Stabilization of clay soils contaminated with zinc nitrate & lead nitrate using metakaolin geopolymer

One of the most critical environmental problems that human beings face is the subject of soil pollution, which occurs in various factors and affects different soil parameters. one way to tackle this phenomenon is the stabilization of soils. This study presents the result of using metakaolin geopolymer to stabilize contaminated clay. In this study, the basic and contaminated soil without stabilizing are subject to various tests; The results of the first phase of the experiments showed that increased contamination concentration had a negative effect on soil parameters. The results of these experiments also showed that the most critical concentration of soil contamination was among the concentrations of 10,000 ppm. Then the soil contaminated with the most critical concentration was stabilized by metakaolin geopolymer at 5, 10, and 15% weight and was tested with a stabilizer within seven days of curing time. The results showed that by increasing the percentage of metakaolin geopolymer, the soil strength parameters have significantly increased, and adding geopolymer to contaminated soil of 10,000 ppm has improved soil properties. In addition, the experiment results indicated that the 15% metakaolin geopolymer to the 10000ppm contaminated soil in the optimum value, in which the liquid limit increased by 39.47%, the plastic limit rose by 51.06%, and the plasticity index surged by 20.68%. Furthermore, the optimal moisture content increased by 19.84%, and dry Unit Weight decreased by 3.23% compared to the unstabilized 10000ppm contaminated soil.