Electrochemical Hardening of Clay Soils

TLDR: In this paper, the role of pH and pH buffering during treatment was examined and the effect of electrochemical hardening was found to be most pronounced in high water content, high pH, bentonitic soil due largely to hydroxy-aluminium interlayering in the clay.

Abstract: Synopsis Clay soils were strengthened by introducing aluminium into the soil under an electrochemical gradient. Changes in both the composition and physical properties of the treated soils were investigated. The role of pH and pH buffering during treatment was also examined. Strength increases or decreases in the treated samples were separated into three components: those caused by a change in water content, electroosmotic effects; those caused by age hardening, thixotropic effects; and those caused by electrochemical action, ion exchange and mineralization. Nearly all treated samples exhibited some degree of electrochemical hardening. Induration was most pronounced in ahigh water content, high pH, bentonitic soil due largely to hydroxy–aluminium interlayering in the clay. In a low pH. illitic soil interlayering was negligible and hardening appears to have resulted primarily from ion exchange. Both X-ray diffraction and selective extraction methods were used to determinethe distribution and mode of occurr...