Microstructural Evaluation of Progress of Lime Pozzolanic Reactions in Stabilization and Solidification of Zn Contaminant

The results of this research show that the addition of 10% lime to the contaminated natural clay not only stabilizes the soil, but also for a sample contaminated with 250 c mol/kg-soil concentration of zinc as a heavy metal, more than 37% increase in retention observes. The XRD evaluation shows that the presence of heavy metal contaminant reduces the extent of lime-clay interaction; consequently a reduction in the formation of C-S-H and C-A-H nano structures happens. Based on the results of XRD experiment and soil contaminant retention measurement of the treated sample with less than 6% lime, the presence of heavy metal contaminant was probably the main cause for peak intensity reduction of clay minerals. The results of this research show that the formation of C-S-H nano structure improves absorption characteristics due to its high specific surface area. In addition, its formation reduces contaminant mobility through encapsulation of heavy metal ions (solidification).