Using the duplicate portion of sand at SSD to determine the dry mass of the sample removes the necessity to dry the entire contents of the pycnometer at the end of the procedure in order to determine the dry mass.

• A. True
• B. False
• C. Not applicable
• D. Only for large samples

Answer: (A)

The method hinges on getting the dry mass from the amount of solid material, not from drying everything in the pycnometer. When you use a duplicate portion of sand that is at saturated surface dry (SSD) and determine its moisture content separately, you can relate that moisture to the SSD mass you’ve already measured in the pycnometer. Since SSD means the solids are saturated with internal pore moisture but without surface moisture, the mass in SSD equals the dry mass plus the water held in the pores. If you know the moisture content w (as a decimal) from the duplicate, you can calculate the dry mass as dry_mass = M_ssd / (1 + w). This lets you determine the required dry mass without waiting to dry the entire contents of the pycnometer, which saves time while still giving an accurate dry mass—as long as the moisture content is representative of the sample. Thus, using a duplicate SSD portion to find moisture content makes it possible to avoid drying the whole pycnometer, so the statement is true.