the sample tested is the loss in the test and is to be expressed as a percentage of the initial weight for use in Table.
Observations and Calculations
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