MICRO-STRUCTURAL CHARACTERIZATION OF CEMENT STABILIZED TROPICAL lATERITE CLAY SOIL CONTAMINATED BY HEAVY METALS
The presence of contaminated soils due to industrials and mining activities is a major concern in today’s heavily industrialized world. The contaminants lead to poor engineering properties for these soils. In this study 10% cement is used to stabilize laterite clay soil contaminated by heavy metals of Cu and Zn. However, the effect of these contaminants on the geotechnical properties of clayey soils can be altered through chemical stabilization using traditional stabilizers like cement, which result in achieving suitable material for construction purposes. The micro-structural characterization of the cement-treated Laterite clay is presented in this research. The changes in the mineralogy and morphology structure due to the effect of stabilizer of cement and heavy metals were discussed based on X-ray Diffractometry (XRD), and Field Emission Scanning Electron Microscopy (FESEM). According to the micro-structural characterization of the stabilized soils, cement was effective stabilizer in terms of improving the strength of contaminated treated soils. However, the heavy metals have retarded effect on the cement treated samples. This was due to precipitation of the metals onto the surface of calcium and aluminium silicates as insoluble hydroxides or sulphates. Thus, these compounds form an impermeable coating that acts as a barrier to inhibit cement hydration by impending transport of water into cement grain. Finally, it can be concluded that the mechanical and the physico-chemical behaviours of the compacted specimens, as determined during testing, formed the basis for evaluating both the degree of immobilization of the heavy metal in the soil matrix, and the potential for rehabilitation of contaminated sites.