The morphology and elemental variation for contaminated clay soil using Energy Dispersive X-Ray Spectrometry

Abstract

It is known that the stabilization of normal soils with chemical substances will gradually affect their properties like shape, size and soil particles arrangement. The current study concerns with artificially contaminated clayey soils immobilized by fly ash waste materials and quicklime (CaO). In this research, the time-dependent factor changes the morphology of stabilized - contaminated soil. Energy Dispersive X-ray Spectrometry is performed to further examine components on the clay particles' surface. The results showed that with an increase in hardening time, morphology analyses by FESEM shows a transformation of soil fabric due to the effect of chemical treatment, and due to the production of cementitious pozzolanic compounds (CSH and CASH). However, with the presence of contamination, it can notice a transformation in the fabric of clay particles towards a more flaky nature at the early curing time due to precipitation of heavy metals as hydroxide or sulphates on the surface of particles. Regarding the EDAX analysis, the Al:Si ratio for cement - fly ash treated clayey soil decreases over time. This is attributed to the increased release of alumina from the mineral of clay structure. However, an increasing Ca:Si ratio is observed, especially after 100 days related to the formation of the portlandite compound from cement hydration over time. While, it is detected variation in these ratios with respect to contaminated soil with time.