Long-term performance of aged waste forms treated by stabilization/solidification

Area of Science:

• Environmental Engineering
• Geotechnical Engineering
• Materials Science

Background:

• Current regulatory testing for stabilized/solidified (S/S) soils relies on short-term methods, inadequately predicting long-term stability and service life.
• There is a notable scarcity of literature detailing the long-term field performance of S/S materials.
• This study addresses the need for robust, long-term performance data in S/S waste management.

Purpose of the Study:

• To evaluate the long-term field performance of stabilized/solidified (S/S) waste materials.
• To analyze the microstructural characteristics of S/S materials after extended field exposure.
• To compare field performance with laboratory-based testing limitations.

Main Methods:

• Extraction of S/S material from full-scale remedial operations.
• Application of diverse analytical techniques, including X-ray analysis, optical and electron microscopy, and leaching tests.
• Examination of microstructural features and comparison across different soil types, contaminants, treatments, and field conditions.

Main Results:

• The microstructure of retrieved S/S samples resembles other cement-based materials but shows variability based on soil type, contaminants, treatment, and exposure.
• Key microstructural features from USA and UK field sites are summarized.
• The investigated S/S wastes demonstrated satisfactory performance over a 16-year service period.

Conclusions:

• Long-term field performance data are crucial for validating the effectiveness of S/S technologies.
• The microstructural analysis provides insights into the durability and stability of S/S materials in real-world conditions.
• The study confirms satisfactory performance of S/S wastes over 16 years, suggesting the adequacy of the applied methods for long-term stability.