Which statement about SSD conditioning is true?

• A. A current of warm air may be used to assist getting the sand to an SSD condition.
• B. Shaking the basket to release any entrapped air as it is placed in the water bath is not recommended due to potential sample loss.
• C. The sample is covered with water either by complete immersion or by adding approximately 6 % moisture.
• D. The specified time period for the sand to soak in the water is 24-48 hours.

Answer: (A)

SSD conditioning is about bringing the sand to a saturated surface dry state, where the surface is moist but there is no free water on the surface and the pore spaces are filled without excess drainage. A current of warm air helps reach that state more quickly by drying surface moisture and allowing any entrapped air to escape, so the sand can become SSD without over-drying or leaving pockets of moisture that would affect test results.

Shaking the basket to release entrapped air is part of ensuring air can escape and the sample reaches uniform wetting and saturation; the claim that this should be avoided because of sample loss isn’t accurate, so that statement isn’t correct.

Covering the sample with water by complete immersion or by adding a fixed amount of moisture (like 6 percent) isn’t how SSD conditioning is defined—the goal is surface saturation without free standing water, not a specific fixed moisture addition.

A soak time of 24–48 hours is longer than typical SSD conditioning requirements, which are much shorter to prevent over-saturation or drying beyond the SSD state.