Investigating the Effect of Zeolite and Rice Husk Ash with Different Clay Minerals on the Behavior of Contaminated Soils

Heavy metal contaminants are the most important and most hazardous type of pollution that needs to be studied both environmentally and geotechnically. There are different concentrations of heavy metals in the soils (Zhang et al, 2019). Engineering properties of contaminated soil tend to significantly change due to chemical reactions between the soil mineral particles and the contaminants (Arasan and Yetimoglu 2008). Chu et al. estimated the shear strength parameters of contaminated soil by lead, zinc and cadmium. The direct shear experiment was performed and results indicated that increase of heavy metal concentration increases shear strength and cohesion. Also, the electrical resistivity of soils decreased with the increase in concentration (Chu et al, 2016). Based on the spreading of the heavy metals such as Lead and Zinc in the most parts of China, Li et at. conducted research on lead contaminated soil in these areas. Samples were made in OMC and MDD and cured for 2 days. Obtained results showed that the increase of the concentration decreased the thickness of diffuse double layer (DDL) and particles were in a flocculated micro structure form. Increasing the flocculation, increased the permeability coefficient of samples (Li et al., 2015). In this study, the effects of zeolites and rice husk ash were investigated. It should be noted that the soil mixture was sand with 20% kaolinite and also sand with 20% bentonite. After determining the performance of these two types of clay minerals in contaminated and uncontaminated conditions, 10% of the fine-grained fraction were reduced and the equivalent of 10% of zeolite or rice husk adsorbents were added.