Fine aggregate subjected to soundness testing should have a maximum average loss of how much when sodium sulfate is used?

When fine aggregate undergoes soundness testing using sodium sulfate, it is essential for the material to demonstrate good durability under cyclical wetting and drying conditions. The purpose of the sodium sulfate soundness test is to evaluate the potential for disintegration of aggregates upon exposure to these environmental conditions.

The established standard for soundness testing specifies that fine aggregates should have a maximum average loss of 10%. This loss indicates that the aggregate can withstand a certain level of stress from environmental factors without significant degradation. If the loss exceeds this threshold, it suggests that the aggregate may not be suitable for use in concrete, as it could lead to compromised strength and durability in the final product.

Keeping the maximum average loss to 10% ensures that the fine aggregate maintains its integrity over time, which is crucial for the long-term performance of concrete structures. This standard is vital for ensuring the overall quality and reliability of concrete as a construction material.