This aggregate basket is used to test the soundness of an
aggregate’s resistance to disintegration by weathering and
freeze-thaw cycles, aggregates that are durable (resistant to
weathering) are less likely to degrade in the field and cause
premature HMA pavement distress and potentially, failure.
The soundness test repeatedly submerges an aggregate sample in a
sodium sulfate or magnesium sulfate solution. This process causes
salt crystals to form in the aggregate’s water permeable pores. The
formation of these crystals creates internal forces that apply
pressure on aggregate pores and tend to break the aggregate. After
a specified number of submerging and drying repetitions, the
aggregate is sieved to determine the percent loss of material.