- Free-liquid content: Current EPA regulations allow no free water in the final waste form.
- Low-permeability: The treated waste should be reasonably impermeable (typical acceptable permeability range from 10-6 to 10-9 cm/s). Higher permeability would result in increased leaching of contaminants.
- Biodegradation: Biological activity is undesirable and should be avoided because it can produce acids that could dissolve and leach pollutants from the waste. Tests such as ASTM G-21 and G-22 (ASTM 1989) are used to determine the ability of wastes to withstand biological attack.
- Strength: Unconfined compressive strength of the hardened waste depends on its final use. Usually, only 140 kPa is required for burial. However, if the solid waste is to be used for other purpose such as construction materials, greater strength may be required ( up to 580 kN/m2). ASTM C-39 (ASTM 1989) is usually employed to evaluate the compressive strength of cementitious stabilized /solidified wastes.
- Durability: If exposed to freeze- thaw and wet-dry cycles, stabilized/solidified waste should be tested for durability. For moderate exposure, ASTM D-560 (freeze-thaw durability) and ASTM D-554 (wet-dry durability) (ASTM 1989) are used. However, for harsh exposure, ASTM C-666 (ASTM 1989) can be recommended.