Laboratory Study of Stabilization and Solidification of Lead and Zinc Contaminated Soil Using Geopolymer Cement

Document Type : Research Article

Authors

1 Civil engineering department, Faculty of Engineering, Civil Engineering Department, Kharazmi University

2 Faculty of Engineering, Civil Engineering Department, Kharazmi University, Tehran. Iran

3 Faculty of Engineering, Civil Engineering Department, Kharazmi University, Tehran, Iran

Abstract

This research investigates the capabilities of geopolymer cement in the stabilization and solidification of heavy metal-contaminated soils, particularly those contaminated with lead and zinc. One of the key aspects of this research is the use of steel and blast furnace slags, considered as industrial waste, as raw materials in the production of geopolymer cement. To this end, contaminated soil samples were stabilized using both types of binders, and various tests, including compaction, uniaxial compressive strength (UCS), toxicity characteristic leaching procedure (TCLP), and scanning electron microscopy (SEM), were conducted to evaluate the performance of the binders. The results of the uniaxial compressive strength tests showed that the samples stabilized with geopolymer cement exhibited higher strength at all curing times compared to those stabilized with Portland cement, with a strength increase of approximately 100 to 200 kPa. Moreover, the leaching test results indicated that steel slag significantly reduced the concentration of lead ions from 26,000 ppm to less than 1 ppm. In the case of zinc, the concentration was reduced from 16,000 ppm to 0.3 ppm, demonstrating the high potential of this material in the stabilization of heavy metals. However, despite the high compressive strength of sodium silicate-containing samples, they were less effective in reducing the concentrations of heavy metals in the leaching tests. This research also showed that increasing the binder content improved the mechanical strength of the samples and enhanced the stabilization of contaminants.

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Amirkabir Journal of Civil Engineering
Volume 57, Issue 11
February 2026
Pages 1875-1896

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