Experimental Studies on Stabilized Clays at Various Leaching Cycles

The effectiveness of chemical stabilization and its permanency were investigated by subjecting chemically treated soils to leaching tests by internal water flushing, which simulates moisture ingress/digress into subsoils from rainfall events. Control and chemically stabilized soils from eight different locations were subjected to these leaching tests over 14 cycles in the laboratory. Each leaching cycle represents one pore volume of water flushed through the soil specimen. Leaching samples were collected after 3, 5, 7, and 14 cycles and were chemically analyzed to address pore fluid chemical composition changes and possible leaching of the chemical additives. Unconfined compressive strength tests were conducted on soil specimens after 3, 7, and 14 leaching cycles to study soil strength variations. The effects of soil type, stabilizer type and dosages, and the curing method on the leaching of stabilizers are analyzed. Test results and analyses indicate that leaching of stabilizer did occur, but the amounts are too low to induce strength losses in the soils analyzed. Also, approximate correlations are developed between leaching cycles and field precipitation and moisture infiltration processes to determine the number of years replicated in the field. (C) 2013 American Society of Civil Engineers.